Program with Abstracts, Volume 65, Number 4 by Association of Environmental & Engineering Geologists (AEG)

News News Vol. 65, No. 4 – Program with Abstracts ConferenceAEG2022 –Las Vegas ProgramAbstractswith

Portland, Oregon’s largest city, sits on the Columbia and Willamette rivers, in the shadow of snow-capped Mount Hood. It’s known for its parks, bridges, and bicycle paths, as well as for its eco-friendliness and Powell’s Books, its microbreweries and coffeehouses.

The city hosts thriving art, theater, and music scenes. Surrounded by Portland hot spots and more than 60 breweries, the Marriott Portland Downtown Waterfront hotel reflects the vibrancy of the city and is located directly on the waterfront in downtown. Wind down with friends by sampling some of the 150 types of whiskey at their on-site restaurant, Proof Reader. The hotel even helps you go green with complimentary carcharging stations, biodegradable straws and easy access to light rail from the nearby Morrison Subway Station. At night, retire to elevated guest rooms with 24-hour room service, waterfall showers, free Wi-Fi, premium channels and views of Portland. Don’t miss all of the exciting Field Courses, Guest Tours and the Special Event at the Oswego Hills Vineyard planned for this incredible 2023 Annual Meeting.

AEG SeptemberDowntownPortlandAnnual2023MeetingMarriottWaterfront19–24

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Table of Contents

Wednesday, September 14 48 Thursday, September 15 50 Friday, September 16 54

AEG News (ISSN 0899-5788; USPS 954-380) is published by the Association of Environmental & Engineering Geologists (AEG), 3053 Nationwide Pkwy., Brunswick, OH 44212, four times a year in April, July, and December with the Annual Report and Directory in March. The Annual Meeting Program with Abstracts is published only digitally, in September, and the digital copies are distributed at the AEG Annual Meeting. Association members receive an electronic copy of all five issues of the AEG News as part of their dues. Print subscription for Association members, which includes all three regular issues of the AEG News and the Annual Report and Directory issue, is $40 in addition to annual membership dues. Nonmember annual subscription is $50. Back copies of AEG News regular issues are $12 each. Inquiries should be sent to AEG Headquarters: Association Manager, 3053 Nationwide Parkway, Brunswick, OH 44212 330-578-4900.

Planet Hollywood Meeting Space 4

Exhibitors 21

Keynote Speaker 33

Las Vegas Map 59

Welcome Letter – Las Vegas Mayor, Carolyn G. Goodman 15

Author and Title Index 104

Index to Advertisers 26

Vice President/President Elect: NATHAN SARACENO Senior Geologist, DiGioia Gray and Associates, Monroeville, Pennsylvania, VP@aegweb.org

Secretary: RENEE WAWCZAK Hydrogeologist, Norridge, Illinois, secretary@aegweb.org

Managing Editor/Production: Andrea Leigh Ptak, Communicating Words & Images, 206-300 -2067, andrealeighptak@me.com, www.andrealeighptak.com

Table of Contents

1. Send files via email, preferably as attachments, to both email addresses above. Optimum file format is MSWord. Users of other software programs should convert their file to ASCII or text only. Photos and other images, charts, graphs, etc.) should be sent as separate images but may be included in the Word.doc for placement purposes.

On the Cover — Red Rock Canyon National Conservation Area lies in Nevada’s Mojave Desert. It’s known for geological features such as towering red sandstone peaks and the Keystone Thrust Fault, as well as Native American petroglyphs. WWW.REDROCKCANYONLV.ORG

Technical Program Schedule

Acquisitions Editor: Martha Whitney, Principal Engineering Geologist, Whitney Geologic, news@aegweb.org

AEG Foundation 2022 Scholars 18

Outstanding Environmental & Engineering Geologic Project 37

Periodical Postage paid at Brunswick, OH, and additional mailing ofﬁces: POSTMASTER: Send address changes to AEG News, 3053 Nationwide Pkwy., Brunswick, OH 44212.

Meeting Abstracts 61

Welcome Letter – AEG 2022 Co-chairs, Jerry King and Nick Saines 12

Sponsors 27

J&M Business Solutions 3053 Nationwide Parkway, Brunswick, OH 44212 330-578-4900, manager@aegweb.org

Welcome Letter – AEG President, Maddie German 11

AEG Foundation—President: KEN NEAL, president@aegfoundation.org

Past President: WILLIAM GODWIN Consulting Geologist, Carmel, California, PP@aegweb.org

AEG 65th Annual Meeting – Program with Abstracts

Poster Sessions 58

Schedule of Events 5

The 2022–23 AEG/GSA Richard H. Jahns Distinguished Lecturer 35

The 2021–22 AEG/GSA Richard H. Jahns Distinguished Lecturer 34

President: MADDIE GERMAN Consulting Geologist, Atlantic Coast Consulting, Atlanta, Georgia, president@aegweb.org

Contact

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Undeliverable Canadian Addresses to:

AEG News Editors

Welcome Letter – Governor, Steve Sisolak 13

AEG 2022 Awardees 16

Treasurer: SARAH KALIKA Consulting Geologist, DiabloGeo Environmental, San Ramon, California, treasurer@aegweb.org

Advertising in the News AEG Headquarters at advertising@aegweb.org.

Planning Committee 9

3. The policy of AEG News editorial staff is to limit the credentials of an individual to two. No effort will be made by the AEG News editorial staff to determine if individuals whose credentials are missing from the submitted copy actually have academic or professional credentials, nor will the staff verify the existence or correctness of the credentials submitted.

2022 Technical Program

2021–22 Ofﬁcers

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Content Editor: Bill Roman, Chief Geologist, Gannett Fleming, Inc., wroman@gfnet.com

Association Contacts

Views expressed in this publication are not necessarily those ofﬁcially representing the Association of Environmental & Engineering Geologists except where expressly stated.

The association

Submission Information

Technical Session Numbers and Names 8

Welcome Letter – Nevada State Geologist, James E. Faulds 14

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 3

Special Thanks 10

Planet Hollywood Meeting Space

AEG 2022 ANNUAL MEETING 4 AEG 65th Annual Meeting Program with Abstracts September 2022

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 5 EVENT PLACE TIME

MONDAY, SEPTEMBER 12

Registration Celebrity Foyer 7:00am–7:00pm

Meet at the Mezzanine 8:00am–1:00pm

Santa Monica 4 12:00pm–1:00pm

Celebrity 1–3 12:00pm–5:00pm

AEG Foundation Board Meeting Santa Monica 1 8:00am–5:00pm

Student/Professional Networking Reception Wilshire 5:15pm–6:15pm Sponsored by Ruen Drilling Welcome (Icebreaker)

Celebrity Foyer 7:00am–5:00pm

Meet at the Mezzanine 8:00am–1:00pm Discovery of Extensional Tectonics

Field Course #3: The Great Unconformity, Las Vegas Valley Shear Zone, and the

AEG Executive Council Meeting Westwood Boardroom 8:00am–5:00pm

Cafe Hollywood 8:00pm–10:00pm Sponsored by RJH Consultants, AEG SYPSC, and University of Pennsylvania

WEDNESDAY, SEPTEMBER 14

Meet at the Mezzanine 8:00am–1:00pm

Poster Session Presentations Celebrity Foyer 8:00am–4:00pm

Sunset 1 12:30pm–1:30pm

Field Course #2: Hard Hat Tour of the Hoover Dam and the Hoover Dam Bypass Bridge

Exhibit Hall 6:30pm–8:30pm Sponsored by Kleinfelder

Opening Session

Meeting Co-Chair Welcome (Jerry King and Nick Saines) 8:05am–8:10am

2021/2022 AEG/GSA Richard H. Jahns Distinguished Lecturer: Richard Wooten 11:00am–11:30am 2022/2023 AEG/GSA Richard H. Jahns Distinguished Lecturer: Vincent Cronin 11:30am–12:00pm

8:00am–8:05am

Young at Heart Student/Professional Special Event (Ticketed Event)

Exhibit Hall 12:00pm–1:30pm

Dams and Levees Technial Working Group Meeting

Field Course #4: Las Vegas Valley Water District Groundwater Recharge Well Field

Speaker Preparation Room Westwood Boardroom 8:00am–5:00pm Exhibitors Exhibit Hall 7:30am–5:00pm

Sunset 1 8:00am–5:00pm

Exhibitor Hosted Lunch – Sponsored by Exponent

Morning Break – Sponsored by RJH Consultants

TUESDAY, SEPTEMBER 13

Exhibitor Move In

Opening Session Welcome (AEG President Maddie German)

Exhibit Hall 10:00am–10:20am

Field Course #1: Field Analysis of the Blue Diamond Landslide

Melrose 3–4 8:00am–12:00pm Sponsored by Gannett Fleming

Schedule of Events

Meet at the Mezzanine 8:00am–1:00pm Sponsored by BC2 Environmental

Speakers’/Moderators’ Breakfast Wilshire 6:30am–7:30am Sponsored by BC2 Environmental Registration

Committee Room

AEG Volunteer Recognition Awards 8:10am–8:25am

Keynote Speaker: Colby Pellegrino, Deputy General Manager of Resources for the Southern Nevada Water Authority 9:00am–10:00am

AEG Foundation Awards (AEG Foundation President Ken Neal) 8:30am–9:00am

Joint Luncheon – AEG EC and AEG Foundation Board (Invitation Only)

AEG Outstanding Environmental & Engineering Geologic Project Award 10:20am–11:00am

Melrose 4 8:00am–12:00pm Sponsored by Schnabel Engineering

Sunset 3–4 1:40pm–5:00pm

Technical Session #6: Naturally Occurring Asbestos Symposium

Technical Session #9: Infrastructure and the Environment: Impacts on the Built-World Symposium

Melrose 4 1:40pm–5:00pm Sponsored by Schnabel Engineering

Mid-Afternoon Break

THURSDAY, SEPTEMBER 15

Technical Session #11: Hydrogeology and Groundwater Recharge

Departs from Lobby 6:00pm–10:00pm Sponsored by Cascade Drilling

Celebrity Foyer 5:00pm–6:30pm Sponsored by Enviro-Equipment

Annual Banquet (Ticketed Event)

Wilshire 7:00pm–10:00pm Sponsored by Spotlight Geophysical

Melrose 4 2:00pm–5:00pm Megadroughts and Mega-Floods Symposium

WEDNESDAY, SEPTEMBER 14 …continued

Strength through Equity - AEG Inclusion Luncheon (Ticketed Event) Wilshire 12:00pm–1:30pm Sponsored by Schnabel Engineering Lunch on your own for attendees 12:00pm–1:30pm

EVENT PLACE TIME

Speaker Preparation Room Westwood Boardroom 7:30am–5:00pm Exhibitors

Wilshire 6:30am–7:30am

Technical Session #3: Tectonics and Seismicity of the Walker Lane: A Potential Incipient Plate Boundary Symposium

Sunset 3–4 8:00am–12:00pm Sponsored by ConeTec

Speakers’/Moderators’ Breakfast – Sponsored by BC2 Environmental

Special Event – “A Night on the Town” – Free shuttle loop to several stops along the Strip

AEG 2022 ANNUAL MEETING 6 AEG 65th Annual Meeting Program with Abstracts September 2022

Melrose 3 2:00pm–5:00pm

Exhibit Hall 10:00am–10:20am

Technical Session #2: Tunneling Symposium Sunset 3–4 2:00pm–5:00pm Sponsored by Aldea Services, Inc. & Brierley Associates

Sunset 2 1:40pm–5:00pm Sponsored By Bryan Environmental Consultants

Afternoon Break

Technical Session #4: Water Management in the Era of Climate Change Caused

Exhibit Hall 3:00pm–3:20pm

Exhibitor Move Out Exhibit Hall 3:40pm–5:00pm

Registration Celebrity Foyer 8:00am–5:00pm

Sunset 2 2:00pm–5:00pm Sponsored by Deborah Green – GeologyWriter

Sunset 2 8:00am–12:00pm Sponsored by EMSL Analytical

Technical Session #7: Wild Problems with Geophysics Solutions Symposium

– SCHEDULE OF EVENTS

Sunset 1 8:00am–5:00pm

Poster Reception and Happy Hour

Melrose 3 8:00am–12:00pm Sponsored by Geosyntec

Exhibit Hall 3:00pm–3:20pm Sponsored by DiabloGeo Environmental Consulting

Exhibit Hall 7:00am–3:20pm

Technical Session #12: Landslides, Part II

Melrose 3 1:40pm–5:00pm Sponsored by DiGioia Gray

Technical Session #1: Diversity, Equity, and Inclusion—Words Matter Symposium

Poster Session Presentations Celebrity Foyer 8:00am–4:00pm

Technical Session #8: Dams and Levees Symposium, Part I

Morning Break

Technical Session #10: Dams and Levees Symposium, Part II

Committee Room

Technical Session #5: Landslides, Part I

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 7

FRIDAY, SEPTEMBER 16

Past President’s Luncheon (Invitation Only) Sunset 5–6 12:00pm–1:00pm Lunch on your own for attendees 12:00pm–1:00pm

AEG’s Corporate Business Meeting and Closing Session Wilshire 3:00pm–5:00pm Sponsored by Lettis Consultants International Closing Beer/Wine Reception Wilshire Foyer 5:00pm–6:00pm Sponsored by Lettis Consultants International SEPTEMBER 17

Wilshire Foyer 10:00am–10:20am

Technical Session #15: Dams and Levees Symposium, Part III

EVENT PLACE TIME

Technical Session #20: Wild Problems, Unique Solutions, and Lessons Learned Sunset 3–4 1:00pm–2:40pm Afternoon Break Wilshire Foyer 2:40pm–3:00pm

Speakers’/Moderators’ Breakfast

AEG 2022 ANNUAL MEETING – SCHEDULE OF EVENTS ANNUAL MEETING WIFI ACCESS: NETWORK: Caesars Resorts Open a Browser, the Caesars splash page will appear > Select Free Wiﬁ Provide an email address and follow the prompts to connect. LEAVE THE PAPER BEHIND! AEG2022 HAS GONE MOBILE! Schedule, Maps, Networking and more on your mobile device – completely free! We will be sending all attendees the QR Code and complete details to download the app ONE WEEK before the meeting.

Technical Session #19: Geohazards and Site Characterization

Technical Session #18: Geologic and Seismic Hazards, Part II

Field Course #6: Geology of the Skywalk at the Grand Canyon, Hualapai Nation, Arizona

Sunset 3–4 8:00am–12:00pm Sponsored by ConeTec

SUNDAY, SEPTEMBER 18

Morning Break

Celebrity Foyer 7:00am–1:30pm

SATURDAY,

Wilshire 6:30am–7:30am Sponsored by BC2 Environmental Registration

Melrose 3 8:00am–12:00pm Sponsored by Geosyntec

Technical Session #14: Land Subsidence Symposium

Technical Session #16: Landslides, Part III Sunset 2 8:00am–10:00am Sponsored by ConeTec

Sunset 1 8:00am–3:00pm

AEG Board of Director’s Meeting Wilshire 8:00am–12:00pm

Melrose 4 8:00am–12:00pm Sponsored by Schnabel Engineering

Speaker Preparation Room Westwood Boardroom 8:00am–3:00pm Committee Room

Melrose 3 1:00pm–2:40pm Sponsored by Geosyntec

Melrose 4 1:00pm–2:40pm Sponsored by ImpulseRadar USA

Technical Session #17: Get a Job and Make it Your Own Sunset 2 10:20am–12:00pm

Meet at the Mezzanine 8:00am–5:00pm

Technical Session #13: Geologic and Seismic Hazards, Part I

AEG Board of Director’s Meeting Wilshire 8:00am–5:00pm

Technical Session #2: Tunneling Symposium Sponsored by Aldea Services, Inc. & Brierley Associates

Melrose 4 2:00pm–5:00pm

Technical Session #15 - Dams and Levees Symposium, Part III – Sponsored by Schnabel Engineering

Technical Session #10: Dams and Levees Symposium, Part II – Sponsored by Schnabel Engineering

Technical Session Numbers and Names

Melrose 4 1:00pm–2:40pm

Melrose 4 1:40pm–5:00pm

Technical Session #13: Geologic and Seismic Hazards, Part I – Sponsored by Geosyntec

Technical Session #14: Land Subsidence Symposium, Part I – Sponsored by ConeTec

Sunset 3–4 8:00am–12:00pm

THURSDAY, SEPTEMBER 15

Melrose 3 8:00am–12:00pm

Technical Session #5: Landslides, Part I – Sponsored by Geosyntec

FRIDAY, SEPTEMBER 16

Poster Session Presentations Celebrity Foyer 8:00am–4:00pm

Poster Reception – Sponsored by Enviro-Equipment

Melrose 4 8:00am–12:00pm

The 2021–2022 AEG/GSA Richard H. Jahns Distinguished Lecturer in Applied Geology: Richard Wooten Melrose Ballroom 11:00am–11:30am

PLACE TIME

Sunset 3–4 8:00am–12:00pm

AEG 2022 ANNUAL MEETING 8 AEG 65th Annual Meeting Program with Abstracts September 2022

Sunset 2 8:00am–10:00am

Melrose 4 8:00am–12:00pm

Melrose Ballroom 8:00am–8:10am

Technical Session #3: Tectonics and Seismicity of the Walker Lane: A Potential Incipient Plate Boundary Symposium

Melrose 3 2:00pm–5:00pm

Opening Session: Sponsored By Gannett Fleming Melrose Ballroom 8:00am–12:00pm

Technical Session #6: NOA Symposium – Sponsored by EMSL Analytical

Technical Session #17 – Get a Job and Call it Your Own – Student and Young Professional Session

Welcome (AEG President Maddie German and Annual Meeting Co-Chairs Jerry King and Nick Saines)

Technical Session #16 - Landslides, Part III – Sponsored by ConeTec

Melrose 3 1:40pm–5:00pm

SESSION

Technical Session #20 – Wild Problems, Unique Solutions, and Lessons Learned

AEG Foundation Awards Melrose Ballroom 8:30am–9:00am

WEDNESDAY, SEPTEMBER 14

Sunset 2 2:00pm–5:00pm

Keynote Speaker: Colby Pellegrino, Deputy General Manager of Resources for the Southern Nevada Water Authority Melrose Ballroom 9:00am–10:00am

Sunset 3–4 1:00pm–2:40pm

Technical Session #9: Infrastructure and the Environment: Impacts on the Built World Symposium Sponsored by Bryan Environmental Consultants

Poster Session Presentations Celebrity Foyer 8:00am–4:00pm

Technical Session #4: Water Management in the Era of Climate Change Caused Megadroughts and Mega-Floods Symposium

AEG Outstanding Environmental & Engineering Geologic Project Award: Lake Mead Intake No. 3 and Low Lake Level Pumping Station Melrose Ballroom 10:20am–11:00am

Technical Session #8: Dams and Levees Symposium, Part I – Sponsored by Schnabel Engineering

Sunset 2 8:00am–12:00pm

Technical Session #19 - Geohazards and Site Characterization – Sponsored by ImpulseRadar US

See page 48 for full Technical Session listings.

Introduction of the 2022–2023 AEG/GSA Richard H. Jahns Distinguished Lecturer in Applied Geology: Vincent Cronin Melrose Ballroom 11:30am–12:00pm

Technical Session #7: Wild Problems with Geophysics Solutions Symposium – Sponsored By ConeTec

Sunset 3–4 1:40pm–5:00pm

Technical Session #11: Hydrogeology & Groundwater Recharge

Melrose 3 1:00pm–2:40pm

Technical Session #1: Diversity, Equity, and Inclusion—Words Matter Symposium Sponsored by Deborah Green, GeologistWriter

Sunset 3–4 2:00pm–5:00pm

Sunset 2 10:20am–12:00pm

Technical Session #12: Landslides, Part II – Sponsored by DiGioia Gray

Melrose 3 8:00am–12:00pm

Celebrity Foyer 5:00pm–6:30pm

Sunset 2 1:40pm–5:00pm

Technical Session #18 - Geologic and Seismic Hazards, Part II – Sponsored by Geosyntec

Volunteer Recognition Awards Melrose Ballroom 8:10am–8:25am

AEG Headquarters

65th Annual Meeting would not be possible without the hard

AEG’s work and dedication of following the

Deborah Morales, University of Nevada, Las Vegas

Ann Backstrom

Linda Ramirez, Ninyo & Moore

Field Courses

Marty Goff, United States Army Corps of Engineers

Barbara Luke, UNLV Civil Engineering

The Planning Committee

Meeting Management

Sheri Maskow, AEG Association Manager

Becky McWilliam, AEG Association Administrator

Geologic Project Award

many more volunteers that serve on these committees. MCO.KLEINFELDER. astructure.ate infrother priv , energy, andr,trtatansporion, waterve our clients’osolutions that impr onmentaland testing, and envir construction materials inspection design, constructionovidesmanagement,engineering,Kleinfelder pr WWW towntofromWater on GTrentRiverContinuitandy of theTaleBTravelersACreekFCharacterizationforDetailedGeologicver:aultStepoHealdsburg-Rodgers ER SPRE S EN TURO WG EWLEDKN OUROYAN CEVAD GrStateoupslack-e ITH #39 P CollegeEngandRealEstateEvaluationineeringMitigation OTHBOATSEXPERTOURTMEECOME KLEINFELDER IS A PROUD GOLD SPONSOR OF AEG’S65TH ANNUAL MEETING Learn more about our Engineering Geology services!

John Peck, Consulting Geologist

Heather Clark, AEG Meeting Manager

committee chairs and

Nick Saines

Guest Tours

Outstanding Environmental & Engineering

the

Gary Beckman

Technical Program

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 9

Sponsorship

Student Coordination

AEG Annual Meeting Co-Chairs

Jerry King

Special Event

United States Army Corps of Engineers

, NJ Department of Environmental Protection, retired

Symposium Conveners and Technical Session Moderators

Mark Bailey, Asbestos TEM Labs

Renee Wawczak, AEG Secretary

Sarah Kalika, DiabloGeo Environmental Eric LorenKuhnLasky

Deborah Green, GeologistWriter

AEG 2022 ANNUAL MEETING 10 AEG 65th Annual Meeting Program with Abstracts September 2022

Mike Piepenburg, Mott MacDonald

Hawkins Gagnon, Schnabel Engineering

Special Thanks

Jim Borchers, Consulting Hydrologist

Paul Headland, Aldea Services, Inc.

Sarah Kalika, AEG Treasurer

Jennifer Bauer, Appalachian Landslide Consultants

William Godwin, AEG Past President

James Faulds, Nevada State Geologist

James Prieur, Southern Nevada Water Authority

Andrea Ptak, AEG News Managing Editor/Production

Jeffrey Keaton, Wood, PLC

John H Peck, Consulting Geologist

AEG wishes to acknowledge the following companies for their support by allowing their employees to assist with the planning of the 2022 Annual Meeting:

Kathryn Murdock, Exponent Inc.

Holly Nichols, California Department of Water Resources

Ike Isaacson, Brierley Associates

Scott R. Walker, Tennessee Valley Authority

Curt Schmidt, H2M Architects & Engineers

Nick Saines, AEG 2022 Co-Chair

Gerry Stirewalt, Nuclear Regulatory Commission

Field Course Leaders

James Prieur, Southern Nevada Water Authority

Steve Rowland, University of Nevada, Las Vegas

Bryan Simpson, US Bureau of Reclamation

James Faulds, Nevada State Geologists, Nevada Bureau of Mines and Geology

AEG wishes to thank the following individuals for their assistance with the planning of the 2022 Annual Meeting: Ninyo & UniversityMooreofNevada, Las Vegas

Nate Saraceno, Vice President/President-Elect

Maddie German, AEG President

Patricia Bryan, Bryan Environmental Consultants

Ellen Engberg, Schnabel Engineering

Give back to AEG as a Volunteer! Interested in applying your time and talents to benefit AEG's members? We're always looking for new Technical Working Group members! f you are interested in volunteering for a group, please contact AEG HQ at contact@aegweb.org. Technical Working Groups: ■ Dams & Levees ■ Environmental Characterization & Remediation ■ Coastal Hazards ■ Geophysics ■ Hydrogeology ■ Landslides ■ Naturally Occurring Asbestos ■ Rock Mechanics ■ Geologic and Seismic Hazards ■ Subsidence ■ Tunneling To join a meeting with a group at the Annual Meeting, please see the Meeting Mobile App for Details.

Gregory Hempen, EcoBlast, LC

Mark Swank, Aspect Consulting

Kelley Shaw, Slate Geotechnical Consultants

Welcome to the 2022 AEG Annual Meeting and Viva Las Vegas! I am privileged to welcome you all to AEG’s 65th Annual Meeting! This will be AEG’s third Annual Meeting held in Nevada; we visited Reno in 2002 and Las Vegas in 2005. We have a “stacked deck” of technical talks, field courses and networking events for your enjoyment this week.

Our Exhibitor’s Hall has a high “chip-count” of vendors providing new technologies, products, and services as well as other organizations, colleges, and universities who work hard to “buy-in” to the applied geology field. Many of our exhibitors showed up “in spades” this year and are also sponsors helping to “bankroll” this meeting and AEG. I encourage each of you to “wager” some time with our Exhibitors and make a point to “go all-in” and meet a group of folks you haven’t met before.

I want to “double down” with gratitude for the amazing volunteers who have been working diligently to make this meeting possible. The 2022 Annual Meeting Planning Committee has met regularly and worked tirelessly to schedule technical sessions, guest tours, and special events to make this annual meeting a “big winner.” The Student and Young Professional Support Committee has arranged a “full-house” of programs to help our younger members meet other young professionals, network with more seasoned professionals, and provide travel funding and opportunities to attend. The Meetings Advisory Committee has helped promote the meeting and provided the “winning-hand” with the Reasons to Convince Your Boss to Attend the AEG Annual Meeting flyer and informational webinars for the speakers and moderators.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 11

Finally, I want to thank you and all our attendees for your participation in what promises to be another outstanding Annual Meeting. There is no “game-of-chance” here, take advantage of this opportunity to reconnect with old friends, meet new friends, and share your experience with committee members, Chapter officers, Regional Directors, and members of the Executive Council.

High Unite…Rollers

Cheers and “may the odds be ever in your favor.”

Las Vegas is more than lights, shows, casinos, and quick weddings. Sin City was founded in 1905 as a stopover on the railroad line between Los Angeles and Salt Lake City and has become a convention destination, home to the Stratosphere observation tower at 1,149 feet, and contains an abandoned town underneath Lake Mead. On the geologic and environmental front, Las Vegas averages less than five inches of rain per year, is home to its own landslide complex and shear zone, and is a short “dice-roll” from “a pair” of epic destinations: the Hoover Dam and the Grand Canyon.

Maddie German

I also want to thank all the individuals, companies, and Chapters that have “anted-up” for various aspects of the meeting or who are exhibitors. Without commitments like yours, these annual meetings would not be economically feasible and/or the quality would suffer. I also want to wish “lucky-sevens” to the many speakers, symposia organizers, field course leaders, and session moderators who have gone “double-or nothing” giving their time and without whom this meeting would not be possible.

AEG President, 2021–2022

It is my pleasure to welcome you all “Into the Wild!”

“After you, Mr. Papagiorgio!”

AEG is “dealing-out” six field courses where everyone is a winner! Regardless if you are interested in the inner workings of the Hoover Dam, want more information about the groundwater recharge well field, choose to cruise Lake Mead, or marvel at Earth’s natural wonder on the Grand Canyon Skywalk, we have something for you. Step outside for “big money and no whammies” there is plenty of room to explore!

Our Technical Symposia are “high-rolling” with symposia on dams, landslides, geologic and seismic hazards, and tunneling to name a few. These technical presentations are a sure-fire way to earn the “payout” of continuing education for your license as well as, “raising-the-pot” with the newest technologies and case studies. The “jackpot” for these talks is “head and tails” above any slot machine, “…you know, put in a dollar, win a car. Put in another dollar, win another car....”

AEG 2022 ANNUAL MEETING 12 AEG 65th Annual Meeting Program with Abstracts September 2022

In 2005, before “pandemic” was a household word, Las Vegas hosted a very successful Annual Meeting. The co-chairs, Jim Werle and Barbara Luke, prepared an excellent welcome. What they said in 2005 holds true today: “Where else can over four hundred geoscientists, engineers, and environmental scientists converge for a week of 24-hour non-stop action? You bet, only in Las Vegas!” The Southern Nevada Chapter is placing bets that through the combined talents of our Steering Committee and the AEG Meeting Manager we will hit the jackpot again in holding a fabulous Annual Meeting. The odds are pretty good that you will agree. After all, it is happening in the Entertainment Capital of the World!

For those of you concerned about damaging or destroying valuable brain cells because of too much Vegas nightlife, we have planned an outstanding technical program and field courses guaranteed to stimulate your intellect, advance your professional capabilities, and increase your technical knowledge. The technical sessions cover the full range of disciplines including asbestos, tunneling, seismology, water management, landslides, geophysics, dams and levees, hydrogeology, groundwater recharge, geologic hazards, subsidence, and more.

Our Keynote Speaker, Colby Pellegrino of the Southern Nevada Water Authority (SNWA), will give us an update on the response to the devastating drought that is plaguing the West on the one hundredth anniversary of the signing of the Colorado Compact that divided up the water of the Colorado River. And we will give an award to the SNWA for the construction of the “Third Straw” beneath Lake Mead.

Jerry King and Nick Saines General Co-Chairs

And what about the field? What about outside Las Vegas? Las Vegas, at an elevation of 2,000 ft, is in the middle of the Mojave Desert, with nearby Red Rock Canyon and the Spring Mountains to the northwest rising to almost 12,000 ft. To the east is Lake Mead, and farther east is the Grand Canyon. All these places will be visited on field courses and guest tours where you will enjoy great geology and wild Southwestern scenery.

The 64th AEGMeetingAnnual

to Las Vegas!

Our hotel, Planet Hollywood, is in the best location imaginable—on Las Vegas Boulevard just south of Flamingo Road, across the street from the Bellagio Fountains. In the hotel and within easy walking distance are dozens of great restaurants, shops, and tourist attractions. Our Special Event is a trip on the High Roller Ferris Wheel.

Special thanks to our Steering Committee, especially John Peck (Field Courses), Ann Backstrom (Guest Tours), and Barbara Luke (Outstanding Environmental and Engineering Geologic Project award). We also want to thank our superb and indefatigable AEG Meeting Manager, Heather Clark, and Marty Goff who organized the meeting and put together the technical programs.

Las Vegas is the entertainment capital of the world and is surrounded by amazing, exposed geology. If you have never been here, or have been here a dozen times, we could not be happier that you will be here to enjoy Geology in the Wild with us this September 12–17!

Welcome…

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AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 13

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AEG 2022 ANNUAL MEETING 14 AEG 65th Annual Meeting Program with Abstracts September 2022

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AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 15

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This award is presented to a member for outstanding active and faithful service to AEG over a minimum period of nine years to coincide with Floyd T. Johnston’s tenure as Executive Director.

No Award Given in 2022

Douglas R. Piteau Outstanding Young Member Award: Minda Moe

Honorary Member

Claire P. Holdredge No Award Given in 2022

The Association’s highest publication award, the Claire P. Holdredge Award, is presented to an AEG Member who has produced a publication within the past five years that is adjudged to be an outstanding contribution to the Environmental and Engineering Geology Profession.

Schuster Medal

This award, established in 1985, is named in honor of Douglas R. Piteau is presented to a Member who is age 35 or under and has excelled in the following areas: Technical Accomplishment, Service to the Association, and Service to the Engineering Geology Profession.

Vincent Cronin

A joint committee of AEG and the Engineering Geology Division of the Geological Society of America selects the Jahns Lecturer, who presents an annual series of lectures at academic institutions in order to increase awareness of students about careers in Engineering Geology.

No Award Given in 2022

AEG 2022 Awardees

Established in 2008, it recognizes outstanding individuals for their achievements as mentors throughout their career. The recipient should be an individual who has made lifelong efforts in providing professional, ethical, and technical mentoring for environmental and engineering geologists.

The recipents will be accepting their awards at the Awards Ceremony on Thursday, September 15 from 7:00–10:00pm

A joint award from AEG and the Canadian Geotechnical Society that recognizes excellence in geohazards research in North America (NA). Nominees must be residents of NA and meet at least two of the following criteria: professional excellence in geohazards research with relevance to NA, significant contribution to public education regarding geohazards, international recognition for a professional career in geo-hazards, influential geohazards research or development of methods or techniques, or teacher of geohazards students.

Cynthia Palomares

AEG confers an honor of such high esteem that the distinction is recognized as a membership class: Honorary Member. This recognition is given to those whose careers have exemplified the ideals of AEG.

J. David Rogers

Floyd T. Johnston Service Award

AEG 2022 ANNUAL MEETING 16 AEG 65th Annual Meeting Program with Abstracts September 2022

Karl and Ruth Terzaghi Mentor Award

NOMINATE a Deserving AEG MEMBER for One of Our 2022 AWARDS These are just a few of the AEG awards that recognize the contributions our members make to the Association and to the profession. For a complete list of the awards and requirements for each, visit https://www.aegweb.org/awards-scholarshipsAEGCorporateBusinessMeeting&ClosingSessionFriday,Sept.16–3:00–5:00pm This session will highlight AEG’s 2022 accomplishments and upcoming goals and projects for 2023. We will also be introducing our new Executive Council and honoring AEG Awardees for 2022.

Richard H. Jahns Distinguished Lecturer in Engineering Geology — 2021–22

The Stillwater Scarp, Central Nevada, USA; Coseismic Gravitational Failure on a 1.200-M-High Range-Front Escarpment

Jesse Ruzicka – past Chapter Chair and continued advisor for the Great Basin Chapter

Environmental & Engineering Geoscience Journal, Volume XXVII, No. 4, pp. 377–393

Dale Andrews – work on SIC and revamping strategic plan

David Abbot – long-term Treasurer for the San Francisco Chapter

Dr. Chris Stohr – Chicago Chapter Chair as well as serves as a representative to the Champaign County Board of Representatives

This award was established by the Board of Directors in 2001 to honor a Chapter of the Association judged to excel in a number of areas including professional activities, communications, membership, and networking.

AEG Outstanding Environmental & Engineering Geologic Project Award

AEG Publication Award

First presented in 2007, this award is given to an individual who has provided extended service by reviewing numerous manuscripts, including critical evaluations, detailed comments, corrections of grammar and syntax, thoughtful suggestions for changes to improve the quality of the manuscript, and guidance to the editors in making a decision regarding the manuscript.

Issac Pope – for stepping up to chair communications committee alone while finishing school and continuing to write articles for AEG Publications

Patricia Bryan – an AEG workhorse who is quietly but diligently helping our profession by organizing technical sessions and initiating/maintaining research and industry contacts

See page 37…

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 17

AEG 2022 Awardees

James McCalpin and Leon C.A. Jones

No Award Given

Rick Kolb – for helping to reinvigorate the Carolinas Chapter while stepping in as a temporary Co-chair for the SYPS committee and organizing several ASBOG-related webinars

Courtney Johnson – long-term San Francisco Chapter Officer

Lake Mead Intake No. 3 and Low Lake Level

Kathleen Rodrigues – Prior Great Basin Chapter Secretary and now Vice Chair. She has great attention to the details of our meeting announcements and for working on all matters during the meetings themselves to insure they ran smoothly

Gary Luce – past Chapter Chair and continued advisor for the Great Basin Chapter

Cornelia Marin – a quiet, long-serving AEG Chicago Chapter Officer who has served as Vice Chair and done an amazing job of finding venues for in-person meetings, especially after the global pandemic closed so many restaurants and caused others to have to raise prices and require large fees

In addition to honoring outstanding AEG Members, AEG also recognizes the following:

Pumping Station, Nevada

Outstanding Student Professional Paper No Award OutstandingGivenChapter Award

We recognize those volunteers within AEG that have worked so hard on helping to move AEG forward over the past year or so. These awards will be handed out during the Opening Session on Wednesday morning.

Dr. Andrew Stumpf – a quiet, long-serving AEG Chicago Chapter Officer who has served as Treasurer for a very long time and has done a superior job of tracking expenses

Environmental & Engineering Geoscience Journal Outstanding Reviewer Award

This award was established by the Association in 1968 and is presented to the author(s) of the most outstanding paper published in any AEG publication during the fiscal year. Winning papers can be viewed online at GeoScienceWorld.

Chester (Skip) F. Watts

Volunteer Recognition

California State University, Fresno Graduate DivisionMasters–

AEG 2022 ANNUAL MEETING 18 AEG 65th Annual Meeting Program with Abstracts September 2022

ScholarshipJustinToller

AEG Foundation 2022 Scholars

Graduate Division – Masters

Established in 2015 with a gift from the Carolinas Chapter, this scholarship supports geologic studies by undergraduate students enrolled in a geology or geoscience program at an accredited university in North Carolina or South Carolina.

Carolinas Scholarship

The Marliave Scholarship Fund was established in 1968 to honor the late Chester E. Marliave, Burton H. Marliave, and Elmer C. Marliave, outstanding engineering geologists and supporters of AEG. The funds are distributed as grants, which are intended to support academic activity and reward outstanding scholarship in Engineering Geology and Geological Engineering.

The Susan Steele Weir Scholarship Fund was established by the AEG Foundation in 2017 to create a scholarship fund that promotes and supports the continued development and advancement of women in the profession of engineering geology.

Cora Lee McCrary Northeast Alabama Community College

William Isaac Pugh

Robert J. Watters Great Basin Chapter

University of Nevada, Reno

Colorado School of Mines Graduate Division – Masters

Lauren Miller

Appalachian State University

Justin Coley University of North Carolina at Charlotte

The recipients will be honored at the Opening Session on Wednesday, September 14.

Martin L. Stout

Marliave Scholarship No Award Bestowed in 2022

ScholarshipOscarRoberto Lemus

The Robert J. Watters Great Basin Chapter Scholarship Fund supports geoscience studies by students at the undergraduate and graduate levels.

Susan Steele Weir (Women of “Steele”) Scholarship

Cal State University, Fullerton

The Beardsley-Kuper Field Camp Scholarship Fund supports expenses for geology field camps with applied environmental and engineering geology components that will be useful to the students’ future profession as an environmental or engineering geologist. The scholarship was established in 2009 by Cathryne Beardsley with her daughter Dorian Kuper and son-in-law Tom Kuper.

Ashely Scholder

Sam Bartish University of Washington

KatelynWilcoxIrene

Beardsley-Kuper Field Camp Scholarship

Dr. Martin L. Stout was Professor of Geology at California State University, Los Angeles from 1960 to 1990. He is remembered by his students for his passionate and insightful instruction in engineering geology. Dr. Stout was known for his expertise on landslides, his travels, his good humor, and his gracious manner. This scholarship supports his legacy.

Colorado School of Mines

Graduate Division – Masters

John Chibundu Akidike

Diversity

Rodriguez Castro California State University, Fresno

Ohio State University Graduate Division – Masters

University of Alaska Fairbanks

Undergraduate Division

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 19

Cassia Noelle Snyder

Ohio StateversityUni-

Appalachian State University

Indiana University Undergraduate Division RoumelisChristianDavid

Erika Hernandez

Graduate Division – PhD

Established by the AEG Diversity, Equity, and Inclusion Committee (DEIC) in 2021, this $5,000 scholarship is awarded annually to one student who is a geoscience major in their sophomore, junior, or senior year at an accredited college or university. The successful applicant will have a GPA of 2.9 or better.

Norman R. Tilford Field Study Scholarship

Texas Tech University

ScholarshipMarco

Nicholas Ferry University of Kansas

Established in 2007 as the Texas Section Scholarship, the Scholarship was renamed in 2011 to honor Dr. Christopher C. Mathewson. Recipients of the scholarship are undergraduate or graduate students enrolled in an accredited Texas college or university, or graduate students conducting field studies in Texas.

Fresno State

The Shlemon Quaternary Engineering Geology Scholarship supports graduate geology students conducting Quaternary engineering geology research. Initial funding for the Scholarship was provided by a gift from Roy J. Shlemon, Honorary Member of the AEG.

The Tilford Scholarships are awarded to both undergraduate and graduate students for the summer field season, and were established in memory of Norman R. Tilford, who was a leader in engineering geology and a professor at Texas A&M University. Norm died in 1997 while flying his small aircraft to meet a student field trip. Norm was dedicated to teaching geology in the field and these scholarships support his legacy.

West-Gray ScholarshipJackStewart

Shlemon Quaternary Engineering Geology ScholarshipAbdallahBasiru

Elijah Werlyklein

Indiana University-Purdue University at Indiana

ChristianRoumelisDavid

Christopher C. Mathewson Scholarship

Established in 2014 with initial funding provided as a gift from AEG Past Presidents Terry R. West and Richard E. Gray, this fund supports undergraduate and graduate geology students studying in the eastern half of the United States.

LocatingFindingKarstHazardoids/CavityDectectiooundTgrgSinkHoleDectectioAquiferStudiesGravityfor:UnderVsonioanksnFindingKarstHazar TheGravitySpecialist

Dorothy Combs, dkc@aipg.org 303-412-6205

The American Institute of Professional Geologists (AIPG), founded in 1963, is the largest association dedicated to promoting geology as a profession. It has more than 5,000 members in the United States and abroad, organized into thirtysix regional Sections. The Institute adheres to the principles of professional responsibility and public service and is the only international organization that certifies the competence and ethical conduct of geological scientists in all branches of the science. AIPG emphasizes competence, integrity, and ethics. AIPG is an advocate for the profession and communicates regularly to federal and state legislators and agencies on matters pertaining to the geosciences.

Alex Vazquez, staff@aegfoundation.org www.aegfoundation.org

Simon Boone, simon@alccinc.com 805-592-2230 www.accesslimitedconstruction.com

Association of Environmental & Engineering Geologists (AEG) Booth – Registration Area

AEG Foundation Booth and Silent Auction

Our exhibitors offer an excellent platform to interact one-on-one with you and your company. Your active interest and participation during the exhibit hours will help to ensure that vendor support will remain strong during the years to come. Remember, without these exhibitors, the AEG 65th Annual Meeting would not be successful.

www.aipg.org

Icebreaker Welcome

Access Limited Construction is a general contractor located in San Luis Obispo, California. An industry leader, we provide rockfall mitigation, slope stabilization, and difficult drilling services for transportation, energy, mining, and private sector clients. With our fleet of Spyder Excavators, we can access steep terrain and hard to reach projects throughout the United States from the East Coast to Hawaii.

Mark your calendar to join us for the 66th AEG Annual Meeting at the Marriott Portland Downtown Waterfront, Portland, Oregon, September 19–24, 2023. Stop by our booth to get all the details.

ASBOG® serves as a connective link among the individual state geologic registration licensing boards for the planning and preparation of uniform procedures and the coordination of geologic protective measures for the general public.

AEG welcomes you to Las Vegas! We hope your stay is filled with informative technical sessions, great meals, and of course lots of networking. Stop by our booth to see some of the latest publications and merchandise available. We will also have information on the various committees and what each has been working on to advance the AEG and the profession.

Exhibitor–Hosted Luncheon

EXHIBIT HALL HOURS: Tuesday, Sept. 13 6:30pm–8:30pm Wednesday, Sept. 14 7:30am–5:00pm Thursday, Sept. 15 7:30am–3:20pm

Established by three Past Presidents of the Association of Engineering Geologists (AEG) in 1992, the AEG Foundation plays a key role in the success of our profession. The AEG Foundation’s vision is to create a culture of giving back to the profession, and to instill complete confidence in donors that their money is well-invested and well-spent. Our core programs emphasize scholarship, research, and professional development to improve professional practice. We support outreach to increase the public’s appreciation of environmental and engineering geology in geo-hazard evaluation and risk reduction.

Exhibitors

AEG 2023 Annual Meeting – Portland, Oregon – Booth #7

Association of State Boards of Geology® (ASBOG) –Booth #13

Sheri Maskow, manager@aegweb.org 844-331-7867 x3229 www.aegweb.org

Tuesday, Sept. 13, 6:30–8:30pm – Exhibit Hall

William Schenck, rockmanwss@gmail.com 678-713-1251 www.asbog.org

The Exhibitor-Hosted Luncheon is a great way to connect with colleagues, gather information about innovations in the industry, and relax with friends old and new over a delicious meal. FREE for all full, Wednesday one-day and student registrations

Mark Swank, mswank@aspectconsulting.com Mike Marshall, mmarshall@gri.com

American Institute of Professional Geologists –Booth #32

Join us in the Exhibit Hall to meet the Exhibitors and socialize with your fellow attendees. We will have light appetizers and a cash bar (one drink ticket included).

Wednesday, Sept. 14 12:00–1:30pm – Exhibit Hall

Access Limited Construction – Booth #11

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 21

ANNUAL MEETING WIFI ACCESS:

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Beta Analytic, Inc. – Booth #14

Exponent is a leading engineering and scientific consulting firm comprised of scientists, engineers, physicians, and regulatory consultants from over ninety disciplines. Our technical excellence, objectivity, and disciplinary diversity allow us to solve some of the toughest science, engineering, and business problems in industry and government—from forensic analysis to risk assessment. We use our expertise to contribute safe, healthy, and sustainable solutions in the most complex environments.

AEG 2022 ANNUAL MEETING 22 AEG 65th Annual Meeting Program with Abstracts September 2022

Boart Longyear Company – Booth #2

Doug Laymon, PG, doug@colliergeophysics.com 512-851-8740

www.conetec.com

Collier Geophysics – Booth #28

NETWORK:

Collier Geophysics is a service-disabled, veteran-owned, small business with offices in Texas, Colorado, Georgia, North Carolina, Tennessee, and Wisconsin. Collier Geophysics has assembled one of the most respected and experienced team of geophysicists and hydrogeologists in the industry. We possess a depth of experience in surface, borehole, and marine geophysics throughout the US and internationally.

Jeff Leberﬁnger, PGp, PG, jleberfinger@exiusa.com 717-303-5406 www.exiusa.com

The One-stop solution for all your environmental and geotechnical drilling needs. Established in 1993, we are driven by the mission to be the preeminent environmental drilling and field service company by providing an unparalleled commitment to client service and operating with the highest standards of integrity, safety, and professionalism.

Bruce Miller, 224-228-6286bmiller@conetec.com

Exploration Instruments LLC – Booth #24

Caesars Resorts

www.cascade-env.com

Exploration Instruments is the best-known geophysical equipment rental firm in North America specializing in near-surface applications. We maintain a diverse inventory including seismic, radar, EM, lidar, magnetics, resistivity, hydrologic, marine and drone tools. Offices in Austin, Texas, and Harrisburg, Pennsylvania, are ideally situated to service your projects worldwide.

Provide an email address and

Cascade Drilling L.P. – Booth #15

Tim Stine, 801-330-3965TStine@cascade-env.com

Julien Cohen-Waeber, jwaeber@exponent.com www.exponent.com

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BC2 Environmental, LLC – Booth #33

https://www.radiocarbon.com/ Beta Analytic is an ISO 17025-accredited radiocarbon dating laboratory with standard turnaround time of fourteen business days. Respected worldwide for accuracy, quality, and customer care. Sample submission is easy and convenient through our global forwarding facilities.

Erica Avalos, 714-744-2990eavalos@bc2env.com

www.bc2env.com

Cascade is the leading provider of environmental and infrastructure drilling, site characterization, and environmental remediation applications. We are the only nationwide integrated field services firm with expert technical capabilities and fleet to provide seamless environmental and geotechnical solutions, from concept to completion.

John W. Roberts, PG, john.w.roberts@boartlongyear.com 385-218-7508 www.boartlongyear.com

Boart Longyear offers drilling and geological data services, and drilling products. Drilling services include surface and underground core and RC, sonic, water well and large rotary, and long-hole percussing drilling. Geological data services (GDS) includes survey and core orientation tooling and high-quality, continuous XRF scanning technology, and drilling parameter data collection technology. Drilling products include, but are not limited to drill rigs (sonic, surface, and underground core, long-hole percussive), bits, rods, casing, and downhole tooling.

ConeTec, Inc. – Booth #1

www.colliergeophysics.com

Exponent – Booth #25

Customer Care, lab@radiocarbon.com 305-667-5167

In Situ Testing contractor specializing in CPTu, SCPTu, HPT, UVOST, MIP, DMT, PMT, and other surface and in situ testing methods for geotechnical, environmental and marine site characterization.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 23

Geobrugg North America, LLC – Booth # 5

GF Instruments/THG Geophysics, Ltd. –Booth #23

GEOKON is a recognized world leader in the manufacture of structural and geotechnical instrumentation for a wide range of industries including tunnels, dams, mines, piles, bridges, pipelines, landfills, embankments, transportation, and wind turbines.

https://www.thggeophysics.com/gf-instruments/ THG Geophysics serves as the US representative for GF Instruments, a manufacturer of measuring instruments for geophysical, geological, environmental, and laboratory use including gamma-ray spectrometers and dose rate meters, DC resistivity systems, electromagnetic conductivity meters, magnetic susceptibility meters, and laboratory instruments.

www.geostabilization.com

Jared Warner, PG, CEG, CPG, jwarner@geosyntec.com 858-716-2885

Gregg Drilling – Booth #20

Kelly Cabal, 949-903-6873kcabal@greggdrilling.com

www.hitechrockfall.com

Gannett Fleming – Booth #26

www.gannettﬂeming.com

Noah Nelson, noah.nelson@impulseradar.se 714-316-8185

HI-TECH Rockfall Construction, Inc., is a general contractor that provides natural hazard mitigation solutions, with focus on rockfall mitigation and slope stabilization systems. HI-TECH Rockfall, founded in 1996, is based in Forest Grove, Oregon. Our vast experience and innovative installation techniques allow us to work in limited access areas and overcome challenging situations, which all have made us the leader in the rockfall mitigation and slope stabilization industry.

www.geosyntec.com

www.geokon.com

Geosyntec Consultants – Booth #31

Kate McKinley, ksm@thggeophysics.com 724-325-3996

GEOKON – Booth #30

provides specialized geotechnical and geological services for public and private sector clients nationwide. We are a practicecentered business with a strong desire for continuous selfimprovement and ongoing reinvention to meet the evolving needs of our current clients and to productively engage with new ones.

Innovative solutions that provide comprehensive protection from natural hazards. We’re the right, highly sustainable and economical choice for every situation. Along with easy installation, we offer total support during installation and beyond. Geobrugg, where safety is our nature.

Gregg Drilling LLC is a full-service contractor offering services from CPT and drilling to advanced site characterization and remediation services within California and the Western United States. Gregg is an Alaska Native-owned, 8a-certified small business focused on quality and safety with a proven history of exceptional performance.

HI-TECH Rockfall Construction, Inc. – Booth #6

GeoStabilization International – Booth #21

www.impulseradar.se

Matthew Morris, mmorris@gfnet.com 412-503-4938

Shawn Dedeker, sdedker@geokon.com 603-448-1562

ImpulseRadar, USA – Booth #17

www.greggdrilling.com

Tim Shevlin, 503-423-7258tim.shevlin@geobrugg.com

Buddy Johnson, buddy@hitechrockfall.com 503-357-6508

www.geobrugg.com

Gannett Fleming is a planning, design, construction management, and alternative delivery firm. Our geotechnical and geological services include analysis, site characterization, geophysics, groundwater studies, digital photogrammetry, instrumentation and monitoring, ground modification, and SPRAT Certified rope access for foundations, dams, levees, earth retaining structures, tunnels, and mining operations. As an ISO 9001:2015 Certified firm, we provide excellence delivered as promised.

Josh Wagner, Joshua.wagner@gsi.us

Ground Penetrating Radar

Our passion is to innovate and implement optimized solutions that protect people and improve infrastructure. We specialize in emergency landslide repairs, rockfall mitigation, and grouting using design/build and design/build/warranty contracting. GeoStabilization’s team includes some of the brightest and most dedicated professionals in the geohazard mitigation industry. Our expertise, proprietary tools, and worldwide partnerships allow us to repair virtually any slope stability or foundation problem in any geologic setting.

Michael Cook, PG, CEG, mcook@kleinfelder.com 951-801-3721 www.Kleinfelder.com

Since 1996, Rocscience has envisioned and built world-class solutions for civil, mining, and geotechnical engineers. We have created a solid foundation of software development that brings research and innovation together, building a suite of eighteen tools capable of handling your most challenging rock and soil problems. Our mission is to continue developing geotechnical software solutions that work for you today and evolve with your needs tomorrow.

Bill Kane, 209-472-1822william.kane@kanegeotech.com www.kanegeotech.com

Jerry Marasovich, jerry.marasovich@ruendrilling.com 209-988-4261 www.ruendrilling.com

Kleinfelder – Booth #34

Sheri Maskow, sheri@jmbsohio.com 330-273-5756

Eric Cross, 336-335-3174eric@pyramidenvironmental.com

www.PyramidGeophysics.com

Michael Koutsourais, m.koutsourais@maccaferri.com 301-223-6910 www.maccaferri.com

Rocscience, Inc – Booth #22

Ruen Drilling was established in 1974 and today is still proud to be a leader in quality core drilling for mining and geotechnical industries. The family owned and operated fleet includes surface, flyable, difficult access, and underground drill rigs. Continuing to adapt and capture new techniques and technologies, investing in specialty customized rigs to exceed the demand of deeper heliportable drilling. Recently, we have set our sights on changing how core orientation is performed with new workflows for highly accurate data. Ruen Drilling takes pride in our people and our clients.

Founded in 1961, Kleinfelder is a leading engineering, design, construction management, construction materials inspection and testing, and environmental professional services firm. Kleinfelder employs more than 3,000 professionals and operates from over 100 office locations in the United States, Canada, and Australia. Using our multidisciplinary services, we collaborate with clients throughout the entire project lifecycle, providing solutions that improve our clients’ transportation, water, energy, and other private infrastructure.

AEG 2022 ANNUAL MEETING 24 AEG 65th Annual Meeting Program with Abstracts September 2022

KANE GeoTech, Inc. – Booth #3

National Drilling Association – Booth #27

Maccaferri’s extensive engineering capabilities and range of products help clients overcome challenges associated with geohazards, landslides, and other natural disasters. Maccaferri, known for its Double-Twist Wire Mesh Gabions, has developmental product lines for rockfall mitigation, retaining wall and soil reinforcement, natural disaster response, and other critical infrastructure needs. We are global engineers with 140 years’ experience, providing local solutions for complex projects around the world.

Pyramid Geophysical Services offers a full line of geophysical capabilities to North Carolina and across the United States. We have experience in a wide variety of geographical areas and projects, including hazardous waste sites, underground storage tanks, landfills, groundwater studies, and geotechnical investigations. We design geophysical surveys that meet the client’s needs in the most efficient and cost-effective manner possible.

The National Drilling Association is a nonprofit trade association of contractors, manufacturers, and affiliated members from the drilling industry representing the geotechnical, environmental, and mineral exploration sectors of this industry. The NDA mission is to promote the use of professional drilling contractors and their methods. Founded in 1972, NDA has more than 200 member companies, some of which are international.

Pyramid Geophysics – Booth #19

Rite Geosystems – Booth #8

Rite Geosystems is a geotechnical instrumentation supplier, where we provide geotechnical instruments, data loggers and cloud based online monitoring platform in house. Rite Geosystems offers reliable and robust geotechnical monitoring solutions for the construction, transportation and infrastructure sectors. Our people are customer focused and supportive, and we worked tirelessly in partnership with contractors and monitoring companies, over fifty years, to ensure we provide you with stable, precise and highly userfriendly data from any of your installations.

Maccaferri – Booth #9

Melih Demirkan, melih@ritegeosystems.com 412-680-2526 www.ritegeosystems.com

Ruen Drilling, Inc. – Booth #29

KANE GeoTech, Inc. specializes in challenging civil and geotechnical engineering problems. Our services include rockfall, debris flow, avalanche, and landslide mitigation through extensive geotechnical analysis and design based on nearly thirty years of experience. We are also experts in geotechnical instrumentation and automated data collection for remote monitoring. With multiple offices throughout the country and professional registration in thirty states, we build partnerships with our clients and affiliates by understanding time-sensitive project goals and delivering the best and most effective solutions.

https://www.nda4u.com/

Robert Bradford, robert.bradford@rocscience.com 416-698-8217 www.rocscience.com

The USGS Research Drilling Program supports scientist across the nation on a variety of research projects. Our focus is on the quality of data collected and the platforms we install. Our expertise includes drilling, borehole geophysics and installation of extensometers for land deformation, instrumented boreholes for managed artificial recharge, nested ground-water monitoring wells for groundwater studies, low deviation cased holes for global and local seismic monitoring sites and coring for energy assessments and both geologic and hydrologic properties. We also core for energy assessments, 3D landscape evolution and seismic assessments.

https://www.lps.upenn.edu/degree-programs/msgo Advance your career and make an impact in environmental geology, hydrogeology, and engineering geology with an online master’s degree. Whether you are an experienced geoscientist or preparing to expand your science or engineering experience, you can advance in the field without relocating or interrupting your career. Penn’s rigorous Master of Science in Applied Geosciences program is now online.

UPenn – Masters in Applied Geoscience Online – Booth #12

Seequent software empowers customers to make better, more sustainable decisions about their earth, environment, and energy challenges. It’s our mission to unite the insights of geotechnical, geology, geophysics, geochemistry, hydrogeology, and GIS teams—and their stakeholders. We enable geo-data to tell a story with software that combines in-depth analysis, 2D and 3D visualization, and data management. Accessible on desktop and Cloud, Seequent brings together the trusted power of Leapfrog 3D, Geosoft, and GeoStudio software. Our solutions integrate with industry-leading tools and have an open API so that all data and workflows can be considered.

United States Geological Survey – Research Drilling Program – Booth #18

https://www.schnabel-eng.com/ Schnabel is a leading provider of dam, tunnel and geotechnical engineering solutions nationally and abroad, with risk management rounding out a full-service approach. Our 450+ employee/owners in 23 locations have a passion for client service and tough technical challenges.

Schnabel Engineering – Booth #10

Hawkins Gagnon, jgagnon@schnabel-eng.com 336-274-9456

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 25

Steven Crawford, smcrawfo@usgs.gov 702-823-1235 www.usgs.gov

Tony Sauder, sauder@sas.upenn.edu 215-704-2307

Samantha D’Sa, samantha.dsa@seequent.com www.seequent.com

Seequent – Booth #4

Tuesday, September 13 6:30–8:30pm – Exhibit Hall Join us to meet the exhibitors and socialize with your fellow attendees. We will have light appetizers and a cash bar (one drink ticket included). 26 AEG 65th Annual Meeting Program with Abstracts September 2022

AEG 2022 ANNUAL MEETING

The Exhibit Hall is located in the Celebrity Ballroom, Rooms 1–3.

Icebreaker Welcome

Exhibit Hall

Index

to Advertisers Advertiser Page AEG 2023 Annual Meeting Inside Front Cover AEG Corporate Sponsors 32 AEG Future Meetings 103 Cascade 31 ConeTec 102 EnviroEquipment 31 Exponent 25 Gannet Flemming 47 Geobrugg 58 Geosyntec 31 Gregg Drilling 60 Kleinfelder 9 Lettis 56 Ruen Drilling 101 Advertiser Page Nick Saines 53 Schnabel 102 Scintrex 20 Spotlight Geo 56 Infrastructure and the Environment: Impacts on the Built World Symposium 36 University of Arizona Inside Back Cover UPenn Back Cover

Bruce Miller, 224-228-6286bmiller@conetec.com

www.gannettﬂeming.com

Scintrex Limited

Hawkins Gagnon, jgagnon@schnabel-eng.com 336-274-9456 https://www.schnabel-eng.com/ Schnabel is a leading provider of geology and geotechnical engineering solutions for tunnels and dams, nationally and abroad. We provide geophysical, geostructural, instrumentation and monitoring systems (IMS), with risk management rounding out a full-service approach. Our 450+ employee/owners in 23 locations have a passion for client service and tough technical challenges.

www.conetec.com

Gannett Fleming is a planning, design, construction management, and alternative delivery firm. Our geotechnical and geological services include analysis, site characterization, geophysics, groundwater studies, digital photogrammetry, instrumentation and monitoring, ground modification, and SPRAT-Certified rope access for foundations, dams, levees, earth retaining structures, tunnels, and mining operations. As an ISO 9001:2015 Certified firm, we provide excellence delivered as promised.

Sponsored by Geosyntec

Earthquakes, sinkholes, tsunamis, sea level rise, and differing site conditions are all issues that challenge the best of our profession. Share your experiences, adaptions, and solutions for addressing and living with these issues. Tell us the good, the bad, and the ugly; we want to hear it all.

1:20–1:40 David Hibbard ArcGIS for Geohazard Inventory, Analysis, Site Design, and Mitigation

2:20–2:40 Martin Derby Geohazard Identification, Monitoring and Mitigation Methods Using Soil Nail Technology for Shorelines and Infrastructure

Technical Session #20

Time Speaker Title

Geologic and Seismic Hazards, Part II

Room: Melrose 4

Gary Norris Modeling the Stress-Strain Curve of Las Vegas Area Caliche

Geohazards and Site Characterization

1:40–2:00 Karl Schuler Risk Assessment Needs for Redeveloping Industrial Property to Residential Use

2:00–2:20

Wild Problems, Unique Solutions, and Lessons Learned

Room: Melrose 3

Scientific and Political Issues Confronting Protection of the Sole-Source Mahomet Aquifer, East-Central Illinois, and Supplementary Civics

1:00–1:20 Evan Lindenbach

Science in Elected Office: Observations from Five Years in Public Office

Update to the Carson City and New Empire Quaternary Fault Maps 1979–2022

February 2019 Alluvial Fan Flood Characteristics Inferred from Available Information, Central Riverside County, California

Moderator: Mark Swank

Room: Sunset 3–4

FRIDAY, SEPTEMBER 16 – AFTERNOON

Technical Session #19

Rock Dilatometer Testing: Field Observations and Comparisons to Empirical Correlations

2:20–2:40

1:20–1:40 Loyd West Washington State School Seismic Safety Project: Geologic and Structural Engineering Assessments of 561 School Buildings

Stephen Evans

2:00–2:20 James Aurthurs

1:00–1:20 Stella Finch Groundwater Plume Delineation, Comparability of FROG-4000 Split-Sample Analyses of Volatile Organic Compounds

Ever encounter a problem that seems to have no explanation; a problem that seems to redefine everything you know? The Wild Problems, Unique Solutions, and Lessons Learned is the session for you. Tells us about your problems, strategies, and resolutions.

Facades of Futures Past – Reusing Historic Facades

Chris Stohr

1:20–1:40

2:00–2:20 Alexander Greene Post-Wildfire Geohazard Assessments of Impacted Natural Gas Pipeline Corridors

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 57

Technical Session #18:

Matthew Wagoner

Daisy Herman Analysis of the Long-Term Effects of Construction on Rockfall along the Parks Highway

Wednesday, September 14 & Thursday, September 15 – 8:00am–4:00pm

Shawna Hunnicutt Analyses of Spring Water Chemistry and Microbiology in the Spring Mountains, Nevada

Anne Fehrenbach

Anomalous Rate of Subsidence at Early-Stage of Groundwater Pumping from Subsurface Heterogeneous Aquifer/Aquitard System

AEG 2022 ANNUAL MEETING 58 AEG 65th Annual Meeting Program with Abstracts September 2022

Speaker Title

John Oswald Post-Fire Geologic Hazard Assessment of the 2021 Bond Fire and Hillslope Response to Significant Storms During Year-One Natalie Renkes Can Recrystallization of Fibrous Amphibole Produce Asbestos Morphologies?

Geochemical Analysis of Metavolcanic and Ultramafic Rocks and Soils in Magalia, California, Show Ni and Cr Toxicity Potential

Khalid Haji Omar Removal of a Mixture of Toxic Metals and Metalloids from Petroleum Produced Water by Dolomite Filtration

Ajit Joshi

Poster Sessions

(See each poster for their available schedule. Schedule changes can be found in the Mobile App.)

We will once again be holding a student poster competition. There will be three cash prizes ($200, $100, and $50) for the top three vote recipients of the poster sessions. Voting will be conducted exclusively through the Mobile App, so bring your mobile device to vote for your favorite. Winners will be awarded at the Poster Reception on Thursday evening.

Vote for Your Favorite Poster!

Comparison of Shallow and Deep-Seated Landslides on Privately Managed Timberlands in Ah Pah Creek, Humboldt County, California

Scott Sochar A Program to Review Engineering Geology for Schools and Hospitals

Dirk Grahl A Travelers Tale – Continuity of the Black River and Trenton Groups from Watertown to State College

ReceptionPoster Thursday 5:00–6:30pm in the Celebrity Foyer Sponsored by Enviro-Equipment Cash Bar. Each Full, Thursday One-day, and Student Registration receives one drink ticket. WITH GEOHAZARDS VOMEOERC omcoompr tabilizationSlope Smised withhtidthtb ³TEM T®TECCO S Aesthetics do not have to be YS p lAlgodones NMlGeobrugg NA www.geobrugg.coml505.771.4080

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 59

During well start-up (<2 hours; turbidity>3 NTU), L. pneumophila averaged 2792MPN/100 mL, with median of 105 MPN/100 mL, and range of < 1 to 90,490 MPN/100 mL across 61 seasonally operated (April-October) groundwater wells. After initial flushing (turbidity<3 NTU), the average concentration decreased by more than two orders

The Role of Internal Erosion in the Development of Ground Fissures around Lake Ziway, Ethiopia Admassu, Yonathan, James Madison University, admassyx@jmu.edu; Trufat Gugsa, trufat.hailemariam@aau.edu.et (TS #13)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 61

Assessment of the Clogging Behavior of Fine-Grained Soils through Geologic History

Arthurs, James, Federal Highway Administration, james.arthurs@dot.gov; Rebecca Borst, rebecca.borst@dot.gov (TS #18)

Legionella Occurrence Monitoring in Las Vegas Valley Groundwater

Atkinson, Ariel, Southern Nevada Water Authority, ariel.atkinson@snwa.com; Christina Morrison, christina.morrison@snwa.com; Wilbur Frehner, wilbur.frehner@lvvwd.com; Daniel Gerrity, Daniel.Gerrity@lvvwd.com; Eric C. Wert, eric.wert@lvvwd.com (TS #9)

Legionella occurrence monitoring is not required by USEPA drinking water regulations. The Surface Water Treatment Rule (SWTR) establishes an MCLG of 0 MPN/mL for Legionella and advises if virus and Giardia standards are achieved, Legionella is adequately controlled. Legionella is not regulated by the Groundwater Rule. Going beyond the regulations, SNWA initiated a Legionella occurrence monitoring program. This presentation will provide an overview of the findings along with SNWA’s response plan. Legionella occurrence was monitored in Las Vegas Valley drinking water sources including raw surface water, seasonal groundwater (61 wells, before and after chlorination), finished water (after treatment at WTFs), and chlorinated distribution system water (at 9 chlorinated reservoirs and 75 sample locations throughout network). Legionella pneumophila was detected at least once at each LVVWD well, with overall positivity rate of 38 percent (343/908).

Geotechnical Design of Permafrost and Wetland Mitigation for Colorado State Highway 5 (Mt. Evans Road)

Abstracts

Akeju, Victor, Brierley Associates, vakeju@brierleyassociates.com; Tom Pullen, tpullen@brierleyassociates.com (TS #2)

Tunneling through fine-grained soils can result in clogging of excavation equipment, which can lead to delays and affect project overruns. In some cases, it may lead to conflicts among project parties and even, abandonment of equipment or project. To avoid clogging during tunneling, practitioners usually evaluate the clogging potential of finegrained soil formations to identify possible mitigation measures. In real-life projects, clogging classification charts which are based on empirical correlation of geotechnical parameters are commonly used to determine clogging potential. To effectively apply the charts, a significant number of site-specific data is needed. However, the site-specific data obtained during geotechnical investigation programs are usually limited and sparse due to time and financial constraints. This presentation explores how the clogging behavior of fine-grained soil formations can be assessed through the understanding of their geologic history. The understanding of the geologic history of the soil formations at the preliminary stages of tunneling projects can help practitioners in the early detection of clogging risk. This presentation examines the influence of parent bedrocks, weathering, climatic factors, transportation, depositional environments, and post-depositional processes on clogging behavior. In addition, the relationship between geologic history and the engineering properties of soil that influences clogging is explored. Based on this study, a set of recommendations for determining the clogging behavior of fine-grained soil formations will be presented and applied to some hypothetical scenarios which depict different soil formations.

Ground fissures are linear cracks that are common in the main Ethiopian rift, which is part of the East African rift system. They are unique types of geohazard affecting roads and railway in many parts of the rift valley. The vicinity of Lake Ziway is underlain by pyrolastic sediments that are cut by numerous ground fissures which run for 2–3 kms with up to 3–5 m wide openings. Plausible causes of ground fissure events, as described in previous studies include extensional movement due to active rift tectonics, hydro compaction, and piping. However, the exact mechanism of their evolution is poorly understood. Based on field observations and sediment characterization, we propose a strong case for the role played by internal erosion or piping of pumice deposits in the development of ground fissures. Internal erosion causes the development of subsurface conduits which grow in size and eventually collapse forming ground fissures. Typical sediment piping–related geomorphologic features such as disappearing streams, sinkholes, blind gullies, and piping mounds have been observed. These features indicate the presence of a network of pipes that connect the groundwater with surface water in a manner very similar to karst hydrology. Grain size distribution analysis show bimodal distribution of mainly pumice deposits making them susceptible to piping erosion. In addition, due to their low density (average S.G. = 0.6), the pumice sediments have correspondingly very low critical hydraulic gradient that is significantly less than theoretical values calculated for siliciclastic sediments.

Colorado State Highway 5, also known as the Mount Evans Highway, is a scenic byway that provides access to the summit of Mt. Evans and other popular recreation sites. A segment of the roadway near Summit Lake passes through a high alpine wetland that is underlain by permafrost and coarse glacial deposits. This segment is located at an elevation of approximately 13,000 feet above sea level. Due to this high altitude, the roadway is subject to harsh weather conditions including an annual temperature range of 65°F is summer to -40°F in winter and an average snowfall of 282 inches. Construction of the roadway through this sensitive environment has disrupted surface and subsurface water flow and caused degradation of the underlying permafrost. Degradation of permafrost and on-going solifluction have caused severe damage to the roadway surface including cracking, settlement, and subgrade failure. Repairs are planned for the project roadway, with stabilization of permafrost and wetland restoration as priorities for the design. Based on these criteria, Air Convection Embankments (ACE) are proposed. ACE consist of coarse, crushed rock, placed the fullwidth of the roadway embankment. ACE allow convective air movement to occur during the cold winter months, cooling the underlying soils. As the outside air warms, the convective cell shuts down, and the embankment acts as an insulator, maintaining subsurface temperatures during the summer. The ACE also allows surface water to diffuse through the embankment, rather than being captured in roadside ditches and discharged via culverts. Existing and proposed conditions were evaluated using coupled air and water heat transfer methods to develop recommendations for the embankment configuration. Construction is planned to start in summer 2024.

Naturally occurring asbestos (NOA) has been identified in numerous talc deposits within the US which were mined for their talc content. The USGS has identified three primary types of commercial grade talc deposits based upon their pressure (P) and temperature (T) of formation. The Death Valley asbestos-containing talc deposits are classic low-pressure, high temperature contact metamorphic occurrences where basaltic magma intruded as a sill into the Precambrian Crystal Spring dolomite formation resulting in the formation of large mineable talc deposits in the area adjacent to the intrusion. Unfortunately, the contact metamorphism also created abundant fibrous amphiboles including tremolite and winchite/richterite. The basaltic sill extended to and area over over X by Y miles in areas. The area was then subjected to basin and range faulting which exposed large outcrops of the unit. The presence of NOA in the talc is of concern in the products in which it was used, such as joint compound, paint, plaster, ceramics and cosmetics, as well as within the Death Valley National Park should visitors become exposed when visiting the mines.

High Resolution Electron Microscopy (TEM/SEM) Images of Amphibole Fibers and Their Impact on the Definition of Asbestos Bailey, R. Mark, Asbestos TEM Labs, mark@asbestostemlabs.com (TS #6)

Fibrous Minerals of Lakebed and Alluvial Fan Deposits of the Great Basin

Bailey, R. Mark, Asbestos TEM Labs, mark@asbestostemlabs.com; Mark Rollog (TS #6)

Bauer, Jennifer, Appalachian Landslide Consultants, PLLC, jennifer@appalachianlandslide.com; Stephen Fuemmeler, stephen@appalachianlandslide.com; Philip Prince, philip@appalachianlandslide.com; Rebecca Latham, latham@appalachianlandslide.com; Aras Mann, aras@appalachianlandslide.com; Kenneth Gillon, ken@appalachianlandslide.com (TS #12)

A range of fibrous minerals are commonly found in Basin and Range paleo lakebed and alluvial fan environments. Some of these are authigenic, having formed in their present position when the geologic environment was lacustrine, such as fibrous zeolites (e.g. erionite and ferrierite) and fibrous clays (sepiolite, palygorskite/attapulgite, halloysite and imogolite). Additionally, other fibrous minerals, such as amphibole and chrysotile asbestos may have been eroded from metamorphosed and plutonic rocks and washed down by rivers and streams and deposited into alluvial fan and deltaic deposits. And, some fibrous minerals are aeolian in nature having formed elsewhere and blown in from other distant locations. This talk will discuss these

of magnitude to 24MPN/100. This trend indicates that stagnation (up to 391 days) contributed to greater initial concentrations but flushing alone is incapable of complete L. pneumophila elimination at most wells. L. pneumophila concentration was significantly, positively correlated with total aqueous adenosine triphosphate (ATP), turbidity, orthophosphate, and pump depth. After discussing findings with the state regulatory agency, direct-to-distribution wells (38 of 61) remain out of operation and treatment evaluations are underway. Legionella was not detected in surface water, water treatment plants, chlorinated reservoirs, and the chlorinated distribution system. This study emphasizes the importance of utility-driven, non-regulatory research to protect public health and identifies the need for more occurrence monitoring and guidance for Legionella in groundwater supplies.

various forms of fibrous mineral deposition, their occurrence, and the importance of having laboratory analysts knowledgeable in geology and geologic processes to perform sample testing.

AEG 2022 ANNUAL MEETING 62 AEG 65th Annual Meeting Program with Abstracts September 2022

The definition of what makes an amphibole fiber asbestos has been hotly debated for many years. A review of scientific literature containing high and ultra-high resolution images of amphibole fibers, especially as viewed down the fiber (c) axis, has been undertaken. These images show there is an uninterrupted series of fiber cross-section types from prismatic/acicular (so called non asbestos) to rounded (so called asbestos), with different mineral fiber types exhibiting differing degrees of each. Many of these images also show high concentrations of defects and stacking faults within the fibers, leading to significantly disordered crystals which some investigators have chosen to erroneously designate as mineraloids. Other images reveal the transformation in crystal structure caused by retrograde metamorphism which may make an amphibole more or less fibrous, whether altering from pyroxene to amphibole, amphibole to amphibole, or amphibole to a sheet silicate, with the imposition of the higher grade mineral’s crystal structure upon the lower grade alteration product limiting the ability of fibers to exhibit axial fiber rotation. Retrograde metamorphism is also shown to occur unevenly through fibrous amphiboles leading to coatings and intergrowths which have been used to discredit fibrous amphiboles from being called asbestos. Additionally, viewing fibers at high TEM/SEM magnifications can have important implications onwhether amphibole fibers are seen to exhibit various properties such as flexibility, a commonly described property of asbestos. While most commercial laboratories will never observe an asbestos fiber down the fiber (c) axis, understanding what is revealed by these images is key to understanding the problems and challenges of current asbestos definitions, and how they might be improved.

NOA in Death Valley Talc

Bailey, R. Mark, Asbestos TEM Labs, mark@asbestostemlabs.com (TS #6)

Landslide Mapping in Transylvania County, North Carolina –Historic Storms and New Data

Transylvania County is located in the southern part of the North Carolina Blue Ridge Mountains. The Blue Ridge Escarpment defines the southern border of the county (and the NC/SC line), while the high Tanasee and Pisgah Ridges that the Blue Ridge Parkway follows define the northern border. The Brevard Fault Zone extends through the center of the county, contributing to the geologic, and therefore topographic, variability from the north to the south. Furthermore, portions of the county are dominated by intrusive rocks, changing the character of the slopes and hydrology as well. The high relief and steep slopes, combined with weather patterns and tropical systems that track over the WNC mountains, create the conditions for abundant heavy rainfall and the resulting landslides. These landslide-triggering rain events include the storm of record in August 1916, as well as storms in 1940, 2004, and most recently Tropical Storm Fred on August 17, 2021.The North Carolina Geological Survey has contracted Appalachian Landslide Consultants, PLLC, to create a landslide inventory for southwestern Transylvania County. Prior work had identified general locations impacted by the historic storm events. With the use of high-resolution lidar topography (processed to 0.5m DEM) acquired in 2018, along with help from local historians, the potential initiation zones of these historic landslides were identified. The geologic variability of the county offers an opportunity to compare landslide failure modes with lithology and weathering state. Unique hydrologic conditions during high intensity rain events have led to a “blowout” type of slope failure where the ground bursts forth in response to excessive pore water pressure in the subsurface, but leaves no discernible scour downslope. This talk will discuss the results of this mapping project, and opportunities for future research.

The eastern California shear zone (ECSZ) accommodates a significant component of Pacific-North America plate boundary relative motion. However, the width, longevity, and total displacement of this distributed shear zone is largely underappreciated. Here we reconstruct published data that characterize the full extent, lifespan, and evolution of the ECSZ. GPS, seismicity, and neotectonic studies that define the active ECSZ as a ~100 km-wide, NW-trending belt of active faults and rotating blocks that accommodates ~25 percent of dextral plate boundary shear. Our compilation of fault slip and paleomagnetic data indicates ~65–70 km of total dextral displacement across this zone. However, post-middle Miocene NW-directed dextral shear also occurred on structures west and east of the active ECSZ, including the El Mirage fault, Stateline fault, and distributed faults in SE CA and SW AZ. This compilation includes recent and on-going studies that use stratigraphic, geophysical, and fault-zone mineral geochronology to characterize fault histories. Our animated tectonic reconstruction restores motions of fault-bounded blocks since 11 Ma and highlights how an additional ~30–40 km of dextral shear occurred inboard (northeast) of the active ECSZ, across a second ~100 km-wide, NWtrending belt. This reconstruction illustrates how the ECSZ initiated in late Miocene time (ca. 10 Ma) and was originally a >200 km-wide zone of distributed deformation from the San Andreas Fault to the CA-NV border and southwestern AZ. Distributed dextral plate boundary strain has localized into a narrower zone through time, now mostly focused into the ~100 km-wide central part of the ECSZ. Late Miocene initiation of the ECSZ occurred in unison with faults in the Walker Lane to the north and Gulf of California shear zone to the south, during the incipient development of a >2,000 km-long, kinematically-linked belt of distributed dextral shear related to the evolving Pacific-North America plate boundary.

damage and prompted the need for engineering mitigation. Seismic velocity mapping, via refraction tomography and multichannel analysis of surface waves, was used to infer the depth of landslide shearplanes at multiple locations along the southern portion of Scenic Loop road. Subtle velocity variations in the shallow near-surface were observed in both the p-wave refraction and s-wave surface wave analysis results. Strong correlations emerged when comparing the depths of these subtle velocity anomalies to shear-plane depths measured at sites with borehole inclinometers. These correlations persisted at multiple other landslide locations and allowed for the interpretation of landslide shear-planes at sites with limited in situ measurements of slip and slide-planes. The results of the geophysical investigation have been used to inform slope stability geotechnical modeling and the design of roadway repair and slope stabilization in order to reopen the Scenic Loop road.

The Eastern California Shear Zone and Late Miocene Linkages to the Incipient Walker Lane and Gulf of California Shear Zone Bennett, Scott, US Geological Survey, sekbennett@usgs.gov; Michael H. Darin, mdarin@unr.edu; David M. Miller, dmiller@usgs.gov; Rebecca J. Dorsey, rdorsey@uoregon.edu; Skyler P. Mavor, smavor@usgs.gov; Perach Nuriel, nuriel@gsi.gov.il; Lisa A. Thompson, lathompson@arizona.edu; Michael E. Oskin, meoskin@ucdavis.edu; L. Sue Beard, sbeard@usgs.gov; Ryan Crow, rcrow@usgs.gov; Andrew J. Cyr, acyr@usgs.gov; Timothy A. Brickey, tab488@nau.edu; Paul J. Umhoefer, paul.umhoefer@nau.edu (deceased) (TS #3)

With today’s uncertain and evolving climate challenges, understanding the state of groundwater resources at local to regional scales has never been more important. How do we evaluate the quality and quantity of accessible groundwater? How do we collaborate and share these findings with not only geoscientists, but the affected communities in a timely and efficient manner? There is an abundance of moving parts that need to coalesce in order to resolve these complex problems ranging from political policy, data collection/quality control/analysis process, through data management. An auditable and transparent system for model development is imperative for stakeholder buy-in, especially considering the extensive time it takes to implement the scientific process to achieve well-defined results. It can be said with certainty that understanding the underlying hydrogeology is a critical component to discern groundwater quality and quantity. Using the available public data provided by the Division of Water Resources within North Carolina’s Department of Environmental Quality (NCDEQ), a robust and shareable 3D geologic model of the Coastal Plain of North Carolina was produced to help understand and communicate groundwater challenges. This 3D-geological model is implicitly derived from borehole data that can be dynamically updated with the constant influx of new borehole and groundwater analytical data for a perpetually evolving hydrogeologic understanding. Maintaining this model in a user-friendly, cloud-based environment provides an auditable platform for proper data management and efficient model sharing. Interrogating models in an open and publicly shareable 3D environment truly enables curiosity, stakeholder engagement as well as supports a geographical understanding of the hydrostratigraphy. Communication is two-way when utilizing this cloud-based collaboration approach, where comments can be seamlessly passed between technical stakeholders. Overall, this empowers better decision-making for our most precious resource- water; not only on local/meso scales, but regional/macro scales.

Macroscale to Mesoscale. Using 3D Implicit Modelling to Understand Local to Regional Scale Hydrostratigraphy of North Carolina’s Coastal Plain Physiographic Province

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 63

Applying Seismic Velocity Mapping for Landslide Shear-plane Identification, Theodore Roosevelt National Park Bowling, Roy, Collier Geophysics, roy@colliergeophysics.com; Phil Sirles, phil@colliergeophysics.com; Todd Schlittenhart, tschlittenhart@yeh-eng.com; Sam Holder, sholder@yeh-eng.com; Leyla Safari, lsafari@yeh-eng.com (TS #7)

Scenic Loop road within the South Unit of Theodore Roosevelt National Park, North Dakota, circumnavigates thousands of acres of quintessential Dakota badlands. The southern extent of Scenic Loop road is located at the top of steep hoodoos and buttes. These geologic features are comprised of poorly lithified claystones of the Bullion Creek and Sentinel Butte formations and are highly erodible with residual clay soils being dispersive. As a result, roadway damage due to erosion and landsides is common along this portion of Scenic Loop road. Coldpatching and limited remediation efforts have been completed by the National Park Service during the lifetime of the roadway. During the winters of 2019–2020, a portion of the roadway was destroyed by a landslide making the Loop road impassible. This slide is one of many areas along the southern extent of Scenic Loop road where mass movement has been observed and has caused/is causing roadway

Buchanan, Sean, Seequent, sean.buchanan@seequent.com; Thomas Krom, thomas.krom@seequent.com; Mike Ranck, mike.ranck@ncdenr.gov; Laura Quigley, laura.quigley@seequent.com; Geoff Plastow, geoff.plastow@seequent.com; Stephanie Vanos, stephanie.vanos@seequent.com (TS #4) (Presented by Sean Buchanan and Mike Ranck)

In 2013, naturally-occurring asbestos (NOA) was found in Clark County, Nevada, USA (Buck et al., 2013). Unfortunately for potential human exposures to NOA, Clark County is both the most arid and the most populous county in the State of Nevada. Both natural wind erosion and anthropogenic activities increase the potential for NOA to become airborne, and therefore result in human exposures. The primary sources of the amphibole NOA are plutonic and metamorphic rocks, upon which wind and water erosion, transport, and deposition through time have resulted in widespread contamination of the surrounding soils and sediments, including sedimentary rocks. In 2013, the total surface area either containing or likely to contain NOA was estimated to be approximately 214 km2 or 53,000 acres (Buck et al., 2013). Since then, we have continued to map and analyze rock and soil samples using scanning electron microscope (SEM), field emission scanning electron microscope (FE-SEM) with energy dispersive x-ray analysis (EDS), wavelength dispersive electron probe microanalysis, and the Fluidized Bed Asbestos Segregator preparation method. These new data predict that over 1 million acres (~ 4,411 km2), approximately 20 percent of Clark County, contains NOA. Importantly, this estimate does not include areas with NOA-containing eolian deposits. These include vesicular soil horizons, which form at or near the soil surface through dust accumulation and are ubiquitous in arid environments. These vesicular horizons are not likely to contribute to NOA exposures, unless their delicate surface crusts are disturbed. The most common methods by which such crusts are disturbed are human activities such as ORV driving, solar energy development, and housing construction; all of which are increasing in this area with increased population growth. The continued population growth of Clark County Nevada should require increased attention to NOA as part of a responsible land use management plan for this region.

Carlson, Chad, DWR, chad.carlson@water.ca.gov; Andrew Tate, andrew.tate@water.ca.gov; Holly Nichols, holly.nichols@water.ca.gov; Christopher Blozies, blozies@lettisci.com; Hilary Garibay, hilary.garibay@water.ca.gov (TS #14)

Buche, Matt, Gannett Fleming, mbuche@gfnet.com; Casey Smith, casmith@gfnet.com; Rob Clark, rclark@geokon.com; Drew Kennedy, dkennedy@gfnet.com; Darren Mack, dmack@gfnet.com; Trent Dreese, tdreese@gfnet.com; Robert Saber, rsaber@gfnet.com; Jerry Pascoe, jpascoe@gfnet.com; Josh Brown, jbrown@campbellsci.com (TS #10)

past 20 years, we have witnessed an evolution in geophysical instrumentation designed to provide geophysical capabilities to anyone who can push a button…. i.e. automation. Yes, construction workers, unemployed bank tellers, and anyone who can afford these gadgets can be in the geophysics business, locating rebar and utilities, determining V30, or measuring soil resistivity. Fortunately, there are enough sufficiently challenging engineering, environmental, archaeological, and other problems for us degreed professionals to solve. Some of these are “Hail Mary” geophysical applications, requested after other investigative techniques have been ruled out or unsuccessfully attempted. This presentation will illustrate a few unconventional applications of geophysical methods that were used to solve difficult problems, some of which may be contrary to accepted industry standards. These will include concrete investigations between California wine tastings, soil stability surveys in sunny Bermuda, burning landfills south of the MasonDixon Line, and derriere-freezing ice surveys in anything but green Greenland. We will cover GPR, seismic, and ERT geophysical methods.

A Closer Look at Instrumenting Old Casagrande Piezometers with New Vibrating-Wire Sensors

AEG 2022 ANNUAL MEETING 64 AEG 65th Annual Meeting Program with Abstracts September 2022

Observation wells and Casagrande piezometers (or open-standpipe piezometers) are commonly installed in embankment dams for measuring water levels and pore water pressures, respectively, for the purpose of modeling the phreatic surface and flow patterns. Manual measurements of the height of water within the well or piezometer casing are taken using a water-level indicator. For semi-automated or fully automated measurements, vibrating-wire pressure transducers (sensors) can be placed within the well or open-standpipe casing, which is a popular, cost effective application for increasing the value of older, existing installations. Ideally, the manual and sensor measurements are close, and manual measurements can be used to validate the sensor reading. However, discrepancies greater than 1 foot are known to occur, and a better understanding of the causes will benefit the dam safety and monitoring community. This presentation will summarize preliminary results from initial field and lab testing conducted to compare manual vs. vibrating-wire pressure transducer measurements of observation wells and open standpipe piezometers.

As a key component of the State Water Project, the California Aqueduct (Aqueduct) transports clean water 222 miles south across the San Joaquin Valley before being pumped over the Tehachapi Mountains to southern California. Although subsidence has been documented across the greater San Joaquin Valley, several localized areas of subsidence along the Aqueduct have impacted operational flexibility and storage capacity. Some areas of subsidence are up to 6 ft lower than original construction elevations. These areas of subsidence have resulted in the reduction of Aqueduct freeboard (the vertical distance between the water surface and the top of the Aqueduct’s concrete liner), reduced flow capacity of Aqueduct pools, and caused a control structure between pools to become inoperable (a gated weir now permanently open). The California Aqueduct Subsidence Program (CASP) addresses subsidence problems through a mix of preventive and corrective measures and strategic planning. Several CASP projects have used exploration drilling and mapping of the Quaternary sediments underlying the Aqueduct to elucidate the possible cause(s) of localized subsidence and collect geotechnical data for rehabilitation projects. Over 500 drill holes were completed as part of these projects. Geologic and geotechnical data were collected via cone-penetration testing and continuous-core, hollow-stem auger with geotechnical sampling to depths up to 135 feet, as well as hand auger and shallower drilling in potential borrow areas. This data is complimented by geomorphic mapping of alluvial sediments transported into the San Joaquin Valley from the Coast Ranges. These sediments form the foundation under portions of the Aqueduct and characteristics of the source rock may have a contribution to subsidence. This presentation will discuss the methods of exploration, preliminary data collected, and how the results of this work will be used to repair the Aqueduct to ensure safe and effective delivery of California’s water.

Exploration Drilling and Geomorphic Mapping Along the California Aqueduct for the California Aqueduct Subsidence Program

Why not Geophysics?

Update and Overview on Naturally-Occurring Asbestos in Clark County, Nevada, USA Buck, Brenda, University of Nevada Las Vegas (UNLV), buchb@unlv.nevada.edu; Rodney Metcalf, metcalfr@unlv.nevada.edu; Brett McLaurin, bmclauri@bloomu.edu (TS #6)

Carnevale, Mario, Hager GeoScience, Inc., ihagerg1350@earthlink.net (TS

Over#7)the

Overview of the Hydrogeologic Setting of Las Vegas Valley Childress. Jack, Southern Nevada Water Authority (SNWA), Jack.Childress@snwa.comLasVegasValleyisasediment-filled structural trough in southern Nevada partially surrounded by complexly folded and faulted mountain ranges. The primary source of recharge is winter precipitation in the Spring Mountains, with minimal inflows from other hydrographic basins. Groundwater recharge originating high in the Spring Mountains eventually flows east through thick, coarse basin-fill alluvial material until it encounters interfingered gravel and clay that once promoted artesian pressures with hydraulic head well above land surface. Under pre-development conditions these artesian conditions existed throughout large portions of the basin-fill aquifer and numerous springs surfaced along fault lines resulting in diverse vegetated wetland areas within and adjacent to major washes. After the arrival of western settlers, development of the artesian basin occurred through numerous flowing wells which eventually ceased to flow because of unregulated discharge and over-pumping. Modern use of the aquifer continues to this day mainly by water purveyors augmenting their primary supply of Colorado River water. The major outflow of Las Vegas Valley is Las Vegas Wash which flows to Lake Mead as return flow. Most of the discharge in the wash is highly treated wastewater with a smaller component of groundwater outflow. This presentation is meant to be a largely non-technical introduction to hydrology in Las Vegas for the visiting members of the organization new to, or unfamiliar with the area.

“One Foot on the Banana Peel, and Another in the Grave” George Aubin – a Proud Octogenarian Dam Owner!

Alaska has a lot of big things: big mountain ranges, big glaciers and rivers, big bears…but we do not have a lot of big data that cover the state. Out of 665,384 square miles, only a small fraction of the state has lidar coverage. Thus, it was noteworthy when lidar data covering a portion of the Fairbanks North Star Borough (FNSB) in Interior

resistivity tomography (ERT) can be an effective tool to investigate both geologic and hydrogeologic variability in the shallow subsurface. The inverse relationship between conductivity and resistivity allows for ERT to assist in identifying saturated versus unsaturated conditions and to distinguish between various stratigraphy such as sands, clays, and bedrock of varying integrity. Furthermore, ERT testing can help to identify subsurface anomalies that could be considered geo-hazards for exploration activities. This presentation will provide an overview of an ERT testing program implemented at three sites in the western portion of the United States that was used to: 1) Provide a detailed understanding of subsurface geologic stratigraphy (differentiating between sandy soils, bedrock and clay units), 2) Identify the depth of the water table and the transition to saturated conditions, and 3) Delineate and constrain specific aquifer formations. ERT test results were combined with site-specific drilling logs and regional aquifer depth information to establish a more comprehensive understanding of hydrogeologic behavior at the project sites.

Dalal, Visty, Maryland Dam Safety Program, visty.dalal@maryland.gov (TS #8)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 65

An Overview of the First Published Landslide Inventory in Alaska Darrow, Margaret, University of Alaska Fairbanks, mmdarrow@alaska.edu; Jaimy Schwarber, jaimy.schwarber@shanwil.com (TS #5)

Hydrogeologic Characterization of Sand/Gravel Aquifers and Stratigraphic Analysis Using Electrical Resistivity Tomography Cross, Eric, Pyramid Geophysics, eric@pyramidenvironmental.com (TS Electrical#11)

In our profession, we meet a lot of different individuals when regulating privately owned dams that have aged and need repairs and maintenance. Here, I like to highlight one such heartfelt, personal interaction with a proud octogenarian owner, George Aubin, a retired US Navy Veteran (WWII), who built a small dam on his family’s suburban property (fondly called “Candlelight Farm,” where they raised Black Angus cattle, sheep, chickens, and horses) some 40 years ago. With the construction background, Mr. Aubin professed to have built the dam by “shoving the dirt using a bulldozer….” and slipping a pipe through it for water passage. His family and kids enjoyed the farm pond and even had family weddings there. The Aubin Pond is located in Montgomery County, Maryland. In 2006, the downstream homeowners filed a complaint with the Maryland Department of Environment’s Compliance Division/Dam Safety Program (MDE) regarding the safety of the severely eroded Aubin Dam. Upon inspection, the haphazardly constructed dam was determined to be severely eroded, unsafe, and in need of immediate repairs. MDE issued an ‘Administrative Order/Notice of Violation’ to Mr. Aubin and provided a strict timeline to repair or breach the dam. The dam was repaired by a qualified engineering firm by creating a weir-structure in place of the riser/barrel. Mr. Aubin lamented how the structure had stood for over 40 years without any problems but now he was forced to repair it “when I have one foot on the banana peel, and another in the grave”! Mr. Aubin proudly exhibited his newly repaired dam and enjoyed it for another six years.

The Salton Sea Species Conservation Habitat Project was issued by the California Department of Water Resources (DWR) with the goal of revitalizing nearly 3,800 acres of the southernmost portion of the exposed lakebed. The project aims to restore fish and bird habitat and resubmerge the southern shoreline to reduce fine particle dust emissions. In general, the project includes construction of three, large gravity-fed ponds with islands and areas of varying water depths to serve as fish and avian habitat. To maintain water levels and effectively manage sediment accumulation over the life expectancy of the project, project features include perimeter pond berms, a river intake structure, agricultural runoff interceptor ditches, pump stations including a pier structure, a dredge channel, a causeway, maintenance facilities, sediment basins, water conveyance systems, and appurtenances. Geologic hazards such as highly compressible soft sediment deposits, liquefiable alluvial soils, and high site variability set within one of the most seismically active regions in the country presented the project design team with complex geotechnical challenges. The project’s proximity to significant seismic sources such as the San Andreas Fault Zone, Brawley Seismic Zone, and San Jacinto Seismic Zone required a performance-based approach during selection of the earthquake design criteria for the various project features. The presentation will focus on the selection of the seismic design criteria for the project features and the subsequent seismic hazard analyses used to develop design ground motions that informed the design.

Seismic Design Criteria and Soft Sediment Geology in the Seismically Active Southern Salton Sea Corder, Christopher, Geosyntec Consultants, ccorder@geosyntec.com; Madeline Downing, MDowning@Geosyntec.com (TS #13)

Las Vegas Valley has been a long-term southern element of the Walker Lane. Buried elongate northwest-trending pull-apart basins have been identified in northern Las Vegas Valley and are related to the Las Vegas Valley shear zone (LVVSZ) (Campagna and Aydin, 1994; Langenheim et al., 2001). Two strands of the LVVSZ are recognized in the area, named the northern and southern strands. As the LVVSZ evolved, the southern part of the Las Vegas basin was extended, and although activity along the LVVSZ waned in late Miocene, the southern part of the basin has continued to develop into the Holocene. Latest Quaternary fault and fold scarps, paleoearthquakes, and the offset landscape indicate contemporary tectonic activity. Two parts of the LVVSZ are possibly being reactivated, the southern strand within Las Vegas Valley and the Corn Creek Springs area, northwest of the valley. Late Quaternary reverse faults occur near the projection of the southern strand within Las Vegas Valley. All late Quaternary faults of the Las Vegas Valley fault system are truncated by this southern branch, and it may be acting as a transfer fault between this system and the Frenchman Mountain fault. This contemporary configuration would indicate the southern branch is accommodating left-lateral displacement within the basin. It is unclear how much additional contemporary strike-slip activity occurs within Las Vegas Valley. Three local microearthquakes (M3.5–3.6) had strike-slip focal mechanisms. Some smaller late

Geologic Mapping, Geochronology, and Fault Characterization in the Las Vegas Basin Dee, Seth, NV Bureau of Mines and Geology, sdee@unr.edu; Craig dePolo, eq_dude@sbcglobal.net; Shannon Mahan, smahan@usgs.gov; Wanda Taylor, wanda.taylor@unlv.edu (TS #3)

Alaska became available in 2017. These data provided the opportunity to develop the first published landslide inventory map in Alaska. Prior to our efforts, an existing geologic map indicated the presence of one landslide near Fairbanks, Alaska; using the lidar data, we identified 1,679 landslides in the FNSB, and subsequently field-checked 51 of these features. The landslides vary in age from currently active to prehistoric, and predominantly occur in either bedrock or the loess that blankets much of Interior Alaska. We explored one landslide that occurred in loess in more detail, including collecting soil samples, conducting strength tests, and performing a slope stability analysis. This more in-depth analysis suggests that this event occurred as a flow slide sometime during the late Pleistocene to mid-Holocene. Slope stability analysis results indicate that possible triggers for landslide movement include high-pore water pressure – perhaps from thawing permafrost – and/or seismic loading from a large earthquake event. This presentation will provide an overview of the overall mapping protocol employed, examples of landslide morphology and appearance in the field, and a more detailed look at one investigated landslide in loess.

Dee, Seth, NV Bureau of Mines and Geology, sdee@unr.edu; Rich D. Koehler, rkoehler@unr.edu; Austin Elliott, ajelliott@usgs.gov; Alexandra Hatem, ahatem@usgs.gov; Alexandra Pickering, Alijacqueline@gmail.com; Ian Pierce, ian.pierce@earth.ox.ac.uk; Gordon Seitz, Gordon.Seitz@conservation.ca.gov (TS #3)

The new map of the basin was compiled from existing publications and refined using historic aerial photographs, lidar, and a pre-development topographic model. This new mapping improves the accuracy of Quaternary fault locations and yields consistent characterization of surficial units displaced by the faults. The mapping was accompanied by 37 new luminescence ages to better constrain the age of offset stratigraphy. The luminescence data includes ages from the fine-grained ground water discharge deposits of the Las Vegas Formation (LVF) as well as alluvial fan deposits. The LVVFS is a set of intra-basin fault scarps up to 30 m high that displace LVF and alluvial fan deposits within the Las Vegas metropolitan area. Two paleoseismic trenches were excavated across the Eglington fault, the northernmost in the system and the only LVVFS fault with continuous undeveloped scarps. The trenches exposed broadly warped LVF stratigraphy with 4–5 m of displacement and no evidence for brittle faulting. Luminescence and radiocarbon ages constrain the age of warp formation as occurring between ~27 and ~8 ka, with no displacement for the preceding ~300,000 years. The FMFS is a ~33 km long, arcuate, west-dipping, range-bounding normal and dextral-oblique fault on the eastern side of the basin. We conducted a paleoseismic investigation of a previously excavated fault exposure in late-Pleistocene alluvial fans. Logging of the excavation documents evidence for three paleoearthquakes with luminescence ages from colluvial wedge deposits ranging from ~54 to ~25 ka. Scarp profiles conducted prior to widespread development coupled with new ages from displaced deposits yield a preliminary, vertical slip rate estimate of 0.11–0.20 mm/yr.

Field Response and Surface-Rupture Characteristics of the 2020 M6.5 Monte Cristo Range Earthquake, Central Walker Lane, Nevada

AEG 2022 ANNUAL MEETING 66 AEG 65th Annual Meeting Program with Abstracts September 2022

Las Vegas Basin – A Southern Element of the Walker Lane dePolo, Craig, Nevada Bureau of Mines and Geology, eq_dude@sbcglobal.net (TS #3)

The M 6.5 Monte Cristo Range earthquake that occurred in the central Walker Lane on May 15, 2020, was the largest earthquake in Nevada in 66 years and resulted in a multidisciplinary scientific field response. The earthquake was the result of left-lateral slip along largely unmapped parts of the Candelaria fault, one of a series of east–northeast-striking faults that comprise the Mina Deflection, a major right step in the north–northwest structural grain of the central Walker Lane. The field response documented the characteristics of the surface rupture, including distinct differences in the style and orientation of fractures produced along the 28-km-long rupture zone. Along the western part of the rupture, left-lateral and down-to-thenorth extensional displacements occurred along northeasterly and north-striking planes that splay off the eastern termination of the mapped Candelaria fault. To the east, extensional and right-lateral displacements occurred along predominantly north striking planes that project toward well-defined Quaternary and bedrock faults. Although the largest left-lateral displacement observed was ~20 cm, the majority of displacements were < 5 cm and were distributed across broad zones up to 800-m-wide, which are not likely to be preserved in the geologic record. The complex pattern of surface rupture is consistent with a network of faults defined in the shallow subsurface by aftershock seismicity and suggests that slip partitioning between east-striking left-lateral faults and north to northwest-striking rightlateral faults plays an important role in accommodating northwestdirected transtension in the central Walker Lane. Prominent tectonic geomorphology along the unruptured western Candelaria fault (west of the 2020 surface rupture) including linear side-hill benches and troughs and left-laterally displaced channels suggests that potentially larger earthquakes are possible in the Mina Deflection.

A recent investigation into the seismic hazard of the Las Vegas basin includes a new surficial geology and Quaternary fault map, luminescence dating, and paleoseismic investigations of the Las Vegas Valley fault system (LVVFS) and Frenchman Mountain fault system (FMFS).

Quaternary faults may have had strike-slip displacement (e.g., the West Charleston fault zone). There are also some left-steps evident in the Las Vegas Valley fault system that could indicate a right-lateral component. Nevertheless, the basin continues to develop as an extensional area within the southern Walker Lane.

Using Soil Nail Technology for Shorelines and Infrastructure Derby, Martin, GeoStabilization International, martin.derby@gsi.us (TS Geohazards#19)

Probabilistic seismic hazard assessment (PSHA) is conducted at the bedrock conditions for several locations in the study area, and then the possible site has been introduced into the bedrock hazards. The assessment starts with compiling a comprehensive, long, reliable earthquake catalogue. This catalogue was declustered to include only independent events and then tested for the completeness of different magnitude levels. Two seismotectonic models are identified, comprising the delineation of the contributing seismic zones and the estimation of their earthquake recurrence parameters. Proper ground-motion prediction equations (GMPEs) were selected from recently developed, and validated models for the Middle East region to calculate the seismic hazard for 475 and 2475 return periods in terms of hazard curves, Peak Ground Accelerations (PGA), and Pseudo-Spectral Accelerations (PSA) for important response periods for engineers. The site characterization study provides the fundamental (resonance) frequency, Vs30, site classification according to NEHRP site classification, amplification spectra, and the ground surface seismic hazard maps for return periods of 475 and 2,475 years. The highest 5 percent average spectral acceleration is found at 0.2 s with about 414

Derby, Martin, GeoStabilization International, martin.derby@gsi.us; Mark Saunders, mark.d.saunders@wsp.com (TS #5)

Geologic Hazards Associated with Tunneling

Unstable slopes and landslides are having an increasing impact on our infrastructure in the United States. Infrastructure, such as natural gas pipelines, are often located in difficult terrain with poor soil conditions, which are susceptible to potential slope movement (i.e., creep) and landslides. Recent increases and intensity of weather/precipitation have impacted the integrity of pipelines on unstable slopes by the increased soil saturation and porewater pressure in the slope soils. Numerous methods have been developed to monitor both infrastructure and the adjacent slope soils. In situ or geotechnical instrumentation, such as inclinometers, and extensometers have been utilized to measure soil and rock movement for decades. In situ measuring data can be obtained manually at preselected intervals or in “near real time” with web-based deliverables. Recent advances with remote sensing techniques (spatial) and lasers have made it possible to obtain measurements in soil and rock surfaces without in situ instrumentation. Ground-based (GB) InSAR (Interferometric Synthetic Aperture Radar) utilizes microwave technology to continuously scan a slope and

* This geohazard research was funded by the Pipeline Research Council International (PRCI) and published in December 2021.

A 5-mile-long segment of a 12-foot-diameter tunnel was under construction in south San Antonio, Texas in 2021. The depth of the tunnel varies between about 100 to 120 feet. After the tunnel boring machine had advanced only about 200 feet, there was an ignition of hydrocarbon vapors in the tunnel. The due diligence and design documents for the project failed to identify the existence of a shallow, active oil/gas field within and around the tunnel alignment. Oil/gas was being produced at depths as shallow as 385 feet in the vicinity of the tunnel alignment. The source of the hydrocarbon vapors was inferred to be the shallow reservoirs that released hydrocarbon gases to the tunneling interval via faults. A high-resolution seismic reflection survey was promptly conducted. The seismic data were acquired at a density 20 times than that of deep seismic survey. The resulting high-quality urban seismic data allowed identification of six faults including the one encountered by the TBM when the ignition occurred. Although elevated gas vapors were encountered at the other five faults, changes in the tunneling procedures and equipment enabled safe completion of the tunnel.

Geohazard Identification, Monitoring and Mitigation Methods

El-Hussain, Issa, Sultan Qaboos University, elhussain@squ.edu.om; Ahmed Deif, adeif@squ.edu.om; Adel Mohamed, geotec@squ.edu.om; Yousuf Al-Shijbi, alshijbi@squ.edu.om (TS #13)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 67

monitor displacement and velocity in real time. InSAR is a satellitebased, remote sensing technology that can measure ground displacement over large regions. This research project focused on the comparison of several in situ methods and two remote sensing technologies, GBInSAR and InSAR. Geo-monuments (survey points) and extensometers were used to measure the changes in surface movements (i.e., tension cracks) over time, and then compared to GBInSAR data for accuracy. This research project includes a comparison of spatial and in situ monitoring systems that was performed on a steep slope with natural gas pipeline located in the Appalachian region of the United States. The overall objective of the comparison research is to determine the reliability of the remote sensing methods (GBInSAR and InSAR) compared with in situ instrumentation for slope monitoring, that will ultimately reduce risk and increase pipeline infrastructure integrity.

have the potential to adversely impact infrastructure along US waterways. Unstable slopes, seismic, subsidence, and hydrotechnical (water erosion) hazards are just a few types of geohazards that will be discussed in detail. Performing geohazard identification/assessments along shorelines assists owners and operators in determining if a natural hazard may impact their assets. Geohazard monitoring provides the ability for owners to make more proactive decisions regarding various geohazards that may threaten their infrastructure assets and the public. Additionally, geohazard monitoring provides a meaningful decision framework to assess risk and prioritize mitigation efforts. Various geohazard monitoring methods for unstable slopes will be discussed. These methods include in situ or downhole instrumentation (i.e., inclinometers, shape arrays, piezometers, etc.), and surface instrumentation (i.e., wireline extensometers, physical survey markers, GPS, etc.), as well as other advanced remote sensing methods including: InSAR (satellite), ground based InSAR, and lidar (airborne). There are many types of geohazard mitigation methods for unstable slopes. An engineering method to mitigate unstable natural slopes or construct new or over-steepened slopes, include the method of soil nailing. The soil nailing practice involves drilling solid or hollow bar components to depths specified by a geotechnical engineer. The inserted nails are usually grouted and installed at a slight downward inclination, with the solid/hollow bar elements installed at regular spaced points across the slope. Steel-reinforcing rigid shotcrete or flexible wire mesh is often applied as facing to add strength and erosion control. This presentation will include several examples of soil nail mitigation along our US coasts, and rivers as well as an example of a slope mitigation for a stream bank.

Dobson, Mark, DNA Geosciences, Inc., mdobson@dnageo.com (TS #2)

Seismic Hazard Assessment for Selected Sites in Musandam Region, Sultanate of Oman

A Comparison between In situ Instrumentation & Remote Sensing Methods for Slope Monitoring within a Pipeline Right-of-Way

Seepage Investigation of Embankment Dam to Evaluate Potential Failure Modes

Following two large rockfalls that closed US Highway 95, the Idaho Transportation Department initiated an emergency mitigation of the unstable slope that included drilling and blasting of unstable overhangs and removal of debris. The site is mapped as serpentinite, and a comprehensive geologic investigation to assess the distribution of asbestos and other EMP’s was initiated. The rock face was divided into seven zones based on lithology and structure, which revealed blocks of schist and serpentinite separated by three shear zones. Sampling consisted of three samples per zone using incremental sampling protocols. The testing showed that that the schist contained actinolite in concentrations up to 5.8 percent by weight and 2.0 billion fibers per gram (BFG), and hornblende concentrations up to 0.7 percent and 1.6 BFG. In serpentinite, chrysotile was present in one sample at 0.42 percent and 26.7 BFG, and antigorite present as high as 26.3 percent and 19.2 BFG. Petrographic analysis of thin sections indicated that the actinolite/hornblende crystallized in the prismatic, rather than asbestiform habit, and the fibers, as defined by the test methodology, were produced by cleaving. Antigorite appeared to be highly fibrous and asbestiform, but further analysis by TEM indicated that the fibers were

and 730 cm/s2 for the two return periods. The lowest hazard is calculated with PGA of 95 cm/ s2 and 180 cm/ s2 for 475 and 2,475-year return periods and the highest PGA values reaching about 195 and 325 cm/ s2, respectively. Based upon the adjusted hazard values for the site effects at the study area, the design spectral acceleration at short period and at 1.0 sec (SDS and SD1) are calculated and several design response spectra were provided for different hazard levels at the study area.

The Major Causes of the 2020 Flash Floods in the Jakarta Basin, West Java Indonesia

AEG 2022 ANNUAL MEETING 68 AEG 65th Annual Meeting Program with Abstracts September 2022

A spatial and temporal parameterization arrangement of pilot point, grid-scale, and spatially uniform parameters were used to stochastically account for recognized sources of model-input uncertainty during calibration. Sediment properties were calibrated using subsidence data from 82 benchmarks with long-term data, subsidence contour maps, compaction data from 13 extensometers, and vertical displacement data from 178 Global Positioning System sites. The calibrated parameter values were within the ranges of previously published values and agree with the current understanding of the spatial and temporal patterns of parameter uncertainty for the Gulf Coast aquifer system. Preliminary model projections indicate additional subsidence could occur with current groundwater pumping rates with little or no additional water-level declines.

The Gulf Coast Land Subsidence and Groundwater-Flow Model (GULF 2023) and ensemble is a replacement for the Houston Area Groundwater Model used to simulate groundwater flow and land-surface subsidence in the northern part of the Texas Gulf Coast from 1897 to 2018. Since the release of the previous model in 2012 there have been changes to the distribution of groundwater withdrawals and advances in modeling tools. The GULF 2023 model was developed as a Groundwater Availability Model to reflect these changes, simulate more recent conditions, and provide a platform to simulate probabilistic scenarios to evaluate future groundwater availability and land-surface subsidence under various potential future conditions. The GULF 2023 model adopts the more robust MODFLOW6 groundwater-flow code, uses areally-distributed recharge, and includes the new Skeletal Storage, Compaction, and Subsidence Package. Fine-grained sediments in the GULF 2023 model are represented as slowly compacting sediments. The model parameters were estimated using an Iterative Ensemble Smoother (iES) implementation of the Parameter ESTimation (PEST) software PEST++.

Case Study Response to an NOA-containing Rockfall on Highway 95 near Riggins, Idaho in the Western Idaho Ultramafic Belt

4, 2020. According to Time magazine that at least 66 people died due to landslides, hypothermia, drowning, and electrocution.

The GULF 2023 Model and Ensemble: Modeling Advances and Preliminary Results for the Gulf Coast Aquifer System

At a dam in the Southeast US, unknowns with regards to the origins of seepage through the embankment and potential settlement on the embankment’s upstream slope were identified as concerns during a recent FERC Part 12D inspection. To address concerns raised by the inspection team that could be leading indicators of postulated potential failure modes, an in-depth seepage analysis was completed for the site. Parts of the seepage investigation included creating a full 3D model of the impacted area, a geotechnical investigation at the embankment including 16 borings and installation of 16 piezometers, falling head tests on existing and newly installed piezometers, and developing numeric seepage models of two sections of the embankment in GeoStudio SEEP/W. Kleinschmidt Associates used available subsurface information, site drawings, original construction, past geotechnical investigation documentation, and instrumentation monitoring data to develop the seepage model sections. Evaluation of seepage in the embankment and development of the seepage model were complicated by the intricacies in the embankment including historic clay tile drains, retaining wall drains, and the piezometer readings. The seepage model sections were calibrated by varying hydraulic conductivities, applying zero pressure nodes, and/or applying water sources (i.e., influx or infiltration into the model) at selected locations to assess impacts on the phreatic surface and associated total head contours. Exit gradients from the embankment model sections that most closely simulated existing piezometric conditions within the embankment were then calculated to evaluate the erosion/piping potential. Soils tested from the geotechnical investigation allowed for calculation of plasticity indices and uniformity coefficients Cu (D60/D10) to be related to critical gradients and the piping evaluation. This presentation will summarize the steps taken to evaluate the seepage conditions at the embankment, as well as lessons learned throughout the investigation.

Enberg, Tami, Science Teacher, utamienberg@gmail.com (TS #4)

Erskine, Bradley G., CEG & R.; Mark Bailey, mark@asbestostemlabs.com (Presented by Mark Bailey) (TS #6)

Erhart, Emily, Kleinschmidt, emily.erhart@kleinschmidtgroup.com (TS #10)

On January 1, 2020, the devastating flood occurred throughout the City of Jakarta (the capital City of Indonesia and the most populated city in the country). According to the 2020 census, the population in the City of Jakarta was 10.6 million people. Jakarta lies on a low and alluvial plain with extensive swamp and is located at the Northwest coast of the Java Island. One of the major causes of the flood was the heavy rain (According to the Governor Baswedan that about 400 millimeters or 15.7 inches of rain from the New Year’s Eve of 2020) resulting an unexpected runoff to the Ciliwung and Cisedane rivers. Additionally, the high tide coinciding with heavy runoff affected tremendously to the lowlying areas of the city of Jakarta. The National Disaster Management Agency staff said that 400,000 people had been displaced by January

Ellis, John, US Geological Survey, jellis@usgs.gov; Jacob Knight, jknight@usgs.gov; Jeremy White, jwhite@intera.com; Michelle Sneed, micsneed@usgs.gov; Jason Ramage, jkramage@usgs.gov; Joseph Hughes, jdhughes@usgs.gov (TS #14)

Tunnel Symposium Keynote Address: Geotechnical Baseline Reports – A 25-year Critique with Recommendations (aka Lessons Learned and Forgotten)

Historic timber harvesting throughout Northern California has resulted in significant ground disturbance, which has contributed to increased landsliding throughout the region. As a result, legislation aimed at reducing the amount of erosion and sediment delivery to aquatic environments, such as the California Forest Practice Rules (FPR) in 1973 and the Watercourse and Lake Protection Rules in 1983, has been adopted within California. Green Diamond Resource Company (GDRCo), a privately managed industrial timber company in Northern California, adopted an Aquatic Habitat Conservation Plan (AHCP) in 2006 in agreement with National Marine Fisheries Services and United States Fish and Wildlife Service. This agreement provides more stringent regulations on timber harvest activities in areas sensitive to mass wasting. The AHCP details management strategies for landslides identified during Timber Harvest Plan layout, with separate mitigation prescriptions for shallow and deep-seated landslides.Within the Ah Pah Creek drainage, a tributary of the Klamath River on GDRCo ownership, GDRCo geology staff has mapped over 400 landslides using historical aerial photography, lidar interpretation and field reconnaissance. In order to better understand the geomorphic nature of the hillsides in the Ah Pah Creek drainage, we assessed the prevalence of shallow and deep-seated landslides. Preliminary mapping and analysis indicate that shallow landslides are the most prevalent, at roughly 86 percent of landslides mapped within the Ah Pah Creek drainage. When this data was sorted to show only dormant-historic to active landslides, approximately 94 percent of landslides mapped were shallow. By understanding the geomorphic setting with respect to landslide activity and type within the Ah Pah Creek drainage, foresters can implement more efficient landslide identification trainings, and can make better informed management decisions when laying out timber harvest plans.

Essex, Randall, Mott MacDonald, randall.essex@mottmac.com (TS #2)

Faulds, James, Nevada Bureau of Mines and Geology, jfaulds@unr.edu; Christopher Henry, chenry@unr.edu; Rich Koehler, rkoehler@unr.edu; Corné Kreemer, kreemer@unr.edu (TS #3)

The 2019 Ridgecrest, CA, and 2020 Monte Cristo Range, NV, earthquakes were reminders that the Walker Lane (WL) is a fundamental

Dealing with Mother Nature has always been a challenge for underground projects. To confront the upward spiraling of litigation in the 1970s, the underground industry recommended a number of new contract provisions to help resolve and avoid disputes and thereby trim the litigation trend. One of those provisions was a Geotechnical Baseline Report (GBR), which establishes baselines of anticipated subsurface conditions that provide a single interpretation of the subsurface conditions for all bidders when pricing the work, and when evaluating Differing Site Condition claims. Through the years, the speaker has led the preparation of three ASCE guideline publications on GBRs—the first in 1997, a second edition in 2007 (known as the Gold Book), and a third edition to be published this year. The presentation will address some of the key reasons GBRs were initially developed: the GBR’s fundamental role is as a risk-sharing document, what has and has not worked well in the business of writing and applying GBRs, what lessons had been learned and forgotten over the year, and key findings and recommendations in the upcoming third edition of the GBR guidelines publication.

part of the North American-Pacific plate boundary. Since ~30 Ma, western North America has evolved from an Andean-type margin to a dextral transform marked by arc retreat, orogenic collapse, and inland steps of the San Andreas fault system. Late Miocene inception of the WL coincided with a change in relative plate motions, east shift of the southern part of the transform to the Gulf of California, and development of the Big Bend of the San Andreas. Dextral shear was favored in the WL, because it paralleled new plate motion, aligned with the Gulf of California, and bypassed both the convergent bottleneck of the Big Bend and rigid Sierra Nevada block. The WL currently accommodates ~20 percent of the dextral plate motion (~10 mm/yr). In contrast to the continuous 1,100-km-long San Andreas, the WL has shorter discontinuous faults. Progressive NW-younging in onset of deformation (~10 to <4 Ma) in conjunction with a decrease in length of and offset on dextral faults indicate NW propagation of the WL. The WL ends near the south end of the Cascade arc directly inboard of the Mendocino triple junction. Continued northward migration of the triple junction and NW-propagation of the WL suggest that they will intersect off southern Oregon in ~7–8 m.y. The primary plate boundary may then step inland to the WL, similar to the late Miocene shift to the Gulf of California. Thus, the WL provides a superb natural laboratory for analyzing initiation and progressive development of a major transform fault. Integrated analyses of the late Miocene to recent evolution, Quaternary faults, seismicity, and geodetic data are critical for deciphering the progressive development, earthquake hazards, and future evolution of this incipient plate boundary.

The Capitol Hill district in Seattle has undergone extensive redevelopment in the last decade. Along Pike Street there existed several buildings with historic value, but all buildings were one and two stories. One solution was to preserve the existing historic façade and incorporate it into a new, much larger building. One such effort took place at 501 Pike Street. The project faced numerous challenges, including uncontrolled fill in the yard behind the existing building, as revealed by the exploratory drilling. Other challenges were the stabilization of the façade and stabilization and monitoring of adjoining buildings during excavation of underground parking levels. The uncontrolled fill proved to go deeper than the lowest level of the building, and so had to be over-excavated and replaced with controlled density fill. The façade was stabilized with bracing, and the excavation was stabilized with soldier piles and tiebacks. Construction began in August 2014 and continued through June 2015. The excavation and façade remained stable throughout the construction period, and the historic façade is the new partial face of a 7-story mixed use apartment building.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 69

also produced by cleaving rather than parting of asbestiform bundles. An analysis of fiber dimensions was conducted to help predict the risk of overexposure to off-site receptors and workers. The analysis showed that because relatively few of the fibers exceeded 5.0µm in length and/or were produced, on average, in relatively low concentrations (measured in BFG), the potential that off-site receptors and workers would be over exposed to asbestos and other EMP fibers would be relatively low. Perimeter monitoring results (as compared to a project risk-based threshold) and exposure monitoring of workers (as compared to the OSHA PEL) verified low exposures in both cases.

Evans, Stephen, PanGEO, Inc., sevans5cec@gmail.com (TS #20)

Comparison of Shallow and Deep-Seated Landslides on Privately Managed Timberlands in Ah Pah Creek, Humboldt County, California

The Walker Lane: An Incipient Plate Boundary Dissecting the American West and Potential Heir to the San Andreas Fault

Fehrenbach, Anne, Green Diamond Resource Company, Annie.Fehrenbach@greendiamond.com (Poster)

Facades of Futures Past – Reusing Historic Facades

Surface Sinking due to over Extraction of Groundwater: Case Study of Delhi NCR, India Garg, Shagun, GFZ Potsdam, sg2009@cam.ac.uk; Mahdi Motagh, motagh@gfz-potsdam.de; Vamshi Karanam, ar.vamshikaranam@gmail.com (TS #11) (Presented by Mahdi Motagh)

Groundwater Plume Delineation, Comparability of FROG-4000 Split-Sample Analyses of Volatile Organic Compounds

Protection of Homes in Puerto Rico from Massive Rockfall Forsthoff, Brian, Kane Geotech, brian.forsthoff@kanegeotech.com;Inc.,William F. Kane, william.kane@kanegeotech.com; Carlos Rodriguez, suelosinc@gmail.com (TS #13)

AEG 2022 ANNUAL MEETING 70 AEG 65th Annual Meeting Program with Abstracts September 2022

From November 2021 through February 2022, EA Engineering completed real-time delineation of a chlorinated solvent plume in an alluvial aquifer. Samples collected in the 1990s indicated release of the drycleaning solvent tetrachloroethene (PCE) and degradation product trichloroethene (TCE) in groundwater. Vertical delineation was completed with deep wells installed along the longitudinal plume axis. Groundwater samples were collected via push-ahead sampling tool in advance of sonic casing to depths from 212 feet to 392 feet below ground surface. Samples were collected every 20 feet below the water table and analyzed in real-time using a Defiant Technologies FROG-4000 Portable Gas Chromatograph (GC). The real-time analysis allowed EA and the State Regulator to rapidly agree on well design and screen placement for permanent monitoring wells. To verify the accuracy of the FROG-4000 results, duplicate samples were collected for fixed laboratory analysis. Close correlation was found between the results from the FROG-4000 and the laboratory results. This presentation summarizes portable GC protocols for on-site groundwater sample analysis, accuracy of the results based on the split-sample lab comparison, as well as the associated progression of the chlorinated solvent plume delineation.

Finch, Stella, EA Engineering, Science, and Technology, Inc., PBC, sfinch@eaest.com; Teri McMillan, tmcmillan@eaest.com; Jay Snyder, jsnyder@eaest.com; Patrick Bingaman, patb@defiant-tech.com (TS #19)

In July 2021, massive rockfall event occurred along PR-615, Ciales, Puerto Rico. A 6m x 4m x 2.4m rock wedge fell approximately 220m, striking the roadway, bouncing over a fence, and narrowing missing a home. The energy of the rockfall at the road near the house was estimated at 2500-KJ. The failure occurred in the hard, jointed Upper Breccia Member of the Pozos Formation just above its contact with less resistant Blacho Tuff Member. Weathering of the Blacho Tuff has contributed to undermining of the Breccia and resulting in periodic massive rockfall. The steep terrain and dense vegetation prevented collection of structural data on the rock mass. Instead, joint orientations were determined by measuring strikes and dips on the block and rotating those measurements to the in-place orientation of the block. The original position of the block was clearly seen from below and from drone photography. The reconstructed joint data was used for kinematic analyses and rockfall modeling. The modeling programs DIPS and RocFall were used in the data analyses. The Puerto Rico Highways and Transportation Authority authorized the construction of protection for the neighboring homes. Based on the rockfall modeling of the blocks produced from the Breccia, it was determined to construct a 6m high 10,000-KJ barrier on the lower part of the slope above the road in the Blacho Tuff. Designing and constructing foundations and support rope anchors for such a high energy barrier in difficult ground conditions is challenging. A 10,000-KJ barrier is the largest energy rockfall barrier ever designed. Only two such barriers have been constructed in the world so far, in Austria and India.

Gagnon, Hawkins, Schnabel, jgagnon@schnabel-eng.com; Frederic Snider, fsnider@schnabel-eng.com; Dusty Myers dusty.myers@eaglecreekre.com (TS #15)

Swinging Bridge Dam is a 135-foot-high, 965-foot-long hydraulic fill (“puddle core”) dam located in southeastern New York. The dam was built between 1927 and 1930 on a rock and glacial till foundation and began experiencing issues almost immediately after first filling. Those issues culminated in the formation of an approximately 50-foot-wide by 9-foot-deep sinkhole in the crest of the embankment, directly over the penstock conduit, shortly after a record pool event in April of 2005. The lower edge of the upstream edge of the sinkhole settled to within feet of the reservoir. The reservoir was lowered using the second project penstock and emergency monitoring was performed. The dam was rehabilitated from 2005 to 2007. Remediation included a contact grouting program around the perimeter of the penstock and tunnel conduit, installation of a conduit filter at the downstream toe, decommissioning of the damaged penstock, and installation of a downstream filter blanket. Since rehabilitation, anomalous readings have been read in the embankment and foundation piezometers but have largely been discounted as unreliable data. The objective of this presentation is to review the construction history of the dam and to connect the design, construction, and foundation geology to dam performance. This presentation will cover some of the key design elements that are no longer considered best practices (including the use of hydraulic fill dams), properties of the foundation geology that have impacted performance, and the potential warning signs that were exhibited prior to formation of the sinkhole.

Case History of Swinging Bridge Dam – Lessons Learned in Dam Design, Internal Erosion, Rehabilitation, Instrumentation, and Monitoring

Land subsidence is a major problem worldwide and has been documented around the world. It has developed due to coal, and petrol extraction, salt mining, but most commonly due to overpumping groundwater from aquifers. Urban cities like Jakarta, Indonesia; Tehran, Iran; and Delhi, Indiarimarily depend on groundwater for most of their household needs. This induces pressure on the groundwater management system and underground aquifers. In this presentation, we investigated the effects of depleting groundwater levels on land movement in the National Capital Region (NCR) Delhi which is one of the fastest-growing metropolitan cities in the world. Due to rapid population expansion and unplanned growth, there is a huge gap between water demand and supply. This gap is often fulfilled by drilling the bore wells and extracting underground water in huge amounts. The over-extraction of groundwater, particularly from its unconsolidated alluvial deposits makes the region prone to subsidence. We used a satellite-based technique known as Interferometric Synthetic Aperture Radar (InSAR) to monitor the ground elevation changes in the region from 2014 to 2020. Our analysis reveals two distinct subsidence features in the study area with maximum rates of about 17 cm/year in South Delhi, and 7cm/year in Faridabad, Haryana. The subsidence in these two areas is accelerating and follows the depleting groundwater trend. The third region, Dwarka shows a shift from subsidence to uplift during the years which can be attributed to the strict government policies to regulate groundwater use and incentivize rainwater harvesting. The findings of this study are highly relevant for government agencies formulating new policies against the over-exploitation of groundwater and the development of a sustainable and resilient groundwater management system in Delhi NCR.

Remote Rockfall Hazard Mapping in the Arequipa Region of Peru Grady, Cassidy, Department of Geology and Geological Engineering, Colorado School of Mines, clgrady@mines.edu; Paul Santi, psanti@mines.edu; Gabriel Walton, gwalton@mines.edu; Guido Salas, gsalasa@unsa.edu.pe; Pablo Meza, pmezaa@unsa.edu.pe; Percy Colque, scolquer@unsa.edu.pe (TS #13)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 71

best empirical methods to establish the shear strengths of a failed mass is back analysis of failed slopes coupled general HoekBrown criterion. Estimating friction angles analysis can be a challenge at times because we often don’t have the luxury of selecting representative samples for shear testing in the lab. The following is a practical approach that we sometimes forget about. For back analysis, only one strength parameter is typically used, I prefer friction. There are two practical methods that I encourage my team to use when trying to establish a peak friction angle. The first step is to look at your surroundings and ask yourself to what angle the slopes have eroded. In addition, I look at the angle of the talus deposits at the base of the rock slopes. If you recall from your geology class, this is the angle of repose at which the slopes or residual deposits seek equilibrium. The angle of repose represents the minimum angle of internal friction for these materials with cohesion at zero. Next, I encourage my team to select about 50 rock samples from the talus deposit of interest that have similar surfaces, match the surfaces of the rocks, and tilt them till you observe the slightest movement and measure dip angle. I then compare the results of the observed angle of repose observed around you and tilt tests to see if they make sense. I then employ Slide or RocPlane by RocScience®, to estimate the cohesion value assuming the slopes are in equilibrium and at a factor-of-safety of 1.0. The resultant shear strengths are compared to the Mohr-Coulomb equivalent strengths developed using general Hoek-Brown criterion for the rock masses and charts developed by Hoek and Bray (1981) on back analyses of failed slopes of similar material.

HDR was awarded the responsibility of characterizing the subsurface of an 1,800-acre site for an industrial building pad (Greensboro Randolph Megasite) located near Greensboro, North Carolina. The site is in North Carolina’s Piedmont physiographic province, which is comprised of metamorphic and granitic rock types with highly variable weathering patterns and erratic boulders throughout overburden soils in a gently rolling, hilly topographic setting. The top of rock elevation can vary substantially over relatively short horizontal distances. The grading plans for the building pad plan required over 50’ of cut and fill in a significant portion of the project area. Expeditiously characterizing such a large site required utilizing both conventional geotechnical drilling/testing methods and seismic refraction testing. HDR planned and executed approximately 14 miles of seismic survey lines in a grid pattern, with at least 1 standard-penetration-test (SPT) performed per line for correlation of N-values and seismic compression wave velocities. Over 200 supplemental SPT borings were terminated on or in rock. Seismic data was tied to SPT data for increased confidence in seismic interpretations. HDR referenced the Caterpillar Handbook of Ripping (12th Edition) to set a standard for maximum compression wave velocity (6,000 ft/s) for a typical ripping machine (D8 dozer with single ripping tooth). SPT-N values and compression wave velocities were used to establish the boundaries between strippable, rippable, and non-rippable material such that construction costs could be more accurately estimated for site planning. HDR developed 3D models for strippable, rippable, and non-rippable surfaces. Prior to construction, the contractor performed test pits throughout the site along seismic refraction lines and found excellent agreement with 3D surfaces. The quality and resolution of subsurface characterizations was drastically improved by tying seismic to SPT data and by modeling in 3D instead of traditional 2D profiles and cross-sections.

In the Arequipa region of Peru, numerous geoenvironmental hazards impact communities in the mountains, on the coastline, and in the highlands in between. A lack of hazard susceptibility characterization in the region means that there is limited capability to predict and mitigate hazards, leaving communities without the necessary tools to reduce their vulnerability. At present, there are few methods in the literature for efficient mapping of rockfall hazards over large areas that are applicable to a variety of environments. The primary goal of this study is to develop a method to remotely characterize rockfall hazards, using a database of maps created for twelve communities in the Arequipa region. An array of hazard mapping techniques was used to develop rockfall inventories from aerial imagery, followed by field confirmation and supplemented with calibrated rockfall runout models to predict runout distance. For automatic hazard mapping, we will use GIS-based regression models to map rockfall susceptibility. These methodologies will decrease dependence on time-consuming field investigations to characterize rockfall hazards at remote sites, providing preliminary maps that improve upon current approaches in the literature. These methods will be applicable to regions in the world with similar climatic and geomorphic settings as Arequipa. We will use participatory

Practical Estimation of Friction Angles for Slope Stability Analysis

George, Michael, BGC Engineering, mgeorge@bgcengineering.ca; Cole Christiansen, cchristiansen@bgcengineering.ca; Casey Smith, casmith@gfnet.com; Evan Lucas, emlucas@tid.org (TS #15)

Application of the Block Theory Rock Erodibility Method to Evaluate Scour Potential and Risk at the Don Pedro Dam Emergency Spillway

Scouring processes in rock are complex and present several challenges for practitioners to confidently assess scour potential. This is particularly relevant for dams and spillways where scour can pose a significant risk to infrastructure and individuals present in the flood inundation zone downstream. Scour of rock, particularly in unlined channels, is predominantly controlled by removal of discrete blocks of rock by hydraulic forces. Stability of these blocks is largely governed by the orientations of discontinuities within the rock mass, but until recently, no method was available to incorporate 3D orientations of these discontinuities into scour assessment. The Block Theory Rock Erodibility Method is a new, physics-based methodology developed for that purpose of evaluating erodibility of 3D rock blocks subject to hydraulic loading. This presentation provides an overview of the Block Theory Rock Erodibility Method as well as an example application for evaluation of scour potential of the Emergency Spillway at Don Pedro Dam (the 9th highest dam in the United States) located in the Sierra Nevada foothills near La Grange, California. The results of the scour assessment were used to inform a semi-quantitative risk assessment (SQRA) that was performed to identify key risk drivers at the site.

Gates, William, McMillen Jacobs Associates, gates@mcmjac.com (TS One#16)ofthe

Seismic Refraction Testing as a Rippability Assessment and Excavation Estimation Tool Goode, Brooklyne, HDR Engineering, brooklyne.goode@hdrinc.com; Callan Swafford, callan.swafford@hdrinc.com (TS #7)

methods through workshops and interviews in the community of Achoma to develop a final map design that is informed by local knowledge and perceptions. This will allow us to more effectively communicate hazards and create a useful resource for the community. Local leaders, homeowners, government planners, and hazard-focused organizations will be able to use these maps to prepare for hazardous events and develop mitigation strategies at a community level.

Grahl, Dirk, Kleinfelder, dgrahl@kleinfelder.com (Poster)

Greene, Alexander, Geosyntec Consultants, AGreene@Geosyntec.com; Jared Warner, JWarner@Geosyntec.com (TS #19)

A Travelers Tale – Continuity of the Black River and Trenton Groups from Watertown to State College

Large portions of the existing natural gas infrastructure within California are located in or extend through rural and undeveloped natural terrain. Given the increasing propensity for wildland fires (wildfires) within these non-urbanized areas in the western United States and specifically California, existing utility infrastructure is often subject to adverse impacts resulting from post-fire conditions. Within the last few years, significant wildfires such as the Thomas Fire (2017), Woolsey and Hill Fires (2018), Saddle Ridge Fire (2019), Silverado Fire (2020), and most recently the Alisal Fire (2021) have burned across major natural gas transmission corridors or facilities managed by various utility companies. Direct impacts from wildfire to buried pipelines and support facilities are often minimal, however post-fire conditions in high intensity burn areas can result in secondary affects from loss of vegetation and hydrophobic soil conditions for periods of 2 to 5 plus years following a wildfire. These secondary affects may result in Geohazards which can potentially compromise critical infrastructure resulting from landslide or hydrotechnical hazard damage mechanisms such as dynamic loading, impact loading, fatigue, and increased strain from mass movements of soil and debris or water. An extreme example of these secondary affects was observed in the 2018 Central California debris flow event in which large volumes of wood, sediment, and boulder debris adversely affected several pipeline transmission corridors. This presentation will discuss a qualitative approach to rapid hazard assessments for the identification of critical areas of interest using case studies and highlight examples of engineered mitigation.

Geology as Related to Featured Dams and Cofferdams in Western Pennsylvania Greene, Brian, Gannett Fleming, bgreene@gfnet.com (TS #8)

Kinzua Dam is a USACE dam and reservoir located in northwest Pennsylvania on the Allegheny River that flows south to Pittsburgh. Kinzua Dam is a combination concrete gravity and earth-rock fill dam that impounds a reservoir 26 miles long. Siting of the dam was of paramount importance to optimize location of the structure in the Allegheny River valley and to reduce cost. The original siting for the dam was more than a mile upstream of its present-day location. Due to considerable depth to sound bedrock, the original design called for a rather deep excavation with cofferdam construction for a gravity dam. Geologic studies performed by Dr. Shailer Philbrick led to conforming the dam design and its foundation to a much more optimal and cost-effective location. The Kinzua Dam project completed in 1956 was cited as an outstanding example of geology in the Handbook of Geology in Civil Engineering by Leggett and Karrow (1976). Point Marion Lock, originally built in 1926, had exceeded its design life and a new larger lock chamber was needed to improve structural reliability and passage of river cargo moved by barges. The challenge was to build a larger lock chamber on the landward side of the old existing lock chamber. Construction of a similar project had only been attempted once before at Wheeler Lock and Dam, Alabama. As with Point Marion Lock, Wheeler Lock used the landwall of the old lock as a cofferdam for the excavation for the new structure. In 1961, Wheeler Lock failed catastrophically with loss of life and shutting down of the Tennessee River. Taking lessons from this tragic cofferdam failure, the Point Marion landwall cofferdam was stabilized with nearly 500 prestressed rock anchors and was highly instrumented for movement. The project was successfully constructed and was recognized as an Outstanding Project by ASCE.

Debris Flow History of the Montecito Watersheds, Southern Santa Barbara County, California Gurrola, Larry D., The Project for Resilient Communities (TPRC), lg@larrygurrola.com; J. David Rogers, rogersda@mst.edu (TS #12)

Discharge of post-fire debris flows from the watersheds of the Santa Ynez Mountains in southern California devastated the community of Montecito on January 9, 2018. Debris flows paths through the main creek corridors caused 23 fatalities, destroyed or damaged over 500 homes, and closed US Highway 101 for 13 days. TPRC funded a multi-component study with an objective to construct a historical inventory of flood events that records physical evidence of the severity of

The Ordovician-aged Trenton and Black River Groups are a thick sequence of Carbonate rocks that stretch from upstate New York through the Folded Appalachians of Central Pennsylvania. While seldom planned, the travelling life of the consultant geologist often takes us to places where we can see the same groups of rocks, though hundreds of miles separate the investigation locations. In 2017 and 2020 as part of a permitting project, Kleinfelder installed deep core borings and groundwater monitoring wells that penetrated the Trenton group and terminated within the Black River Group near State College, Pennsylvania. Also in 2020, Kleinfelder performed a subsurface investigation for a proposed horizontal directional drill near Watertown, New York. This investigation also penetrated the Trenton Group and terminated within the Black River Group. It is of interest to observe the similarities and differences in lithology and formation thicknesses despite the significant distance between these locations as well as deformation events that have influenced the condition of these rocks. Opportunities for further study may include geochemical characterization of bentonite beds which were observed at both locations.

Post-Wildfire Geohazard Assessments of Impacted Natural Gas Pipeline Corridors

Mitigations Design and Construction Presentation: Geosyntec developed the mitigation design and provided construction management and oversight services during construction of the Parkway Drive Landslide mitigation. This presentation will discuss the mitigation design, which included an engineered fill buttress at the toe of the slide, subhorizontal drains within the slide mass and underlying formational materials to lower the phreatic surface and control active seeps, surface water conveyance features, and tie-ins to existing stormwater infrastructure. It will also discuss the construction phase of the work and some of the associated challenges such as coordination with multiple property owners, working in a residential neighborhood, unknown utilities, and limited access for the construction work.

Parkway Drive Landslide, Evaluation and Remediation –Risks with the Expanding Urban Interface Part II Griffin, Jay L., Geosyntec Consultants, jlgriffin@geosyntec.com; Ronald S. Johnson, rjohnson@geosyntec.com (TS #12)

AEG 2022 ANNUAL MEETING 72 AEG 65th Annual Meeting Program with Abstracts September 2022

Gurrola, Larry D., The Project for Resilient Communities (TPRC), lg@larrygurrola.com; J. David Rogers, rogersda@mst.edu (Presented by J. David Rogers) (TS #12)

damages, inundation paths, meteorological conditions, and type of events, to understand the history of flood events for the last 200 years. Our study is founded on the principle: The Recent Past is the Key to Understanding the Near Future. Historic records establish 22 debris flow, debris laden flood, and outbreak flood events have occurred in the Montecito watersheds including 1825, two events in 1861–62, 1872, 1879, 1884, 1889, 1907, 1911, three events in 1914, three events in 1926, 1964, 1969, 1971, two events in 1995, 2018, and 2019. These events in the Montecito watersheds account for 61 percent of all debris charged flood events (36) recognized in southern Santa Barbara County. Nearly 70 percent of the Montecito events occurred during post-fire watershed conditions establishing the catchments are sensitive to the environmental impacts of brush fires. San Ysidro Creek and Hot Springs Creek watersheds produced the most debris charged floods in the last 200 years. Five large magnitude debris flow and debris laden flood events were identified in the last 200 years including 1825, 1861–62, 1914, 1995, and 2018 which suggests an average recurrence interval of 48 years. The 1825, 1861–62, and 1914 events produced extensive debris flows from most of the watersheds in southern Santa Barbara County. This inventory establishes that debris charged floods occur more frequently than previously realized and often impact the same flow path corridors.

Bedrock Landslides and Historic Outbreak Flood Events, Community of Montecito and Vicinity, Southern Santa Barbara County, California

Groundwater Depletion and Subsidence in Iran: A Country-Scale Hotspot Survey with Sentinel-1 Haghshenas Haghighi, Mahmud, Institute of Photogrammetry and Geoinformation, Leibniz University Hannover, Germany, mahmud@ipi.uni-hannover.de; Mahdi Motagh, motagh@gfz-potsdam.de (TS #14) (Presented by Mahdi Motagh)

Unsustainable groundwater extraction in past decades has been one of the most critical problems facing the arid land of Iran. Declining groundwater levels and space observations of gravity changes show the effects of groundwater mining in different catchments across the country. The negative impacts of groundwater overexploitation and the increased risk of land subsidence due to the decline in water level are critical issues in many parts of the country. While some local studies assessed land subsidence in major cities and agricultural regions of Iran, up-to-date research on the present-day subsidence and its implication for aquifer systems’ hydraulic parameters and aquifer management has not been performed for the country as a whole. In this presentation, we perform a country-scale land subsidence survey using Interferometric Synthetic Aperture Radar (InSAR) by exploiting the entire archive of Sentinel-1 SAR data from 2014 to 2020. Our findings detect more than 300 areas in Iran suffering from long-term subsidence, in some areas exceeding 35 cm per year. Furthermore, by exploiting theoretical relationships between subsidence and hydraulic head decline, we evaluate elastic and inelastic components of aquifer system compaction and estimate storage loss across different catchments. This is the largest survey of land subsidence hotspots in Iran, the results of which could be utilized for future water management strategies in the country.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 73

In previous studies we showed the possibility of using dolomite filters made of compressed powdered dolomite to remove toxic metals from petroleum produced water (PW) at an economic cost. However, those studies were conducted using a single type of metal (Ba). Most studies on toxic metal removal by dolomite have been conducted at low salinity conditions. The aim of this study was to elucidate the feasibility of using dolomite filtration and guar-gum to remove a mixture of toxic metals from PW characterized by high salinity. To this aim, we conducted core flooding experiments and reactive transport simulations to determine the effect of salinity, injection rate, and grain size on the removal of toxic metals. The focus of this study is on PW containing Sr, Ba, and Cd, and on dolomite collected from the Arbuckle Group. We found that salinity (NaCl) has a significant negative impact on the removal of Sr and Ba, but not on Cd removal from PW. This is due to chloro-complexion reactions that reduce the concentration of free metal ions in the aqueous phase, and thus their sorption on dolomite. Like chloro-complexes of metals, guar-gum complexes inhibit Sr, Ba, and Cd sorption reactions on dolomite. Sorption reactions of metals on dolomite are kinetically controlled reactions that are not limited by the availability of pore surface area, but by the retention time of PW in the dolomite filter. An increase in Sr, Ba, and Cd removal by increasing the number (length) of filters suggests that complete removal of these metals can be obtained by optimizing the relationship between the injection rate and dolomite filter size. Our findings have large implications for the establishment of a new economic PW treatment method and the elucidation of the fate of toxic metals present in PW disposed into deep dolomite saline aquifers.

Haji Omar, Khalid, Oklahoma State University – Stillwater, OK, khalid.haji_omar@okstate.edu; Javier Vilcaez, vilcaez@okstate.edu (TS #9 and Poster)

Removal of a Mixture of Toxic Metals and Metalloids from Petroleum Produced Water by Dolomite Filtration

Bedrock landslides mantle the steep slopes of the Santa Ynez Mountains in southern California and pose a significant hazard to the downstream community of Montecito which is developed on the coastal bajada. The watersheds are underlain by erodible Tertiary sedimentary rocks, and combined with high uplift rates, create steep terrain that are conducive to bedrock landslides, many of which formed landslide dams. TPRC funded a study following the January 9, 2018, debris flows to identify sites for debris catchment basins along the principal watercourses, and parts of this study include the historical inventory of outbreak floods and geomorphologic analyses to assess the hazard posed to Montecito. Ten historic landslides identified in the last 160 years blocked the main or tributary drainages and created dams that formed temporary lakes. The dams were overtopped or breached within 12–24 hours and produced amplified, debris charged outbreak floods inundating Montecito. One of the largest landslides mapped in this study occurred in 1909 which diverted Cold Springs Creek approximately 200 feet. Intense, sustained rain in 1914 remobilized the slide forming one of several landslide dams in the 1914 debris flow event. An observer described a downstream sequence of collapsing dams that created a cascading flood wave of log and boulder debris causing severe destruction to Montecito. Forensic observations after the event also confirmed the presence of landslide dam remnants in the watersheds. Geomorphologic evidence includes landslides that pinch channels, deflected flow paths, and coincident knickpoints. Active undercutting and channel incision often expose basal slip surfaces priming slides for reactivation and increasing the likelihood of forming multiple dams over time. The potential for catastrophic outbreak flood waves appears to increase under post-fire conditions. Landslide dams increase the peak flood flows and volume of mobilized debris, significantly elevating the flood and debris flow hazards to Montecito.

cover large areas or long corridors with minimal additional effort. When combined with design alternatives assessments, the decision maps produced using our method help GAM teams prioritize their geohazard remediation efforts, optimize budgets, and ensure public and environmental safety.

AEG 2022 ANNUAL MEETING 74 AEG 65th Annual Meeting Program with Abstracts September 2022

Using GIS, Remote Sensing, Machine Learning, and Multi-Criteria Analysis to Prioritize Geohazard Risks

Haugen, Benjamin, Geostabilization International (GSI), benjamin.haugen@gsi.us; Lex Ivey, lex.ivey@gsi.us; Cody Stopka, cody.stopka@gsi.us (TS #13)

Rockfall is a prevalent geologic hazard that affects road systems throughout the United States. The state of Alaska contains several highway locations that are impacted by frequent rockfall activity. This research compares two slopes within the Nenana Canyon in the Alaska Range. The western slope is natural, with the Nenana River flowing along its base; the eastern slope was cut back to accommodate the construction of the Parks Highway. We used the computer programs ArcMap, CloudCompare, and Rockfall Activity Morphological Bigdata Optimizer (RAMBO) to compare historical aerial imagery and repeat terrestrial lidar scans of both slopes. In ArcMap, we created polygon shapefiles that outlined the active and prehistoric rockfall extents depicted in aerial images spanning 1957 to 2008. With this method, we correlated slope disturbance to construction in the early 1970s. We used both CloudCompare and RAMBO to process and analyze the lidar data collected from 2013 to 2021. These data were integral in completing a change detection analysis and calculating the failure rates for comparable slopes on both sides of the river. The analyses indicate that the east side of the river is more active than the west. Visually, both slopes are experiencing rockfall activity, but we postulate that the higher rate of failure of the eastern slope is due to the significant increase in the active area resulting from slope modification during construction. This work will contrast rockfall activity on both natural and anthropogenically-modified rock slopes, providing insight into the controls on rockfall hazards to inform engineers and geologists managing infrastructure.

The village of Laprak was built on a dormant landslide at an elevation of about 2200 m above sea level in the Gorkha District of north-central Nepal. Part of the landslide was reactivated during unusually heavy summer monsoon rains in 1999 and movement continued intermittently during wet years, claiming one life, a few buildings, and several hectares of cultivated land. Field-based investigations and slope stability analyses during the subsequent decade showed that the landslide occurred in a structurally controlled wedge of colluvium that would be susceptible to future movement during periods of high pore-water pressure or seismic shaking, with the worst-case scenario comprising a major earthquake during the summer monsoon season. The buildings of Laprak were reduced to rubble during the 2015 Mw 7.8 Gorkha earthquake, the epicenter of which was located about 6 km from the village, which gave rise to an estimated 1.29 g PGA and 116 cm/s PGV at Laprak. Post-earthquake field visits and preliminary examination of before-and-after satellite images suggested little downslope movement had occurred; more detailed kinematic analysis revealed a complicated pattern of approximately 80 cm of downslope movement that extended upslope and significantly beyond a head-scarp mapped after the 1999 reactivation. To better understand why a known landslide moved such a small amount in response to such a large earthquake, we performed a series of Monte Carlo simulations using six previously published simplified Newmark models of coseismic displacement, geotechnical properties from our pre-earthquake investigations of the landslide, and an inferred distribution of physically plausible pre-monsoon pore-water pressures. Five of the six models produced results in good to marginal agreement with our satellite image results, as did a seventh composite model, suggesting the comparatively gentle topography and low pre-monsoon pore-water pressures provide a geomechanically reasonable explanation of the observed coseismic movement.

Laprak Revisited: Understanding the Response of a Large Himalayan Landslide to the 2015 Gorkha Earthquake Haneberg, William, University of Kentucky, bill.haneberg@uky.edu; Sarah E. Johnson, johnsonsa@nku.edu; Narayan Gurung, jyonus@hotmail.com (TS #12)

Best practices in Geotechnical Asset Management (GAM) have started to place more emphasis on debris flow, rockfall, avalanche, and landslide risks. Unfortunately, incorporating geohazards into GAM programs can be difficult because they often initiate outside right of way extents, are obscured by vegetation or terrain, or are only identified when infrastructure damage has already occurred. We have developed a GIS- and remote sensing-based approach to help asset managers identify, characterize, and prioritize geohazard risks using customizable multi-criteria analyses. Data inputs typically include RGB, infrared, and/or multi-spectral imagery, lidar or photogrammetric point clouds, and available ground-based observations and instrumentation data. From these data, multiple parameters can be derived, including textural and structural geology information, vegetation health indices, slope geometries, and measurements of the infrastructure itself (e.g., sight lines for motorists on a roadway). The parameters are then weighted and combined to create ‘decision maps’ that identify high-risk areas. We use machine learning to automate portions of our analyses (e.g., identifying rockfall source areas based on textural or structural features), which enables our analytical process to be scaled up to

Advantages of Multiple Geophysical Methods at Pre-1970 Dams Hempen, Gregory, EcoBlast, LC, greg@ecoblst.com; Ahmed Ismail, ahmed.ismail@okstate.edu; Daniel A. Laó-Dávila, daniel.lao_davila@okstate.edu (TS #7)

Analysis of the Long-Term Effects of Construction on Rockfall along the Parks Highway, Alaska Herrman, Daisy, University of Alaska Fairbanks, dmherrman@alaska.edu; Margaret Darrow, mmdarrow@alaska.edu; Michael Olsen, olsen@oregonstate.edu; Joseph Wartman, wartman@uw.edu; Ben Leshchinsky, ben.leshchinsky@oregonstate.edu (Poster)

Dams designed before the 1970s seemed to have less geological input to the design than more recent practice. Geophysics played an even smaller role in older dams’ construction. When these older dams have their periodic inspections or design reviews, adequate geologic data may not exist from the original design, or the construction and engineering data may not have been fully retained. A multitude of surficial and overwater geophysical procedures have been continually improved that may allow geologic investigations of older dams to be less extensive, more solution oriented, shorter in duration, and less expensive. These investigations certainly require the ground truth of geologic data and engineering testing, but would likely benefit from the acquisition of geophysical interpretation to guide the acquisition of expensive facts. Some of the issues of these older dams may include: unconsidered design elements or structural revisions for additional project purposes, revised state-of-practice or regulatory considerations, project revisions to improve operability or lower maintenance costs, karst or karst-like erosion or releases, outlet erosion, and, poolsediment accumulation. The broad range of beneficial geophysics utilized at a southern dam will be presented.

In early December 2020, heavy rainfall triggered a series of landslides around the community of Haines in Southeast Alaska. The landslides destroyed roads and houses and killed two people. As part of an NSFfunded research project, a joint research team from the University of Alaska Fairbanks and the Natural Hazard and Disaster Reconnaissance (RAPID) facility at the University of Washington traveled to Haines to collect perishable data in and around several of the landslides. Included in this data collection were scans of landslides in the greater Haines area, taken with a terrestrial scanning lidar system. The scans covered areas where roads and buildings were impacted by different forms of mass movement. Analysis of this data will help inform residents of the risk of future landslide events in this area. In between the exciting field visit and interesting analysis of the data is an often overlooked and tedious step: data processing. Data processing is necessary to transform sometimes messy field data into an accurate product that can be used for geological or engineering analysis. We are using MapTek Pointstudio to compile the collected lidar point clouds and to conduct quality control/quality assurance before the data are converted into digital elevation models for analysis. The data we were dealing with were centered in two areas: we have nine scan locations of an area where a debris flow covered Lutak Road and seven scan locations where a sand flow destroyed a house along Lutak Spur. This presentation will detail the process of compiling multiple point clouds into useful data and summarize some of the potential challenges along the way.

ArcGIS for Geohazard Inventory, Analysis, Site Design, and Mitigation

Land Subsidence in Wuhan, China: Monitoring, Driving Factors and Risk Assessment Hu, Jiyuan, College of Geography and Environmental Science, Henan University, plgk@whu.edu.cn; Motagh Mahdi, Motagh@gfz-potsdam.de; Qin Fen, qinfen@henu.edu.cn; Guo Jiming, 40150028@henu.edu.cn

While Geographic Information Sciences has been integral for a plethora of land use, geologic and engineering applications around the world, utilization of ArcGIS for geohazard inventory, analysis, planning, and mitigation is often underutilized. By developing a single source application (ArcGIS) to incorporate existing land records, aerial remote sensing, and field data collection, has become Brierley’s primary platform for geohazard investigation and mitigation which continues to provide numerous valuable tools that our team and clients have relied on for several years This presentation will discuss Brierley’s approach to spatial inventory, analysis, and mitigation planning, specific to subsidence occurrences within the state of Wyoming.

Horning, Kayla, University of Alaska Fairbanks, khorning2@alaska.edu; Margaret Darrow, mmdarrow@alaska.edu; Matthew Encelewski, mtencelewski@alaska.edu (TS #5)

is facing severe consolidation subsidence of soft soil and karst collapse hazards. Through a combination of multiple Synthetic Aperture Radar (SAR) data from Sentinel-1 and TerraSAR-X satellites, this study evaluates ground deformation in Wuhan and assesses its driving factors based on spatial variation analysis of the geological conditions. We also produce a risk map using Analytic Hierarchy Process (AHP) and Logistic Regression (LR) to quantify the level of risk posed by land subsidence to existing infrastructures in the city. An integrated analysis using remote sensing and hydrgeological measurements resulted in the following findings: We detected two governing subsidence mechanisms in Wuhan, namely, soft soil consolidation subsidence in non-karstic soft soil areas, and karst subsidence in well-developed karst areas. The first mechanism is observed in Hankou, Xudong-qingshan, and Jianshe-Yangluo zones, while the second mechanism is found in the Baishazhou-Jiangdi zone. Spatial variation analysis of the geological conditions indicates that the stage of karst development plays the most important role in influencing kart subsidence, followed by municipal construction, proximity to major rivers, and overlying soil structure. Both AHP and LR risk models perform well in identifying high-risk zones with only a 3 percent discrepancy in area. However, for the medium-and low-risk classes, risk zoning results from the above models show similar spatial distribution but with varying spatial extent.

Mosul Dam Foundation and Emergency Grouting Hlepas, Georgette, US Army Corps of Engineers, Georgette.Hlepas@usace.army.mil (TS #10)

As an extension of a Pilot Program conducted by Brierley Associates during the Summer of 2019, there was question as to whether or not void fill grouting as a means of subsidence mitigation was feasible in an area known to exhibit high artesian head pressures. This pilot program provided the foundation and methodology to create a design approach to alleviate any potential risk of abandoned coal mine mitigation to the densely populated overlying subdivision. After extensive analysis of this pilot study, a specialty design was created for mitigating the mine immediately below the sub-development in question taking place during the Summer of 2021. This presentation covers surface and subsurface controls to handle high artesian head pressures and groundwater while mitigating underground abandoned coal mines in a densely populated subdivision.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 75

(Poster)Wuhan(China)

Hibbard, David, Brierley Associates, dhibbard@brierleyassociates.com; Josh Zimmermann, jzimmermann@brierleyassociates.com; Cole Archer, carcher@brierleyassociates.com (TS #14)

Abandoned Coal Mine Mitigation in High-Pressure Artesian Conditions

Mosul Dam was built on a complex foundation including soluble gypsum material. Without continuously maintained grouting, the project is susceptible to seepage and piping through the foundation. Although subsurface exploration programs were conducted during the original design and to support limited studies undertaken prior to 2016, the extent of solutioning of the foundation was not adequately understood to allow for meaningful understanding of the project’s risk of failure. Data was especially limited on the subsurface conditions outside the centerline of the dam. From 2017–2019, the US Army Corps of Engineers led investigations to further define subsurface conditions along the dam axis as well as downstream and at the abutments. Subsurface information obtained from a variety of available technologies to better define the geologic conditions at the project. Instrumentation and monitoring at the project was vastly upgraded and helped guide subsurface investigations. Subsurface exploration along with emergency grouting and instrumentation data were used to guide the foundation grouting program and verify its satisfactory implementation. A Site Information model was developed and used to aid in compilation of data sets and communication of results. This presentation summarizes the results of the subsurface investigations, extent of deteriorated foundation conditions, and their relationships to project potential failure modes as well as the challenges on site and the conclusion of the work performed.

Hibbard, David, Brierley Associates, dhibbard@brierleyassociates.com; Ike Isaacson, iisaacson@brierleyassociates.com (TS #19)

Watching Paint Dry: An Overview of Lidar Data Processing

Development of Deep Seismic Velocity Profiles for TVA Dams: Data Compilation, Facies Analysis, and Depth Correction for Shear Wave Velocities

Analyses of Spring Water Chemistry and Microbiology in the Spring Mountains, Nevada

Hyskaj, Ambra, Department of Mineralogy, Eötvos Loránd University, ambra.hyskaj@ttk.elte.hu; Erzsébet Harman-Tóth, celadonite@gmail.com; Tamás G. Weiszburg, glauconite@gmail.com (TS #6) (NOA) is mostly present in ophiolitic settings, identified asbestos outcrops in Albania remain a possible hazardous material exposure source even though asbestos-related mining activity had never been performed, only exploration took place in 1966–1990 for the then needed material. Both serpentine (chrysotile in Buces, Gomsiqe, Qarrishte) and amphibole (tremolite in Boboshtice) asbestos were identified. Chrysotile is found closely related to pyroaurite-2H (Mg6Fe3+2(OH)16(CO3)x4H2O and brucite (Mg(OH)2) located in the Gomsiqe ultramafic massif (western Mirdita ophiolite belt). The three minerals show intimate intercalation in slip-fibre arrangement while frequent chrysotile cross-fibre veins are most cases present. Pyroaurite-2H is aligned parallel to the chrysotile slip-fibres, being distinguished by its characteristic goldbrownish colour and platy morphology, while brucite intergrowth is present in more than one direction. Whether harmful or not, the presence of other elongated mineral particles (EMPs like fibrous brucite) brings challenges in evaluating chrysotile occurrences. Quantitative

Hunnicutt, Shawna, Nevada State College, hunnicutt.shawna@gmail.com; El Hachemi Bouali, elhachemi.bouali@nsc.edu (TS #9 and Poster)

Tennessee Valley Authority (TVA) Dam Safety developed shear wave velocity (Vs) profiles that extend from the base of each dam to crystalline basement rock as part of a recent inventory-wide PSHA update; these profiles are necessary to scale ground motions produced for the reference rock site profile (i.e., top of crystalline basement) to the foundation level of each site. Site Vs profiles were developed using: 1) balanced geologic cross sections based on regional and 1:24,000-scale geologic mapping and data from regional and site-specific investigations, 2) shallow Vs data from P-S logs acquired at each dam, and 3) Vs from publicly available deep boreholes. One of the challenging aspects of this project involved the potential presence of thick shale units at depth. In particular, Conasauga Group rocks throughout the Tennessee Valley exhibit pronounced facies variations (shale versus carbonate) across the region. This could result in potentially thick, low velocity units that would strongly influence the resulting Vs profiles and site amplification. Additionally, Vs in shale is dependent on depth (higher Vs with increased confining pressure). The relative amount of shale to carbonate in Conasauga Group rocks was qualitatively determined for each cross section. Cross sections in the eastern part of the Tennessee Valley typically include repeated layers of Conasauga Group rocks in successive thrust sheets that were deposited at different positions along the Laurentian margin (i.e., potentially different lithologic facies). This analysis utilized limited palinspastic restoration of foreland fold-thrust belt sections to determine the position of strata along the continental margin prior to late Paleozoic shortening, and also used existing geologic maps to inform the lithology of the rocks in each thrust sheet. Vs adjustment factors for shales were determined using measured shale Vs from deep commercial boreholes, and adjustments were applied to shale units based on regional facies determinations.

Hughes, Joseph, US Geological Survey, jdhughes@usgs.gov (TS #14)

The Spring Mountains are an isolated mountain range located in the northern section of the Mojave Desert. It is a range known for its diversity, which is sustained by the approximate 300 springs that populate it. Because of the uniqueness of the Spring Mountains, emphasis should be placed on the ecological health of the springs, which has not been extensively studied for many years. However, due to increased recreation to the Spring Mountains, the springs are facing new disturbances; this poses an issue because there are few references for what the health of the springs were in the past. This poster will present preliminary results from ongoing research. Spring water samples collected throughout the Spring Mountains are analyzed with a variety of methods. Living microorganisms in the spring water are studied by isolating microorganisms from each water sample, creating bacterial cultures, identifying them using 16S rRNA amplification, and sequencing them. Water chemistry of the spring water is quantified using general parameters like water temperature, pH, salinity, alkalinity, conductivity, total dissolved solids, dissolved oxygen, and turbidity which are measured with a desktop multimeter. Relationships between microbial communities and water chemistry are investigated at each spring and across multiple springs. Future deliverables may include an inventory of microorganisms, community comparisons and overlap tests of spring microbiomes, and correlation to groundwater models generated in a geographic information system (GIS) to show how the springs could be interconnected and what influence that may have on microorganism communities and water chemistry.

Textural Arrangement of Naturally Occurring Asbestos with Accompanying Minerals in the Albanian Ophiolites

Simulating Aquifer-System Deformation in Response to Groundwater-Level Changes in Unconfined Conditions with MODFLOW 6

simulation of aquifer-system deformation in response to water table changes. The Newton-Raphson formulation can also be used simulate the continued drainage of slowly draining fine-grained material above the water table. Examples will be presented that demonstrate use of the CSUB package to simulate 1) elastic and inelastic deformation of aquifer-system material in water table conditions; and 2) inelastic deformation of fine-grained material above the water table and the resulting contribution to water table recharge.

The skeletal storage, compaction, and subsidence (CSUB) package for MODFLOW 6 can be used to simulate deformation of aquifer material in response to effective-stress change. Calculations in the CSUB package are based on Terzaghi’s elastoplastic model that relates effective stress to 1D deformation. Effective-stress changes in aquifersystems are commonly the result of groundwater-level changes. Deformation that reduces (compaction) or increases (expansion) the thickness of aquifer materials reduces or increases the volume of water that can be stored in an aquifer-system, respectively. When the CSUB package is used, it accounts for all aquifer-system storage change in the model; this includes storage changes that occur as coarse-grained material deforms elastically, fine-grained material deforms elastically and inelastically, and water compresses and expands. Fine-grained material in an aquifer system can be represented as units that drain quickly and maintain equilibrium with the surrounding coarse-grained material or units that drain slowly and are in disequilibrium with the surrounding coarse-grained material. Individual fine-grained units that drain slowly and have the same hydraulic properties can be represented as a single equivalent unit to simplify model setup and reduce simulation runtimes. A Newton-Raphson formulation of Terzaghi’s elastoplastic model is available in the CSUB package for

AEG 2022 ANNUAL MEETING 76 AEG 65th Annual Meeting Program with Abstracts September 2022

Huebner, Matthew, Tennessee Valley Authority, mthuebner@tva.gov; Joshua Shinpaugh, jeshinpaugh0@tva.gov; Jeffrey Munsey, jwmunsey@tva.gov; Husein Hasan, hahasan@tva.gov (TS #15)

evaluation of asbestos content in a rock body is biased by an intimate textural arrangement of similar minerals at a time when we still lack comprehensive standards and analytical methodology on NOA identification and management. Albania, just as several countries in Europe, demonstrates a NOA recognition gap, accompanied by a consequent lack in the legislation to prevent 1) unnecessary human exposure to hazardous natural materials and 2) environment quality degradation due to increasing asbestos concentration in air, water and soil due to human activities. The presentation gives a short overview on the current legislative background of NOA in Europe, too.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 77

A Case History of Aquaculture Litigation

Parkway Drive Landslide, Evaluation and Remediation –Risks with the Expanding Urban Interface Part I

In 2014 the Parkway Drive Landslide occurred in dramatic fashion destroying several structures in a hillside development of North Salt Lake, Utah. Historical land use included decades of aggregate mining and in the more recent years, development progressively moved into the foothills where the area was sculpted to accommodate the urban interface. The landslide provides several excellent examples of how geological conditions, when combined with decades of anthropogenic influences, result in the initiation of the mass movement and ultimately the loss of property. This presentation will provide an overview and details of the historical and local geological setting, a review of causal factors and associated analyses and instrumentation, development of mitigation solutions and related analyses, and implementation and construction of the landslide stabilization.

The design of surficial stormwater infrastructure often hinges on the results of hydrologic models focused on the rainfall, runoff, and routing of stormwater through a system. Sophisticated coupling of surfacegroundwater interactions is often limited due to modeling constraints, the complexity of area-wide subsurface characterizations, or overlooked due to the relative magnitude of seepage contributions versus overall rainfall runoff. Moreover, identifying situations when surficial drainage design must include seepage interactions can be challenging for water resource engineers who may lack the awareness, experience, or expertise to properly consider or characterize advanced hydrogeologic conditions. This presentation summarizes the findings of a peer review for a regional drainage infrastructure project on the protected side of a levee system adjacent to the Ohio River. With an area seepage study already completed in the area, a request was made by the levee sponsor to determine the potential impact, if any, that local groundwater seepage forces due to Ohio River flood events may have on a proposed channel designed to convey regional surface water. First, this presentation will summarize the findings of the multi-phase seepage evaluation of the levee system which incorporated geotechnical and geophysical investigations with an extensive monitoring network to calibrate advanced hydrogeologic models of stream-aquifer interactions. Next, these results were incorporated into an evaluation of the drainage design to determine potential failure pathways due to heaving, piping or unaccounted for seepage flows. The study concluded that the channel design did not adequately account for seepage forces and described potential implications along with recommending additional design considerations. This assessment highlights the need for better collaboration between geological and water resource professionals particularly in areas where stream-aquifer interactions are critical but may not be readily apparent, such as areas protected by levees but well beyond the immediate vicinity of the levee itself.

Joshi, Ajit, Department of Environment Systems, Graduate School of Frontier Sciences, The University of Tokyo, ajoshi@edu.k.u-tokyo.ac.jp; Masaatsu Aichi, aichi@k.u-tokyo.ac.jp; Tomochika Tokunaga, tokunaga@k.u-tokyo.ac.jp (Poster)

Man-controlled planting and harvesting of marine life (i.e., “aquaculture”) has become a viable, lucrative practice throughout the world, as well as in the United States. One site in Coastal Alabama was recently involved in litigation, however, where the owners alleged a “milliondollar loss” was caused by the State of Alabama “recklessly” allowing dredged mud generated during enlargement of a 52-acre wetland habitat to impact their site. Bottom sediment in Mississippi Sound was obtained by dredging from a site approximately 1 mile south of the habitat and it was argued that a significant quantity of the estimated 637 thousand cubic yards of dredged sediment that was pumped to the island restoration site “escaped” and was transported as plumes of suspended sediment and fluid mud flow along the bottom northward 3.5 miles to the aquaculture site. There it became “resuspended” and settled “smothering” the recently planted oyster spat (eggs), destroying the farm. Evidence produced by the defense, however, completely refuted this allegation. Published information from NOAA disclosed that the dominantly westward current directions of water flow in Mississippi Sound, as well as ambient wind directions, would render such “northward” transport of any significant quantity of “remobilized” sediment from the borrow site highly improbable. Further, mineralogical evidence from samples collected at, and near, the aquaculture site provided irrefutable evidence that the source of contaminating mud was discharge from the proximal Fowl River. This river’s mouth is located less than 1000 feet from the oyster reef and both XRD information from the clay fraction and detrital heavy mineral data conclusively show that the overwhelming source of sediment at the aquaculture site is discharge from nearby Fowl River. When apprised of this, the plaintiff grudgingly agreed to a “token settlement” offered by the State thereby eliminating any need for actual trial.

Johnson, Ronald, Geosyntec Consultants, rjohnson@geosyntec.com; Jay L. Griffin, jlgriffin@geosyntec.com (TS #12)

Anomalous Rate of Subsidence at Early-Stage of Groundwater Pumping from Subsurface Heterogeneous Aquifer/Aquitard System

Sediment heterogeneity, such as variation in grain size and clay content in a subsurface aquifer, can alter hydro-mechanical properties of the medium which can affect groundwater flow and deformation of the medium. Presence of such depositional structure-scale heterogeneities in a subsurface aquifer/aquitard system can be important in analysis of groundwater extraction related land subsidence. A coupled 2D numerical model for flow and poroelastic deformation of a water-saturated geologic medium was developed, and heterogeneity in a medium was modeled using a porosity-permeability relationship, which was represented by the Kozeny-Carman equation, and an exponential relationship for porosity-drained modulus obtained from field data for marine sediments. Results showed that pressure drawdown in a sandstone aquifer with little clay content, interbedded with low-permeability mudstone aquitards, resulted in a wider and larger subsidence zone than

Wind, Water, and Slope. Taken Together They All Say “NOPE”!

Isphording, Wayne, Tierra Consulting, isphordingw@bellsouth.net (TS #9)

Advanced Monitoring/Modeling of Surface-Aquifer Interactions of a Levee System and Infrastructure Design Implications Johnstone, Luke, Mundell & Associates, Inc., LJohnstone@mundellassociates.com; John A. Mundell, JMUNDELL@mundellassociates.com; Tyler Balson, TBalson@MundellAssociates.com; Forrest Kunkel, FKunkel@mundellassociates.com (TS #10)

efforts. Geosyntec has completed PFAS investigation and sampling at one site in Nevada, along with various locations throughout the United States. This presentation will summarize the evolving status of site investigation techniques (decontamination process for drilling, various groundwater sampling techniques pros and cons, and potential sampling biases to consider), analytical methods, and lessons learned (importance of identification of “clean water source” and schedule considerations for sampling setup and decontamination) from completed assessment projects for planning purposes.

The geosciences have a long history of the lowest diversity of any STEM field. This situation has begun to change over the last five years through a fragile and uneven process. Yet that does not change the ethical and operational imperatives for continued efforts to make the geosciences representative of the communities we serve. Since geosciences applications are ubiquitous, impacting every town and city, a fully representative geoscience enterprise in the United States would not only address the ethical imperatives, but it will yield better outcomes in geosciences applications and make the discipline a force for social and economic growth. The geosciences enterprise can provide not only solutions to environmental and natural impediments that impact social and economic growth in communities, but because of its spatial ubiquity, can provide employment pathways that expand opportunity and social mobility for all populations. A fully representative geosciences enterprise will be equipped to engage impacted populations justly and coherently through aligned cultural engagement, just as it is critical in social licensing efforts. The challenge is to transform the geosciences into a welcoming discipline that has the appropriate equity supports to enable success for all comers. We will examine the state of diversity in the geosciences, as well as look at select initiatives which have been launched among the geoscience societies and how they fit into a broad strategy for creating an inclusive and representative discipline. A key part of these efforts includes improving the inclusivity and equity of the process of becoming a geoscientist and recognizing the cultural changes required to recognize, engage, and value talented people regardless of their pathway to the geosciences.

Katlein, Adam, Geosyntec Consultants, akatlein@geosyntec.com (TS #9)

Per- and Poly-fluoroalkyl Substances (PFAS) Site Investigation and Management Planning Strategies

We all have biases, even if we don’t think we do. This presentation will talk about unconscious bias – we all have it and must learn to recognize when we’re making automatic decisions based on bias, and when/how we should take a few minutes to analyze. Understanding implicit bias can help us to recognize when own biases are kicking in and help us to retrain our brains. We’ll talk about strategies we can use (and encourage our workplaces and organizations like AEG to use) in an effort to minimize the impacts of implicit biases. We’ll also discuss the differences between equity and equality, and define what “having privilege” really means, as it those issues and our biases are all related. It is complex, and this talk will demystify a bit that complexity.

Keane, Christopher, American Geosciences Institute, keane@americangeosciences.org; Susan Sullivan, susan.sullivan@colorado.edu (TS #1)

the aquifer with pore spaces filled mostly by clay. Increase of clay contents in sandstone reduced porosity and permeability, and consequently, decreased subsidence by increasing rock stiffness. Moreover, drawdown in a sandstone aquifer interbedded with soft and less permeable mudstone caused a short-term reduction in subsidence around the pumped well, over a timescale of 10s to 100s of days, that depended on contrasting properties of aquifers and aquitards, and their thicknesses in a depositional basin. Modeling results of subsidence anomaly produced at earlier stage of groundwater pumping should be taken into consideration when analyzing field data for land subsidence monitoring.

Fostering a Thriving Geoscience Community Through Inclusivity – A Look at Current Initiatives

Kalika, Sarah, DiabloGeo, sarah@georx.net (TS #6)

Kalika, Sarah, DiabloGeo, sarah@georx.net (TS #1)

Fresh-looking features of a localized flood event on a bouldery alluvial fan ~30 km east southeast of Indio, Riverside County, California, were observed in May 2021 from a westbound passenger vehicle on Interstate Highway 10. Google Earth images revealed fresh channel features on December 11, 2019, compared to weathered features on August 26, 2018. A search for “Indio storm 2019” produced reports of a major Valentine’s Day (2/14/2019) storm with widespread flood damage in the Coachella Valley. The elongated (shape 5.1), southsoutheast-flowing, 4.66-square-km basin in the Cottonwood Mountains above the bouldery alluvial fan ranges from 560 to 1350 m elevation and exposes Mesozoic granitic and Precambrian granitic and metamorphic rocks. Older alluvial fan segments have well developed desert pavement and very dark desert varnish. Intermediate fan segments have developing desert pavement and noticeable desert varnish. Active channels near I–10 are slightly to moderately incised into the

AEG 2022 ANNUAL MEETING 78 AEG 65th Annual Meeting Program with Abstracts September 2022

NOA Basics and Case Studies

This presentation is a must-attend for professionals who are new to the world of Naturally Occurring Asbestos (NOA) and will include an overview of the basics (what is it, what minerals are regulated, what minerals are not regulated but still potentially hazardous, analytical methods, who regulates NOA, and how it’s technically regulated in every state within the USA). This presentation will also discuss some recent projects involving asbestos monitoring, mitigation methods that worked (and some that did not), and a story about the different analysis methods that highlights what can happen when we import aggregate base from a quarry (sampled using CARB 435 PLM), then perform asbestos air sampling (using CARB Modified AHERA TEM).

But I’m Not Biased! Understanding the Connection between Your Brain and Your Implicit Biases

Per- and poly-fluoroalkyl substances (PFAS) have drawn a significant amount of recent regulatory attention and scrutiny, as certain PFAS have been documented to result in adverse human health and ecological effects. These PFAS are found throughout the current environment and are also present within a variety of commonly used household and retail goods. Although the hazard has been identified, further assessment efforts are necessary to investigate potential soil and groundwater contamination present at current or historical sites that utilized or disposed of PFAS containing products. Standards and guidance issued by federal and state agencies are constantly evolving and new analytical methods are being developed to analyze for the large group of existing and emerging PFAS compounds. With current detection limits now applicable to soil and groundwater at the sub-nanogram per liter (ng/L) concentration, diligent management and field planning is necessary to ensure that assessment activities are able to provide accurate results while limiting potential sampling bias and unnecessary costs and

February 2019 Alluvial Fan Flood Characteristics Inferred from Available Information, Central Riverside County, California Keaton, Jeffrey, Wood Environment & Infrastructure Solutions, jeff.keaton@woodplc.com; Rosalind Munro, rosalind.munro@woodplc.com (TS #18)

relatively steep (4.69 ± 1.15 deg; n = 1,658; 10m DEM) intermediate and older fan surfaces and appear light gray because of the absence of desert varnish and dominance of felsic granitic rocks. Online national radar reflectivity mosaics, probably utilizing four NEXRAD Level III stations within 230 km, indicate that precipitation began falling in the watershed at 02:40 PST and persisted until 15:35 PST. Approximately 43.8 percent of the 86.66 mm storm total fell in a 01:35period of the strongest reflectivity (~40–50 dBZ). NOAA Atlas 14 precipitation depth and intensity indicate that <3-hr duration values were less than 25-yr return period; 12-hr duration values exceeded 50yr return period. USGS StreamStats online application for the watershed above the alluvial fan reports a mean annual precipitation depth of 136.4 mm, suggesting that the Valentine’s Day storm was 63.7 percent. Peak discharge estimates are 5.748, 15.376, and 28.883 cubic m/s for 10-, 25-, and 50-yr average return periods. These values cannot be checked without channel geometry and flow depths.

Using Paleoflood Analyses to Improve Hydrologic Loading for USACE Dam Safety Risk Assessments: A Nationwide Approach

The USACE has initiated a regional paleoflood analysis of the Willamette River Basin upstream of Salem, Oregon, in order to improve the long-term hydrologic loading characterization for risk assessments of multiple dams located in the Western Cascades. In 2017, an initial paleoflood assessment of the Middle Fork Willamette River (MFWR) yielded evidence of a large late Holocene flood approximately 400 to 500 years ago, with an estimated discharge magnitude that exceeds the largest flood in the gaged record. Subsequent Tier 1 paleoflood efforts along the South Santiam River (SSR), located about 35 miles north, provided evidence of a large flood within the same time period, but also an earlier, even larger flood about 1,000 years ago. These questions arise: Do the MFWR and SSR have consistent or inconsistent paleoflood chronologies? Do extreme meteorological events in the Western Cascades have regional or localized extents? To address these questions, USACE has initiated paleoflood analyses within the intervening McKenzie River (MKR) watershed, as well as more detailed, Tier 2 analyses in the MFWR and SSR watersheds. The present-day analyses also are examining paleoflood records at the river confluences near Eugene and Albany, Oregon. This regional approach is designed to improve uncertainties in the timing and magnitudes of large historical floods and paleofloods, and develop an overall paleoflood chronology for the SSR, MFWR, and MKR watersheds. These efforts will provide data for evaluating the timing and magnitudes of extreme paleoflood events over the past few thousand years in each of the three sub-watersheds. Concurrently, independent analysis of regional precipitation frequency is being conducted to improve the understanding of extreme meteorologic event likelihoods. Collectively, the updated regional precipitation-frequency and paleoflood-chronology data sets will address the spatial and temporal variability of extreme flood events in the Western Cascades region.

Since 2015, results from paleoflood analyses (PFA) have been used to reduce uncertainties in hydrologic loading components of USACE damsafety risk assessments. A tiered approach allows reductions of uncertainties through analyses having progressively greater detail, if supported within the risk-based decision framework. Tier 1 efforts are conducted to address watershed PFA viability and to recommend actions for minimizing uncertainties in initial hydrologic loading estimates. If appropriate, Tier 2 PFA are conducted where results are likely to improve confidence and reduce uncertainties in hydrologic loadings, and therefore benefit the risk assessment. Tier 2 PFA involve an integrated program of geologic and hydraulic analyses to identify and characterize paleostage indicators (PSI) and non-exceedance bounds (NEB) that constrain long-term paleoflood chronologies. Tier 2 often includes geologic and geomorphic characterization of riverine flood-terrace and slackwater deposits to identify and date specific flood events in the historic and pre-historic record, coupled with detailed hydraulic modeling to characterize peak flood magnitudes. These efforts involve state-of-the-art deposit and soil characterization and dating, and 1D/2D hydraulic modeling using HEC-RAS software to define flood water-surface elevations. The best estimates and ranges in peak discharge and age for all PSI/NEB are included into flow-frequency statistics through use of perception thresholds and flow intervals, and sensitivity analyses provide guidance on the value of PFA datasets in reservoir-stage frequency analyses. Tier 3 efforts are then conducted to resolve specific technical issues, if needed. Incorporating PFA results into flow-frequency curves has shown that frequencies of rare and extreme peak discharges can be either over- or under-estimated compared to analyses using only historical data. PFA have been successfully applied to USACE dam-safety risk assessments throughout many geographic and meteorologic domains, demonstrating applicability across the Nation. Overall, PFA improve confidence and reduce uncertainty in hydrologic loadings and add significant value to USACE dam-safety risk assessments.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 79

Kelson, Keith, US Army Corps of Engineers, keith.i.kelson@usace.army.mil; Justin Pearce, justin.t.pearce@usace.army.mil; John England, john.f.england@usace.army.mil (TS #10)

Developing a Regional Paleoflood Chronology for Dam Safety Risk Assessments in the Upper Willamette River Basin, Oregon Kelson, Keith, US Army Corps of Engineers, keith.i.kelson@usace.army.mil; Carolyn Pearson, carolyn.m.pearson@usace.army.mil; Haden Smith, cole.h.smith@usace.army.mil; Ryan Clark, ryan.l.clark@usace.army.mil; Erica Medley, erica.a.medley@usace.army.mil; Tessa Harden, tharden@usgs.gov (TS #10)

Naturally Occurring Asbestos in the Paradise, California Area Kennedy, Elisabeth, California State University, Chico, elisabethmkennedy@gmail.com; Alonso Diaz, adiaz34@mail.csuchico.edu; Julianna McCracken, jjgroteguth@mail.csuchico.edu; Hannah Aird, haird@csuchico.edu (TS #6)

Naturally occurring asbestos (NOA) refers to six regulated minerals in the serpentine and amphibole mineral groups that occur in a natural geologic setting. NOA minerals are resistant to heat and corrosion and have high tensile strength with habits ranging from elongated and bladed to fibrous and acicular. NOA is a recognized public health hazard due to the carcinogenic effects when inhaled or consumed and the mapped distribution of NOA is important to protect the public and workers from the associated health risks. The basement rocks underlying Magalia and Paradise are a series of interbedded serpentinites and metavolcanic rocks. The serpentinites are currently mapped by the California Geological Survey as potential NOA sources, while the metavolcanics are not. Results have confirmed the presence of chrysotile fibers in the serpentinite and analysis of the metavolcanics show they contain unregulated asbestiform amphibole minerals, which have been shown to pose the same health hazards as regulated asbestos amphiboles. The Tuscan Formation is a Pleistocene debris flow and a widespread formation in Northern California, including the

A New Method for Providing Accurate Locations for Geophysical Data in GPS Denied Areas: SLAM Lidar Leberfinger, Jeffrey, Exploration Instruments Inc, jleberfinger@exiusa.com; David Carpenter, dcarpenter@schnabel-eng.com (TS #7)

Achieving centimeter accuracy positioning when collecting geophysical data in areas with heavy tree canopy, overhead and onsite obstructions, and other GPS denied areas is now a reality using Simultaneous Localization and Mapping (SLAM). This methodology was developed by Kaarta and USACE using the Stencil 2 SLAM system to work with Advanced Geophysical Classification and Digital Geophysical Mapping Sensors for mapping UXO on sites across the United States. Since the Stencil 2 allows for customizing the GPS NMEA positional data string the next step was to integrate the SLAM positioning with GPR, EM, magnetometers, and other sensors for environmental and engineering projects. Now the SLAM technology can be used to replace or augment Robotic Total Stations for generating global position data for these types of geophysical projects. This process involves creating a 3D georeferenced point-cloud by using a terrestrial lidar and multiple ground control points of the GPS denied areas for generating centimeter accuracy global positioning data for geophysical sensors. An

King, Michael, The Hydrodynamics Group, LLC, hydrodynamics@rconnect.com; John Bredehoeft, jdbrede@aol.com (TS #11)

Funeral Mountain Nevares 2 and BLM-1 Wells: A Window into Inter-Basin Flow & Potential Off World Life

The Nevares 2 and BLM-1 wells were drilled by Inyo County’s Yucca Mountain Nuclear Waste Disposal program to evaluate inter-basin flow between Yucca Mountain and Death Valley through the Amargosa Valley and Funeral Mountain Range. Both wells were drilled and completed in the Lower Carbonate Aquifer (LCA) system that extends from below Yucca Mountain to Death Valley. The location of the BLM-1 well was identified using gravity and TEM geophysical surveys to find the deep LCA. Groundwater modeling of hydrologic data from these wells with spring flow data from the Furnace Creek area of Death Valley National Park provided evidence of inter-basin. A benefit of the Nevares 2 wells was a water supply well to the Cow Creek Park Service community. A unique colony of Desulforudis audaxviator bacteria was found in BLM-1 and Nevares 2 wells. The existence of this

bacteria in an isolated deep geologic environment suggests the potential of life in off world extreme environments. The results of these studies are presented.

AEG 2022 ANNUAL MEETING 80 AEG 65th Annual Meeting Program with Abstracts September 2022

Geodetic Insights into Present-Day Strain Accumulation and Release in the Walker Lane

Kreemer, Corné, University of Nevada – Reno, kreemer@unr.edu; William C. Hammond, whammond@unr.edu; Zachary M. Young, zyoung@nevada.unr.edu; Nina Miller, ninamiller20@gmail; Geoffrey Blewitt, gblewitt@unr.edu (TS #3)

The Walker Lane is a recent and tectonically complex component of the Pacific/North America plate boundary system. The complexity is, however, not apparent from the current strain accumulation measured with very high precision velocities of crustal motion by GPS stations. The Nevada Geodetic Laboratory operates a large network of GPS stations extending from Arizona to Oregon that provides an important densification to the network of continuous GPS stations operated by other agencies. Across the Las Vegas Valley, extensional east-west deformation amounts to ~0.5 mm/yr. In the Walker Lane, deformation consists predominantly of right-lateral shear of 5–7 mm/yr. The same strain rate pattern is consistently observed from the central to northern Walker Lane, even though recent faulting in these areas does not necessarily exhibit NW-oriented strike-slip faulting. This was emphasized by the occurrence of the 2020 Monte Cristo and 2021 Antelope Valley earthquakes; the former occurred on an East-striking left-lateral fault, and the latter on a North-striking normal fault. Although the Monte Cristo earthquake exhibited significant slip complexity, we can explain the coseismic GPS displacements with a simple dislocation model with constant slip of ~1 m, consistent with the event’s overall seismic moment. We show that the event’s rupture is consistent with the predicted orientation of the conjugate fault plane from the inter-seismic strain accumulation. In the northernmost Walker Lane, the GPS data predict very constant strain rate across the vertical strike-slip faults that accommodate deformation between the Sierra Nevada microplate and Basin and Range. The GPS data reveal no evidence of strain accumulation above these faults. This surprising finding suggests that either these faults there are late in their viscoelastic seismic cycles and/or that there are no discrete dislocations below the locking depth. This could indicate that deformation at depth is instead uniformly distributed across the entire shear zone.

GIS-Based Landslide Susceptibility Mapping Using Analytic Hierarchy Process (AHP) in Fairbanks North Star Borough, Alaska Kidanu, Shishay, University of Alaska Fairbanks, stkidanu@alaska.edu; Margaret Darrow, mmdarrow@alaska.edu; Jaimy Schwarber, jaschwarber2@alaska.edu (TS #5)

A landslide susceptibility map delineates the potential zones for landslide occurrence, which is critical in landslide management strategy. This study aims to produce a landslide susceptibility map of the Fairbanks North Star Borough (FNSB), Alaska, using Geographical Information Systems (GIS)-based spatial analysis and the Analytical Hierarchy Process (AHP). To produce the susceptibility map, seven landslide influencing factors: surficial geology, slope angle, slope aspect, distance to the nearest road, plan curvature, profile curvature, and average annual precipitation were selected. Spatial databases and thematic layers of all the aforementioned factors were created in a GIS environment. According to their relative importance in landslide occurrence in the study area, these thematic layers were assigned suitable weights on the Saaty’s scale. The evaluation of the relative importance was made using experts’ knowledge and a mathematical/statistical method. The assigned layer weights and class ranks were then normalized using the AHP technique. Finally, all thematic layers were integrated using a Map Algebra tool in a GIS environment to generate a landslide susceptibility map of the area. The landslide susceptibility map classifies the study area into five different landslide susceptible zones, i.e., very low, low, moderate, high, and very high. Validation of the model was carried out by calculating zonal statistics, and it revealed a good correlation between the susceptibility model and the landslide inventory. The results of this study may help identify the landslide susceptibility zones.

foothills surrounding Paradise, California. The Tuscan Formation flowed over the asbestiform-mineral-bearing basement rocks and potentially incorporated detrital NOA within the formation. x-ray diffraction, scanning electron microscopy, petrographic and energy dispersive spectral analysis will be performed on the Tuscan Formation to determine the presence or absence of detrital NOA minerals. Preliminary analysis of the lowest member of the Tuscan Formation using Scanning Electron Microscope and Energy Dispersive Spectra confirms the presence of amphibole minerals. Further XRD and SEM-EDS, and petrographic analysis needs to be performed to determine the type of amphiboles, different amphibole mineral morphologies and presence or absence of chrysotile. The findings of this study may result in local and statewide reclassification of potential NOA sources.

LeFebvre, Amy, US Army Corps of Engineers, amy.f.lefebvre@usace.army.mil; Keith Kelson, keith.i.kelson@usace.army.mil; Ryan Clark, ryan.l.clark@usace.army.mil;; Brian Hall, brian.m.hall@usace.army.mil; Tessa Harden, tharden@usgs.gov TS #10)

Rock Dilatometer Testing: Field Observations and Comparisons to Empirical Correlations

and catastrophic events, like landslides, debris avalanches, and floods. On June 18, 2020, more than 5,400,000 m3 of soil and weak rock slid into the Colca River valley near the town of Achoma. The rotational slide involved 40 hectares of land that was displaced 500 meters. The event destroyed the agricultural land, impacting the economy of many families, and the displaced material over the Colca River created a dam that increased the risk of flooding for the towns upstream. The exact factors that led to the landslide in Achoma, including triggering factors, are uncertain. The activity of farms, most of which are currently irrigated or have been irrigated in the past, and the presence of a large water transportation canal upslope of the landslide are the most likely causes of the increase in groundwater levels leading to failure. The purpose of this work is test various groundwater and infiltration scenarios to estimate the amount of water involved in the destabilization and triggering of the Achoma landslide, using numerical simulation of changing groundwater conditions. While not definitive, our early work indicates that, even though the landslide occurred during the dry season and before the irrigation began for the year, we cannot yet rule out irrigation as a contributing factor. On the other hand, increasing groundwater levels from leakage from the water conveyance canal appears to be a necessary component to cause slope failure.

Although moduli can be estimated using published correlations for various rock mass properties, values obtained from direct measurements can provide a better representation of site-specific foundation conditions. Moduli measured in an in situ rock mass may be a fraction of the intact moduli obtained from laboratory testing of drill core specimens. These differences are due to field/laboratory testing methods, the heterogeneous nature of the rock mass, and presence of discontinuities (fractures, joints, faults etc.), which act as planes of weakness. Bureau of Reclamation compared moduli obtained from a flexible dilatometer and empirical correlations. A flexible dilatometer was used in several NQ-sized boreholes to determine the in situ rock mass moduli for use in a finite element analysis of an existing structure. A key field condition that can significantly influence results is having an open borehole above and below the dilatometer for failure to deform into, potentially resulting in biased-low moduli values. Without an open borehole, rock/discontinuities are completely confined, and deformation is restricted, however, it is not possible to measure unconfined moduli values in the field. A comparison of field-derived values and empirical values are necessary to evaluate data quality/confidence level. The in situ values were compared to values developed from commonly used empirical relationships. Input data for the empirical relationships were determined for each interval where there was dilatometer data. Results indicate that the dilatometer-measured and empirically estimated values are similar where the rock is massive and relatively intact but vary significantly where the rock is fractured or weathered. These significant variations appear to be related to how the rock deforms in unconfined/semi-confined conditions (i.e., failure occurs into open space) and are particularly influenced by borehole conditions near the dilatometer test interval. Such variation and deformation are not expected to be present in a fully confined, in situ condition.

The US Army Corps of Engineers is developing paleoflood data across the country to reduce uncertainties and improve confidence in hydrologic loading for dam safety risk assessments. Libby Dam in northwestern Montana, which was constructed in part because of flooding and damage during the May 1948 flood along the Kootenai River, is currently under analysis. Existing historic and systematic flood records along the Kootenai River contain only 93 years of observation. To lengthen this record and to evaluate peak flow frequencies of rare and extreme events, paleoflood features were identified and characterized. Geologic and geomorphic analyses of aerial imagery and high-resolution topographic data identified extents of fluvial terraces providing evidence of large, pre-historic floods. The fluvial (flood) terraces are differentiated and correlated based on height above the river, vegetation, geomorphic position, relative soil development, and stratigraphy of associated alluvial deposits. We interpret the paleoflood chronology of the river reach based on the presence of multiple inset terraces and age estimates from relative soil development and optically stimulated luminescence (OSL) and radiometric (14C) analyses. Paleodischarges corresponding to the various terraces along the reach are estimated from detailed hydraulic modeling using HEC-RAS software and lidarderived elevations. Uncertainties in paleodischarges are captured through consideration of down-valley and cross-valley variability in topographic and hydraulic data, multiple sensitivities in hydraulic model parameterization, and estimated water depths keyed to flood-deposit characteristics. This analysis establishes the occurrence of at least two late Holocene and potentially two early to mid-Holocene large floods along the Kootenai River downstream of Libby Dam. The timing and magnitudes of these floods greatly improve the effective record length above and beyond the limited historic and systematic flood record and provide a range in uncertainty for floods with remote annual exceedance probabilities.

River valley in southern Peru is the longest waterway of the Pacific Peruvian hydrologic basins, starting in the Peru Altiplano, and crossing the western Andean Cordillera to the Pacific Ocean. The area has been regularly impacted by large landslides of the valley slopes, and geologic evidence documents intense, recurrent,

Improving Hydrologic Loading for Libby Dam Using Paleoflood Analysis Along the Kootenai River, Northwestern Montana

additional advantage of the SLAM methodology is the lidar point cloud data of the investigation area that can be used to create terrain and contour maps. This presentation will discuss case studies and present examples of SLAM integration with geophysical sensors. One project performed in spring 2022 used the SLAM technology with EM61 metal detector data and GPR data under a bridge to investigate the reservoir bottom conditions for a bridge replacement project. Conventional GPS would not have provided adequate spatial positioning accuracy for the project goals. The Stencil 2 has been used on numerous projects for the USACE mapping UXO in wooded GPS denied areas. Several of these projects will also be discussed.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 81

Lemus, Oscar, Colorado School of Mines, orlemus@mines.edu; Paul Santi, psanti@mines.edu; Percy Colque; Pablo Meza; Guido Salas (Poster)TheColca

Failure Conditions and Triggers of the Achoma Landslide, Central Andes Region, Arequipa Peru

Lindenbach, Evan, Bureau of Reclamation, elindenbach@usbr.gov; Steve C. Dalton, sdalton@usbr.gov; Richard G. Bearce, rbearce@usbr.gov; Gergo D. Arany, garany@usbr.gov (TS #20)

Causes of Voids Behind Spillways, Conduits, Canals, Tunnels, and Siphons

The presence of voids behind a structure can limit operations at best and at worst be a precursor to failure. Voids could lead to hydraulic jacking, ground instability, and a roofed path for internal erosion processes. Any and all of these conditions could result in a failure, as seen recently at the Fort Laramie tunnel or the Oroville Dam spillway. Void formation has been attributed to many causes, from soil settlement and frost heave, to movement of materials caused by scour processes or internal erosion. In many cases it is likely a combination of factors. This presentation seeks to help identify geotechnical conditions and soil types that may be more susceptible to void formation, elucidate on design or construction practices that have a higher probability of void formation, and comment on observable indicators of void formation. A series of questions aimed at guiding the investigator towards structures (inventory-wide) and areas (structure-specific) most likely to have voids is provided to streamline detection efficiency. Ongoing laboratory-scale efforts to improve void detection and repair techniques will also be discussed.

Loar, Todd, USACE-RMC, todd.n.loar@usace.army.mil; Amy LeFebvre, Amy.F.Lefebvre@usace.army.mil; Daniel Smith, Daniel.K.Smith@usace.army.mil; Brian Hall, Brian.M.Hall@usace.army.mil; Reuben Sasaki, Reuben.A.Sasaki@usace.army.mil (TS #15)

Bull Shoals is a 256-foot-high, 2,256-foot-long concrete gravity dam constructed between 1947–1951 and located on the White River in northern Arkansas. The dam was authorized primarily for flood control management but also generates hydropower and provides recreation. A 2020 semi-quantitative risk assessment identified overtopping of abutment monoliths causing rock scour and undermining leading to structural instability as a potential risk driving failure mode (PFM’s). The hydrologic analysis indicates 4–10 feet of bypass water flowing around the upper right abutment simultaneously with 1–7 feet of dam crest overtopping for 1.5 to 3 days. These bypass and plunging flows generate high erosion capacity applied on the right abutment backfill and rock mass as it merges with the tailwater. The abutment consists of sub-horizontally layered, alternating beds of crystalline dolomite and cherty-limestone with shale laminations, and lenticular algal chert reefs. The rock layers are variably fractured and observed during construction and in photographs to have open karstic dissolution features, soft sediment deformation, and irregular weathering profile. Initial assessment indicated high stream power and hydraulic energy dissipation resulting in rock erosion of the abutment bedrock. This prompted PFM-specific geological investigations and advanced hydraulic modeling to better characterize the erosion potential of the abutment. USACE performed field mapping, geophysical surveys, and further analysis of construction-era boring logs and construction photos to specifically assess the rock mass erodibility applying multiple methodologies. Hydraulic calculations and a computational fluid dynamics model were performed to better quantify the likely stream power for

AEG 2022 ANNUAL MEETING 82 AEG 65th Annual Meeting Program with Abstracts September 2022

Liu, Yi, Morgan State University, yi.liu@morgan.edu; Jiang Li, jiang.li@morgan.edu (TS #14)

the town of Libby, MT and about 42 miles south of the Canadian border. The dam was authorized primarily for flood management but also generates hydropower and provides recreation. During the 2020/2021 risk assessment the project team identified four risk driving potential failure modes (PMF’s): overtopping; concentrated leak erosion through fill around the right abutment; deep-seated rockslide on left abutment that damages and destabilizes monoliths; and large rockslide upstream in reservoir causes overtopping. The project is positioned on Precambrian “Belt Series” meta-sedimentary rock consisting of layered and fractured argillite and quartzite that has been folded and faulted. The bedding strikes approximately across the river (subparallel to the dam alignment) and dips downstream about 42 degrees exhibiting some slippage and shearing along bedding planes. There are a series of faults that also strike across the river but dip upstream about 65–70 degrees. This discontinuity configuration forms classic wedge-shaped blocks on the left abutment and reservoir slope. In fact, there are two very large, wedge-controlled paleo-rockslides upstream of the dam that temporarily blocked the river. In 1971 a rock wedge failed out of a cut slope during construction. While this 1971 well-studied wedge was cleaned up and the remaining, underlying potential wedges stabilized, the potential for an earthquake, or increased pore pressure induced deep seated rockslide that potentially undermines and/or deforms the left abutment monoliths had not been characterized. This presentation gives a summary of the left abutment rock wedge characterization and stability analysis related to assessing the PMF and risk of an abutment rockslide that may cause monolith deformation and instability at the dam.

The compaction measurements of Quaternary and Tertiary Gulf Coast aquifer system sediments in the Houston-Galveston region (TX) show spatially variable compression of 0.08 to 8.49 mm/yr due to geohistorical overburden pressure when groundwater levels in the aquifer system were stable after about the year 2000. An aquifer-system creep equation is developed for evaluating this variable compression with a thickness-weighted average creep coefficient based on Taylor’s (1942) secondary consolidation theory. The temporal variation of aquifer system creep can be neglected in a short-term observation period (such as a decade) after a long-term creep period (such as over 1000 years) in geohistory. The creep coefficient of the Gulf Coast aquifer system is found to be in a range of 8.74×10^(-5) to 3.94×10^(-3) (dimensionless) with an average of 1.38×10^(-3). Moreover, for silty clay or clay dominant aquitards in the Gulf Coast aquifer system the creep coefficient value varies in the range of 2.21×10^(-4) to 3.94×10^(-3), which is consistent with values found by Mesri (1973) for most soils (1×10^(-4) to 5×10^(-3)). The equivalent aquitard thickness of the Gulf Coast aquifer system in the HoustonGalveston region is estimated to be 3.4 to 3.7 m. Land subsidence due to creep of the Gulf Coast aquifer system is estimated to be 0.04 to 4.33 m in the 20th century and 0.01 to 0.64 m in the 21st century at the 13 borehole extensometer locations in the Houston-Galveston region. Creep is significant and should be considered in addition to tectonic subsidence and primary consolidation due to groundwater withdrawal when estimation relative sea level rise.

Lindenbach, Evan, Bureau of Reclamation, elindenbach@usbr.gov (TS #15)

Loar, Todd, USACE-RMC, todd.n.loar@usace.army.mil; Sharon Gelinas, Sharon.L.Gelinas@usace.army.mil; Jessica F. Rudd, Jessica.F.Rudd@usace.army.mil (TS #8)

Libby dam is a 422 foot (128.5 m) high, 2,887 foot (880 m) long concrete gravity dam constructed between 1967–1973 and located on the Kootenai River in northern Montana, 17 miles east (upriver) from

Abutment Rock Erosion Analysis Due to Overtopping –Risk Assessment for Bull Shoals Dam, Arkansas

Land Subsidence Due to Creep of the Gulf Coast Aquifer System in the Houston-Galveston Region

Abutment Stability Analysis – Quantitative Risk Assessment for Libby Dam, Montana

public. These studies have greatly extended that level of knowledge for the subject areas. Two of the important takeaways from the studies in the Carson City area that have broader implications for the Western Nevada area. 1) A portion of the faults have broad scarps that have no evidence of Holocene activity and morphological analyses work well coupled with field trenching. 2) Many faults mapped as older than Holocene particularly on the east side of the basin have been draped by eolian sand deposits that masked the Holocene ages. This “eolian masking” phenomenon warrants consideration when conducting fault investigations in this region and more broadly the Basin and Range province in general. Trenching is essential for these masked faults.

Girlboss vs. Misogyny – Inspire or Destroy?

A Preliminary Comparison of Rock Strength and Turbidity in the Coastal Belt Franciscan Assemblage, South Fork Wages Creek versus South Fork Caspar Creek, Using the Hoek-Brown Criterion, Mendocino County, California

Update to the Carson City and New Empire Quaternary Fault Maps 1979–2022

In 1979 a Nevada Bureau of Mines and Geology produced a series of Map Folios for Western Nevada. As part of the map folios, Earthquake Hazard Maps were published that addressed Quaternary Fault locations and estimated liquefaction potential. These maps have been the cornerstone of fault investigations in the region since the folios were published. This presentation addressed what has been learned for two specific quadrangles; The Carson City and New Empire maps that cover the Carson City urban core area. The original maps were produced based on analyses of low-sun angle aerial photography produced during 1974 for Western Nevada and limited field mapping and observation. Through the authors careers, many sites have been investigated as part of geotechnical investigations for private and public projects. In the process of performing the authors investigations, document searches have been conducted that resulted in the compilation of other consultants and agency studies that became available to the

How do we keep women in STEM? I have some insight about this as a newer recruit to the industry. The graduation rate is high and the retention rate is low. Interest, education, or women “believing in ourselves” are not the issues. The issue is how to navigate industry wide mindsets towards “others” in STEM. I have many friends who have left the industry as a result of mistreatment on the job. Many women feel we must either keep silent or leave instead of inciting conflict. And I know others share my instinct to attack those hostile or too friendly to my presence on the job. So how can we handle these conflicts in the middle ground? There’s a fine line separating people who seem beyond reform and make us feel unsafe, and extending a hand to people who are simply not used to the influx of racial diversity, women, transfolk, and neurodivergent people. I’ve been in a situation where someone projected awful fantasies onto me, even while I was sitting in an office. And I felt no guilt about reporting his words to my boss and HR, to mete out whatever consequences they deemed necessary. But I’ve also dealt with an overly friendly client who didn’t know how to behave around women on the job. Or maybe in the past his behavior was considered okay, and no one had set the record straight for him. Fortunately, after a serious discussion, I told him that I knew he could do better, and I was able to set boundaries for how I expected to be treated on and off the job. He respected my boundaries and we didn’t have another issue. I shouldn’t have had to deal with either of these situations, but they are an unfortunate part of geotech. We can do better.

Mace, Jason, Las Vegas Valley Water District / Southern Nevada Water Authority, james.prieur@snwa.com (TS #11)

the overtopping events. This presentation described the geologic, geotechnical, and hydraulic analysis methods and results to assess the potential magnitude and impact of abutment erodibility during potential overtopping events.

A study compares rock strength between the South Fork Wages Creek watershed and the South Fork Caspar Creek experimental watershed in Mendocino County, California. The SF Caspar Creek watershed has been studied by the USFS and State of California since the 1980s. The SF Wages Creek watershed has been managed by various landowners; most recently acquire by the Lyme Timber Company. Published geological maps show both watersheds as being underlain by the same rock unit, the Coastal Belt Franciscan Assemblage, deformed rocks accreted to the western North American coastline. Both watersheds have recently undergone harvest activities with similar levels and types of harvest. Turbidity studies conducted after activities show higher turbidity values measured in the SF Caspar Creek. The Generalized Hoek-Brown Criterion, a method used to estimate the strength of a rock mass based on an evaluation of the physical properties of a rock exposure, was used to characterize rock strengths in both watersheds. Rock strength and deformational properties were determined by estimating Uniaxial Compressive Strength, Material Constant, Modulus Ratio, and Geological Strength Index at sample locations using an ESRI based Collector app. Bedding orientations, where present, were also measured. Preliminary results suggest higher rock strengths in the SF Wages Creek watershed where intact turbidites were observed compared to deformed rock in the SF Caspar Creek. The preliminary results emphasize the importance of characterizing rock strength when evaluating water quality and management activities and that mapping of the Coastal Belt Franciscan Assemblage along the Mendocino coastline could be better differentiated.

Luce, Gary, Wood Rodgers, Inc., gluce@woodrodgers.com; Jim Koch, jkoch@woodrodgers.com (TS #18)

Longstreth, David, California Geological Survey, david.longstreth@conservation.ca.gov; Patrick Brand, patrick.brand@conservation.ca.gov; Kevin Doherty, kevin.doherty@cconservation.ca.gov; Morgan Renner, morgan.renner@conservation.ca.gov; Stefani Lukashov, Stefani.lukashov@conservation.ca.gov (TS #5)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 83

LVVWD and SNWA operates over 100 production, recharge, and irrigation wells in the Las Vegas Valley, surrounding small communities and program areas. A well management program was developed in order to optimize well performance and maintain long term system production capacity. Well and pump attribute data, historical operation and hydrologic databases track well performance and condition. The longevity of each well is estimated based upon construction date, casing materials and condition to establish well replacement priorities. Pump performance is monitored including amperage and flow rates and changes in sand content, turbidity and well specific capacity are tracked to identify screen damage or plugging in order to identify wells requiring rehabilitation or repair. After pump removal, wells are inspected using downhole videos and Casing Inspection Thickness Measurement tools to identify casing competency and provide a baseline for future comparison. The presentation presents the well management program elements and well performance and repair case studies.

Well System Management Program

Mackey, Alexia, Universal Engineering Sciences, AMackey@universalengineering.com (TS #1)

In December of 2020, a record-breaking, rain-on-snow event caused dozens of landslides in the Haines, Alaska area. The community was greatly impacted, with damage reaching out around Haines in a 7-mile radius. Houses and roads were destroyed and damaged by landslides and flooding, leaving a mandatory evacuation in effect for several months at one location. Mapping how the events of that storm unfolded both spatially and chronologically in ArcPro and presenting it in StoryMaps will help the community to understand the storm event better. Emergency response services can use the results in planning for the future. Although still a work in progress, the interactive StoryMaps will include the location of each landslide or area impacted by flooding, date and time of occurrence, and description in the order the events happened. This presentation will cover the creative and technical processes of telling the story in StoryMaps using photographs, lidar, and news and emergency response reports.

Healdsburg-Rodgers Creek Fault Stepover: Detailed Geologic Characterization for Engineering Mitigation and Real Estate Evaluation

Modeling the Effects of a Drain and Active Groundwater Pumping System on Storm Water Flooding in a Coastal Setting

Clatskanie, Oregon: Case Study of an Active Landslide in the Oregon Coast Range

The impact of a drain in an active-pumping system on flood-mitigation efficacy in a coastal environment is investigated. Large precipitation events in coastal regions typically induce storm water and/or groundwater flooding that may require proficient flood-mitigation strategies for ameliorating flood-related impacts on coastal communities. In this study, a 3D groundwater model was used to simulate the effects of a drain and active pumping on the groundwater system during different precipitation events. Results from the simulations reveal significant reductions of water levels in the unconfined aquifer when combined drain and active-pumping flood mitigation strategies are implemented. The results suggest that combined drain and active-pumping strategies may represent viable options for reducing groundwater flooding, thereby reducing the potential for storm water flooding in coastal regions.

significant vertical and horizontal displacement of slope material. During the landslide reactivation, the inclinometer casing installed in a boring at the top of the landslide sheared at a depth of approximately 19.8 ft, confirming our initial interpretation of the failure plane depth. Based on results of our landslide investigation, a rock buttress with subsurface drainage was selected as the best mitigation option for the site and was constructed in summer 2021. This case history presents regional context, geologic conditions of the site, historical land use practices affecting slope stability, a chronology of slope movement, and a discussion of mitigation measures used at the site.

McCosby, Bodie, Aspect Consulting, bmccosby@aspectconsulting.com; Mark Swank, mswank@aspectconsulting.com (TS #8)

The Eightmile Lake Restoration Project – Characterization of a Landslide Dam

Mallett, Kristin, University of Alaska, Fairbanks, ksmallett@alaska.edu; Margaret Darrow, mmdarrow@alaska.edu (TS #5)

The County of Sonoma needed to sell a 72-acre surplus hospital campus in Santa Rosa, California that had been abandoned due to fault rupture hazards associated with a complex zone of shearing of a “stepover” zone along the Healdsburg-Rogers Creek fault. Conflicting and inaccurate reporting/locating of fault features from previous individual consultant studies and published maps resulted in low bids by potential buyers because of the unknowns, such as how much of the property could be developed. A comprehensive campus-wide geologic investigation, which included reinterpretation of trench logs from 26 previous studies and detailed logging and surveying of 12 additional trenches totaling over 3,000 lineal feet of exploration, was conducted to evaluate the surface rupture hazard at this site. The study identified 3 primary zones of ground surface faulting, as well as a zone of secondary shearing located between two primary zones. Refined building setback zones for structures intended for human habitation were able to be established because of the detailed surveying of fault-related features and engineering solutions alternatives were provided in order to make the zone of secondary shearing potentially developable. The detailed study determined that 48 of the 72 acres are potentially developable and it was agreed with civic entities that no additional fault studies would be needed for future development permitting. The detailed geologic study was provided to bidders and resulted in a purchase price for the property of 3 times the original bid.

AEG 2022 ANNUAL MEETING 84 AEG 65th Annual Meeting Program with Abstracts September 2022

McCormick, William, Kleinfelder, bmccormick@kleinfelder.com (TS #13)

Eightmile Lake, an alpine glacial lake within The Enchantments region of Washington state’s Cascade Mountain Range, was further impounded and enlarged by a massive prehistoric landslide that blocked the drainage. The natural impoundment was originally modified by the local irrigation districts approximately 90 years ago by constructing a man-made dam at the head of the creek. Restoration of the dam’s capacity and modernization of its structures triggered reviews by Washington State Department of Ecology – Office of Dam Safety (DSO), who requested further investigations for the surface conditions of the areas surrounding the impoundment and explorations of the subsurface conditions to complete engineering analyses. Through geologic mapping of the rim and impoundment, and using geophysics, test pits, and borings, analyses of the site and the impoundment were completed for foundation and seismic designs, rim slope and embankment stability, and seepage.

Manda, Alex, East Carolina University, Mandaa@ecu.edu; Alexis Kussman, kussmana19@students.ecu.edu (TS #4)

Martin, Greg, Geotechnical Resources Incorporated (GRI), gmartin@gri.com; George Freitag, gfreitag@gri.com; Mike Marshall, mmarshall@gri.com (TS #12)

Telling the Story: Developing StoryMaps for the 2020 Haines, Alaska Landslides

A slowly moving landslide in Clatskanie, northwestern Columbia County, Oregon experienced accelerated movement during the wet season of 2019–2020 which threatened a regionally critical electrical substation. Located in the northern Oregon Coast Range, the area receives over sixty inches of average annual precipitation. As the slope encroached on the substation, our landslide investigation moved quickly to include landslide hazard mapping, test pits, drilled borings with instrumentation (inclinometer and vibrating wire piezometer), and an evaluation of concept-level remediation approaches. The arcuateshaped landslide measured approximately 100 ft wide, with about a 25-ft elevation difference from toe to head scarp area. Electrical substations are located both above the crown and below the toe area of the landslide. During our landslide investigation, slickensides indicative of basal slope movement were identified at a depth of approximately 19.8 ft in a soil boring located near the top of the landslide. The landslide reactivated during the 2020–2021 wet season, resulting in

Per- and Poly-Fluoroalkyl Substances (PFAS) – Occurrence and Update on Regulatory Framework

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 85

McElhany, Joseph, KANE GeoTech, Inc., joey.mcelhany@kanegotech.com; William F. Kane, william.kane@kanegeotech.com (TS #8)

Moan, Ben, Nevada Division of Environmental Protection, bmoan@ndep.nv.gov (TS #9)

From#16)2015

Landslide Analysis with Incomplete Data: Developing a Framework for Critical Parameter Estimation

Environmental concerns have led to a renewed interest in small hydropower facilities. Many of these generating plants were constructed in the early part of the 20th Century and are still in use today. Large power companies have found them too difficult to maintain economically for a relatively small production. There is now a trend to sell the small plants to private investors who specialize in rehabilitating and maintaining these plants and selling the power. One such plant is located in the rugged Kern River Canyon in Southern California. A 12 megawatt generator at the mouth of the canyon is powered by water from a small check dam approximately 3/4 miles up the canyon. The water flows through a tunnel and penstock to power the turbine in the plant. Massive rockfall had severely damaged the check dam and rendered it inoperable. The first priority of the new owner was to protect the workers during reconstruction and use the rockfall system to protect the dam in the future. Given the tremendous potential energy of the rock blocks, an innovative protection system consisting of a rockfall attenuator, a debris flow/rockfall barrier, and a berm to protect the facilities were implemented at the site. The attenuator was made of high-strength steel wire mesh, 200 ft high and 180 ft long. It was hung from 250-ft-long steel wire ropes that spanned the canyon. The rockfall barrier was 110 ft long and 25 ft high. It was held in place by 48 wire rope anchors grouted into rock. The berm was constructed of boulder material held together with steel wire mesh anchored into the subgrade. The berm was 150 ft long, 20 ft to 30 ft wide, and 20 ft high.

Rockfall Protection for a Small Hydroelectric Dam in a Steep Canyon

through 2019 Applied Earth Sciences conducted a series of geotechnical, geologic and environmental studies on a Brownfield property, located in the city of Los Angeles. The site location was complicated by numerous factors: it is situated at the toe of an ascending slope near two mapped landslides; within the wider Newport-Inglewood Fault Zone; adjacent to Ballona Creek (a major watershed draining the northern Los Angeles Basin); in a liquefaction zone, near existing oil wells/fields, a methane zone, and was previously used as a petroleum product transfer terminal by Chevron, with ten (leaking) underground tanks and three aboveground tanks. Prior to our involvement on the property, several other firms had conducted extensive geotechnical and environmental studies, which needed to be reviewed and incorporated into our analysis. Prior environmental reports indicated abundant gasoline and diesel contamination, which were partially remediated/removed. The site is also adjacent to a dry cleaner with a history of PCE and TCE contaminant discharges. Our client was a major corporation with plans to establish a mixed-use manufacturing and office facility on the site. AES conducted a multidimensional, multiyear investigation and analysis consisting of prior records review, five geotechnical borings and laboratory testing, six environmental borings with corresponding chemical analysis of samples, 13 cone penetrometer soundings for fault study, site and regional geologic mapping for landslide hazard, and preparation of numerous geotechnical, geologic and environmental reports. Mitigation recommendations included an impact wall and debris basin for debris storage as form of mitigation for landslide and mudflow hazard; mat foundation supported on piles to support the proposed buildings to mitigate the high groundwater and liquefaction potential; a portion of site set aside for dewatering and contaminated groundwater treatment prior to discharge into the creek; site grading to provide toe of slope setback; and a soil vapor mitigation system for the habitable buildings. Our reports were eventually approved by the LADBS for the construction of the proposed buildings, but the environmental remediation challenges remain, and the site remains vacant.

Miller, Lauren, Colorado School of Mines, laurenmiller@mines.edu; Paul Santi, psanti@mines.edu (TS #5)

Landslides are one of the most common geohazards, posing significant risks for infrastructure, recreation, and human life. Slope stability analyses rely on detailed data, accurate materials testing, and careful model parameter selection. However, these factors are not always readily available, and estimations must be made, introducing uncertainty and error to the final slope stability analysis results. The most critical slope stability parameters which are often missing or incompletely constrained include slope topography, depth to water table, depth to failure plane, and material strength parameters. The goal of this research is to develop a standard engineering design approach for the estimation of these parameters when they cannot be directly measured, or when the accuracy of the measured values is in question. It could be argued that even sites that have ample, accurate data would require the estimation of at least one of these critical parameters. Though estimation of these values is common practice, there is limited guidance or best practice instruction for this important step in the analysis. This research also quantifies and highlights the need for uncertainty communication and accurate representation of probabilistic approaches in slope stability analysis results, particularly where data is sparse. Guidance is provided for the estimation of original and/or post failure slope topography via traditional methods as well as the use of open-source digital elevation models, water table depth across variable hydrologic settings, and the iterative estimation of depth to failure plane and slope material properties based on predicted slide type (predominately translational or rotational). Workflows are proposed for the systematic estimation of critical parameters based primarily on slide type and scale. Ongoing research will provide verification of functionality of these workflows, as well as parameter estimations derived from them.

Per- and poly-fluoroalkyl substances (PFAS) are anthropogenic chemicals used in the manufacturing of many common products, including food packaging, water and stain resistant materials, firefighting foams, cosmetics, and more. PFAS are very resistant to biochemical breakdown and can accumulate in organic tissue. For these reasons they are sometimes referred to as “forever chemicals.” Studies indicate that at least 97 percent of United States citizens, and those of other industrialized nations, have detectable levels of PFAS in their blood. Exposure to specific PFAS, even at relatively low levels, has been associated with adverse health effects. Research into the health effects of PFAS exposure and the extent of PFAS contamination in the environment is ongoing. The US Environmental Protection Agency (EPA) is working to finalize new rules and guidance regarding PFAS as related to the Safe Drinking Water Act, Clean Air Act, Resource Conservation and Recovery Act, and other regulations. The talk will summarize PFAS industrial sources, environmental deposition, exposure pathways, and provide an update on current and planned federal regulations, primarily as pertaining to drinking water.

Minas, Shant Minas, Applied Earth Sciences, Shant@aessoil.com (TS

Nichols, Holly, California Dept of Water Resources, holly.nichols@water.ca.gov; Dan Whisman, daniel.whisman@water.ca.gov; Jim Lopes, james.lopes@water.ca.gov; Leroy Ellinghouse, leroy.ellinghouse@water.ca.gov (TS #14)

Fires, whether naturally occurring or anthropogenically caused, have long been known to cause the enhancement of magnetic susceptibility in soils. The increased magnetic susceptibility of soils post-fire as compared to bedrock was first described in the 1950s and was discovered to be related to changes in magnetic mineralogy due to reductive processes during burning, creating magnetite (Fe3O4) from hematite (Fe2O3). Magnetite has an average susceptibility approximately three orders of magnitude larger than hematite (1 SI versus 1.3x10-3SI in volume susceptibility, respectively). This relationship between increased magnetic susceptibility and the high temperatures produced in fires has long been used in archaeological investigations to determine the location of settlements and metalsmithing abilities of ancient and historic civilizations. In a modern context, magnetic methods can also be used in detecting, delineating, and monitoring past or present fires such as underground coal fires or wildland fires. Approaches typically used in underground coal fire detection and monitoring are borehole temperature measurement and infrared remote sensing. These can be time-consuming and expensive, and the latter requires the heat

In December of 2020, a substantial and irregular storm event occurred in Southeast Alaska that generated unusually high amounts of rain and unseasonably high temperatures. This event resulted in dozens of landslides in the Haines Borough, which washed out roads, blocked residents from evacuation routes, and threatened access to the ferry terminal and fuel supplies. The largest slide occurred in a residential area and resulted in two deaths. The goal of this project is to gain an understanding of what—besides the heavy rainfall—caused significant sliding in some areas, and not in others. We are using geologic maps augmented with field mapping, soil and rock sampling, and engineering index property testing to draw connections between occurrence of mass movement type and geologic units. Using ArcGIS Pro and airborne lidar, we are mapping evidence of prehistoric landslides to identify areas predisposed to sliding. We identified debris flows that occurred within existing channels, as well as multiple debris flows that occurred in colluvium and underlying glacio-marine sediments along quasi-stable slopes. In one neighborhood, a series of sand flows caused damage to several structures, including the complete destruction of one house. We hope to provide community members with knowledge they can use to protect themselves and create disaster plans, to avoid future property damage. This presentation will include a version of the landslide inventory map, and preliminary interpretations on what geologic units were failing in the wake of heavy rainfall.

Magnetic Methods as a Hazard Assessment Tool: Detecting, Delineating, and Monitoring Underground and Surface Fires

A primer on pronouns, and why they are important to an LGBTQ+ inclusive workplace, will be presented. Strategies for adjusting to new pronouns will be discussed. Time permitting, we’ll also do a participatory exercise on pronoun-inclusive introductions.

Moe, Minda, Arcadis, Minda.Moe@arcadis.com (TS #1)

Murdock, Kathryn, Exponent Inc., kmurdock@exponent.com (TS #7)

Flood Mapping and Monitoring by Using Remote Sensing and Artificial Intelligence (AI): Examples from AI4 Flood Project

Motagh, Mahdi, Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, motagh@gfz-potsdam.de; Shagun Garg, sg2009@cam.ac.uk; Binayak Gosh, bgosh@gfz-potsdam.de; Sandro Martinis, sandro.martinis@dlr.de; Mike Sips, sips@gfz-potsdam.de (TS #4)

AEG 2022 ANNUAL MEETING 86 AEG 65th Annual Meeting Program with Abstracts September 2022

Mapping and Categorizing Landslides Around Haines, Alaska Nelson, Victoria, University of Alaska Fairbanks, vanelson@alaska.edu; Margaret Darrow, mmdarrow@alaska.edu (TS #5)

California Aqueduct Subsidence Program

Professionalism & Pronouns – An Exercise

source to be less than 10 meters from the surface. Airborne or ground magnetic surveys can delineate areas of burned/burning coal and unburned coal without the need for additional measures. While several remote sensing methodologies are used to determine wildland fire risk, laboratory measurements of soil samples can determine whether the area had previously burned and coupled with stratigraphy can be used to determine the frequency of past wildland fires. Using a combination of magnetic methods in surveying and laboratory methods reduces the cost and time spent detecting, delineating, and monitoring underground fires and can help delineate areas of previous fires for hazard assessment.

The Department of Water Resources (DWR) built the State Water Project (SWP)—a network of canals, pipelines, reservoirs, and hydroelectric power facilities—in the 1960s–70s. It now delivers clean water to 27 million Californians, 750,000 acres of farmland, and businesses throughout California. The California Aqueduct (Aqueduct) serves as the main artery of the SWP and a linchpin of California’s water security. In 2006, the SWP’s San Luis Field Division began to see a reduction in flow capacity through a portion of the Aqueduct in the San Joaquin Valley. Subsidence had lowered portions of the Aqueduct and caused the concrete liner freeboard (the vertical distance between the water surface and the top of the concrete liner) to be reduced from its normal of 3 feet, to less than 1 foot of freeboard in some areas. Subsidence has also decreased the ability to store water in segments of the aqueduct, known as pools, which allow operational flexibility and efficient management of pumping at the Aqueduct’s pumping plants. While subsidence has reduced the amount of

Floods are one of the most frequent and the costliest natural disasters that affect lives, infrastructures, economics and local ecosystems all over the world. Accurate and rapid mapping of flooded areas is important not only for disaster relief and recovery efforts but also for proper water and land-use management to better mitigate the risk of floods. The availability of high-resolution optical and radar remote sensing imagery and advances in deep learning technologies have significantly improved our ability to use space-born technologies for accurate flood mapping. Within the AI4Flood project (Artificial Intelligence for Near Real Time Satellite-based Flood Response), financed in 2020 by the Helmholtz organization in Germany, a multi-parameter Synthetic Aperture Radar (SAR)-based approach, coupled with deep learning, was developed for near real time flood mapping by the cooperation between GFZ German Research Centre for Geoscioences (GFZ) and German Aerospace Agency (DLR). In this presentation, we focus on achievements made in this project for flood monitoring and rapid mapping using SAR data. In particular, we discuss example applications on how various parameters extracted from SAR imagery improve existing satellite-based flood analysis methods in arid and semiarid regions, elaborate on our experience for using deep learning methods and role of labelled benchmark datasets for automatic delineating of flooded regions, and finally introduce a publicly available Data Analytics toolbox for rapid detection of flooded areas from SAR data, where the developed models in the project are deployed.

The 2020 Mw5.8 Lone Pine Normal-Faulting Earthquake Sequence, Eastern California

The 2020 Mw 5.8 Lone Pine earthquake was the largest earthquake to occur within the Owens Valley fault zone in eastern California since 1872 and ruptured an extensional stepover beneath Owens Lake. Owens Valley separates two normal-faulting regimes, the western margin of the Great Basin and the eastern margin of the Sierra Nevada, forming a complex seismotectonic zone, and a possible nascent plate boundary. Foreshocks began on 22 June 2020 with the largest being a Mw 4.7 event, with primarily normal faulting motion. This was followed ~40 hours later on 24 June 2020 by the Mw 5.8 mainshock exhibiting predominantly normal faulting, on a fault striking 330° (north-northwest), dipping 60°–65° to the east-northeast. Comparison of background seismicity and 2020 Ridgecrest aftershock rates showed this earthquake was not an aftershock of the 2019 Mw7.1 Ridgecrest mainshock. The aftershocks form a NNW-trending, NNE dipping, 5-km-long zone of seismicity, consistent with the rupture length estimated from analysis of regional waveform data. The mainshock seismic energy triggered rockfalls at high elevations in the eastern Sierra Nevada, at distances of 8–20 km, and liquefaction along the northwestern edge of Owens Lake. No surface rupture was observed along the 1872 Owens Valley fault zone, even though the dipping rupture zone of the mainshock projects to the surface in the general area. ShakeAlert, the earthquake early warning system, provided first warning within 9.9 s, as well as subsequent updates.

Underground tunneling has become a necessity in many heavily urbanized areas such as Singapore to support the complex infrastructures needed by the rapidly increasing population. In both tunneling methods, it’s essential to get the exact information on the geology condition in front to avoid potential hazards like voids, sudden geology changes, and construction foundations. Existing boreholes can provide geology information at specific points, but limited knowledge of rock characteristics from boreholes will increase the probability of risks happening. Geophysical methods like ground-penetrating radar (GPR), DC resistivity, and tunnel seismic prediction (TSP) are widely used to get a real time look ahead results in the open tunnel. But in the TBM tunnel, with the existence of the metallic TBM machine, the signal of EM-based methods like GPR and DC resistivity methods will be strongly disturbed. Commonly used seismic methods like TSP need to drill holes in the sidewall to deploy sensors and exploding sources. It will destroy the built ring, and the explosive source will also disturb the surrounding soil and may cause some potential risks in the urban area. There are built-in, look-ahead solutions for the newly constructed TBMs, but many existing TBMs need a standalone in-tunnel look-ahead solution. Therefore, we propose a standalone high-resolution in-tunnel seismic look-ahead method without cutterhead access or through-lining drilling requirements. In this seismic tunnel, look-ahead system, we received the signal using active seismic observation, which has manually generated vibration sources, and passive seismic observation, which listens to the vibrations from the working TBM machine to predict the potential hazards in front. We can accurately predict potential risks like sudden geological changes and abandoned piles using this system.

Modeling the Stress-Strain Curve of Las Vegas Area Caliche Norris, Gary, Civil and Environmental Engineering Dept., University of Nevada, Reno, norris@unr.edu (TS #20)

The June 2020 Mw5.8 Lone Pine earthquake was centered in southern Owens Valley, south of Lone Pine in eastern California. Despite being a moderate earthquake, it triggered numerous rockfalls at high elevations in the eastern Sierra Nevada and induced extensive liquefaction in the Owens Lake playa. Several backpackers hiking the eastern Sierra trails felt the earthquake and witnessed rockfalls on the slopes east of Mount Whitney, including a ~2,500 m3 rockfall at the Mount Whitney Trailhead Campground that destroyed several campsites and part of the Whitney Portal National Recreation Trail. Peak ground accelerations in the Whitney Portal area were notably low (likely < 0.10g) suggesting either the rockfall source areas were ideally positioned for failure or some amount of topographic amplification of ground motions played a part in triggering the rockfalls. Most of this debris fell on the talus slope below; however, three outlier boulders traveled beyond the talus slope, causing significant damage to some campsites. There were no injuries or fatalities as the campground was closed due to the Covid-19 pandemic, although the adjacent parking lots, trails, and other facilities were open to visitors and hikers. The presence of these and prehistoric outlier boulders identified throughout the campground indicates rockfalls are a continued hazard to people and infrastructure in the steep, bedrock canyons of the eastern Sierra. Closer to the earthquake epicenter, and approximately 25 km from Whitney Portal, seismic shaking induced liquefaction of sediments within the relatively flat Owens Lake playa. Post-event field observations documented surface evidence of liquefaction, including sand boils and ground fissures, which is rare for <M6 earthquakes and provides an important data point for existing empirical procedures that link site-specific soil conditions and ground motions to predict liquefaction triggering.

Earthquake-Induced Rockfall and Liquefaction from the 2020 Mw5.8 Lone Pine Earthquake in Eastern California Olson, Brian, California Geological Survey, brian.olson@conservation.ca.gov; Brian Collins, bcollins@usgs.gov (TS #13)

Olson, Brian, California Geological Survey, brian.olson@conservation.ca.gov; Egill Hauksson, hauksson@caltech.edu (TS #3)

Tunnel look ahead using the Active and Passive Seismic Method

freeboard and flow capacity at specific locations, contracted deliveries have not been curtailed due to subsidence. The California Aqueduct Subsidence Program (CASP) was developed to address the adverse effects of subsidence on the Aqueduct in the San Joaquin Valley. This presentation will give an overview of the program, subsidence issues observed along the Aqueduct, and DWR’s current and planned actions to mitigate and monitor those effects.

As part of the project, “Improving Strain Wedge Model (SWM) Capabilities in Analyzing Laterally Loaded Drilled Shafts in Caliche,” undertaken for Nevada Department of Transportation (by Professors Elfass and Watters of the University of Nevada, Reno), that modeling of the stress-strain curve of the caliche from the Las Vegas area, was required. Shear and P wave velocities (Vs,Vp) of drilled cores, from block samples transported to the UNR rock mechanics lab, were assessed prior to unconfined compressive strength (UCS) tests. The UCS tests were undertaken under displacement control. Displacements were measured with LVDTs, a compressometer, strain gages, and a laser. Unconfined compressive strengths (qu) from 53 samples, tested for both lab Vs and UCS using LVDT’s, ranged from 30 to 20,325 psi. It is modeling of the stress-strain curves of the 53 UCS tests, based on the SWM equation, that is presented here.

Nilot, Enhedelihai, National University of Singapore, ceeen@nus.edu.sg; Elita Li, li4017@purdue.edu (TS #2)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 87

Post-Fire Geologic Hazard Assessment of the 2021 Bond Fire and Hillslope Response to Significant Storms During Year-One Oswald, John, California Geological Survey, john.oswald@conservation.ca.gov; Paul W. Burgess, Paul.Burgess@conservation.ca.gov; Brian Olson, Brian.Olson@conservation.ca.gov; Francesca Valencia, Francesca.Valencia@conservation.ca.gov; Stefani Lukashov, Stefani.Lukashov@conservation.ca.gov; Justin Epting, Justin.Epting@conservation.ca.gov (Poster)

Unsheltered#9)

Characterizing the Chemical and Microbial “Fingerprint” of Unsheltered Homelessness in an Urban Watershed Papp, Katerina, Southern Nevada Water Authority, katerina.papp@lvvwd.com; Daniel Gerrity, daniel.gerrity@snwa.com (TS

homelessness is rapidly becoming a critical issue in many cities worldwide. The worsening situation not only highlights the socioeconomic plight, but it also raises awareness of ancillary issues such as the potential implications for urban water quality. The objective of this study was to simultaneously leverage diverse source tracking tools to develop a chemical and microbial “fingerprint” of direct human inputs into Las Vegas’ tributary washes and flood control infrastructure. By evaluating a wide range of urban water matrices using general water quality parameters, fecal indicator bacteria (FIB), human-associated microbial markers [e.g., HF183, crAssphage, and pepper mild mottle virus (PMMoV)], 16S rRNA gene sequencing data, and concentrations of 52 anthropogenic trace organic compounds (TOrCs), this study was able to differentiate principal sources of these constituents, including contributions from unsheltered homelessness. For example, HF183 (31% vs. 0%), crAssphage (61% vs. 5%), and PMMoV (72% vs. 55%) were more frequently detected in tributary washes with higher homeless census counts vs. ‘control’ tributary washes. Illicit drugs or their metabolites (e.g., heroin, acetylmorphine, amphetamine, and cocaine) and select TOrCs (e.g., acetaminophen, caffeine, ibuprofen,

and naproxen) were also detected more frequently and at higher concentrations in the more anthropogenically-impacted washes. These data can be used to raise awareness of the shared interests between the public and those who are experiencing homelessness, including the importance of protecting environmental health and water quality. Ultimately, this may lead to more rapid adoption of proven strategies for achieving functional zero homelessness.

AEG 2022 ANNUAL MEETING 88 AEG 65th Annual Meeting Program with Abstracts September 2022

Paulose, Presty, KANE GeoTech, presty.paulose@kanegeotech.com;Inc.,Brian Forsthoff, brian.forsthoff@kanegeotech.com (TS #13)

June 24, 1971 Sylmar Tunnel Fire – A Grim Reminder Piepenburg, Michael A., Mott michael.piepenburg@mottmac.comMacDonald,(TS#2)Inmid-June1971,fivemilesofthe18-foot-diameter

The December 2020 Bond Fire occurred burned a total of 6,681 acres within the Santa Ana mountains in Orange County, California. A CalFire and California Geological Survey Watershed Emergency Response Team (WERT) was deployed to identify and evaluate post-fire geologic hazards to residents downstream of the Bond Fire burned area. The WERT identified 64 values at risk (VAR) within and downslope/downstream of the burned area that were rated low, moderate, and high risk to property and life safety from post-fire geologic hazards. Seventy-seven percent of the VAR are identified as having a moderate to high life-safety threat with 19 VAR identified as a high life-safety threat. Four significant storms impacted the burn scar during the first year following the fire. The four storm events generally produced rainfall rates that met or exceeded threshold values for debris flow initiation set by the WERT following the investigation. On December 14, 2021, a major storm impacted the Bond Fire burn scar causing extensive property damage in areas delineated by the WERT as VAR. The storm event followed a National Weather Service (NWS) weather advisory and flash flood warning with predicted one-hour rainfall rates at, or exceeding, threshold levels set for predicted initiation of debris flow impacts. The identification of VAR, NWS warnings, and locally mandated evacuations likely saved lives. This report documents: 1) impacts observed and reported across the Bond Fire burned area in response to year-one storm events, 2) calculations of debris yields at several locations for each storm event, 3) ranking of the magnitude of the storm response to each storm event, and 4) evaluation of the approximate expected recurrence interval of the storm intensities recorded using empirical rainfall data.

Water Tunnel located in Sylmar California (near Los Angeles) had been completed. Only a half mile of excavation remained to be completed when natural gas (methane) pockets entering into the tunnel were ignited and four workers seriously injured. Less than 24 hours after this first incident, a more severe natural gas explosion occurred in the tunnel resulting in 18 miners being trapped underground at a distance of five miles from the portal. Despite heroic efforts by firefighters and rescuers, 17 miners died that day—including one miner who had been treated from injuries caused by the previous day’s explosion. Only one man survived and the Sylmar Tunnel Explosion of June 24, 1971,

Time Domain Reflectometry (TDR) has been available for decades and is widely used for monitoring and diagnostic purposes in various fields. For geotechnical applications, TDR is used to detect and locate subsurface movement by monitoring coaxial cables grouted in boreholes. The electrical properties of the TDR sensor cable change as it deforms. A TDR reflectometer sends an electrical pulse along the cable, and then measures the changes in that pulse. Rapid data collection and simple installation methods make TDR a cost-effective solution to slope monitoring over other popular methods such as inclinometers. This methodology has been successfully implemented on infrastructure projects, including railways, pipelines, and dams. TDR systems are configured for manual readings or remote monitoring. Manual readings routinely take less than a minute. In remote monitoring, alerts such as emails and text messages, notify key personnel of critical activity. It is possible to monitor dozens of installations from one location. Sensor cables are either installed horizontally or vertically. For example, in Tennessee an approximately 4,000-ft-long horizontal TDR sensor cables were installed along a potentially liquefiable dam embankment. In California, vertical TDR sensor cables were implemented to alert gas company personnel of landslides that could damage pipelines. The City of Los Angeles now requires that tensioned tie-back slope stabilization systems be monitored for 25 years after installation. TDR is now being implemented to meet this requirement in a cost-effective manner. One drawback of conventional slope inclinometers is that they are unusable once the casing has deformed, and reliable readings become unobtainable. Since the TDR cable is smaller and more flexible, the TDR sensor mimics the deformations in the inclinometer casing. By retrofitting unusable inclinometer casing with TDR sensors in a California landslide, the life of the existing monitoring system was extended. This presentation describes the goals, design, construction, and challenges involved in implementing TDR systems and includes previous described examples where TDR has been successfully installed.

San Fernando

Time Domain Reflectometry for Innovative Landslide and Slope Monitoring

Lessons from Libby, Montana: Autoimmune mechanisms of Asbestos Health Outcomes

GIS and other digital tools were available to rapidly collect and compile field data leading to the timely synthesis of data for situational awareness maps, images for media, areas of interest for lidar collection, and assisting field teams to efficiently map a broad rupture region. The 2019 Ridgecrest earthquake sequence provided an opportunity to test and refine methods for rapidly collecting and disseminating field observations after a large and complex surface rupturing earthquake.

Groundwater quality has been an important element in the development of Las Vegas Valley (LVV) since early settlement and has been documented in numerous scientific publications since 1909. Southern Nevada Water Authority and Las Vegas Valley Water District maintain a monitoring network of over 200 wells across LVV to track hydrologic and groundwater quality conditions and trends. LVV groundwater quality is controlled by recharge of precipitation primarily in the Spring Mountains and a minor amount from the Sheep Range and subsequent interaction with basin sediments along the groundwater flow paths. The direct injection of treated Colorado River water through the Aquifer Storage and Recovery Program and secondary recharge from infiltration of irrigation water and septic system effluent also influences groundwater chemistry. This presentation reviews the three primary hydrochemical facies associated with Principal Aquifer System. A fourth hydrochemical facies associated with the shallow groundwater system is characterized by very poor water quality derived from dissolution of evaporites and concentration of minerals due to evapotranspiration. Current groundwater quality trends are also discussed.

Prieur, James, Las Vegas Valley Water District / Southern Nevada Water Authority, james.prieur@snwa.com (TS #11)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 89

Debris Flows are the extremely rapid (often channelized) movement of unconsolidated and saturated slope forming materials. Once triggered, these catastrophic mass movements can gain enough momentum to destroy life and infrastructure exposed to their travel path. Exceptional historic debris flows have even killed thousands of people in a single event (for example, 15,000 deaths due to the 1999 rainfall-triggered debris flows in Venezuela). However, not enough studies have addressed the societal risk of global debris flow occurrences in isolation, as they are mostly considered/combined together with all other types of landslides (sliding or rotational failure, rockfalls, etc.). In one study, Dowling and Santi (2013) compiled a database of 213 fatal debris flows that occurred from 1950 to 2011, recording a total of 77,779 deaths. No similar global database has been created after this study, which would be essential to understanding the evolution of fatal debris flow occurrence over the last decade. To address this gap, we created a new database of all fatal debris flow events in 2019. Around 70 events were recorded with more than 1,500 fatalities, which accounted for ~50 percent of the total landslide fatalities in 2019. We further studied the evolution of the societal risk of debris flow to find that the annualized probability of fatality from debris flow has decreased (probably due to improvement in debris flow mitigation measures) but is still higher than landslides in general.

After a major and/or damaging earthquake in California, the California Geological Survey is mandated to establish a clearinghouse in coordination with its managing partners, United States Geological Survey, Earthquake Engineering Research Institute, California Office of Emergency Services, and California Seismic Safety Commission, to provide disaster response managers, affected agencies, and the scientific community with prompt information on ground failure, structural damage, and other consequences of a significant seismic event. The July 2019 Ridgecrest earthquake sequence provided an opportunity to exercise the Clearinghouse, including seven days onsite, coordinating response and access to restricted areas, with over 50 experts from federal, state, public, and private organizations. Expertise spanned many disciplines: geosciences, geotechnical engineering, structural engineering, nonstructural components, insurance, lifelines, transportation, risk analysis, and business continuity. The EERI “Learning From Earthquakes” program provided event virtual clearinghouse support to share field data, photos, preliminary reports, and links to imagery. A suite of

Following the damaging 1971 San Fernando Earthquake, after-action reports recognized the collective efforts of scientific and engineering responders and the value and urgent need for organized crisis response and communication, especially for urban areas. In 1972, the California Post-Earthquake Information Clearinghouse was established.

LVVWD operates the water supply systems for Kyle Canyon and Blue Diamond located in the Spring Mountains west of Las Vegas. The communities rely solely on groundwater resources which are recharged primarily by winter precipitation. The systems are constrained by area hydrogeology and variability in recharge. Hydrologic conditions over that past 20 years are characterized by several years of extreme above and below normal precipitation and extended periods of drought. An overview of the hydrogeologic framework and groundwater system for the communities are presented along with historical hydrologic conditions. Groundwater recharge dynamics and production well performance are presented. Long-term climate trend uncertainty in regard to groundwater recharge, the water resource outlook, and management plans are discussed.

Groundwater Chemistry of Las Vegas Valley

Fatalities from Debris Flow: Is the Societal Risk Higher than Landslides?

The California Earthquake Clearinghouse – Ridgecrest Earthquake Sequence 2019

remains one of the worst tunnel disasters in California history. The disaster not only resulted in the toughest mining and tunnel regulations in the nation but also led California to create a state occupational safety agency, known as Cal/OSHA. This talk is part history lesson and part grim reminder that we should never be complacent or (over)confident about working in potentially gassy or gassy conditions underground.

Hydrogeology and Climate Effects on Municipal Water Supply Systems in the Spring Mountains, Nevada

Prieur, James, Las Vegas Valley Water District / Southern Nevada Water Authority, james.prieur@snwa.com (TS #11)

Ptau, Jean, Montana State University, jean.pfau@montana.edu (TS #6)

Pridmore, Cynthia L., California Geological Survey/Dept. Conservation, cynthia.pridmore@conservation.ca.gov;KateThomas,kate.thomas@conservation.ca.gov (TS #13)

Twenty years after the world learned of the Asbestiform Amphibole exposures in Libby, Montana, significant advances in our understanding of the health effects of mineral fibers have occurred. Unexpected outcomes of exposure include autoimmune diseases and a unique progressive pleural fibrosis never previously described. Studies on erionite, crocidolite, and fluoro-edenite reveal that other mineral fibers evoke autoimmune responses as well. Immune mechanisms driving both of these outcomes are now beginning to be elucidated. Oxidative and apoptotic mechanisms cause antigen modifications,

Prakash, Nikhil, Colorado School of Mines, nprakash@mines.edu; Paul Santi, psanti@mines.edu (TS #16) (Presented by Paul Santi)

That Sinking Feeling: Reexamining 100 Years of Land Subsidence in the Greater Houston Area, Texas, Based on Multiple Measurement Types Ramage, Jason, USGS, jkramage@usgs.gov; John Ellis, jellis@usgs.gov (TS #14)

The greater Houston area is one of the largest subsidence areas in the United States. Subsidence has primarily occurred in six historical population centers concurrent with substantial groundwater-level declines from rapid groundwater development. The earliest recorded subsidence began prior to 1918 in downtown Houston and the Goose Creek oil field. Sustained groundwater-level declines of up to 14 feet per year generally starting in the 1930s contributed to more than 4 feet of subsidence in Baytown and Texas City by 1951. By 1978, more than 9 feet of subsidence had occurred in Pasadena and Baytown, concurrent with groundwater-level declines of more than 300 feet. Rapid groundwater-level recoveries and subsequent subsidence decreases occurred with the advent of groundwater use regulation in the mid-1970s. Since 1978, the center of subsidence in the region has shifted northward and westward of the historical population centers based on groundwater-level declines of more than 400 feet. Observed subsidence in these areas through 2021 based on extensometer, leveling, and global positioning system (GPS) data is more than 2.5 feet, most of which has occurred since 1978. Estimated Jasper aquifer compaction in Harris and Montgomery Counties accounts for about 16 percent and between 33 and 57 percent of subsidence, respectively, based on the Gulf Coast Land Subsidence and Groundwater-Flow Model. In the greater Houston area, the ratio of subsidence per 100 feet of water-level decline ranges from 0.5 feet to more than 2.5 feet. Although most subsidence has been broad-based, a subsidence differential of up to 1.6 feet occurred within less than half a mile in Baytown and Texas City. These differences are due to the

resulting in the production of anti-nuclear autoantibodies (ANA) and associated systemic autoimmune diseases. Mesothelial Cell Autoantibodies (MCAA) elicited by exposure to amphibole fibers seem to drive the progressive pleural fibrosis through citrullination of cell-surface receptors, making it a localized autoimmune disease of the pleura. These findings begin to provide targets for therapeutic modalities for diseases that are refractory to current treatments.

AEG 2022 ANNUAL MEETING 90 AEG 65th Annual Meeting Program with Abstracts September 2022

Lake Mead is the largest manmade reservoir in the United States. Its upstream neighbor, Lake Powell, is the second largest. Both reservoirs were built and are operated by the Bureau of Reclamation. Together the two reservoirs have the capacity to store over 50 million acre-feet of Colorado River water, over three times the long-term average annual natural flow of the Colorado River, about 14.7 million acre-feet per year at Lees Ferry, Arizona. Over the past 22 years, and accelerating over the past two years, the Colorado River has experienced worsening drought and low-runoff conditions that demonstrate the accelerating impacts of warming temperatures and climate change and increased system risk. Lake Powell’s 2022 April - July unregulated inflow was 59% of average, despite getting approximately 90% of snowpack. Both Lake Powell and Lake Mead are at their lowest levels since initial filling. The two reservoirs are projected to end the calendar year with a combined

Rapid Collaboration on Water Resource Management Projects in an Ever-Changing Climate

Quigley, Laura, Seequent, laura.quigley@seequent.com; Sean Buchanan, sean.buchanan@seequent.com; Stephanie Vanos, stephanie.vanos@seequent.com (TS #4)

Discover how the effective combination of geophysical inversion results from airborne electromagnetic (AEM) data with a geological model derived implicitly using borehole information can accurately constrain the underlying aquifer, in a shareable 3D model. To truly understand the subsurface, a multidisciplinary approach is required, with the ability to rapidly collaborate with colleagues. The collaboration of this study shows how Geophysical inversion can be incorporated with borehole data to improve our understanding of large-scale aquifer structures in a region of Eastern Nebraska. The alliance between geologists and geophysicists allows for the refinement of the subsurface model and more accurate interpretation of the aquifer extents. The resistivity distribution of the subsurface can be related to various geological units in the developed geological model. Furthermore, the high spatial resolution of the geophysical data provides additional insight into the geological units, which have been interpolated from borehole information, often kilometers apart. This integration can aid in subsurface understanding and ultimately inform better drilling decisions in the future. To facilitate collaboration, the project is hosted on a cloud server so that different teams and stakeholders can access the evolving model and raw data, view the subsurface digital twin in 3D, and track the changes made to the project as they happen. Tools for 3D visualization and commenting on each revision permits interactive correspondence directly within the project, so important discussions are easily accessible to everyone. This enhanced communication can streamline the decision-making process, keeping all stakeholders and decision makers up to date with project refinements. In addition to this efficient process, new data can be easily integrated, allowing for iterative updates to the model to monitor any changes in geologic understanding and groundwater conditions well into the future.

Keynote: Bureau of Reclamation’s Senior Management to Discuss the Impact of the Southwest Drought on Hoover Dam and the Colorado River

Raff, David, Bureau of Reclamation, DRaff@usbr.gov (TS #4)

storage of roughly 25 percent of their capacity. A warmer, drier West coupled with the lowest reservoir capacities on record is now the norm in which Reclamation must manage its systems. Over the last two decades, Department leaders have engaged with Colorado River Basin partners on various drought response operations. However, given that water levels continue to decline, additional action is needed to protect the System. As the worsening drought crisis continues to impact communities across the West, the Department of the Interior on August 16, 2022, announced urgent action to improve and protect the long-term sustainability of the Colorado River System, including commitments for continued engagement with impacted states and Tribes. The Bureau of Reclamation also released the Colorado River Basin August 2022 24Month Study, which sets the annual operations for Lake Powell and Lake Mead in 2023 in light of critically low reservoir conditions. Reclamation’s 2023 operations honor existing agreements as approved by Congress that have been developed over the past two decades and lay out detailed operational rules for these critical Colorado River reservoirs. Due to declining reservoir levels, downstream releases from Glen Canyon and Hoover dams will be reduced again in 2023. In the Lower Basin the reductions represent the second year of increasing “shortage” declarations—demonstrating the severity of the drought and low reservoir conditions. Based on projections in the August 2022 24-Month Study, Lake Powell will operate in the Lower Elevation Balancing Tier in water year 2023, and Lake Mead will operate in its first-ever Level 2a Shortage Condition in calendar year 2023. Reclamation is committed to working closely with the Basin states and Tribes to work toward collectively mitigating the impacts of drought and climate change on the Colorado River- and our shared goal of formulating durable and equitable solutions.

The presence of naturally-occurring asbestos (NOA) is increasingly concerning for scientists, health and regulatory agencies, and citizens living in impacted areas. It is commonly believed that fibrous amphibole asbestos can only form through neocrystallization. In southern Nevada, NOA occurs as a result of hydrothermal alteration of granitic rock producing fibrous amphibole both as crosscutting neocrystallized veins and via recrystallization of original magmatic hornblende crystals. Fibers with a greater aspect ratio are known to have increased toxicity. This study measured the maximum length and average width of both neocrystallized and recrystallized fibers to see if the morphologies were similar. Neocrystallized and recrystallized fibers from the McCullough Range, NV were identified using a petrographic microscope, extracted from polished thin sections using a motorized drill, and analyzed using the scanning electron microscope (SEM), and field emission scanning electron microscope (FESEM) with energy dispersive x-ray analysis (EDS). Neocrystallization produced fibers with an average width of 0.53 +/- 0.018 µm, an average length of 4.26 +/0.257 µm, and an average aspect ratio of 8.7 +/- 0.38. Recrystallization produced fibers with an average width of 0.64 +/- 0.023 µm, an average length of 7.31 +/- 0.0233 µm, and an average aspect ratio of 13. +/- 0.86. The Mann-Whitney U-test indicates that there is significant difference in the aspect ratios, width, and length of neocrystallized and recrystallized fibers having similar mineralogy and chemistry. Because the recrystallization process produces fibers that have greater average aspect ratios, they may be more toxic than those produced through neocrystallization. We hypothesize that the likely reason for this are increased chain width defects resulting from fluctuating conditions during recrystallization. Because hydrothermal alteration and recrystallization of primary minerals is a very common geologic process, this finding may significantly increase the number and distribution of rocks and soils that contain NOA.

The Time is Right to Add Deep Aquifer Recharge as a Resiliency Planning Tool

is defined by the United States Environmental Protection Agency (USEPA) as “a cost-effective, resilient approach to managing wet weather impacts that provides many community benefits.” Nationwide, it seems that the vast majority of green infrastructure projects completed to date involve diverting stormwater or treated

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 91

Attention to emergency spillways at United States dams increased substantially following the Oroville Dam spillway incident. The incident stimulated intensive investigations by dam owners across the country, utilizing lessons learned from Oroville. Common characteristics of emergency spillways are 1) common feature at dams which is either lined or unlined, 2) unlined minimizes cost by allowing for some erosion during infrequent loading events, 3) rely on a hardened control section with or without deep cutoffs to prevent breach, 4) concrete lining designs vary considerably, 5) control structure designs vary considerably, 6) consequence assessments vary considerably. Erosion of unlined spillways is evaluated from hydraulic shear velocity or shear stress using relationships such as the Shields parameter or empirical studies of stream power. Models such as USDA SITES or WinDAM and USACE HEC-RAS or Computational Fluid Dynamics model (CFD) assess spillway erosion. The Annandale method provides deterministic methods to assess the erosive power of water in various hydraulic environments with the Erodibility Index method to assess erodibility of geomaterials. Common criteria are that the local hydraulic environment and erodibility of geomaterials in that environment control the amount, type, and rate of erosion. This presentation is a case history of an unlined spillway evaluated by the US Army Corps of Engineers. Such an assessment requires close collaboration of Engineering Geologists and Hydraulic Engineers. The spillway chute is variously weathered claystone, mudstone, and shale and contains a control structure consisting of a reinforced concrete sill with inclined sidewalls, a 10-ft-deep cutoff wall with cantilevered apron. Challenges include lack of studies of breach parameters for unlined spillways, lack of methods for assessing erosion under cantilevered aprons, erodibility of transitional materials, temporal effects of nodal probabilities for spillway erosion, site characterization, consequence analyses for spillway breach. A method to assess risk of unlined spillways is presented.

Renkes, Natalie, University of Nevada, Las Vegas, renkes@unlv.nevada.edu; Brenda Buck, buckb@unlv.nevada.edu; Rodney Metcalf, metcalfr@unlv.nevada.edu (Poster)

A Digital Twin System to Manage the Uncertainties Associated with the Ground Conditions on Tunneling Projects

“Green#4)infrastructure”

The earth conditions present several uncertainties in the design and monitoring of tunnelling projects. Due to the linear extension of tunnels, they will encounter wide variabilities in geology and ground conditions at and below the ground surface. Subsurface conditions can have a dramatic impact on the stability of a tunnel. Tunnelling will unlock stresses that have built up over millions of years, which may affect the soil’s shear strength and increase the risk of landslides. Therefore, bringing together all the available data in a comprehensive digital twin—a digital representation of the tunnel which encompasses its site information— helps us understand and model the tunnelling projects in a detailed and insightful manner. It allows for a full representation of the data even when the nature of that data is enormously diverse. But more importantly, this twin can be continuously updated from multiple sources long after the completion of the tunnel construction to monitor the safety and reliability

of the structure. This presentation will show how we encounter the uncertainties around a tunnelling project by setting up a shareable holistic digital twin model. We use geophysical data and a geological model—derived implicitly using borehole information and other site data to provide detailed insights into soil properties and layers. Through a dynamically connected workflow, we will analyze ground conditions, validate designs and evaluate the slope stability at different locations of the tunnel entrance. Lastly, we show how the modelling process and communication with a multi-disciplinary team is efficiently streamlined through an interactive cloud-based data management system. This invites all to interactively share, version-control, communicate and visualize their models in a secure and auditable environment. The cloud-based platform will dynamically connect data and models from geophysicists and engineering geologists together with geotechnical engineers to enhance information flow and reduce superfluous data.

Assessment of Breach and Consequences for an Unlined Emergency Spillway Richards, Kevin, US Army Corps of Engineers, kevin.s.richards@usace.army.mil (TS #15)

Rezapour, Aida, Seequent, Aida.Rezapour@Seequent.com; Laura Quigley, Laura.Quigley@Seequent.com; Sean Buchanan, Sean.Buchanan@Seequent.com; Stephanie Vanos, Stephanie.Vanos@Seequent.com (TS #2)

Robinson, John, Dewberry Engineers Inc., jrobinson@dewberry.com (TS

Can Recrystallization of Fibrous Amphibole Produce Asbestos Morphologies?

concentrated groundwater use in these areas combined with substantial fine-grained sediment compared to the more spatially distributed wells and coarser sediment in other parts of the greater Houston area.

Forensic Analyses of Megalandslides along the Echo and Vermilion Cliffs of Northern Arizona

Rogers, J. David, Missouri University of Science & Technology, rogersda@mst.edu (TS #8)

wastewater to recharge water table aquifers. Groundwater extracted from deep and confined aquifers is often “mined” and is depleted faster than it recharges. Groundwater is a renewable resource, although not immediately, and the mining of deep groundwater temporarily disrupts a portion of the natural water cycle. Extracted groundwater from deep or confined aquifers is used at the ground surface and also ultimately makes its way into the ocean, thereby contributing to sea level rise. The United States Geological Survey (USGS) estimates that the depletion of combined aquifers in the United States alone accounted for 3.1 millimeters per year, or 2.3 percent of the observed rate of sea level rise between 2001 and 2008. Another unintended consequence of groundwater over-pumping is land subsidence. Subsidence is a result of groundwater withdrawal— commonly reported in California, Arizona—and is linked to the ongoing development of sinkholes throughout areas overlying the Floridan Aquifer. Combating sea level rise through enhanced continental absorption via the creation of green infrastructure, as well as the use of desalination and deep aquifer recharge, is viable. A very long-term strategy designed to protect both surface and subsurface infrastructure as urban build-out and replacement occurs is important. The USEPA offers several grant funding sources that could be used to fund deep aquifer recharge pilot projects, including the Drinking Water State Revolving Fund (DWSRF) and the Water Infrastructure and Resiliency Finance Center (WIRFC).

The Vermilion and Echo Cliffs form a nearly continuous escarpment more than 160 kilometers long within the Colorado Plateau physiographic province. The cliffs overlie the Marble Platform in northern

AEG 2022 ANNUAL MEETING 92 AEG 65th Annual Meeting Program with Abstracts September 2022

Hydrogeology of Stress-Relief and Regional Fracture Regime Integration – Engineering and Environmental Case Studies Rogers, A. Bruce, US Army Corps of Engineers, Nashville District, adrian.b.rogers@usace.army.mil (TS #11)

Arizona and are located along the Colorado River just upstream of the Grand Canyon. Large rotational block landslides mantle the erosional escarpment along most of its extent. Although these landslides have been noted for over one hundred years, their likely origin has never been explained. Landslide failure surfaces appear to be influenced by the Petrified Forest Member of the Triassic Chinle Formation, a shale layer containing smectite clay weathered from volcanic ash. Although landslides are common along the majority of escarpments comprising the Colorado Plateau where the Petrified Forest member and other shales outcrop, most appear to have been inactive since the early Holocene. There are multiple generations of landslides and remnants of previous slides exist up to three kilometers from the present cliff face. Multiple working hypotheses explaining these landslides were investigated over the past two decades, including past landslides and/or lava dams along the Colorado River within the Grand Canyon, periods of wetter climate with higher groundwater levels, and seismotectonic influences related to active faulting and volcanism. Various sliding modes along these cliffs are described along with potential triggering mechanisms. Back-analysis of these landslides have been conducted using mechanical properties of the formations involved as well as varying groundwater levels. Calculated factors of safety for existing slides under present conditions are greater than unity, consistent with their apparent stability.

The movement of groundwater in Appalachia is typically controlled by the occurrence of stress-relief fractures within the near-surface bedrock beneath the floor of the stream valleys. Consequently, the strength of rock foundations are also heavily dependent upon the extent of stress-relief fracture regimes. The modern studies of this phenomenon were pioneered in 1967 by Harry F. Ferguson, a geologist with the USGS and later the US Army Corps of Engineers. Every stream valley in Appalachia is affected to some degree by the presence of stress-relief fractures. Their development, spatial extent and integration of stress-relief regimes with the regional fracture regimes are dependent on a variety of site-specific variables such as stratigraphy, geomorphology and structure. The characterization of these integrated fracture regimes will provide the first step in accurately mapping both groundwater flow and foundation issues in the clastic bedrock. Both the spatial extent and orientation of near surface rock fractures are typically controlled by the integration of regional and local fracture regimes. These are of critical concern in the geologic engineering design of dams, locks, underground mines and rockslides. They also form major conduits for groundwater flow and their characterization provides the hydrogeologist with crucial information on determining site hydrogeology for environmental projects. This presentation will look at several engineering and environmental case studies involving the integration of regional and stress-relief fracturing regimes at sites that I have personally worked on.

Rogers, J. David, Missouri University Science & Technology, rogersda@mst.edu; Conor M. Watkins, cwatkin@mst.edu (TS #12)

According to the US Geological Survey, 254 dams have been unknowingly constructed on or against prehistoric landslide features. Of these, 153 are within the United States. Landslide dam sites share a number of physical attributes that are important to evaluate to confirm or deny their occurrence. A river’s thalweg is one of the most telling features to consider before making a site reconnaissance. Most rivers develop a pool and riffle profile with “hydraulic chokes” where side canyons deposit sediment, constricting the channel sufficiently to form riffles or rapids with shallow flow depths. The severity of the riffles are in proportion to the watershed area of the side-canyon tributaries entering the mainstream. Natural landslide dams are always removed, usually by overtopping. These overtopping flows are usually very short-lived, depositing a discontinuous series of terraces above the present-day low flow channel. Unlike classic river terraces, those left by catastrophic outbreak floods are characterized by being comprised of only one rock type, from the landslide dam site. After an outbreak flood the remnants of the old landslide dam often form a “hydraulic choke” with a meandering channel upstream of the blockage. This low gradient reach may also exhibit anomalously fine-grained sediments, deposited in the landslide dam reservoir. “Skeletal blocks” in the channel at the dam sites are often revealed in a thalweg profile as noticeable knickpoints. The particle sizes of the outbreak flood terraces are increasingly finer upward. The gravels and boulders are usually the same lithology as those exposed at the landslide dam site. Deposition from a waning current is typical of outbreak floods because they are shortlived. The sediment package is characterized by a fining upward trend with discernable contacts between successive flows.

Recognition of Prehistoric Landslide Dams and Catastrophic Outbreak Floods

The urban development of Chattanooga, Tennessee is experiencing neglected industrial properties being redeveloped for mixed-use, including residential purposes. The increased repurposing of industrial property to residential use always presents site-specific challenges for environmental assessments. Environmental issues that surface when redeveloping an industrial property for residential use include the typical Recognized Environmental Conditions (RECs) identified within the scope of ASTM E1527-13 and ASTM E1527-21 “Standard Practice for Environmental Site Assessment: Phase I Environmental Site Assessment Process” (Phase I). During an environmental risk assessment of industrial property, the use of both the Phase I standard and nonscope environmental data is an integral part of a complete risk assessment. While investigating an industrial property, other issues beyond the scope of Phase I could impact the development of the site. Typical non-scope issues include asbestos, lead in soil (or paint), mold, wetlands, threatened & endangered species, indoor air quality, and many more. Identifying both the scope and non-scope environmental

Features of the 2019 M6.4 and M7.1 Ridgecrest Earthquakes Rosa, Carla, California Geological Survey, Carla.Rosa@conservation.ca.gov; Timothy Dawson, Timothy.Dawson@conservation.ca.gov; Reva Kakaria, Reva.Kakaria@conservation.ca.gov (TS #3)

We present mapping of surface ruptures and ground-deformation features associated with the 2019 Ridgecrest Earthquake Sequence. The mapping utilizes high-resolution (up to 80 pulses per square meter) airborne lidar flown post-earthquake by the National Center for Airborne Laser Mapping (Hudnut et al., 2020). The MW 6.4 and MW 7.1 earthquakes produced rupture and ground deformation zones approximately 18 km and 50 km in length, respectively, with widespread deformation occurring off the main fault strands. Our goal is to produce a comprehensive, spatially accurate dataset depicting surface ruptures associated with the Salt Wells Valley and Paxton Ranch Fault Zones. This work is focused on delineating features attributed directly to tectonic surface rupture rather than ground shaking and liquefaction. We used seamless lidar-derived hillshades, illuminated at 45- and 315-degrees and supplemented with a multi-directional hillshade as the base imagery. Mapping was done at a consistent (1:500 – 1:1000) scale, the largest scale at which imagery resolution is not degraded. Use of this large scale increases our confidence that we have only mapped features that are related to ground deformation from the earthquake. The surface rupture was mapped to highlight the width of deformation zones and to characterize the rupture’s expression through varying terrain, such as along pre-existing fault scarps, hillslopes, fan surfaces, and relatively flat playa surfaces. Our mapping shows that the lidar can reliably resolve ruptures with tens of centimeters and more of relative vertical displacement. Areas with known surface rupture, mapped either in the field or on aerial imagery, but with little relative vertical displacement, are less likely to be well-resolved on the lidar. Thus, characterizing zones of deformation, important for the assessment of fault displacement hazard, will likely require a paired approach using both lidar and high-resolution aerial imagery.

Risk Assessment Needs for Redeveloping Industrial Property to Residential Use

When asked to draw or find the image of a scientist at the beginning of an introductory geoscience class, students mostly draw Einstein, Bill Nye, or a male with glasses in a lab coat holding test tubes. The image of a geoscientist is rarely the first one to appear when you search the web for the word “scientist.” Most of the images drawn or found show someone who looks different than most of my students, or I. This is especially important at Nevada State College, a four-year undergraduate Hispanic Serving Institution with majority first-generation, nontraditional students. My position as a female Mexican professor allows me to challenge the stereotype of how a scientist looks and to introduce the relevance of geosciences in everyones’ lives. Few of our students see themselves as scientists, and even less know about the professional opportunities offered by the geoscience field as a career path. My choices as an instructor derive from my personal experience as I became a geoscientist but are also continuously under revision in order to provide equitable and inclusive opportunities. I search for the best practices to prompt students’ awareness, build on previous knowledge, explore their surroundings, pose their own questions, identify the relevance of the topic in their everyday lives, and perhaps see themselves as a geoscientist. These future geoscientists’

Mapping of Surface Fault Rupture and Ground-Deformation

rapid earth flows and spreads when the soil structure collapses, the strength decreases to a lower remolded strength and subsequently liquefies. On September 16, 2020, a 10,000 cubic yard sensitive clay earth flow occurred on the south bank of the Presumpscot River in Westbrook, Maine and formed a landslide dam, raising the upstream river level by 11.5 feet. A 12.75-inch natural gas pipeline operated by Enbridge Gas Transmission (Enbridge) crossed the river immediately downstream of the landslide; the pipeline was taken out of service immediately after the event until the geohazards posed to the pipeline could be evaluated. This case study examines Enbridge’s response to the landslide and the associated hazard evaluation provided by BGC Engineering Inc. (BGC). BGC completed a desktop study in tandem with a site visit to evaluate the pipeline’s vulnerability to the geohazards. BGC classified the landslide as a rapid to extremely rapid earth flow and estimated that it ran out approximately 300 feet, reaching a depth of 25 feet. BGC evaluated four hazard scenarios with potential to impact the pipeline: landslide dam rupture and outburst flood, deepseated ground movement, lateral retrogression or rapid lateral expansion, and formation of a new landslide collocated with the pipeline. Following three days of field inspections, Enbridge and BGC concluded that the pipeline was unlikely to be adversely impacted, and the pipeline was returned to service. In order to remotely monitor for further ground movement, BGC developed a near-real time tilt meter network that could be rapidly deployed and was simple to install. BGC’s analysis of post-landslide in-line inspection data supports the evaluation that the pipeline was not impacted by the landslide event. Enbridge’s response to the landslide demonstrates an effective and collaborative approach to evaluate and manage pipeline geohazards.

Schuler, Karl, Marion Environmental, Inc., kschuler@marionenv.com (TS #19)

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 93

will become the images and will bring perspectives and words that will continue building diversity, equity and inclusion in our field.

Quick Response to a Sensitive Situation: A Case Study of a Pipeline Operator’s Response to a Sensitive Clay Landslide Rosenbaum, Cole, BGC Engineering Inc., crosenbaum@bgcengineering.com;DaveGauthier,dgauthier@bgcengineering.ca;CaseyDowling,cdowling@bgcengineering.com;DougCook,doug.cook@enbridge.com(TS#16)Sensitiveglaciomarinefine-grainedsoilscanexperience

Teaching Geoscience as a Latino Female Professor in Nevada: A Small Door to Increase Diversity in the Field Rosales-Lagarde, Laura, Nevada State College, Physical and Life Sciences, Environmental & Resource Science Program, laura.rosales@nsc.edu (TS #1)

issues during the initial site investigation allows clients to best anticipate critical development needs for the future intended use of a property. This presentation will summarize many of the environmental issues encountered when redeveloping industrial property for residential use and will discuss why identifying all of the issues is best for human health and the environment.

Shinpaugh, Joshua, Tennessee Valley Authority, jeshinpaugh0@tva.gov; Kristen Smith, klsmith2@tva.gov; Melissa Setz, msetz@geosyntec.com; Molly O’Connor, oconnorm@bv.com (TS #15)

Dam safety modifications to Isabella Auxiliary Dam are currently under construction to address actionable potential failure modes. Isabella Lake is located on the Kern River 34 miles upstream of the City of Bakersfield in Kern County, California. Isabella Dam has been designated as a Dam Safety Action Class (DSAC) 1 project by the US Army Corps of Engineers (USACE), requiring action to reduce probabilities of failure and associated consequences. Isabella Dam construction began in 1948 and was completed in 1953. The project consists of two embankment dams that provide flood control, water supply, power generation and recreation benefits to the region. The modifications under construction are addressing actionable potential failure modes identified over three primary areas of deficiency, including hydrologic overtopping, internal erosion of the foundation, and seismic instability from strong ground motion and/or fault rupture. This paper includes an overview of the dam safety project, and specifically a summary of the potential risk, dam safety modification design, and construction to address the potential for active fault rupture of the Kern Canyon fault beneath the right abutment of the Isabella Auxiliary Dam. This paper summarizes results from geologic and paleoseismic investigations and subsequent analyses used to design the size and location of modifications to the Auxiliary Dam. This paper also provides a summary of the photogrammetric foundation map concurrent with construction and includes suggestions for future photogrammetric mapping efforts. The paper also provides a summary of the conditions encountered during construction and the foundation character in the vicinity of the fault at the Isabella Auxiliary Dam.

A Systematic Approach to Address Risk Uncertainty in a Karst Environment

Small, Molly, Geosyntec Consultants, msmall@geosyntec.com; Randy Brandt, rbrandt@geosyntec.com; Keaton Belli, kbelli@geosyntec.com; Paul Dockweiler, pdockweiler@geosyntec.com (TS #9)

presentation provides insightful detail regarding the history, current operations and future challenges of USBR Hoover Dam Facility, located near Boulder City, Nevada. If you get a chance to take the AEG Conference hardhat tour, take it! Historic Design and Construction: Hoover Dam is a testimony to a country’s ability to construct monolithic projects in the midst of adverse conditions. Built during the Depression; thousands of men and their families came to Black Canyon to tame the Colorado River. It took less than five years, in a harsh and barren land, to build the largest dam of its time. Now, years later, Hoover Dam still stands as a world-renowned structure. The Dam is a National Historic Landmark and has been rated by the American Society of Civil Engineers as one of America’s Seven Modern Civil Engineering Wonders. Current Operations: Hoover Dam and Lake Mead, spanning the Arizona-Nevada state line, are located in the Black Canyon of the Colorado River about 35 miles southeast of Las Vegas, Nevada. It is a concrete thick-arch structure, 726.4 feet high and 1,244 feet long. The dam contains 3.25 million cubic yards of concrete; total concrete in the dam and appurtenant works is 4.4 million cubic yards. The hydroelectric powerplant consists of 17 main Francis turbine generators and two Pelton Waterwheel station service units (one for each plant wing). The total plant capacity is 2,079,000 kW. Future Challenges: Climate change resulting in a reduced reservoir recharge in conjunction with an increased demand for municipal water and hydroelectric power generation make for unique water resource challenges in the Southwest. Viable solutions to these challenges are limited. Paradigm adjustments regarding water supply and demand is not an easy task to define or implement to ensure adequate water resources in the future.

In an effort to establish concentrations of Naturally Occurring Radioactive Materials (NORM), specifically uranium, across Nevada, the Nevada DEP has begun requiring analysis of uranium in groundwater at mining facilities. Data will be used to define baseline groundwater uranium concentrations against which to compare groundwater monitoring data at sites where technologically enhanced NORMs (TENORMs) are suspected to be present or generated by mining and/or processing operations. TENORM is generated through activities that concentrate pre-existing NORM in soil, rock, and groundwater and may include overburden grading, tailings and waste rock management, groundwater management, and processing operations. The new mandate requires analysis of total uranium in groundwater, which uses

The Tennessee Valley Authority’s (TVA) Dam Safety organization was tasked with designing an investigation to reduce uncertainties related to internal erosion captured during a risk assessment for Little Bear Creek Dam, an impervious rolled-fill embankment dam in northwest Alabama. The foundation bedrock at the site consists of Mississippian Bangor Formation carbonates that are highly susceptible to dissolution. The primary objective of the investigation was to better inform the risk of internal erosion of embankment material into the karst foundation. The Project Team adopted a systematic approach with four principal components: 1) a surface geophysical investigation; 2) a subsurface investigation; 3) instrumentation installation and automation; and 4) development of a site hydrogeological model (hydrogeomodel). The implementation of a suite of geophysical methods aided in identification of multiple foundation anomalies that were confirmed and characterized via drilling operations. Piezometers were placed

AEG 2022 ANNUAL MEETING 94 AEG 65th Annual Meeting Program with Abstracts September 2022

Serafini, David C., US Army Corps of Engineers, david.c.serafini@.usace.army.mil;F.JamesMartin,F.James.Martin@usace.army.mil;KeithI.Kelson,keith.i.kelson@.usace.army.mil;HenriV.Mulder,henri.v.mulder@.usace.army.mil(TS

Establishing the NORM for Nevada – Mining Regulatory Updates for Uranium in Groundwater

Dam and Safety Modifications to Address Active Fault Rupture Beneath an Embankment Dam

both to monitor the encountered features and address spatial gaps from previous installations. Piezometers across the site were temporarily automated, acquiring hourly data for a duration of approximately one year. As part of the hydrogeomodel development, all applicable exploratory, construction, and instrumentation data were leveraged produce a 3D model. A comprehensive instrumentation analysis was then performed to understand how pore pressures respond to seasonal and episodic loadings. The investigative approach executed for Little Bear Creek Dam proved to be of great value to TVA’s understanding of project risk and serves as a flexible, scalable solution that can be applied to projects across its portfolio.

Hoover, Not Just Another Dam Lecture Simpson, Bryan K., Bureau of Reclamation, BKSimpson@usbr.gov (TS This#8)keynote

#8)

Smith, Tiffany, AISES, TSmith@aises.org (TS #1)

The California Department of Water Resources (DWR), in coordination with federal, state, and local agencies, has developed and maintains a statewide subsidence monitoring network to support Sustainable Groundwater Management Act (SGMA) implementation. This subsidence monitoring network includes ground-based measurements and reporting of groundwater levels, extensometers, continuous GSP, and traditional surveying as well as aerial-based measurement and reporting of interferometric synthetic aperture radar (InSAR) and light detection and ranging (lidar). During the presentation, DWR will provide an introduction to SGMA and DWR’s technical assistance efforts, an overview of the statewide subsidence monitoring network, and highlight the available subsidence data and tools.

A Program to Review Engineering Geology for Schools and Hospitals

Sochar, Scott, California Geological Survey, scott.sochar@conservation.ca.gov (Poster)

Due to the tumultuous history of colonists seeking to “save the man and kill the Indian,” Indian education was created to assimilate Indigenous peoples and strip us of our cultures, languages, and traditions. Consequently, Indigenous peoples still have a distrust of westernized educational systems. As sovereign nations, we exercise our self-determination to take care of our own tribal peoples. WE ARE STILL HERE, thanks to the resilience and wisdom of our ancestors. Mori scholar Linda Tuhiwai Smith (2012) asserts that “the past, our stories local and global, the present, our communities, cultures, languages and social practices—all may be spaces of marginalization, but they have

Overview of California Dept. of Water Resources Statewide Subsidence Monitoring Efforts

Following the spillway-related incidents at Oroville Dam in 2017, a focused spillway assessment was performed for the controlled and emergency spillways at Don Pedro Dam (the 9th highest dam in the United States) located in the Sierra Nevada foothills near La Grange, California. The focused spillway assessment identified potential erosion concerns along the left emergency spillway training wall which separates flow within the emergency spillway from the adjacent controlled spillway structure and channel. An erodibility study was performed in two phases which included an initial phase to review existing information and performing a geologic reconnaissance and seismic refraction survey to develop Erodibility Index Method input parameters to assess the erosion potential along the training wall foundation. The second phase included performing surficial cleaning of the emergency spillway channel materials along the training wall to better characterize bedrock conditions and to locate two bedrock shears that were mapped within the adjacent controlled spillway during construction. This presentation provides an overview of the studies performed and a summary of how the results were used to inform a semi-quantitative risk assessment (SQRA) that was performed to identify key risk drivers at the site. It also serves as a lead in to the second presentation regarding use of the Block Theory Rock Erodibility Method on the right abutment of the emergency spillway.

unfiltered samples and may be impacted by turbidity at the time of sampling. Analysis of total uranium in a turbid sample may include not only dissolved uranium but also uranium that is adsorbed to soil particles and/or (co-)precipitated as solids. If total uranium is detected at a concentration of 0.03 mg/L or greater, additional radiological analyses will be required. The addition of uranium to groundwater monitoring programs has the potential to increase operating, compliance, and closure costs for existing mines. For future operations, concentrations of NORM may influence go/no-go decisions and result in additional planning, bonding, and closure costs. Nevada surface soils have some of the highest uranium concentrations in the United States, and thus, it has become important that multimedia baseline investigations are performed at potential sites to establish NORM concentrations so that potential impacts from future mining operations, if any, can be properly quantified and environmental liabilities reduced. If future uranium impacts are predicted or confirmed, design, operation, and closure plans will need to be specially prepared and continuously reevaluated throughout the mine’s life cycle to avoid generation or release of TENORM and reduce liability and life cycle costs.

also become spaces of resistance and hope.” Our connection to place—to include the land, waters, and cosmos – is one which is unmatched as first peoples. Our relationships and commitment to building up our nations give us strength, and unique strengths in STEM fields, particularly. Ignorance around Indigenous peoples and deficit statistics continue to cause harm to our communities today. Changing the narrative by amplifying our words, and our stories, the presenter will share the problem with the “American Indian asterisk” in statistics, and ways in which Indigenous scholars are combatting these through a decolonizing lens and bringing our gifts to the STEM fields. As a Cherokee and Muscogee scholar who has employed Indigenous methodologies in her own research toward liberation, I will share how our epistemologies and methodologies are a gift to the westernized ideologies guiding STEM fields and careers.

Smith, Casey, Gannett Fleming, Inc., casmith@gfnet.com; Michael F. George, mgeorge@bgcengineering.ca; Cole Christiansen, cchristiansen@bgcengineering.ca; Evan Lucas, emlucas@tid.org (TS #15)

Engineering geology consultants helping to build projects at schools and hospitals in California need to follow specific steps to obtain a permit by ensuring that the construction reasonably minimizes the risk of damage from notable natural hazards. The 2019 California Building Code requires an engineering geologist to evaluate the geologic hazards for construction at California public schools, hospitals, skilled nursing facilities, and essential-services buildings. The California Geological Survey (CGS) serves as an adviser to the State agencies that enforce regulations by reviewing the reports of engineering geologists and other consultants to ensure construction managers have accounted for the geologic forces likely to affect the future improvement. To obtain a permit, the geology consultants must adequately characterize the site for subsurface geology and geotechnical concerns; calculate potential earthquake ground motions; evaluate fault rupture hazards; analyze the potential for liquefaction and seismic settlement; analyze the site’s slope stability; and document other significant hazards. The program has been successful because technical reviews lead to interactions between State agencies and private consultants that improve mutual understanding and the safety of schools and hospitals.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 95

Erodibility Studies Performed at the Don Pedro Dam Emergency Spillway

Springhorn, Steven, California Department of Water Resources, steven.springhorn@water.ca.gov; Benjamin Brezing; Tad Bedegrew; Patrick Tami (TS #21)

WE ARE STILL HERE: Amplifying Indigenous Languages and Knowledges in STEM

A 2017 initiative to repeal registration of Professional Geologists in Illinois taught the Chair of the Chicago Chapter [myself] how best to interact with elected state representatives and other officials, namely start before you need to talk with them. Learning from that experience and as chair of a neighborhood committee, election judge, and later Plan Commissioner appointed to the County Board enabled the funding of $500,000 Helicopter-borne Transient Electro-Magnetic geophysical study of the Mahomet Aquifer, a sophisticated technology that is mostly puzzling to other Board members. Some lessons that I learned: 1) There is no money for your project. Although ARPA has changed this for 2022–2023, this is a nearly universal condition for most issues. 2) Most elected officials are part-time, have a paying job to support their families, and work/meet/endure more than you know. 3) When approached about an issue, elected officials will test your knowledge of the topic at determine YOUR knowledge of that issue. Be prepared to know the science, history and relevant current controversy about that issue. Be succinct. My best advice is: 1) Serve as an election judge, you will learn a lot about the role of partisan politics in government, 2) Meet your public officials and tell them what you do for a living, and 3) Volunteer to serve on a neighborhood association, plan commission or park district board to learn about government and governance in YOUR locale.

The US 95 corridor near Riggins, Idaho, is subject to frequent rockfall from a variety of unstable slopes due to combination of generally over steepened highway cuts/native slopes and locally adverse structure. During the winter of 2021, a rock slope locally referred to as “Bullseye,” immediately north of the town of Riggins experienced a slope failure on an adversely oriented joint set, resulting in temporary closure of the highway and local destabilization of the lower portion of the slope. At this location on US 95, the slope to the west of the highway consists of dip slope exposure of schistose rock that rises more than 350 feet above the roadway elevation. The Idaho Transportation Department (ITD) assessed the slope condition and, rather than remove the failed rock mass and risk further destabilization of the slope, elected to seek supplemental funding for more comprehensive slope mitigation. McMillen Jacobs and HMH Engineering were retained to perform geotechnical evaluation of the slope, develop mitigation design, and develop a contract package for mitigation of the slope. Due to constraints on the supplemental funding, development of the mitigation plan, contract development, and advertisement of the work were required to occur within a 3-month window, with construction initially programmed two months following advertisement. Design development relied extensively on drone imaging and modelling and the collection of on slope design data using roped access techniques. The design team worked with ITD project engineers and program managers to develop a suite of mitigation options including rock slope scaling,

A 2019 legislation was drafted, passed, signed into a public act [enrolled]. However, no action was taken to compile information about legacy landfills, allegedly for absence of funding. In 2022, a 25member Mahomet Aquifer Council was appointed with agricultural, industrial, commercial, and political stakeholders having overlapping

AEG 2022 ANNUAL MEETING 96 AEG 65th Annual Meeting Program with Abstracts September 2022

demands on the potable water which currently can be pumped without limit in the absence of comprehensive scientific data-based information. Protecting groundwater quality, providing sustainable local withdrawals, but also assuring reasonable use of an irreplaceable resource requires balancing scientific and political pressures.

Scientific and Political Issues Confronting Protection of the Sole-Source Mahomet Aquifer, East-Central Illinois Stohr, Chris, Champaign County Board and Mahomet Aquifer Council, Illinois, cstohr@illinois.edu; Carol Ammons, chief@staterepcarolammons.com (TS #20)

Bullseye Rock Slope Mitigation Development, US 95 Riggins, Idaho

Following US Nuclear Regulatory Commission (NRC) requirements, in August 2006 Plant Vogtle owners submitted an application for an Early Site Permit (ESP) for new nuclear power Units 3 and 4 located near operating Units 1 and 2 in Burke County, Georgia. Primary geologic issues were whether the Pen Branch fault that underlies Units 3 and 4 posed a hazard and whether seismically induced paleoliquefaction features occurred in the site area. NRC geologists addressed these issues by reviewing pertinent sections of the ESP application and conducting site audits to examine geologic features in the excavations for safety-related engineered structures at Units 3 and 4 and in the site area. During the audits, NRC geologists reviewed the applicant’s geologic maps of the excavations, including the Blue Bluff Marl foundation-bearing lithology, to verify that geologic features observed were accurately captured on the maps. NRC geologists evaluated all information related to evidence for tectonic and non-tectonic surface deformation and paleoearthquakes at the site and confirmed the applicant’s conclusions that the Pen Branch fault did not pose a fault displacement hazard and that seismically induced paleoliquefaction features did not occur in the site area. NRC geologists prepared parts of the publicly available Safety Evaluation Report presenting results of their evaluations and testified in a mandatory public hearing on the ESP to confirm the applicant’s conclusions about geologic site suitability. The NRC granted the applicant an ESP and a Limited Work Authorization for placement of engineered backfill in August 2009. The applicant submitted an application for a Combined License (COL) to construct and operate new Units 3 and 4 in March 2008 and the NRC granted a COL for the new units in February 2012. This action enabled construction and operation of the first nuclear power facility in the United States in more than three decades.

Struthers, James, McMillen Jacobs Associates, struthers@mcmjac.com; William CB Gates, gates@mcmjac.com; Ethan Guzek, guzek@mcmjac.com; Alexis Judy, judy@mcmjac.com (TS #13)

Stohr, Chris, Champaign County Board and Mahomet Aquifer Council, Illinois, cstohr@illinois.edu (TS #20)

The Mahomet Aquifer is East-Central Illinois’ only regional potable water resource, serving more than 500,000 people in 15 Illinois counties, providing an estimated 220 million gallons of water per day to communities, agriculture, industry, and rural wells. An aquifer is a “sole source” if contamination of it would create a significant hazard to public health and there are no physically available or economically feasible alternative sources of drinking water to serve the population that relies on the aquifer. However, the designation only authorizes USEPA review of Federal projects that receive financial assistance. In 2018 the Mahomet Aquifer Protection Task Force recommended: 1) Developing a state plan to maintain the groundwater quality of the Mahomet Aquifer, 2) Identifying current and potential contamination threats to the water quality of the Mahomet Aquifer, 3) Identifying actions that might be taken to ensure the long-term protection of the Mahomet Aquifer, and 4) Making legislative recommendations for the protection of the Mahomet Aquifer including identifying potential threats and actions to the aquifer to be addressed.

Evaluating Geologic and Seismic Hazards for Plant Vogtle Nuclear Units 3 and 4, Burke County, Georgia, at the US NRC Stirewalt, Gerry L., US Nuclear Regulatory Commission, gerry.stirewalt@nrc.gov (TS #18)

Supplementary Civics and Science in Elected Office: Observations from Five Years in Public Office

Swank, Mark, Aspect Consulting, mswank@aspectconsulting.com; Bodie McCosby, bmccosby@aspectconsulting.com (TS #10)

The River’s Edge – the Story of a Levee Setback and Restoration Project

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 97

rock reinforcement, and rockfall mitigation using a rockfall attenuator. This suite of options was developed so that it could be implemented in part or fully in order to best fit the Agency’s needs with respect to risk management and forward compatibility with future improvement for this segment of the route.

The Rivers Edge Levee Setback Project for the Jamestown S’Klallam Tribe along the Dungeness River removed the constricting USACE levee and built a new setback levee along the formerly agricultural land to restore floodplain processes, improve fish passage and habitat, and increase flood storage. The existing USACE levee was constructed in 1962–1963 for flood control and does not meet current design standards, requiring replacement to prevent overtopping or failure and ensure public safety. To accomplish these goals, the project removed the existing levee and constructed a new 5,200-foot-long setback levee designed to current standards. The work included various explorations, monitoring groundwater conditions in the floodplain, characterizing borrow sources, and engineering evaluations for seismic, settlement, seepage, and stability analyses to develop the new setback levee geometry and fill requirements in conformance with USACE design guidance. The new levee embankment used materials from a nearby quarry pit to streamline efforts through permitting and reduce the lifecycle cost and emissions associated with construction, which required modifying designs to a wider levee embankment for the readily accessible gravel materials. Other innovative design elements included geogrid reinforcement at the levee base to improve the soft subgrade and, for scour protection, launchable riprap to eliminate deep excavations extending below the shallow groundwater table. The new levee setback was substantially completed in the summer of 2021, less than 14 months from the start of design to construction. In March 2022, the project was awarded the ASCE’s Local Outstanding Civil Engineering Achievement Award in the Geotechnical category.

Taylor, Gabriel, Washington State Department of Transportation, taylorg@wsdot.wa.gov; Neal McCulloch, neal.mcculloch@shanwil.com; Jason Buenker, jason.buenker@shanwil.com (TS #5)

Washington State Route 112 (SR 112) traverses the landslide-prone north coast of the Olympic Peninsula. Adverse subsurface conditions and heavy rainfall cause chronic roadway deformation and periodic catastrophic landslide events that result in long-term closures of the highway. These issues, especially when combined with high seismic loads and low traffic counts, make this a difficult route to maintain and operate. During the last two winters (2020–2021 and 2021–2022), large landslides destroyed SR 112 in multiple locations, resulting in months-long closures that are challenging for the Agency, as well as those rural and tribal communities that are isolated by these events. At Jim Creek, a deep-seated landslide remobilized in November 2021. This landslide had activated during the prior winter, and in the winter of 1990, when approximately one thousand feet of highway was destroyed. The most recent event, the November 2021 Jim Creek landslide, dropped an approximately 300-foot-long section of highway 3–4 feet. The landslide surface was found to be approximately 40 to 50 feet below the highway, failing through weak siltstone bedrock. The Washington State Department of Transportation (WSDOT) and Shannon and Wilson (S&W) conducted subsurface exploration and considered

Status of the USACE Drilling Program Plans (DPP) Reviews Terry, Thomas, USACE, thomas.terry@usace.army.mil (TS #15)

two alternatives for mitigating this landslide, pile stabilization and drainage improvements. Drainage improvements were ultimately selected, designed, and constructed. These improvements included deep trench drains, horizontal drains, new cross-culverts, and rebuilding the highway with low-density cellular concrete (LDCC). This case history will discuss the challenges related to operating a public highway on this landslide-prone corridor and will share details of the investigation, analysis, design, and construction of the 2022 SR 112/ Jim Creek landslide stabilization project.

Using InSAR and GRACE Satellite Data to Monitor Hydrological Variations within Tulare Basin, CA

Vasco, Donald, Lawrence Berkeley Laboratory, dwvasco@lbl.gov; Kyra Kim, kyra.kim@jpl.nasa.gov; Tom G Farr, tfarr@pipeline.sbcc.edu (Presented by Tom Farr) (TS #14)

SR 112 / Jim Creek Landslide Stabilization – Alternatives and Lessons Learned

This presentation is a status update on USACE’s Engineering Regulation (ER) 1110-1-1807 which provides the regulations for Drilling in Embankments Dams and Levees after over review of over 375 DPPs. Where have we been? Where are we going and what is changing? The presentation will provide an overview of the program, general statistics on reviewed plans, improvements in the submitted plans due to the review process, proposed changes in the ER, and proposed training on DPPs and hydraulic fracturing.

Subsidence induced by groundwater depletion is a grave problem in many regions around the world, leading to a permanent loss of groundwater storage within an aquifer and even producing structural damage at the Earth’s surface. California’s Tulare Basin is no exception, experiencing about a meter of subsidence between 2015 and 2020. However, understanding the relationship between changes in groundwater volumes and ground deformation has proven difficult. We employ surface displacement measurements from Interferometric Synthetic Aperture Radar (InSAR) and gravimetric estimates of terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE) satellite pair to characterize the hydrological dynamics within the Tulare basin. The removal of the long-term aquifer compaction from the InSAR time series reveals coherent short-term variations that correlate with hydrological features. For example, in the winter of 2018–2019 uplift is observed at the confluence of several rivers and streams that drain into the southeastern edge of the basin. These observations, combined with estimates of mass changes obtained from the orbiting GRACE satellites, form the basis for imaging the monthly spatial variations in water volumes. This approach facilitates the quick and effective synthesis of InSAR and gravimetric datasets and will aid efforts to improve our understanding and management of groundwater resources around the world.

Flagship of the TVA: A Case History of Norris Dam

New Insights into Deformation Characteristics of the Hoseynabad Kalpush Landslide in Iran and its Catastrophic Failure in Spring 2019

Walker, Scott, Tennessee Valley Authority, srwalker3@tva.gov (TS #8)

Constructed by the Tennessee Valley Authority between 1933 and 1936 on the Clinch River northwest of Knoxville, Norris Dam has a total length of 1,860 feet, a maximum height of 265 feet, and consists of a concrete gravity structure with a short earth embankment section on the left (east) abutment. Originally known as the Cove Creek site, the project location has a long history. Initially considered by private entities and later investigated by the Corps of Engineers, the dam and appurtenances were designed by the Bureau of Reclamation before becoming the first of more than 40 river dam projects completed by the TVA. Primary purposes are hydroelectric power generation, flood control, and flow augmentation for navigation on the Tennessee River, with secondary purposes of recreation, water supply, and aquatic ecology. Norris Dam is located on the on the southwest limb of the Powell River anticline and founded on Copper Ridge Dolomite, which is the lowest member of the Cambrian-age Knox Group. The bedrock is highly jointed, and extensive foundation treatment (including consolidation grouting, cutoff grouting, and mining tunnels to excavate clay seams) was required to address solutioning and related defects within the carbonate bedrock. While most cavities and

Boone Dam was constructed between 1950 and 1952 by the Tennessee Valley Authority (TVA) on the South Fork Holston River near Johnson City in northeast Tennessee. The embankment portion of the dam is founded on a combination of alluvial and residual soil underlain by epikarst and Conococheague limestone and dolomite of the Cambrian-age lower Knox Group. In October 2014 a sinkhole was discovered at the downstream toe of the embankment and muddy seepage was observed in the tailrace. Subsequent analyses suggested the original cutoff trench below the embankment was compromised and dam safety risks associated with internal erosion mechanisms were judged to be unacceptably high. The reservoir was immediately lowered and alternatives for mitigation were evaluated. Due to the presence of clay-filled voids in the epikarst zone, the primary remedial measure selected by TVA was a concrete diaphragm cutoff wall (COW), supplemented by injection of both low- and high-mobility grout and construction of upstream and downstream rockfill berms. After evaluating contractor proposals and considering subsurface conditions at the site, a secant pile design was selected for the COW. Construction required lowering the crest by about 10 feet to provide an adequate work platform, and installation of concrete pile elements was completed between mid 2019 and early 2021. The reservoir was then progressively raised, and performance of the dam was monitored through the summer and fall of 2021. The project concluded with construction of a concrete floodwall to restore the design crest elevation of the embankment section.

such as nickel and chromium, are elements with a high atomic weight and are naturally occurring in the environment. Nickel is shown to be toxic in humans with the World Health Organization having a recommended safe limit of 0.05 parts per million (ppm) for agricultural soil and intervention concentrations at 210 ppm. The Paradise and Magalia areas consist of both ultramafic and metavolcanic rock formations which erode and contribute heavy metals to the surrounding soil. Ultramafic rocks, including serpentinite, and their derivative soils have been shown to have elevated levels of nickel and chromium. Analysis of two ultramafic rocks, two metavolcanic rocks, and their derived soils was conducted using an inductively coupled plasma mass spectrometer (ICP-MS) and a portable XRF spectrometer to determine the concentrations of nickel and chromium, as well as major element oxides. Nickel and chromium levels for the ultramafic rocks and soil were recorded at concentrations between 3,000 to 5,000 ppm of chromium, and 3,000 to 4,000 ppm for nickel in the

Geochemical Analysis of Metavolcanic and Ultramafic Rocks and Soils in Magalia, CA, Show Ni and Cr Toxicity Potential Wagoner, Matthew, California State University Chico, mwagoner3@mail.csuchico.edu; Alonso Diaz, adiaz34@mail.csuchico.edu; Elisabeth Kennedy, emkennedy@mail.csuchico.edu; Hannah Aird, haird@csuchico.edu

Vassileva, Magdalena, GFZ German Research Centre for Geosciences, Potsdam 14473, Germany, magda88@gfz-potsdam.de; Motagh Mahdi, Motagh@gfz-potsdam.de; Roessner Sigrid, roessner@gfz-potsdam.de; Akbari Bahman, akbari_71@yahoo.com; Fadaifard Mostafa, mostafa.fadaeifard@gmail.com (Presented by Mahdi Motagh) (TS #5)

AEG 2022 ANNUAL MEETING 98 AEG 65th Annual Meeting Program with Abstracts September 2022

rocks and soil, well above levels that have been shown to cause stunted growth and necrosis in crops. Similarly, the nickel and chromium concentrations from the metavolcanic rock and soil samples were also recorded in the toxic concentration range, around 400 ppm for chromium and around 100 ppm for nickel in the soil. This study has potential implications for the agricultural communities in Butte County area due to the concentration of elements, specifically nickel and chromium, at levels well above toxicity thresholds that affects any crops that residents in the area may grow for personal use, and possibly toxic to residents themselves.

(Poster)Heavymetals,

Boone Dam, Part 3: Mitigation of Internal Erosion Failure Modes through a Karst Foundation Walker, Scott, Tennessee Valley Authority, srwalker3@tva.gov (TS #15)

The Hoseynabad Kalpush landslide in Semnan province of north-central Iran has been drawing considerable attention after a catastrophic failure in 2019, which caused widespread damage to more than 300 houses, 163 of which uninhabitable due to the severity of the destruction. Although in the aftermath of this catastrophic event, it was taken for granted that it occurred as a result of the exceptionally heavy rainfall in March–April 2019, many aspects of the landslide remained unknown. Here we first use a combination of Synthetic Aperture Radar (SAR) and optical remote sensing to characterize pre-, co- and postfailure kinematics of this landslide. Then a correlation analysis between the observed displacements, rainfall conditions and in situ measurements is performed for a better physical understanding of the Hoseynabad Kalpush landslide and its triggering mechanism. Our results suggest that, influenced by water level changes of a dam reservoir that was completed in 2013 on the opposite side of the slope in a valley to the south, a previously abandoned landslide was reactivated in spring 2015. The precursory slow slip movement of approximately 10 cm/year in 2015 then accelerated rapidly in January 2019 and culminated in a catastrophic collapse with more than 35 m of horizontal motion in April 2019. In the year and a half of observations after the main failure, we documented a maximum cumulative displacement value of 20 cm at the bottom and middle part of the landslide affected area with the rate of displacement being higher at the beginning and progressively reduced after November 2019. This work shows a successful example of how recent advances in satellite remote sensing techniques could prove useful for systematic slope monitoring and analyzing cascades of effects that can increase landslide hazards surrounding water reservoirs and built environments.

Colorado State Highway 145, a segment of the San Juan Skyway scenic loop, experiences debris flows on annual to decadal timescales, with recent debris flow cycles occurring during the monsoon seasons of 2016 and 2021. The 85-mile mountain corridor, which provides access to the town of Telluride and other mountain communities in southwestern Colorado, traverses steep terrain, crossing numerous debris flow basins and fans. To address the debris flow problem on the corridor, we are conducting an investment study to characterize the debris flow hazards, quantify the risks to the highway, and evaluate the feasibility of debris flow mitigation. In this study, we combine geomorphic mapping, field observations, GIS analyses of basin parameters, and input from Colorado Department of Transportation (CDOT) roadway maintenance staff to develop preliminary debris flow hazard ratings, which are used as inputs in our quantitative debris flow risk assessment. We estimate that typical debris flow volumes along the corridor are on the order of 102 to 103 m3 (yd3) for recurrence intervals of 1 to 10 years, while volumes up to 104 m3 may be possible for longer recurrence intervals. Although these volumes are relatively low when compared to other debris flow regions in North America, the costs to CDOT and the traveling public are significant. In an attempt to reduce these risks to an acceptable level and improve highway resiliency, we identify the critical hazard zones and perform cost-benefit analyses to evaluate feasible alternatives for debris flow mitigation.

Subsidence in Coastal Cities Throughout the World Observed by InSAR Wei, Meng, University of Rhode Island, Bay Campus, matt-wei@uri.edu; Pei-Chin Wu, peichin_wu@uri.edu; Steven D’Hondt, dhondt@uri.edu (TS #14)

Women in Tunnels – From Prohibited to a Career Weir, Susan Steele, Past President AEG, Honorary Member, steeleweir@aol.com (TS #1)

Many electrical utility companies have recently developed fire risk mitigation programs to proactively address fire risk by “hardening” critical electrical distribution circuits within service areas most at risk for wildfires. Utility companies are replacing existing “high risk” circuits and wood distribution poles in undeveloped areas more susceptible to fire or wind damage, and thousands of new foundation excavations will be drilled to set the replacement for steel distribution poles. Unexpected subsurface conditions, which can result in difficult or slow drilling during foundation excavation can have significant impact on project construction and cost, but due to the number of poles to be replaced, site specific investigation at each location is not economically feasible. To support utility companies with front end project planning and design, performance of targeted geologic and geotechnical evaluations is performed to characterize various “typical” ground conditions into representative reaches along distribution circuits extending across variable terrain. General engineering recommendations and soil parameters input are developed for generalized design groups to inform pole foundation design using the Moment Foundation and Design (MFAD). Geologic and geotechnical information obtained from the targeted evaluations can also be provided to bidding contractors to help them provide more accurate cost estimates and reduce potential change orders associated with unforeseeable field conditions during construction activities. This presentation will discuss implementing a four-phase

West, Loyd, Washington Geological Survey, travis.west@dnr.wa.gov; Jade Cooley, Jade.Cooley@dnr.wa.gov; Alex Wernle, awernle@usgs.gov; Corina Allen, Corina.Allen@dnr.wa,gov (TS #18)

Wallace, Cory, Yeh and Associates, Inc., cwallace@yeh-eng.com; Matthew Tello, matthew.tello@state.co.us (TS #12)

Subsurface Characterization and Development of Pole Foundation Design Groups for Utility Fire Risk Mitigation Programs

We measured subsidence rates in 99 coastal cities around the world between 2015 and 2020 using the PS Interferometric Synthetic Aperture Radar method and Sentinel-1 data. In most cities, part of the land is subsiding faster than sea level is rising. If subsidence continues at present rates, these cities will be challenged by flooding much sooner than projected by sea level rise models. The most rapid subsidence is occurring in South, Southeast, and East Asia. However, rapid subsidence is also happening in North America, Europe, Africa, and Australia. Human activity—primarily groundwater extraction—is likely the main cause of this subsidence. Expanded monitoring and policy interventions are required to reduce subsidence rates and minimize their consequences.

Washington State ranks second in the nation in earthquake risk and almost 70 percent of Washington schools are in high seismic risk zones. Schools are arguably the backbone of a community, responsible for educating the next generation, hosting community events, and providing shelter post-disaster. The purpose of this study was to assess the seismic risk of permanent, public, K–12 school buildings in Washington State. Each assessment took into account the local geology, engineering, and construction. In total, 561 school buildings (274 schools at 245 campuses) across the state were assessed. The project was conducted in two phases, over two biennia of work,

Characterization of Debris Flow Hazards along the San Juan Skyway, Colorado

investigation program as well as the challenges to develop generalized foundation design groups representative of the large distribution circuits extending for across moderate to steeply sloping terrain and variable subsurface conditions.

tunnels were ultimately backfilled with concrete, one large cavern in the west abutment was left open and is accessed from the gallery as part of routine dam safety inspections. This presentation will cover the history of the Norris Project, including planning, design, construction, and the influence of modernist architect Roland A. Wank.

Warner, Jared, Geosyntec Consultants, jwarner@geosyntec.com; Alexander Greene, agreene@geosyntec.com (TS #7)

Geologist Susan Steele Weir stepped onto an open suspended platform attached to a crane. The platform jerked and dropped; she clung to the crane cable as she swung out over an abyss, and then, with great faith in the crane operator, she was lowered 300 feet down a narrow vertical shaft through solid rock that her geologic mapping would shed an important light concerning the regional stratigraphy for tunnel construction. But that was the easy part, compared to the more nerve-wracking aspect of that particular job, which was the old miner she had to walk past every day to get there—a shift boss who refused to acknowledge her and who glared every time she walked by. There had been many like him throughout her career, but Weir remembers this one in particular. He was probably remembering the days when it was considered bad luck for women to be underground and they were prohibited from going there, secretly hoping for those days to return. Susan became a geologist when the field was completely dominated by men. It was a career she never expected. After college graduation she landed a job with the USGS, her first step into a world where, she would find, the first female footprints would often be her own.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 99

Washington State School Seismic Safety Project: Geologic and Structural Engineering Assessments of 561 School Buildings

Continuous Surface Wave (CSW) testing has been the “next big thing” in ground characterization for the last 25 years. The technique uses surface geophones to measure the speed at which Rayleigh waves (generated by a vibratory source) travel through the ground over a range of frequencies. The velocity at which surface waves travel through the ground is directly related to ground stiffness; the velocity of shorter wavelengths is influenced by the stiffness of shallower soil layers, while the velocity of longer wavelengths is influenced by the stiffness of deeper layers. Measuring the surface wave velocity over a range of frequencies, therefore, allows a stiffness / depth profile to be produced. Using the small-strain stiffness data measured by the CSW technique greatly improves the accuracy of simple limit state analyses; the data are also of sufficient quality for use in Finite Element modelling. Nonetheless, the technique has suffered from a perception of high cost, low productivity, and poor repeatability. An improved Advanced Continuous Surface Wave (ACSW) testing system has been developed by Ground Stiffness Surveys in the United Kingdom, has been deployed there commercially for several years, and is now available in the United States. ACSW uses an automated electronic control system that generates vibrations (from a purpose designed and manufactured portable seismic “shaker”) at different frequencies, measured across a 3m (10 foot) array of geophones, linked to a robust data acquisition and analysis software package. The range of applications in geologic and geotechnical site characterization includes rapid preliminary non-intrusive site assessments (utilizing published soil correlations); stiffness profiling to detect discrete layers (such as a variation in rockhead); average stiffness profiling for earthwork or ground improvement control testing, Working Platform stability assessments, foundation settlement analysis, rock quality and rippability assessments, and void detection.

Lique-What-The-Faction!?! A Practitioner’s Discussion of Atypical Liquefiable Soils and Implications to Slope Stability

Timber harvesting and related management practices associated with industrial timberlands have changed dramatically in the last two decades. Industrial timberlands are now more carefully assessed and mitigated than ever before. Our recent studies of mass wasting in northern California included a review of historical aerial photographs from the early 1940s through 2016, and field measurements of nearly 3,000 shallow landslides on industrially managed timberlands. Through our work we have seen significant improvements in management practices over time that includes but is not limited to; reduced harvest unit sizes, increased streamside tree retention, reduced road density, and improved road building practices. These improvements come from a

Assessment Of the Efficacy of Deep Two-Component Polymer Injection in Soil and Weak Rocks

funded by the 2017– 2019 and 2019–2021 WA capital budgets. The Washington Geological Survey (WGS) worked with the Office of the Superintendent of Public Instruction and a team of engineers led by Reid Middleton Inc. to complete the seismic risk assessments in two parts: (1) a geologic assessment to determine site class per the National Earthquake Hazard Reduction Program guidelines, and (2) a tier-1 seismic screening evaluation, per American Society of Civil Engineers 41-17. The geologic assessments of site class used multichannel analysis of surface waves and the microtremor array method to model shear wave velocity profiles. WGS scientists also incorporated refraction analysis and horizontal-to-vertical spectral ratios of microtremor to help characterize lateral changes in the subsurface. Measured site classes were compared to predicted site classes that were based primarily on 1:100,000-scale surficial geologic maps. Of the 245 campuses assessed for site class, 59 measured site classes differed from those that were predicted. This stresses the necessity for site-specific studies over proxy maps. When site-class measurements were incorporated into the engineering assessments, more efficient seismic retrofit designs and more accurate cost estimates were developed. Our results can help prioritize school retrofit efforts.

AEG 2022 ANNUAL MEETING 100 AEG 65th Annual Meeting Program with Abstracts September 2022

Polyurethane “grout” is an established method of near surface ground stabilization and is widely used to fill near-surface voids, compact and stiffen foundation soils, and bind soil to allow excavation on a vertical face. The technique is generally limited in its depth of application, with single polymer permeation grout being effectively delivered to depths of around 10 feet (3m) and dual polymer expanding foam grout typically only deliverable to depths of between 7 to 10 feet (2 to 3m). Polymer Technologies USA Inc. recently patented a device to allow delivery of two-component, fast reaction polymer to depths of more than 100 feet (30m) below surface. Their Deep Horizons Injection Grout (DHIG) method has been successfully deployed on several projects, including stabilization of soil surrounding a 35-foot-deep sewer line (encapsulating the pipe and sealing all external infiltration) and the repair of ground loosened by sinkhole activity. The purpose of this study is to provide independent verification of the DHIG technique using a variety of direct sampling and geophysical methods and in different soil conditions. Two test sites were studied, one in predominantly sandy, karst-loosened soil in Pasco County, FL and a second in

Wildman, Charlie, Arcadis US, Inc., Charlie.Wildman@arcadis.com

Whether it is a dam in a tidal zone, a dam spanning a former river channel, or a coastal floodwall built atop uncontrolled urban fill—water management infrastructure is often located in areas with high potential for liquefaction of underlying soils. However, the classical, textbook case of uniform, loose, clean sand below the water table is so rarely as clear in real life as it is in the classroom. This presentation will provide a brief overview of the theory and the state of the practice regarding liquefiable soils and will discuss real-world examples of the classic case of liquefiable sands, the atypical case of liquefiable finegrained soils, and the unique case of soil layers that appeared at first glance to be liquefiable but, upon further inspection, were deemed to be non-liquefiable, with special attention to focus on implications to slope stability. Examples will include sites on the Atlantic coast and in Puerto Rico.

predominantly clay-rich soils (also karst-weakened) in Columbia County, FL. Rotary wash borings with Standard Penetration Testing (SPT), Cone Penetration Testing (CPT), Ground Penetrating Radar (GPR) and Advanced Continuous Surface Wave (ACSW) seismic testing were all deployed to assess the depth of injection and changes in relative soil stiffness around single-point injection sites advanced up to 68 feet below surface. This paper documents the procedures used to achieve the deep dual-component polymer delivery, then assesses the efficacy of the DHIG technique of deep polymer delivery using conventional geotechnical and geophysical exploration techniques.

Advanced Continuous Surface Wave Testing (ACSW): Geologic and Geotechnical Site Characterization for the 21st Century Wilshaw, David, Integrity Drilling & Geophysical Services, LLC, davidw@idgsfl.com (TS #7)

Wilshaw, David, Integrity Drilling & Geophysical Services, LLC, davidw@idgsfl.com; Mark V. Richter, richter@engineer.com (TS #16)

Industrially Managed Timberlands: A Comparison of Erosion Rates to Historical and Contemporary Practices

Woodward, Jason, Green Diamond Resource Co, jwoodward@greendiamond.com (TS #5)

Zero-valent iron nanoparticles (nZVI) has been studied extensively as an option for soil remediation and water treatment. The major drawback of nZVI is a reduction of reactivity due to agglomeration or a loss in surface area. One method proposed to prevent agglomeration is the immobilization of nZVI onto SBA-15. The use of a secondary catalyst such as peroxymonosulfate to promote further Free Radical production to enhance decomposition and reactivity, was observed through the scope of this project. The potential of nZVI/SBA-15/PMS system to degrade different types of antibiotics (sulfamethoxazole, tetracycline, and amoxicillin) exposed to different conditions specifically dosages of the nZVI/SBA-15 (0.5, 1.0, and 1.5 g L-1) and PMS (5 mmol L-1), were recorded using HPLC. The degradation rate of >97 percent for sulfamethoxazole, >89.8 percent for tetracycline and >63.9 percent of amoxicillin. The use of the nZVI/SBA-15/PMS system has shown to be an interesting alternative treatment for antibiotic removal and water treatment.

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 101

Land Subsidence Contributions to Relative Sea Level Rise at Tide Gauge Washington, D. C. Zhou, Xin, Morgan State University, xin.zhou@morgan.edu; Yi Liu, yi.liu@morgan.edu (TS #14)

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USNO and USN9 are two GPS stations seated in the ~15 m thick Quaternary unconsolidated upland deposits, underlain probably by the uplifted Lower Cretaceous Patuxent Formation, a confined aquifer, and Cambrian basement rock. The GPS stations have been measuring land surface height since 1997 for 25 years in Washington DC. Tide gauge Washington DC, 6.5 km southeast of the two GPS stations, is seated in the ~45 m thick Quaternary unconsolidated lowland deposits. The tide gauge has been monitoring sea level since 1931 for 91 years. USNO and USN9 are only 300 m apart, and their measurement combination indicates a subsidence rate of 1.58 ±0.03 mm/year, which may include major tectonic subsidence of the basement rock and, because groundwater well PGBc16 demonstrates a water level stability from 1962 in the Patuxent formation, perhaps very little subsidence due to creep of the Quaternary deposits. Relative sea level rise has increased since 1992. Relative sea level rise at tide gauge Washington DC is assumed to be the sum of GPS detected land subsidence and absolute sea level rise. Before 1992, an absolute sea level rise rate of 1.10 mm/year in trend was estimated by removing the subsidence rate of 1.58 mm/year from the relative sea level rise rate of 2.68 mm/year; after 1992, the absolute sea level rise accelerates in a quadratic trend with an acceleration of 0.227 mm/year2 due to fast global warming. Projection of sea level rise from 2020 to 2100 based on global mean sea level rise (GMSLR) highest and intermediate–high scenarios indicates that Washington DC’s relative sea level rise of 2.68 m is about 74 percent of 3.6 m under the highest scenario and 127 percent of 2.1 m under the intermediate–high scenario. Land subsidence attributed to tectonic and creep subsidence contributed as much as 59 percent of the estimated relative sea level rise in the 20th century but will possibly decline to 6 percent by 2100.

Degradation of Antibiotics in Aqueous Phase using Immobilized Zero-Valent Iron Nanoparticle

Zeidman, Ahdee, Desert Research Institute, ahdee.zeidman@dri.edu; Jaeyun Moon, jaeyun.moon@unlv.edu; Natasha Sushenko, natasha.sushenko@dri.edu; Yeongkwon Son, yeongkwon.son@dri.edu; Erick Bandala, erick.bandala@dri.edu (TS #9)

variety of sources such as evolving state regulations, voluntary conservation plans, and increased professional oversight. Subsequently we are seeing significant decreases in management related erosion across the study area. Our observations indicate that improvements in management practices have affected regional mass wasting in a positive way. In this study we have seen significant changes in both causal mechanisms and landslide erosion rates. Our data indicates that prior to the year 2000, nearly 85 percent of landslide related erosion was determined to be the result of historical logging, either by harvesting or roads (generally poor design and/or location). Shallow landslide erosion rates have varied over the time-period reviewed for this study and peaked in the 1960s. Since 2000, erosion rates across the study area are at their lowest rate of 20 m³/km²/yr, which is a 92 percent reduction compared with the historical rate.

AEG 2022 ANNUAL MEETING 102 AEG 65th Annual Meeting Program with Abstracts September 2022 Proud to be a Gold Sponsor! Geotechnical Engineering, Dam and Levee Engineering, Water Resources, Tunnel Engineering, Risk Management, and Construction and Contractor Support Get in touch: jgagnon@schnabel-eng.com or 336.274.9456 SAFETY. QUALITY. PEOPLE. EQUIPMENT. GLOBAL LEADERS IN SITE CHARACTERIZATION GeophysicalTesting OverwaterDrilling InstrumentationInstallations BETTER INFORMATION BETTER DECISIONS CONETEC.COM In-Situ Testing (SCPTu, eVST, PMT, DMT, iBPT) Drilling Sampling& Limited & Remote Access

SEPTEMBER 10–14, 2024

Philadelphia, Pennsylvania

Hilton Philadelphia at Penn’s Landing

AEG 67th Annual Meeting

Westin Chicago River North

Chicago is one of the top tourist destinations in the United States for a reason. It’s a welcoming city with plenty of world-class attractions. Located on Lake Michigan in Illinois, Chicago is famed for its bold architecture. In additional to engineering geology, the AEG 2025 Annual Meeting will focus on sustainability, health, climate change, and environmental geology.

Located in the heart of downtown Chicago in the prestigious River North neighborhood of the city, the Westin Chicago River North’s location makes it a perfect base to explore the historic and energetic Windy City with nearby attractions including the Millennium Park, The Chicago Theatre District, and the vibrant Chicago Riverwalk. Refreshed in early 2020, the flexible event space offers the perfect setting for meetings. Recharge in your choice of accommodations, from traditional rooms to luxury suites, all with a view of the Chicago River or the downtown skyline. Maintain your health goals with the delicious and healthy on-site dining at 320 RiverBar and the state-of-theart WestinWorkout fitness studio. Enjoy complimentary fitness classes as well as Rise + Ride with Westin and Peloton.

The Meeting Hotel

AEG 68th Annual Meeting Chicago, SEPTEMBERIllinois23–27, 2025

Save the Dates…

Philadelphia, the nation's birthplace and capital from 1790 to 1800, is renowned for its rich history on display at the Liberty Bell, Independence Hall (where the Declaration of Independence and Constitution were signed), and many other historical sites. Also iconic are its cheesesteaks and the steps of the Philadelphia Museum of Art immortalized by Sylvester Stallone’s triumphant run in the film “Rocky.”

for these future AEG Annual Meetings

Overlooking the Delaware River with views across to New Jersey, the hotel is less than a mile from the Liberty Bell, the Museum of the American Revolution, and the Benjamin Franklin Museum. They are adjacent to Spruce Street Harbor Park, and Society Hill is less than a mile away. The hotel is located on the waterfront in Center City’s Historic District and steps from numerous attractions and an eclectic array of restaurants.

AEG 2022 ANNUAL MEETING

Admassu, Yonathan The Role of Internal Erosion in the Development of Ground Fissures Around Lake Ziway, Ethiopia

Bearce, Richard G. See Lindenbach, Evan (1) Beard, L. Sue See Bennett, Scott Bedegrew, Tad See Springhorn, Steven Belli, Keaton See Small, Molly Bennett, Scott The Eastern California Shear Zone and Late Miocene Linkages to the Incipient Walker Lane and Gulf of California Shear Zone Bingaman, Patrick See Finch, Stella Binayak, Gosh See Motagh, Mahdi Blewitt, Geoffrey See Kreemer, Corné Blozies, Christopher See Carlson, Chad Borchers, James Busted Casings and Broken Dreams: Subsidence Damaged Wells in California Borst, Rebecca See Arthurs, James Bouali, El Hachemi See Hunnicutt, Shawna Bowling, Roy Applying Seismic Velocity Mapping for Landslide Shear-plane Identification, Theodore Roosevelt National Park Brand, Patrick See Longstreth, David Brandt, Randy See Small, Molly Bredehoeft, John See King, Michael Brezing, Benjamin See Springhorn, Steven Brickey, Timothy A. See Bennett, Scott Brown, Josh See Buche, Matt Buchanan, Sean Macroscale to Mesoscale. Using 3D Implicit Modelling to Understand Local to Regional Scale Hydrostratigraphy of North Carolina’s Coastal Plain Physiographic Province

104 AEG 65th Annual Meeting Program with Abstracts September 2022

Author and Title Index

Akeju, Victor Assessment of the Clogging Behavior of Fine-Grained Soils through Geologic History Al-Shijbi, Yousuf See El-Hussain, Issa Allen, Corina See West, Loyd Ammons, Carol See Stohr, Chris Arany, Gergo D. See Lindenbach, Evan (1) Archer, Cole See Hibbard, David (2) Arthurs, James Geotechnical Design of Permafrost and Wetland Mitigation for Colorado State Highway 5 (Mt. Evans Road) Atkinson, Ariel Legionella Occurrence Monitoring in Las Vegas Valley Groundwater Bahman, Akbari See Vassileva, Magdalena Bailey, R. Mark (1) High Resolution Electron Microscopy (TEM/SEM) Images of Amphibole Fibers and their Impact on the Definition of Asbestos Bailey, R. Mark (2) Fibrous Minerals of Lakebed and Alluvial Fan Deposits of the Great Basin Bailey, R. Mark (3) NOA in Death Valley Talc Bailey, R. Mark See Erskine, Bradley G. Balson, Tyler See Johnstone, Luke Bandala, Erick See Zeidman, Ahdee Bauer, Jennifer Landslide Mapping in Transylvania County, NC – Historic Storms and New Data

Name Title

Aichi, Masaatsu See Joshi, Ajit Aird, Hannah See Kennedy, Elisabeth Aird, Hannah See Wagoner, Matthew

Dalal, Visty

Cross, Eric Hydrogeologic Characterization of Sand/Gravel Aquifers and Stratigraphic Analysis Using Electrical Resistivity Tomography Crow, Ryan See Bennett, Scott Cyr, Andrew J. See Bennett, Scott D’Hondt, Steven See Wei, Meng

Dalton, Steve C. See Lindenbach, Evan (1) Darin, Michael H. See Bennett, Scott Darrow, Margaret An Overview of the First Published Landslide Inventory in Alaska Darrow, Margaret See Herrman, Daisy Darrow, Margaret See Horning, Kayla Darrow, Margaret See Kidanu, Shishay Darrow, Margaret See Mallett, Kristin Darrow, Margaret See Nelson, Victoria Dawson, Timothy See Rosa, Carla Dee, Seth (1) Field Response and Surface-Rupture Characteristics of the 2020 M6.5 Monte Cristo Range Earthquake, Central Walker Lane, Nevada Dee, Seth (2) Geologic Mapping, Geochronology, and Fault Characterization in the Las Vegas Basin Deif, Ahmed See El-Hussain, Issa dePolo, Craig Las Vegas Basin – A Southern Element of the Walker Lane dePolo, Craig See Dee, Seth (2)

Name Title

Derby, Martin Geohazard Identification, Monitoring and Mitigation Methods Using Soil Nail Technology for Shorelines and Infrastructure (1)

Buchanan, Sean See Quigley, Laura Buchanan, Sean See Rezapour, Aida Buche, Matt A Closer Look at Instrumenting Old Casagrande Piezometers with New Vibrating-Wire Sensors

“One Foot on the Banana Peel, and Another in the Grave” George Aubin – a Proud Octogenarian Dam Owner!

Buck, Brenda Update and Overview on Naturally Occurring Asbestos in Clark County, Nevada, USA Buck, Brenda See Renkes, Natalie Buenker, Jason See Taylor, Gabriel Burgess, Paul W. See Oswald, John Carlson, Chad Exploration Drilling and Geomorphic Mapping Along the California Aqueduct for the California Aqueduct Subsidence Program Carpenter, David See Leberfinger, Jeffrey Christiansen, Cole See George, Michael Christiansen, Cole See Smith, Casey Clark, Rob See Buche, Matt Clark, Ryan See Kelson, Keith (2) Clark, Ryan See LeFebvre, Amy Collins, Brian See Olson, Brian (1) Colque, Percy See Grady, Cassidy Colque, Percy See Lemus, Oscar Cook, Doug See Rosenbaum, Cole Cooley, Jade See West, Loyd Corder, Christopher Seismic Design Criteria and Soft Sediment Geology in the Seismically Active Southern Salton Sea Crockford, Anna Temporary Rock Support Design Based on Rockmass Mapping for the Cut-And-Cover Tunnels of the Ottawa Light Rail Transit Extension, Ontario, Canada

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 105

Gates, William See Struthers, James

Gelinas, Sharon See Loar, Todd (1)

Derby, Martin A Comparison between In-situ Instrumentation & Remote Sensing Methods for Slope Monitoring within a Pipeline Right-of-Way (2) Diaz, Alonso See Kennedy, Elisabeth Diaz, Alonso See Wagoner, Matthew Dockweiler, Paul See Small, Molly Dobson, Mark Geologic Hazards Associated with Tunneling Doherty, Kevin See Longstreth, David Dorsey, Rebecca J. See Bennett, Scott Dowling, Casey See Rosenbaum, Cole Downing, Madeline See Corder, Christopher Dresse, Trent See Buche, Matt El-Hussain, Issa Seismic Hazard Assessment for Selected Sites in Musandam Region, Sultanate of Oman Ellinghouse, Leroy See Nichols, Holly Elliott, Austin See Dee, Seth (1) Ellis, John The GULF 2023 Model and Ensemble: Modeling Advances and Preliminary Results for the Gulf Coast Aquifer System Ellis, John See Ramage, Jason Enberg, Tami The Major Causes of the 2020 Flash Floods in the Jakarta Basin, West Java Indonesia Encelewski, Matthew See Horning, Kayla England, John See Kelson, Keith (1) Erhart, Emily Seepage Investigation of Embankment Dam to Evaluate Potential Failure Modes Epting, Justin See Oswald, John Erskine, Bradley G. Case Study Response to an NOA-containing Rock-fall on Highway 95 near Riggins, Idaho in the Western Idaho Ultramafic Belt

Evans, Stephen Facades of Futures Past – Reusing Historic Facades

Forsthoff, Brian Protection of Homes in Puerto Rico from Massive Rockfall

Farr, Tom See Vasco, Donald

Frehner, Wilbur See Atkinson, Ariel Freitag, George See Martin, Greg Fuemmeler, Stephen See Bauer, Jennifer

AEG 2022 ANNUAL MEETING 106 AEG 65th Annual Meeting Program with Abstracts September 2022

Faulds, James The Walker Lane: An Incipient Plate Boundary Dissecting the American West and Potential Heir to the San Andreas Fault Fehrenbach, Anne Comparison of Shallow and Deep-Seated Landslides on Privately Managed Timberlands in Ah Pah Creek, Humboldt County, California

Fen, Qin See Hu, Jiyuan Finch, Stella Groundwater Plume Delineation, Comparability of FROG-4000 Split-Sample Analyses of Volatile Organic Compounds

Essex, Randall Tunnel Symposium Keynote Address: Geotechnical Baseline Reports – A 25-year Critique with Recommendations (aka Lessons Learned and Forgotten)

Garibay, Hilary See Carlson, Chad

Gates, William Practical Estimation of Friction Angles for Slope Stability Analysis

Gauthier, Dave See Rosenbaum, Cole

Gagnon, Hawkins Case History of Swinging Bridge Dam – Lessons Learned in Dam Design, Internal Erosion, Rehabilitation, Instrumentation and Monitoring Garg, Shagun Surface Sinking due to over Extraction of Groundwater: Case study of Delhi NCR, India

Forsthoff, Brian See Paulose, Presty

Garg, Shagun See Motagh, Mahdi

Name Title

AEG 2022 ANNUAL MEETING

Hibbard, David (1) ArcGIS for Geohazard Inventory, Analysis, Site Design, and Mitigation Hibbard, David (2) Abandoned Coal Mine Mitigation in High Pressure Artesian Conditions Hlepas, Georgette Mosul Dam Foundation and Emergency Grouting Holder, Sam See Bowling, Roy Horning, Kayla Watching Paint Dry: An Overview of Lidar Data Processing Hu, Jiyuan Land Subsidence in Wuhan, China: Monitoring, Driving Factors and Risk Assessment

September 2022 AEG 65th Annual Meeting Program with Abstracts 107

Name Title

George, Michael F. Application of the Block Theory Rock Erodibility Method to Evaluate Scour Potential and Risk at the Don Pedro Dam Emergency Spillway George, Michael F. See Smith, Casey Gerrity, Daniel See Atkinson, Ariel Gerrity, Daniel See Papp, Katerina Gillon, Kenneth See Bauer, Jennifer Goode, Brooklyne Seismic Refraction Testing as a Rippability Assessment and Excavation Estimation Tool Grady, Cassidy Remote Rockfall Hazard Mapping in the Arequipa Region of Peru Graham, Alex See Crockford, Anna Grahl, Dirk A Travelers Tale – Continuity of the Black River and Trenton Groups from Watertown to State College Greene, Alexander Post-Wildfire Geohazard Assessments of Impacted Natural Gas Pipeline Corridors Greene, Alexander See Warner, Jared Greene, Brian, Geology as Related to Featured Dams and Cofferdams in Western Pennsylvania Griffin, Jay L. Parkway Drive Landslide, Evaluation and Remediation – Risks with the Expanding Urban Interface Part II Griffin, Jay L See Johnson, Ronald Gugsa, Trufat See Admassu, Yonathan Gurrola, Larry D. Debris Flow History of the Montecito Watersheds, Southern Santa Barbara County, California Gurrola, Larry D. Bedrock Landslides and Historic Outbreak Flood Events, Community of Montecito and Vicinity, Southern Santa Barbara County, California Gurung, Narayan See Haneberg, William Guzek, Ethan See Struthers, James Haghshenas Haghighi, Mahmud Groundwater Depletion and Subsidence in Iran: a Country-Scale Hotspot Survey with Sentinel-1 Haji Omar, Khalid Removal of a Mixture of Toxic Metals and Metalloids from Petroleum Produced Water by Dolomite Filtration Hall, Brian See LeFebvre, Amy Hall, Brian See Loar, Todd (2) Hammond, William C. See Kreemer, Corné Haneberg, William Laprak Revisited: Understanding the Response of a Large Himalayan Landslide to the 2015 Gorkha Earthquake Harden, Tessa See Kelson, Keith (2) Harden, Tessa See LeFebvre, Amy Harman-Tóth, Erzsébet See Hyskaj, Ambra Hasan, Husein See Huebner, Matthew Hatem, Alexandra See Dee, Seth (1) Haugen, Benjamin Using GIS, Remote Sensing, Machine Learning, and Multi-Criteria Analysis to Prioritize Geohazard Risks Hauksson, Egill See Olson, Brian (2) Hempen, Gregory Advantages of Multiple Geophysical Methods at Pre-1970 Dams Henry, Christopher See Faulds, James Herrman, Daisy Analysis of the Long-Term Effects of Construction on Rockfall along the Parks Highway, Alaska

Name Title

Huebner, Matthew Development of Deep Seismic Velocity Profiles for TVA Dams: Data Compilation, Facies Analysis, and Depth Correction for Shear Wave Velocities

Kane, William F. See Forsthoff, Brian Kane, William F. See McElhany, Joseph Karanam, Vamshi See Garg, Shagun Katlein, Adam Per- and Poly-fluoroalkyl Substances (PFAS) Site Investigation and Management Planning Strategies

Keaton, Jeffrey February 2019 Alluvial Fan Flood Characteristics Inferred From Available Information, Central Riverside County, CA Kelson, Keith (1) Using Paleoflood Analyses to Improve Hydrologic Loading for USACE Dam Safety Risk Assessments: A Nationwide Approach Kelson, Keith (2) Developing a Regional Paleoflood Chronology for Dam Safety Risk Assessments in the Upper Willamette River Basin, Oregon Kelson, Keith See LeFebvre, Amy Kelson, Keith See Serafini, David C. Kennedy, Drew See Buche, Matt Kennedy, Elisabeth Naturally Occurring Asbestos in the Paradise, CA Area Kennedy, Elisabeth See Wagoner, Matthew Kidanu, Shishay GIS-Based Landslide Susceptibility Mapping Using Analytic Hierarchy Process (AHP) in Kim, Kyra See Vasco, Donald King, Michael Funeral Mountain Nevares 2 and BLM-1 Wells: A Window into Inter-Basin Flow & Potential Off World Life Knight, Jacob See Ellis, John Koch, Jim See Luce, Gary Koehler, Rich D. See Dee, Seth (1) Koehler, Rich D. See Faulds, James Kreemer, Corné Geodetic Insights into Present-Day Strain Accumulation and Release in the Walker Lane Kreemer, Corné See Faulds, James

AEG 2022 ANNUAL MEETING 108 AEG 65th Annual Meeting Program with Abstracts September 2022

Hughes, Joseph Simulating Aquifer-System Deformation in Response to Groundwater-Level Changes in Unconfined Hughes, Joseph See Ellis, John Hunnicutt, Shawna Analyses of Spring Water Chemistry and Microbiology in the Spring Mountains, Nevada Hyskaj, Ambra, Textural Arrangement of Naturally Occurring Asbestos with Accompanying Minerals in the Albanian Ophiolites

Isaacson, Ike See Hibbard, David (1) Ismail, Ahmed See Hempen, Gregory Isphording, Wayne Wind, Water, and Slope. Taken Together they all say “NOPE”! A Case History of Aquaculture Litigation Ivey, Lex See Haugen, Benjamin Jiming, Guo See Hu, Jiyuan Johnson, Ronald Parkway Drive Landslide, Evaluation and Remediation – Risks with the Expanding Urban Interface, Part I Johnson, Ronald See Griffin, Jay L. Johnson, Sarah E. See Haneberg, William Johnstone, Luke Advanced Monitoring/Modeling of Surface-Aquifer Interactions of a Levee System and Infrastructure Design Implications Joshi, Ajit Anomalous Rate of Subsidence at Early-Stage of Groundwater Pumping from Subsurface Heterogeneous Aquifer/Aquitard System Judy, Alexis See Struthers, James Kakaria, Reva See Rosa, Carla Kalika, Sarah But I’m not Biased! Understanding the Connection Between Your Brain and Your Implicit Biases Kalika, Sarah NOA Basics and Case Studies

Keane, Christopher Fostering a Thriving Geoscience Community Through Inclusivity – A Look at Current Initiatives

Leshchinsky, Ben See Herrman, Daisy Li, Elita See Nilot, Enhedelihai Li, Jiang See Lui, Yi

Lopez, Jim See Nichols, Holly Lucas, Evan See George, Michael Lucas, Evan See Smith, Casey Luce, Gary Update to the Carson City and New Empire Quaternary Fault Maps 1979-2022 Lukashov, Stefani See Longstreth, David Lukashov, Stefani See Oswald, John Mace, Jason Well System Management Program

AEG 2022 ANNUAL MEETING September 2022 AEG 65th Annual Meeting Program with Abstracts 109

Name Title

Loar, Todd (1) Abutment Stability Analysis – Quantitative Risk Assessment for Libby Dam, Montana Loar, Todd (2) Abutment Rock Erosion Analysis Due to Overtopping – Risk Assessment for Bull Shoals Dam, Arkansas Longstreth, David A Preliminary Comparison of Rock Strength and Turbidity in the Coastal Belt Franciscan Assemblage, South Fork Wages Creek versus South Fork Caspar Creek, using the Hoek-Brown Criterion, Mendocino County, California

Mack, Darren See Buche, Matt Mackey, Alexia Girlboss vs. Misogyny- Inspire or Destroy? Mahan, Shannon See Dee, Seth (2) Mallett, Kristin Telling the Story: Developing StoryMaps for the 2020 Haines, Alaska, Landslides Manda, Ale Modeling the Effects of a Drain and Active Groundwater Pumping System on Storm Water Flooding in a Coastal Setting Mann, Aras See Bauer, Jennifer Marshall, Mike See Martin, Greg Martin, Greg Clatskanie, Oregon: Case Study of an Active Landslide in the Oregon Coast Range Martin, James See Serafini, David C. Mavor, Skyler P. See Bennett, Scott McCulloch, Neal See Taylor, Gabriel McCormick, William Healdsburg-Rodgers Creek Fault Stepover: Detailed Geologic Characterization for Engineering Mitigation and Real Estate Evaluation McCosby, Bodie The Eightmile Lake Restoration Project – Characterization of a Landslide Dam McCosby, Bodie See Swank, Mark McCracken, Julianna See Kennedy, Elisabeth

Krom, Thomas See Buchanan, Sean Kunkel, Forrest See Johnstone, Luke Kussman, Alexis See Manda, Alex Laó-Dávila, Daniel A. See Hempen, Gregory Latham, Rebecca See Bauer, Jennifer Leberfinger, Jeffrey A New Method for Providing Accurate Locations for Geophysical Data in GPS Denied Areas: SLAM Lidar LeFebvre, Amy Improving Hydrologic Loading for Libby Dam Using Paleoflood Analysis Along the Kootenai River, Northwestern Montana LeFebvre, Amy See Loar, Todd (2) Lemus, Oscar Failure Conditions and Triggers of the Achoma Landslide, Central Andes Region, Arequipa Peru

Lindenbach, Evan (1) Rock Dilatometer Testing: Field Observations and Comparisons to Empirical Correlations Lindenbach, Evan (2) Causes of Voids Behind Spillways, Conduits, Canals, Tunnels, and Siphons Liu, Yi Land Subsidence Due to Creep of the Gulf Coast Aquifer System in the Houston-Galveston Region Liu, Yi See Zhou, Xin

AEG 2022 ANNUAL MEETING 110 AEG 65th Annual Meeting Program with Abstracts September 2022

Olson, Brian (1) Earthquake-Induced Rockfall and Liquefaction from the 2020 Mw5.8 Lone Pine Earthquake in Eastern California Olson, Brian (2) The 2020 Mw5.8 Lone Pine Normal-Faulting Earthquake Sequence, Eastern California Olson, Brian See Oswald, John Oskin, Michael E. See Bennett, Scott

Mulder, Henri V. See Serafini, David C. Mundell, John A. See Johnstone, Luke Munro, Rosalind See Keaton, Jeffrey Munsey, Jeffrey See Huebner, Matthew Murdock, Kathryn Magnetic Methods as a Hazard Assessment Tool: Detecting, Delineating, and Monitoring Underground and Surface Fires Myers, Dusty See Gagnon, Hawkins Nelson, Victoria Mapping and Categorizing Landslides Around Haines, Alaska Nichols, Holly California Aqueduct Subsidence Program Nichols, Holly See Carlson, Chad Nilot, Enhedelihai Tunnel look ahead using the Active and Passive Seismic Method

McElhany, Joseph Rockfall Protection for a Small Hydroelectric Dam in a Steep Canyon McLaurin, Brett See Buck, Brenda McMillan, Teri See Finch, Stella Medley, Erica See Kelson, Keith (2) Metcalf, Rodney See Buck, Brenda Metcalf, Rodney See Renkes, Natalie Meza, Pablo See Grady, Cassidy Meza, Pablo See Lemus, Oscar Miller, David M. See Bennett, Scott Miller, Lauren Landslide Analysis with Incomplete Data: Developing A Framework for Critical Parameter Estimation Miller, Nina See Kreemer, Corné Minas, Shant “Everything but the Kitchen Sink”: A Multidimensional Geotechnical, Geologic and Environmental Investigation for a Proposed Manufacturing and Office Facility on a Complicated Brownfield Site, Los Angeles, California Moan, Ben Per- and Poly-Fluoroalkyl Substances (PFAS) – Occurrence and Update on Regulatory Framework Moe, Minda Professionalism & Pronouns – An Exercise Mohamed, Adel See El-Hussain, Issa Moon, Jaeyun See Zeidman, Ahdee Morrison, Christina See Atkinson, Ariel Mostafa, Fad aifard See Vassileva, Magdalena Motagh, Mahdi Flood Mapping and Monitoring by Using Remote Sensing and Artificial Intelligence (AI): Examples from AI4 Flood Project Motagh, Mahdi See Garg, Shagun Motagh, Mahdi See Haghshenas Haghighi Motagh, Mahdi See Hu, Jiyuan Motagh, Mahdi See Vassileva, Magdalena

Name Title

Norris, Gary Modeling the Stress-Strain Curve of Las Vegas Area Caliche Nuriel, Perach See Bennett, Scott O’Conner, Molly See Shinpaugh, Joshua Olsen, Michael See Herrman, Daisy

Name Title Oswald, John Post-Fire Geologic Hazard Assessment of the 2021 Bond Fire & Hillslope Response to Significant Storms During Year-One Palleske, Cortney See Crockford, Anna Papp, Katerina Characterizing the Chemical and Microbial “Fingerprint” of Unsheltered Homelessness in an Urban Watershed Pascoe, Jerry See Buche, Matt Paulose, Presty Time Domain Reflectometry for Innovative Landslide and Slope Monitoring Pearce, Justin See Kelson, Keith (1) Pearson, Carolyn See Kelson, Keith (2) Perry, David Coming Soon Pickering, Alexandra See Dee, Seth (1) Piepenburg, Michael A. June 24, 1971 Sylmar Tunnel Fire – A Grim Reminder Pierce, Ian See Dee, Seth (1) Plastow, Geoff See Buchanan, Sean Prakash, Nikhil, Fatalities from Debris Flow: Is the Societal Risk Higher than Landslides? Pridmore, Cynthia L. The California Earthquake Clearinghouse – Ridgecrest Earthquake Sequence 2019 Prieur, James Hydrogeology and Climate Effects on Municipal Water Supply Systems in the Spring Mountains, Nevada Prince, Philip See Bauer, Jennifer Pullen, Tom See Akeju, Victor Quigley, Laura Rapid Collaboration on Water Resource Management Projects in an Ever-Changing Climate Quigley, Laura See Buchanan, Sean Quigley, Laura See Rezapour, Aida Raff, David See Keynote: Bureau of Reclamation’s Senior Management to Discuss the Impact of the Southwest Drought on Hoover Dam and the Colorado River Ramage, Jason That Sinking Feeling: Reexamining 100 Years of Land Subsidence in the Greater Houston Area, Texas, Based on Multiple Measurement Types Ramage, Jason See Ellis, John Ranck, Mike See Buchanan, Sean Renkes, Natalie Can Recrystallization of Fibrous Amphibole Produce Asbestos Morphologies? Renner, Morgan See Longstreth, David Rezapour, Aida A Digital Twin System to Manage the Uncertainties Associated with the Ground Conditions on Tunneling Projects Richards, Kevin Assessment of Breach and Consequences for an Unlined Emergency Spillway Richter, Mark V. See Wilshaw, David (1) Robinson, John The Time is Right to Add Deep Aquifer Recharge as a Resiliency Planning Tool Rodriguez, Carlos See Forsthoff, Brian Rogers, A. Bruce Hydrogeology of Stress-Relief and Regional Fracture Regime Integration – Engineering and Environmental Case Studies Rogers, J. David (1) Forensic Analyses of Megalandslides along the Echo and Vermilion Cliffs of Northern Arizona Rogers, J. David (2) Recognition of Prehistoric Landslide Dams and Catastrophic Outbreak Floods Rogers, J. David See Gurrola, Larry D. Rollog, Mark See Bailey, R. Mark (2) Rosa, Carla Mapping of Surface Fault Rupture and Ground-Deformation Features of the 2019 M6.4 and M7.1 Ridgecrest Earthquakes

September 2022 AEG 65th Annual Meeting Program with Abstracts 111

Rosales-Lagarde, Laura Teaching Geoscience as a Latino Female Professor in Nevada: A Small Door to Increase Diversity in the Field

Rosenbaum, Cole Quick Response to a Sensitive Situation: A Case Study of a Pipeline Operator’s Response to a Sensitive Clay Landslide Rudd, Jessica F. See Loar, Todd (1) Saber, Robert See Buche, Matt

AEG 2022 ANNUAL MEETING

112 AEG 65th Annual Meeting Program with Abstracts September 2022

AEG 2022 ANNUAL MEETING

Name Title Safari, Leyla See Bowling, Roy Salas, Guido See Grady, Cassidy Salas, Guido See Lemus, Oscar Sandro, Martinis See Motagh, Mahdi Santi, Paul See Grady, Cassidy Santi, Paul See Lemus, Oscar Santi, Paul See Miller, Lauren Santi, Paul See Prakash, Nikhil Sasaki, Rueben See Loar, Todd (2) Saunders, Mark See Derby, Martin (2) Schlittenhart, Todd See Bowling, Roy Schuler, Karl Risk Assessment Needs for Redeveloping Industrial Property to Residential Use Schwarber, Jaimy See Darrow, Margaret Schwarber, Jaimy See Kidanu, Shishay Seitz, Gordon See Dee, Seth (1) Serafini, David C. Dam and Safety Modifications to Address Active Fault Rupture Beneath an Embankment Dam Setz, Melissa See Shinpaugh, Joshua Shinpaugh, Joshua A Systematic Approach to Address Risk Uncertainty in a Karst Environment Shinpaugh, Joshua See Huebner, Matthew Sinrid, Roessner See Vassileva, Magdalena Simpson, Bryan K. Hoover, Not Just Another Dam Lecture Sipps, Mike See Motagh, Mahdi Sirles, Phil See Bowling, Roy Small, Molly Establishing the NORM for Nevada – Mining Regulatory Updates for Uranium in Groundwater Smith, Casey Erodibility Studies Performed at the Don Pedro Dam Emergency Spillway Smith, Casey See Buche, Matt Smith, Casey See George, Michael Smith, Daniel See Loar, Todd (2) Smith, Haden See Kelson, Keith (2) Smith, Kristen See Shinpaugh, Joshua Smith, Tiffany We are Still HERE: Amplifying Indigenous Languages and Knowledges in STEM Sneed, Michelle See Ellis, John Snider, Frederic See Gagnon, Hawkins Snyder, Jay See Finch, Stella Sochar, Scott A Program to Review Engineering Geology for Schools and Hospitals Son, Yeongkwon See Zeidman, Ahdee Springhorn, Steven Overview of California Department of Water Resources Statewide Subsidence Monitoring Efforts Stirewalt, Gerry L. Evaluating Geologic and Seismic Hazards for Plant Vogtle Nuclear Units 3 and 4, Burke County, Georgia, at the US NRC Stohr, Chris Scientific and Political Issues Confronting Protection of the Sole-Source Mahomet Aquifer, East-Central Illinois Stohr, Chris Supplementary Civics and Science in Elected Office: Observations from Five Years in Public Office Stopka, Cody See Haugen, Benjamin Struthers, James Bullseye Rock Slope Mitigation Development, US 95 Riggins, Idaho

September 2022 AEG 65th Annual Meeting Program with Abstracts 113

AEG 2022 ANNUAL MEETING

Name Title Sullivan, Susan See Keane, Christopher Sushenko, Natasha See Zeidman, Ahdee Swafford, Callan See Goode, Brooklyne Swank, Mark The River’s Edge – the Story of a Levee Setback and Restoration Project Swank, Mark See McCosby, Bodie Tami, Patrick See Springhorn, Steven Tate, Andrew See Carlson, Chad Taylor, Gabriel SR 112 / Jim Creek Landslide Stabilization – Alternatives and Lessons Learned Taylor, Wanda See Dee, Seth (2) Tello, Matthew See Wallace, Cory Terry, Thomas Status of the USACE Drilling Program Plans (DPP) Reviews Thomas, Kate See Pridmore, Cynthia Thompson, Lisa A. See Bennett, Scott Tokunaga, Tomochika See Joshi, Ajit Umhoefer, Paul J. See Bennett, Scott Vanos, Stephanie See Buchanan, Sean Vanos, Stephanie See Quigley, Laura Vanos, Stephanie See Rezapour, Aida Vasco, Donald Using InSAR and GRACE Satellite Data to Monitor Hydrological Variations within Tulare Basin, California Vassileva, Magdalena New Insights into Deformation Characteristics of the Hoseynabad Kalpush Landslide in Iran and Its Catastrophic Failure in Spring 2019 Vilcaez, Javier See Haji Omar, Khalid Wagoner, Matthew Geochemical Analysis of Metavolcanic and Ultramafic Rocks and Soils in Magalia, California, Show Ni and Cr Toxicity Potential Walker, Scott Boone Dam Part 3: Mitigation of Internal Erosion Failure Modes through a Karst Foundation Walker, Scott Flagship of the TVA: A Case History of Norris Dam Wallace, Cory Characterization of Debris Flow Hazards Along the San Juan Skyway, Colorado Walton, Gabriel See Grady, Cassidy Warner, Jared Subsurface Characterization and Development of Pole Foundation Design Groups for Utility Fire Risk Mitigation Programs Warner, Jared See Greene, Alexander Wartman, Joseph See Herrman, Daisy Watkins, Conor M. See Rogers, J. David Wei, Meng Subsidence in Coastal Cities Throughout the World Observed by InSAR Weir, Susan Steele Women in Tunnels – From Prohibited to a Career Weiszburg, Tamás G. See Hyskaj, Ambra Wernle, Alex See West, Loyd Wert, Eric C. See Atkinson, Ariel West, Loyd Washington State School Seismic Safety Project: Geologic and Structural Engineering Assessments of 561 School Buildings Whisman, Dan See Nichols, Holly White, Jeremy See Ellis, John Wildman, Charlie Lique-What-The-Faction!?! – A Practitioner’s Discussion of Atypical Liquefiable Soils and Implications to Slope Stability Wilshaw, David (1) Assessment of the Efficacy of Deep Two-Component Polymer Injection in Soil and Weak Rocks Wilshaw, David (2) Advanced Continuous Surface Wave Testing (ACSW): Geologic and Geotechnical Site Characterization for the 21st Century Woodward, Jason Industrially Managed Timberlands: A Comparison of Erosion Rates to Historical & Contemporary Practices

https://www.minesymposium.orgSoon!

Zimmermann, Josh See Hibbard, David (2)

Zhou, Xin Land Subsidence Contributions to Relative Sea Level Rise at Tide Gauge Washington, DC

AEG 2022 ANNUAL MEETING 114 AEG 65th Annual Meeting Program with Abstracts September 2022

The International Council on Mining and Metals (ICMM), which includes the world’s largest mining houses and many leading mining companies as part of its membership, has long recognized that economic growth should never be at the expense of people or the planet. In 2003, ICMM published its 10 Principles for sustainable development for mining to set a standard of ethical performance in line with the UN Sustainable Development Goals. These ICMM mining principles cover all aspects of mining operations throughout the life-of-mine cycle.

The symposium plans to cover this broad sweep with presentations on state-of-the-art aspects of principles,

Virtual

In line with these principles, and cognizant of the value of geoscience in helping deliver and meet sustainable mining performance goals, AEG and the Environmental and Engineering Geophysical Society are convening this online symposium over four half-days in November, 2022. Lifeof-Mine activities cover everything from mine feasibility planning through to closure, with geoscience contributing practical assistance to the life-of-mine site key activities to sustain the mine and leave an acceptable legacy—the 6Rs: “Regulation, Running, Rehabilitation, Repurposing, Retirement and Reclamation.” Customized geoscience workflows contribute through implementation of the 4Ms: “Mapping, Monitoring, Modelling and Management.”

methodologies and case histories of the role of geoscience to assist and facilitate mine engineering, environmental, geotechnical, water and soil management, and regulatory approaches. The aim is to demonstrate the contribution of integrated geoscience to responsible progressive mine operation and monitoring, ore-winning optimization and waste limitation, rehabilitation, repurposing of historical mines (e.g., reprocessing of mine wastes for critical minerals) and closure and reclamation planning and implementation.

The Role of Geoscience in Mine Site Regulation, Running, Rehabilitation, Repurposing, Retirement, and Reclamation Symposium — May 2023 Will Open

Degradation

Zeidman, Ahdee of Antibiotics in Aqueous Phase using Immobilized Zero-Valent Iron Nanoparticle

Name Title Wu, Pei-Chin See Wei, Meng Young, Zachary M. See Kreemer, Corné

Registration

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Program with Abstracts, Volume 65, Number 4

Articles inside

Outstanding Environmental & Engineering Geologic Project Technical Program Schedule

Poster Sessions

Thursday, September 15

Wednesday, September 14

The 2021–22 AEG/GSA Richard H. Jahns Distinguished Lecturer

Keynote Speaker

AEG Foundation 2022 Scholars

Special Thanks

Welcome Letter – AEG 2022 Co-chairs, Jerry King and Nick Saines

Welcome Letter – AEG President, Maddie German

Schedule of Events

Technical Session Numbers and Names