HydroVisions | Winter 2021 by HydroVisions

VOLUME THIRTY WINTER 2021

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HYDROVISIONS is the official publication of the Groundwater Resources Association of California (GRA). GRA’s mailing address is 808 R ST STE 209, Sacramento, CA 95811. Any questions or comments concerning this publication should be directed to the newsletter editor at editor@grac. org or faxed to (916) 231-2141. The Groundwater Resources Association of California is dedicated to resource management that protects and improves groundwater supply and quality through education and technical leadership Editor Rodney Fricke editor@grac.org Editorial Board Steve Phillips John McHugh Adam Hutchinson David Von Aspern Executive Officers President Abigail Madrone West Yost Associates Tel: 530-756-5905 Vice-President R.T. Van Valer Roscoe Moss Company Tel: 323-263-4111 Secretary John McHugh Luhdorff & Scalmanini, Consulting Engineers Tel: 530-207-5750 Treasurer Rodney Fricke GEI Consultants Tel: 916-631-4500 Officer in Charge of Special Projects Christy Kennedy Woodard & Curran Tel: 925-627-4122 Immediate Past President Steven Phillips, Retired U.S. Geological Survey Tel: 916-278-3002 Administrative Director Sarah Erck GRA Tel: 916-446-3626

Directors Jena Acos Brownstein Hyatt Farber Schreck Tel: 805-882-1427 Lyndsey Bloxom The Water Research Foundation Tel: 571-384-2106 Erik Cadaret West Yost Associates Tel: 916-306-2250 Murray Einarson Haley & Aldrich Tel: 530-752-1130 Lisa Porta Montgomery & Associates Tel: 916-661-8389 Bill DeBoer Montgomery & Associates Tel: 925-212-1630 John Xiong Haley & Aldrich Tel: 714-371-1800 Todd Jarvis Institute for Water & Watersheds, Oregon State University Tel: 541-737-4032 James Strandberg Woodard & Curran Tel: 925-627-4122 To contact any GRA Officer or Director by email, go to www.grac.org/board-of-directors

The statements and opinions expressed in GRA’s HydroVisions and other publications are those of the authors and/or contributors, and are not necessarily those of the GRA, its Board of Directors, or its members. Further, GRA makes no claims, promises, or guarantees about the absolute accuracy, completeness, or adequacy of the contents of this publication and expressly disclaims liability for errors and omissions in the contents. No warranty of any kind, implied or expressed, or statutory, is given with respect to the contents of this publication or its references to other resources. Reference in this publication to any specific commercial products, processes, or services, or the use of any trade, firm, or corporation name is for the information and convenience of the public, and does not constitute endorsement, recommendation, or favoring by the GRA, its Board of Directors, or its members.

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TABLE OF CONTENTS

President’s Message

Page 6

PFAS Monitoring In Development

Page 22

WGC 2021

Page 9

Wells and Words

Page 26

The Geochemist’s Gallery

Page 14

Drought Conditions and Impacts

Page 30

So, You’re Interested in ASR?

Page 18

Field Trip

Page 34

Parting Shot

Page 42

THANK YOU TO OUR 2021 GRA DONORS

Mark Peterson, Julie Johnson, Mike Huggins, Nathan Hatch, Douglas Tolley, Joseph LeClaire, Gordon Osterman, Roger Masuda, Heather Jackson, Scott Warner, Christopher Alger, Sodavy Ou, Mark Wanek, Sam Williams, Tiffany Thomas, George E.Moss Recocable Trust, David Abbott, Haley & Aldrich, Tina Leahy, Bianca G Mintz, Valerie Flores, Jeffrey Gutierrez, William D Bone, Lee Paprocki, William R Laton, Thomas Harter, Cordie R Qualle, Graham Fogg, Steven P Phillips, Katrina Kaiser, Peter Dillon, Christopher Johnson, Steve Deverel, Noah R Heller and Peter Mock 4 HYDROVISIONS

2021 Winter Issue

We are ready to assist you with your groundwater needs • Hydrogeologic Studies and Monitoring • Geotechnical Studies and Projects • SGMA Plans, Projects and Management Actions • ASR, Production and Monitoring Wells • Managed Aquifer Recharge Planning, Design, and Construction • Aquifer/Basin Characterization • Water Budget Analysis • Groundwater/Surface Water Modeling • GIS/Data Management System • Exchange, Storage and Transfer Agreements • Regulatory Compliance • Groundwater Governance • Outreach and Facilitation • Website Development and Hosting

Contact Us Today. Chris Petersen 530.304.3330 cpetersen@geiconsultants.com Rodney Fricke 916.407.8539 rfricke@geiconsultants.com

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President’s Message ABIGAIL MADRONE Abigail Madrone, Business Development Director with West Yost. Throughout her 20 year career, Abigail has served and supported groundwater and water resources management through groundwater monitoring and analysis, project and program management and public outreach and education.

As we approach the end to another year, we reflect on our successes, consider opportunities for continued growth, and seek inspiration for the future. The seasons continue to change, but our Vision – Sustainable Groundwater for All, continues to serve as our guiding light. Our Mission, dedicated to resource management that protects and improves groundwater supply and quality through education and technical leadership, keeps us focused on programs, initiatives and events that bring the most value to our members and the water resources community we serve. As my term as President from 2020-2021 ends, it’s a joy to reflect on our collective accomplishments. We have grown in numbers, from over 1000 members in 2020 to 1387 members so far in 2021, and we have grown beyond California, with nearly 100 out of state members. • Over 350 people attended GRACasts • 532 people attended statewide events • 1,311 people attended Branch events

President’s Message

• 10 Annual Sponsors and 36 Event Sponsors

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We developed a 3-year strategic plan: Expand, Diversify & Lead, established a Diversity, Equity, and Inclusion (DE&I) Committee. We successfully integrated meaningful programs and panels throughout our statewide events to inform, educate and help create an environment that is inclusive of all people and their unique abilities, strengths, and differences. As we continue to grow, we embrace diversity in every aspect of our organization, from the way we work together to the way we fulfill our mission. We respect diversity in each other, our members, and all others with whom we interact. We are working toward full equity, inclusion, and accessibility for all who interact with GRA. Our successes are made possible through the support and dedication of our 157 volunteers, currently serving in GRA leadership positions, committees, task forces and Branch leadership, and our amazing sponsors. We have so much to celebrate, especially the emerging leaders of our organization who are an essential part of our future 2021 President Award Recipients Lyndsey Bloxom, Research Program Manager with the Water Research Foundation, GRA Director In Lyndsey’s second year as a Director, she volunteered to Chair our marquee event, the Western Groundwater Congress (WGC). The WGC was a major success for our industry and our organization bringing together thought leaders, experts, and emerging professionals to reflect, learn, and grow. This event is a huge undertaking in any year, but in 2021, it took incredible courage, organization, and dedication. Abhishek Singh, Vice President Western Region with INTERA Inc., Technical Committee Co-chair Abhishek is a dedicated groundwater and water resource professional. He brings significant value to our organization through the Technical and DE&I Committees. Abhishek encourages us to grow and challenge perceived norms to become a stronger and more inclusive organization. Marina Deligiannis, Deputy Water Resources Director with The County of Lake, Sacramento Branch Vice President Marina embodies many characteristics of a natural leader through her charisma, curiosity, passion, and dedication to groundwater management. We appreciate her contributions to the Sacramento Branch and 2021 GSA Summit Chair. CONTINUED ON NEXT PAGE

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A groundwater hero is GRA volunteer who throughout their leadership tenure, consistently prioritized the greater good of our organization, advanced the GRA Mission in their day-to-day actions, whole heartedly believe in the GRA Vision and lives our values. It has been an honor to serve as a GRA leader and volunteer with the following Directors who will be fulfilling the remainder of their term and/or retiring at the end of 2021. It is my honor to acknowledge the following Directors for their service to GRA. John McHugh, Senior Hydrogeologist with Luhdorff & Scalmanini Consulting Engineers, GRA Director and Membership and Communications Committee Chair, former editor of HydroVisions Steve Phillips, USGS (retired), GRA Immediate Past President and Nominations Task Force Lead, former editor of HydroVisions Lisa Porta, Senior Water Resources Engineer with Montgomery & Associates, GRA Director and Technical Committee Chair Jim Strandberg, Senior Project Manager with Woodard & Curran, GRA Director Congratulations President Award recipients and Groundwater Heroes! We sincerely thank you for your service and support of GRA. We are grateful for you, our members, sponsors, affiliates, volunteers, and leaders. I am honored with the opportunity to serve as the GRA President and wish you all good health and happiness in 2022. Many of my groundwater mentors and friends have walked before on this path; you all are an inspiration. Thank you for trusting in me to lead and contribute to the success and future of our incredible organization. Warm Regards,

President’s Message

Abigail Madrone, 2021 GRA President

’e Geochemist Gallery

Recognizing Groundwater Heroes

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The 2021 WGC: A Hollywood Smash! LYNDSEY BLOXOM Lyndsey Bloxom is a Senior Water Resources Analyst with the Water Replenishment District and joined the GRA Board of Directors in 2020. Lyndsey’s role with the District includes management of water supply and groundwater resiliency planning efforts, strategic planning and new program initiation, and development of project budgets and outside funding streams. Lyndsey has a BS in Geology and Environmental Science from the College of William and Mary and a MS in Hydrogeology from Virginia Tech. When not planning future WRD and GRA efforts, Lyndsey spends her time rock hounding and camping in the desert or flying kites on the beach.

The 2021 Western Groundwater Congress: The Hollywood Sequel! The return to Hollywood was a box office success! GRA’s premier groundwater conference brought 200 groundwater professionals together in-person again for the first time – from all over North America, including 15 different US states and Canada. Attendees enjoyed and participated in technical sessions centered on the key groundwater issues of today, including contamination and remediation, sustainable groundwater management, water resources and development, and emerging technologies and challenges within the industry. The event was buzzing with excitement during each break and reception, as new ideas and connections sparked during sessions spilled over into lively conversations outside in the gorgeous Hollywood sunshine. A few celebrities even made an appearance – Cher and Dottie Hinson joined us for the President’s Reception and Zoolander’s signature Blue Steel was perfectly performed by our winning scavenger hunt team during Tuesday’s Branch Reception.

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Two themes in particular secured break-out roles that could be seen throughout the event: Diversity, Equity & Inclusion and Health & Safety. The event opened with a keynote panel: Making Ripples That Lead to Waves: Diversity, Equity, and Inclusion Programs in the Water Industry and closed with the viewing and discussion of the movie: Picture a Scientist, a documentary that “chronicles the groundswell of researchers who are writing a new chapter for women scientists”. These sessions aimed to challenge attendees to listen and learn in new ways, using the heart space in place of the head space that we typically employ during technical sessions. Health & Safety was also a high priority throughout the event! As one event survey respondent noted, they “felt safe at the conference; the team did a good job following through with the requirements and everyone followed the protocol in place.” Our planning team wishes to say THANK YOU to all attendees for their strict adherence to safety protocols. We could not have produced this successful event without every individual’s own commitment to safety. Through this conference, GRA has shown that in-person events can be held again – safe and just as engaging as ever. If you missed the event or any particular session, please remember that access to the conference presentations is available for all members! You can find them via the Member Resources page.

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The Geochemist’s Gallery WILLIAM E. (BILL) MOTZER William E. (Bill) Motzer, PHD, PG, CHG, is a somewhat retired Forensic Geochemist

Toxic Terra - PART FIVE Introduction In Parts 3 and 4 of Toxic Terra (Summer and Fall 2021 HydroVisions), I discussed arsenic as an obvious natural drinking water contaminant. Another so-called “modern” or emerging contaminant is chromium-VI [Cr(VI)], which has been improperly labeled in the literature as “hexavalent chromium” (see October 2007 Vortex newsletter article: Valencing Oxidation States at www.calacs.org).

The Geochemist’s Gallery

Sources Cr species, including Cr(VI), occur in California’s groundwater from both anthropogenic and geogenic (natural) sources. Past investigations largely focused on anthropogenic sources (e.g., added to water as a biocide) popularized by the 2000 movie Erin Brokovitch. More recently, groundwater investigations have considered natural or geogenic sources with California having a unique geologic framework, including numerous areas of ultrabasic or ultramafic and serpentinized rocks. Cr concentrations may range from 1,700 to 10,000 milligrams per kilogram in northern California. These rocks contain abundant Cr(III) minerals, which when weathered, can undergo transformation in the critical weathering zone to complex Cr(VI) oxyanions. When inhaled Cr(VI) compounds (largely from anthropogenic sources such as plating and tanning shops) are known human carcinogens but when ingested (largely from geogenic sources) are suspected carcinogens. Additionally, Cr(III)-bearing serpentinites occur

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’e GeochemistThs Gallery

Figure 1: Worldwide distribution of serpentine and ultramafic rocks containing chromium. Modified from Oze, et al., 2007: www.pnas.org_cgi_ doi_10.1073_pnas.0701085104.

throughout the globe (Figure 1) and therefore Cr(VI) compounds may occur worldwide in drinking water sources. The San Francisco Bay Area has several areas where ultramafic rocks and serpentinite can be observed, including Mount Tamalpais State Park and Ring Mountain Open Space Preserve (RMOSP) in Marin County. In the critical zone, many of the Mount Tamalpais and RMOSP soil types derived

Figure 2: Serpentine barrens on Mount Tamalpais (Marin County) near Rock Springs. Photo by W.E. Motzer, August 12, 2012.

from the underlying serpentinite and ultramafic rocks are serpentine soils with unusually elevated iron, chromium, nickel, and cobalt concentrations. However, these soils are also often deficient in calcium and have low water holding capacities. Such soils can be very stressful to plant growth, consequently forming serpentine barrens (Figure 2) commonly consisting of open grassland or savannas where the climate would normally produce forest growth. Serpentine barrens also result in unique eco- or model-systems for evolution, ecology, and conservation studies of rare plant communities. CONTINUED ON NEXT PAGE 2021 Winter Issue

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Groundwater in alluvial aquifers derived from such ultramafic and serpentinized terrain can contain Cr(VI) oxyanions, particularly chromate (CrO42–) and dichromate (Cr2O72–), generally forming under alkaline pH and oxidizing (+Eh) conditions. In other areas, Cr(III) may be catalyzed by manganese (IV) oxides converting Cr(III) to Cr(VI) oxyanions that sorb to hydrous ferrous oxide (HFO) coatings on quartz grains that may slowly release Cr(VI) oxyanions. Most naturally occurring Cr in source rocks exists as Cr(III) minerals (e.g., chromite: Figure 3: Stability zones under different Eh-pH FeCr2O4), of which many are conditions for the Cr-O-H system. Source: D.G. relatively water insoluble. Brookins, 1987, Eh-pH Diagrams for Geochemistry, For example, under standard Verlag, 176 p. conditions (at 25oC and 1.0 bar atmospheric pressure), in the chromium-oxygen-hydrogen system as shown in Figure 3, the Cr(III) stability zone occurs over a wide Eh and pH field under both reducing to oxidizing and acid to alkaline conditions. In the Figure 3 example, Cr(III) generally forms insoluble chromic oxide (Cr2O3), from about pH 5.0 to 13.5 and from an ~Eh ranging from +0.8 to –0.75 volts (V). However, at slightly less than pH 5.0, Cr2O3 can dissolve, forming soluble chromium hydroxide (CrOH2+). At a pH of approximately greater than 13.5 and an Eh ranging from 0.05 to –0.8 V, the soluble Cr(III) anion (CrO2–) forms. In aqueous environments under low Eh conditions, the main Cr(III) species are the Cr(III) cations (Cr3+) and CrOH2+.

The Geochemist’s Gallery

In another Eh-pH diagram (Figure 4) for the chromium-water-oxygen system under standard conditions that could predominate in groundwater, soluble chromium cations and anions may be produced from relatively insoluble Cr(III) hydroxide. Concentrations could range from 500 micrograms per liter (μg/L) to 5,000 μg/L. However, under most natural groundwater conditions, such concentrations are rarely found, generally not exceeding the 50 μg/L primary MCL for total Cr.

’e Geochemist Gallery

Geochemistry

Note in both Figures 3 and 4 that the Cr(VI) stability zone occurs over a much narrower range than the Cr(III) stability zone. Cr(VI) species primarily occur under oxidizing (+Eh) and alkaline conditions (pH >6.0). In this field, Cr(VI) generally forms soluble chromate (CrO42–) anions from approximately pH 6.0 to 14.0 and an Eh from approximately –0.1 to +0.9 V. How and why this occurs will be discussed in my next article on this topic.

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Figure 4: Stability zones showing possible amounts of dissolved soluble Cr(III) in water. Source: J.D. Hem, 1989, Study and Interpretation of the Chemical Characteristics of Natural Groundwater: U.S. Geol. Survey Water Supply Paper 2254.

Developing a Cr(VI) Maximum Contaminant Level (MCL) In 2014, because of the possible carcinogenic concerns with Cr(VI) ingestion, California established a drinking water primary MCL of 10 μg/L or parts per billion (ppb). However, as of May 5, 2017, this MCL was set aside by a Sacramento Superior Court’s decision, siding with the plaintiff that the State Water Resource Control Board (SWRCB) had not taken economic considerations into account when establishing this MCL. Therefore, until the SWRCB complies with the court’s decision, the total Cr primary MCL of 50 μg/L will remain in effect to be used by water suppliers. A more detailed history of California’s attempt in developing a Cr(VI) primary MCL can be found at: https://www.waterboards. ca.gov/drinking_water/certlic/drinkingwater/ Chromium6.html

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TREVOR KENT GEI Consultants

(530) 844-1659 | tkent@geiconsultants.com

CHRIS PETERSEN GEI Consultants

(530) 304-3330 | Cpetersen@geiconsultants.com

Permitting and Regulation We’ve made it to the final article in our ASR series, this time focusing on permitting and regulations pertaining to ASR operations. Permitting and regulations may vary regionally within the state and depending on the intended use for stored water. This article is based on two fundamental assumptions.

Recharge Project

So, You’re Interested in ASR? Part IV – Permitting and Regulation

1. Since we defined ASR as the aquifer storage of drinking water, we will assume the stored water will be used for drinking purposes once recovered from the aquifer storage. 2. The preferred permitting vehicle for ASR programs in California is the State Water Resources Control Board’s (SWRCB) Statewide ASR General Order 2012-0010 (General Order).

So, You’re Interested in ASR?

However, not all recharge programs are covered under the General Order due to certain injection programs predating the adoption of the General Order, along with the specifics of the General Order covering only programs that inject drinking water treated to the Division of Drinking Water (DDW) standards. Recycled water is not currently covered under the ASR General Order). For programs that meet the specifications of ASR under the General Order, it provides a streamlined review and permitting process for ASR implementation.

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So, You’re Interested in ASRTh

The ASR General Order was adopted by the SWRCB in 2012 to provide a clear and structured pathway to an ASR permit with provisions that protect groundwater quality, the environment and the public receiving the recovered water. The overall process for obtaining coverage under the General Order is summarized below: • Define the ASR Project with a written project description, which will facilitate CEQA compliance and very likely establish the ASR project as lowthreat. • Prepare a Notice of Intent (NOI) for ASR activity, including a Technical Report, for submittal to the Regional Water Quality Control Board (RWQCB). The Technical Report includes: • Hydrogeologic Setting: Description of the local hydrogeology including the target aquifer for ASR activities, groundwater levels, and existing water quality. • Proposed Recharge Site(s) and Well Details: Delineates the proposed ASR location(s) and describes existing or proposed ASR well details for each site. • Hydrologic Impacts: Assess how ASR activities will impact the hydrogeologic system including an area of hydraulic impact and an area of native groundwater displacement due to recharge activity. • Anti-degradation Assessment: Evaluation of existing groundwater quality conditions and impacts of ASR on water quality. This assessment includes the identification of constituents of concern (COCs) to be monitored during pilot testing and program implementation. COCs include drinking water requirements and any requirements identified in applicable management plans or regulations. • Pilot Test (optional): Details for recharge volume and duration, storage period, recovery period, and a sampling and analysis plan. The pilot test will demonstrate the feasibility of ASR in the region. • RWQCB will approve the ASR activities via a Notice of Availability (NOA), which will include a monitoring and reporting program (MRP). CONTINUED ON NEXT PAGE

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• Implement the ASR program or conduct the ASR Pilot Test, following guidelines in the RWQCB monitoring and reporting program and the sampling and analysis plan (see Technical Report). • At the completion of the pilot test, prepare a Technical Addendum, to describe the findings and recommendations of the pilot test and submit to the RWQCB. • For an ASR Program, prepare periodic status reports (quarterly, annual) and submit to the RWQCB. The General Order also regulates groundwater monitoring during program implementation. Monitored parameters include groundwater levels, water quality, extracted and recharged water volumes. For the first year of implementation, monitoring reports must be submitted quarterly with an annual report at the end of the calendar year. Both reports must include the following information: • Groundwater levels, contours, and flow gradients • Water quality sample results including laboratory reports • ASR well operational status and average daily injection and recovery rates • Narrative of ASR operations and total volumes injected and recovered

So, You’re Interested in ASR?

After the first year, the quarterly status report requirement ends, and annual reports are required each year thereafter. Water quality monitoring includes the MRP requirements, which are generally based on the list of Constituents of Concern identified in the Technical Report. In addition to the ASR General Order, it is important to understand that storage of surface water underground may require a water rights modification and issuance of an underground storage supplement. The SWRCB’s current approach to administration of water rights in regard to groundwater recharge is under development and very site-specific. We recommend consultation with SWRCB staff early in the develop of an ASR program to fully understand the water right implications of the proposed activity. The SWRCB is working to streamline this process and more information can be found in the Association of California Water Agencies (ACWA) “Technical Framework for Increasing Groundwater

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Replenishment” as it relates to diversion of high flow events for recharge. Regulatory and permitting requirements can seem daunting, and those associated with ASR are no exception. Luckily, if you plan to operate an ASR program using drinking water, the SWRCB’s General Order provides a consistent and sequential permitting process: • Submit the NOI with a technical report, • Conduct pilot testing, • Submit a technical addendum describing the results and recommendations of pilot testing; and, • Finalize program details for approval. Continued monitoring requirements for an ASR program are described in the General Order, although additional monitoring is usually advantageous for program operators to better understand their ASR system. This concludes our series on ASR. We hope this and our previous articles have been helpful in your understanding of ASR and how to develop a robust and healthy ASR program. Our previous articles included: • Article 1: So, You’re Interested in ASR? Volume 30, Number 1. Spring Issue • Article 2: So, You’re Interested in ASR? Part II – Knowing Your Local Aquifer. Volume 30, Number 2. Summer Issue • Article 3: So, You’re Interested in ASR? Part III – How Much is This Going to Cost? Volume 30, Number 3. Fall Issue Please contact us if you would like more information on these or other ASR topics. Until next time! Association of California Water Agencies. 2019. A Technical Framework for Increasing Groundwater Replenishment. November. State Water Resources Control Board. 2012. General Waste Discharge Requirements for Aquifer Storage and Recovery Projects that Inject Drinking Water into Groundwater. Water Quality Order 2012-0010. September.

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Treatment of PFAS in Groundwater - An Overview

BRUCE MARVIN, JOHN MERRILL, BALAJI SESHASAYEE, MANMEET “MEETA” PANNU, JIM STRANDBERG

PFAS Overview Per- and polyfluoroalkyl substances (PFAS) have garnered significant scientific, regulatory, and public attention due to their recalcitrant, ecological persistence, and widespread occurrence – thus the moniker “forever chemicals”. PFAS has been detected in groundwater and in finished drinking water throughout the United States. Six PFAS were included in the Third Unregulated Contaminant Monitoring Rule, which required sampling of finished drinking water from a subset of U.S. public water systems between 2013 and 2015. Of the samples collected from water systems with a groundwater source, 1.2% contained perfluorooctanoic acid (PFOA) at or above the minimum reporting level of 20 nanograms per liter (ng/L).1,2

PFAS Monitoring

United States Environmental Protection Agency, 2017. The third unregulated contaminant monitoring rule: data summary. January. https://www.epa.gov/sites/default/ files/2017-02/documents/ucmr3-data-summary-january-2017. pdf 2 Hu et al., 2016. Detection of Poly- and Perfluoroalkyl Substances (PFASs) in U.S. Drinking Water Linked to Industrial Sites, Military Fire Training Areas, and Wastewater Treatment Plants. Environ Sci Technol Lett. 11; 3(10): 344–350.

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PFAS in Groundwater - An Overview

Federal Maximum Contaminant Levels (MCLs) for PFAS have not been established; however, some states have developed standards and guidance values for PFAS in drinking water. In California, Notification and Response Levels for PFOA, perfluorooctanesulfonic acid (PFOS), and perfluorobutanesulfonic acid (PFBS) have been established (Table 1), which has resulted in purveyor-lead treatment of groundwater for PFAS. Other states, such as Massachusetts and Michigan, have promulgated state-level PFAS MCLs. The Interstate Technology and Regulatory Council has published and maintains a list of federal and state regulatory levels for PFAS in groundwater and drinking water.3 PFOA

PFOS

PFBS

Notification Level

5.1

6.5

500

Response Level

5,000

Table 1. California Notification and Response Levels (ng/L) for PFAS in Drinking Water4 The unique properties that make PFAS useful in commercial and industrial products (e.g., thermal and chemical stability, hydrophobicity) also make PFAS treatment challenging. PFAS treatment technologies for groundwater can be subdivided into two major categories: field-implemented technologies and indevelopment technologies. Field-implemented technologies include granular activated carbon (GAC), ion exchange (IX) resins, and reverse osmosis (RO). The effectiveness of these technologies is affected by individual PFAS’ functional group and perfluorinated carbon chain length.5 Additionally, as PFAS is often found at low concentrations in groundwater (i.e., nanograms per liter), treatment options are affected by background constituents, including metals, anions, total suspended solids, and total organic carbon, which are often found in concentrations that are orders of magnitude higher than PFAS. Therefore, multiple steps are required to “pre-treat” the influent to a treatment system before effective PFAS removal. 3

Interstate Technology and Regulatory Council, 2021. PFAS Regulations, Guidance, and Advisory Values – Table. August. https://pfas-1.itrcweb.org/wp-content/ uploads/2021/09/ITRCPFASWaterandSoilValuesTables_AUG2021-FINAL.xlsx 4 State Water Resources Control Board, 2021. Drinking Water Notification Levels and Response Levels: An Overview. June 28. https://www.waterboards.ca.gov/drinking_water/ certlic/drinkingwater/documents/notificationlevels/notification_levels_response_levels_ overview.pdf 5 McCleaf et al., 2017. Removal efficiency of multiple poly- and perfluoroalkyl substances (PFASs) in drinking water using granular activated carbon (GAC) and anion exchange (AE) column tests. Water Research. 120: 77–87.

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The effectiveness of GAC and IX resins for PFAS removal can vary depending on site-specific conditions such as the presence of co-contaminants, the background matrix, and the PFAS signatures. When designing a treatment system with adsorbents, bench-scale (e.g., rapid small scale column tests) and pilot-scale testing can be useful for assessing media effectiveness and determining design parameters. For example, the Orange County Water District tested 14 adsorbents in a PFAS pilot study, including GAC, IX, and novel adsorbents. The results showed that while all adsorbents removed PFAS, some adsorbents had a much larger PFAS capacity than other adsorbents. The study informed media selection and design, and construction of a full-scale systems is now underway.7 GAC, IX resins, and RO produce PFAS-containing waste streams that must be appropriately managed. Spent GAC is typically landfilled, incinerated, or regenerated by the GAC supplier, while spent IX resin is typically landfilled or incinerated. Regeneration and reactivation of adsorbent media used for PFAS treatment is being evaluated.8,9 Incineration has received recent attention due to the potential for incomplete combustion and PFAS emissions.9 RO produces a concentrated waste stream containing membrane-rejected constituents such as PFAS. RO concentrate is typically discharged, disposed of, or treated. Costs associated with PFAS-containing waste management vary widely and should be considered when selecting a PFAS treatment technology9.

PFAS Monitoring

6 Patterson et al., 2019. Effectiveness of point-of-use/point-of-entry systems to remove per- and polyfluoroalkyl substances from drinking water. AWWA Wat Sci. e1131. 7 Orange County Water District, 2021. PFAS Phase I Pilot-Scale Treatment Study – Final Report. March 24. https://www.ocwd.com/media/9829/2021-03-24_ocwd-pfas-pilot-i_ finalreport.pdf 8 Interstate Technology and Regulatory Council, 2020. Case Study: Regenerable Ion Exchange Resin Pilot Test and Full-Scale Application. September. https://pfas-1.itrcweb. org/15-case-studies/#15_2_2_2 9 United States Environmental Protection Agency, 2020. Interim Guidance on the Destruction and Disposal of Perfluoroalkyl and Polyfluoroalkyl Substances and Materials Containing Perfluoroalkyl and Polyfluoroalkyl Substances. December 18.

PFAS Monitoring In Groundwater Management Development:

Physical adsorption is the primary PFAS treatment mechanism for GAC, whereas removal of PFAS by IX resins occurs through physical adsorption and the formation of ionic bonds. RO membranes act as a barrier for dissolved salts and organic and inorganic constituents, such as PFAS. Both GAC and IX resins are typically deployed as fixed-bed adsorbers. GAC and IX resins may be employed in a treatment train for PFAS treatment. RO treatment systems require high pressure pumps, filters, instrumentation, and other ancillary equipment. In addition to use in full-scale systems, GAC and RO have been employed for PFAS at the point-of-use and point-of-entry scale for household water treatment.6

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Many in-development technologies are intended to destroy PFAS and remove them from the environment as opposed to concentrating PFAS in a waste stream. The carbon-fluorine bond is one of the strongest bonds in organic chemistry and therefore the thermodynamics of PFAS degradation are inherently unfavorable. In many cases, energy is added to groundwater to initiate the destruction of PFAS, which can be cost prohibitive for treatment of a continuous flow of groundwater. Some in-development technologies for ex-situ groundwater treatment include electrochemical advanced reduction/oxidation (redox), sonochemical degradation, cold argon plasma degradation, enhanced biological treatment, heated redox manipulation, electron beams, gamma irradiation, and UV-sulfite redox. A limited number of indevelopment technologies for PFAS treatment have the potential for in-situ groundwater applications. As regulatory levels are developed for PFAS in drinking water, treatment of PFAS-impacted groundwater is becoming increasingly necessary. GAC, IX, and RO are field-implemented technologies for PFAS groundwater treatment that are readily employable; however, destructive technologies for PFAS treatment are in development.

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Wells and Words DAVID W. ABBOTT, P.G., C.HG., CONSULTING GEOLOGIST Mr. Abbott is a Geologist with 45+ years of applied experience in the exploration and development of groundwater supplies; well location services; installation and design of water supply wells; watershed studies; contamination investigations; geotechnical and groundwater problem solving; and protection of groundwater resources.

Groundwater pumping impacts: Part 1 – Saline Water Encroachment in Coastal Aquifers

Wells and Words

Over-pumping an aquifer or exporting too much water from the contributing watershed of a Coastal Aquifer (unconfined or confined) can result in Saline Water Encroachment or Sea Water Intrusion (SWI) that can have significant and serious negative impacts to water supply wells1 located near the coastline. A Coastal Aquifer is an aquifer that underlies a land area near the sea and extends seaward from the shoreline; the infiltration of rainfall causes a continuous flow of fresh water toward the sea. Upconing and other sources of Saline Water Encroachment (buried and older geologic formations and surface/injection disposal of brines) will be discussed in another article. I was asked once (1986) by an attorney: “Where could my client install a water supply well that would not impact the movement of the Fresh water/Salt water (F/S) interface?”. The simple and flippant answer was: “There is no such place in the watershed that you could install a water supply well that would not impact the movement of the F/S-interface”. The more accurate question by the attorney should have been: “Where could my client install a water supply well in the Coastal Aquifer that would not be impacted by the movement of the F/S-interface?”.

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Wells and Words

The position of the F/S-interface is dynamic and moves according to the amount of groundwater that flows through the aquifer system. Because the specific gravity (density) of salt water (ρs) is about 1.025 gram per cubic centimeter (g/cm3), ranging from 1.020 to 1.030 g/cm3, and is heavier than fresh water (ρf = 1.0 g/cm3); fresh water will float on top of (or override) the salt water. The Δρ (i.e., ρs - ρf) contrast between fresh groundwater and salt water is 1:40 (ρf ÷ Δρ). This means that if one foot of fresh water occurs above sea level then about 40 feet of fresh water occurs below sea level at that location. This hydrostatic balance produces a wedge-shaped feature which is hinged to shoreline seeps (or submarine seeps) and is referred to as the Ghyben-Herzberg relationship. This relationship was formally defined by Badon Ghyben in 1889 and independently verified by Herzberg in 19012. The Coastal Aquifer groundwater discharges along shoreline seeps (springs), which are usually tied to the mean high water sea level elevation for unconfined aquifers. Submarine (subaqueous) groundwater seeps from confined aquifers are also common to Coastal Aquifers3. Typically, the position of the F/S-interface moves because of seasonal and daily changes in recharge to the aquifer; it moves inland during the dry (summer) season and seaward during the wet (winter) season. The position also moves because of daily tidal changes; inland during hightide and seaward during low-tide. Hence, this movement of the F/Sinterface creates a zone of mixing (diffusion) rather than a sharply defined F/S-interface. The amount of groundwater flowing through the Coastal Aquifer can be estimated using Darcy’s Law, water budget calculations of the watershed, synoptic stream flow measurements, etc. Darcy’s Law is Q = k × i × A where Q = discharge to the ocean, k = hydraulic conductivity of the aquifer, i = hydraulic gradient of the water table (unconfined aquifer) or potentiometric (confined aquifer) surface and A = the cross-sectional area of the aquifer. The position and shape of the F/S-interface and the width of the submarine discharge of fresh groundwater from the aquifer can be estimated with the Glover Equation2,4,; a non-linear polynomial.

Term A5

Term B

z =

(2 × ρf × q × d) + q2

(Δρ × k)

(Δρ × k)2

Where,

z = vertical distance of the F/S-interface,

d = horizontal distance from the F/S-interface,

q = fresh groundwater flow per unit length of shoreline,

k = hydraulic conductivity of the aquifer; and

Δρ = (ρs - ρf). CONTINUED ON NEXT PAGE

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Wells and Words

Figure 1 is a sketch of the axial cross section of a narrow CA Coastal Aquifer (unconfined) that is bounded at the base with relatively impermeable decomposed granite. The F/S-interface is a zone of diffusion where fresh groundwater and salt water meet and mix. The approximate position and shape of the wedge depends upon the amount of fresh groundwater underflow that is circulating through the aquifer. Fresh groundwater must exit the aquifer when it reaches the SW wedge. The underflow exits along the shoreline as fresh groundwater seeps. The width of this zone of seepage varies as the SW wedge moves in response to seasonal and daily tidal fluctuations. The salt water is repelled from inland movement by the volume and discharge of fresh groundwater that flows seaward, differences in densities between fresh groundwater and sea water, and by mechanical diffusion aided by chemical diffusion; referred to as “perpetual circulation of sea water” or “reciprocative motion”.2

Wells and Words Wells and Words

This equation describes the parabolic shape and position of the F/S-interface in relationship to the static position. If x = 0 then Term A = 0 and z = (q) ÷ (Δρ × k); and if z = 0, then x = - (ρf × q) ÷ (Δρ × k); which are the width and depth of the interface beneath the shoreline, respectively.

The static position of the wedge, which is here defined as the most landward edge of the fresh groundwater seeps, can be estimated from aquifer test data and was observed during a pumping test on Well 2 for this project. This observed recharge boundary was located about 600 feet down-gradient from Well 1 (about 500 feet down-gradient from Well 2) and corresponds to the mean high water tidal fluctuation (see Figure 1). Transmissivity (90,000 gpd/ft), Storativity (S = 5E-04), and hydraulic conductivity (900 gpd/ft2) could be estimated for this Coastal Aquifer because two observation wells were measured during a 48-hour (240 gpm) pumping test. The shoreline length was about 600 feet. Figure 1 shows the wedge in a dynamic equilibrium position which represents the shape and position of the wedge during a presumed “normal” water year that allows 402 gpm of underflow to circulate through the aquifer. The client wanted 60 gpm for his project; calculations showed that the bottom of the wedge would migrate inland about 20 feet. Correspondingly, the outer edge of the beach seepage zone would migrate inland about 3 feet.

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In 1977 (a drought year), Well 2 became contaminated with salt water. Figure 1 shows the approximate position of the toe of the wedge as a dark band because of the uncertainty of the exact location of the interface. This band was constructed by limiting the SWI wedge position between the bottom of Well 2 and the plugged portion of Well 2 (78-foot depth); the plug allowed fresh groundwater to be pumped from Well 2. Calculations show that, to cause this extensive inland encroachment, the underflow would have to be reduced by 87% (or by about 350 gpm) for a net aquifer discharge of 52 gpm distributed across the 600-foot length of shoreline. Note that it takes only a small amount (2%) of sea water mixed with fresh water to result in a non-potable water resource.4 There are several engineering strategies to reduce or eliminate salt water from contaminating a water supply well: (1) install the water supply well far enough inland so a groundwater divide is created between the fresh groundwater and saline water; (2) reduction of pumping rates from a well and/or reduction of watershed exports; (3) design the well so the bottom of the well is above sea level (although upconing can occur); (4) install injection wells to create a groundwater ridge (barrier) between the salt water and fresh groundwater; (5) install a physical barrier, (6) install an extraction barrier, etc. Even if the well becomes contaminated, treatment strategies (desalination) are available but at a significant cost; the production well may also have to be replaced with a design/materials that can survive chemical deterioration from the sea water. Part 2 of this series of articles will discuss the unforgiving negative impacts of Land Subsidence.

1 Cooper, Jr., Hilton H., F.A. Kohout, H.R. Henry, and R.E. Glover, 1964, Sea Water in Coastal Aquifers, USGS Water-Supply Paper 1613-C, 84 p. 2 Wilson, William E. and J.E. Moore (editors), 1998, Glossary of Hydrology, American Geological Institute, Alexandria, VA, 248 p. 3 Zektser, Igor S., L.G. Everett, and R.G. Dzhamalov, 2007, Submarine Groundwater, CRC Press, Taylor and Francis Group, Boca Raton, 466 p. 4 Todd, David Keith, 1980, Groundwater Hydrology (second edition), John Wiley & Sons, New York, 535 p. or Todd, David Keith and Larry W. Mays, 2005, Groundwater Hydrology (third edition), John Wiley & Sons, Inc., New York, 636 p. 5 Attention: Note that there is a minor mistake in Todd (1980, 2nd edition) on page 499. Equation 14.5 where ρ in the numerator is not defined in the first sentence after the equation is presented (ρ = ρf); in Todd (2005, 3rd edition) this mistake is corrected on page 592, equation 14.3.1 and in the following sentence of that text. 2021 Winter Issue

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Drought Conditions and Impacts in the Western United States AZITA ASSADI , TODD JARVIS & ABHISHEK SINGH

Drought Conditions and Impacts in the Western United States

Well development programs and their importance: Part 2 Drought Conditions and Impacts Droughts and the western United States are no strangers to each other. However, with climate change and increasing water demands, drought impacts have been exacerbated over recent years across the West. Higher temperatures have led to faster snowmelt (and less prolonged snowpack) and more evapotranspiration losses from plants, soils, and reservoirs. Climate change has also shifted precipitation patterns (more rain compared to snow) and led to an increase in the intensity and frequency of extreme weather events (including droughts). Based on all hydrologic metrics, the Western United States is currently in the grips of a historic drought. An unusually dry 2020 and winter of 2021 led to most parts of Utah, Nevada, Arizona, New Mexico, and Oregon, and much of northern California experiencing “extreme drought” conditions by early 2021. By June 2021, “extreme drought” conditions had spread to eastern Washington and parts of Idaho and Montana. Heavy summer rains brought much-needed respite to Arizona and New Mexico. However, by August, “extreme/exceptional drought” conditions spread across much of California, Oregon, Washington, Utah, Idaho, and Montana. In August 2021, California’s reservoirs were at just 60% of average storage for the date. Reservoir levels were less than half of the average in Nevada, New Mexico, and Oregon, as well. Water levels in Lake Mead (an important source of water in the West) fell to the lowest levels since the 1940s, leading the US Bureau of Reclamation to declare a water shortage on the Colorado River for the first time, triggering mandatory water consumption cuts for states in the Southwest beginning in 2022. Several states (especially in the Northwest) experienced heatwaves in the summer of 2021, contributing to large wildfires (for example, the Bootleg Fire in Oregon and the Dixie Fire in California). And, due to declining surface-water supplies, more and more water users have relied heavily on groundwater, which contributes to declining water levels in several groundwater basins. Owing to the ongoing drought, its impacts on groundwater, and water users at large, HydroVisions will present a series of articles in the next several issues to track and summarize drought conditions across the West. The first article focuses on Oregon and California.

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Drought Conditions and Impacts

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Oregon As of August 24, 2021, twenty-two counties have implemented executive drought declarations, including areas considered immune to drought, like coastal Lane County. Storage in reservoirs in eastern Oregon are depleting rapidly. Some of the depletion is attributed to limited snowpack. Other causes include requirements to meet satisfy water requirements for endangered species, such as the spotted frog in central Oregon and fish in the Klamath Basin. Beyond diminished water delivery to irrigators and endangered species, harmful algal blooms are prevalent in surface water, including the Willamette River, for which tens of millions of dollars are invested in ozone treatment to destroy cyanotoxins. One of the largest spring systems in Oregon underscore the importance of hydrogeography and storage: The Metolius River spring system flow dropped nearly 50% to 55 cfs. As a result, some municipalities are converting from surface water sources to groundwater and aquifer storage and recovery due to costs from regional suppliers and reliability (see Figure 1 for location). And wells tapping volcanic rock aquifers have been identified to be of “significant concern” by state agencies, while sand and gravel aquifers are holding steady. The state has implemented a dry well registry as water laws do not permit the state to decline to issue permits for new domestic wells. An Irrigation District Temporary Transfers Pilot Project is also underway as irrigators are looking to neighbors to share supplies under the risk of irrigation canals being shut off. And irrigators are asking the state to investigate a statewide plan to transfer water from locations with plenty of water to those facing drought and other shortages. Agriculturalists are organizing to adapt responses to meeting the needs of threatened and endangered species, including a private aquaculture facility to raise fish in the Klamath Basin. Oregon law provides flexibility in the time of drought. Any person holding both a primary water right originating from a surface water source and a supplemental water right from a groundwater source may apply to the state to temporarily substitute the use of the supplemental right for the primary right, and for temporary preferences of use to water rights for human consumption and/or stock watering.

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Figure 1: 3-D diagram of Metolius and Opal Springs hydrogeology California

Drought Conditions and Impacts in the Western United States

According to the US Drought Monitor report, released on October 21, 2021, about 40 percent of California is in exceptional drought (See Figure 2), the most severe of the Monitor’s four categories1.

Figure 2: U.S. Drought Monitor - California

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As a result of drought, water levels in most state reservoirs (such as Lake Oroville – a key source of water for California) are well below average and the State has taken a dramatic step to curtail Central Valley farmers from diverting water from the main rivers to preserve the waters for drinking water and to support habitat for endangered fish species. Earlier in the year, the California Department of Water Resources (DWR) announced the department expected to deliver only 5 percent of requested supplies through the State Water Project, this water year. The governor has declared a drought emergency across the state asking for a voluntary reduction of 15% by domestic and industrial users. The state is looking at potentially another dry winter, as La Nina climate conditions have been predicted by NOAA’s Climate Prediction Center2. On the other hand, the state continues to experience extreme weather conditions. Recent (late October 2021) atmospheric rivers led to Northern California experiencing the most rainfall in 24 hours since 1880. However, one big rainfall event is not sufficient to end the drought. In the absence of long-term and reliable surface-water supplies, the reliance on groundwater is increasing which could lead to further reduction of groundwater levels and ground storage in critically overdrafted basins still recovering from the 2012 – 2016 drought. As an integrated strategy and water security tool, managed aquifer recharge (MAR) projects are increasingly being relied on to make-up for the loss of snowpack storage and for capturing and storing the more variable and “flashy” stormflows. Supply agencies also have invested in alternative water sources such as ocean and brackish groundwater desalination, and recycled water to make water supplies more resilient to droughts. Broader expansion of these supplies is complicated due to high energy costs for desalination/treatment as well as environmental and engineering challenges to disposal of brine or treatment concentrates. California began implementing the Sustainable Groundwater Management Act (SGMA) in 2015 to identify, characterize, monitor, and mitigate risks to groundwater beneficial use (including during drought conditions) as part of groundwater sustainability plans. In 2021, as part of two executive drought emergency proclamations, the state is advancing the development of principles and strategies related to drinking water well impacts and tracking drinking water supply shortage via an online reporting system3 for household water supply. An integrated approach to managing and regulating surface-water and groundwater withdrawals is key to sustainable water use while minimizing impacts to the environment and other water users. While developing strategies, policies, and tools and bringing innovative technologies and solutions are key water sustainability tools, encouraging public participation in water conservation will remain key to water efficiency and long-term resilience of water supplies. Refer to the US Drought Monitor website for the complete dryness and drought intensity categories and historically observed impacts: https://droughtmonitor.unl. edu/Maps/MapArchive.aspx 1

https://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_advisory/ ensodisc.shtml 2

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https://mydrywell.water.ca.gov/report/

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Mehrten Ranch and Mehrten Formation Field Trip CHRIS BONDS, CHRIS PETERSEN, DAVID VON ASPERN, JULIE GAROFALO, AND BRIAN HAUSBACK, AND RODNEY FRICKE

September 25, 2021 How did the Mehrten Ranch and Mehrten Formation Field Trip come to be?

Mehrten Ranch and Mehrten Formation Field Trip

The fortuitous occurrence that provided the impetus for the field trip was David Von Aspern’s attendance at the December 2019 San Joaquin County and Delta Water Quality Coalition Annual Members Meeting which pertained to his family’s agricultural land near Lockeford, CA. David posed several questions to one presenter, which apparently piqued the interest of fellow Coalition member Joe Mehrten, who likewise was attending. After the meeting ended, Mr. Mehrten approached David from across the large room, and introduced himself. As David’s eyes got as big as half-dollars upon hearing “Mehrten,” rather than introducing himself as would normally occur when people meet each other for the first time, David instead replied in a fascinated manner by saying, “as in THE Mehrten Formation?” They both chuckled and eventually David properly introduced himself, including having a geology degree, serving as a long-term GRA officer, etc., and upon hearing all of that, the extraordinarily gracious Joe Mehrten1 said, without even thinking twice about it, “well, we ought to have your group out to our ranch.” In addition, Mr. Mehrten arranged a drive across the Camanche Dam. 1 The Mehrten family emigrated to California during the gold rush and acquired a considerable amount of land in the vicinity of the Mokelumne River.

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Mehrten Ranch and Mehrten Formation Field Trip

Then COVID-19 hit, but David and Joe maintained contact a couple of times each year until this summer when the prospect of a formal field trip began to be fully vetted, including an on-site preview meeting by David at the Mehrten Ranch, as well as ascertaining provisions for food and hygiene, since COVID unfortunately remains part of our lives. The Sacramento Branch Mehrten Ranch and Mehrten Formation Field Trip (Clements, CA) occurred on September 25, 2021, and an excellent time was had by all attendees (Figures 1 and 2).

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Camanche Reservoir was constructed in 1963 by East Bay Metropolitan Utility District (EBMUD) for flood control and water supply purposes (Figure 3). It lies at the juncture of Amador, Calaveras, and San Joaquin Counties, approximately 40 miles southeast of Sacramento, California. Camanche retains the flow of the Mokelumne River behind an approximate 2,400-foot-long by 171-foot-high earthfill dam that has a volume of 11 million cubic yards (DWR, 2021). It has a total capacity of 417,120 acre-feet, with a surface area of about 7,700 acres and a maximum water depth of around 150 feet. Camanche’s spillway is rated at 182,000 cubic feet per second.

Mehrten Ranch and Mehrten Formation Field Trip

Geologic Overview of the Mehrten Formation

Wells and Words Wells and Words

Overview of Camanche Reservoir

The Mehrten Formation is composed of well-bedded andesitic fluvial and debris flow deposits exposed in outcrops along the east side of the Central Valley and in the Sierra Nevada (Figure 4). The Mehrten Formation is Mid-Miocene to Pliocene in age and the source rock was formed as the result of subductioninduced volcanism of the Ancestral Cascade Arc. Figure 5 is a reconstruction of Mehrten-age composite volcanoes which mostly eroded away by Pleistocene glaciation. Debris flows (lahars) flowed to the west down channels becoming finer grained further from their source vents.

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The andesitic detritus that constitutes the Mehrten Formation was swept westward from the volcanic terrane of the Sierra Nevada as stream sediment and as mud flows. The “type section” (now partially submerged) is located along Clements-Camanche Road, about 1.25 miles east of the Camanche Dam site in the Mokelumne River bluff near NE1/4-SW1/4-Section 5, T4N, R9E (Figure 6). Piper, et al. 1939, mapped and described the “type section” as about 184 feet thick and generally composed of alternating beds of andesitic sandstone conglomerates, coarse and medium sandstones, with interbedded white to yellowish gray pumiceous silt and clay. Other exposures of the Mehrten Formation occur along the American River near Nimbus Dam and in the Sierra Nevada. Figure 7 shows a Mehrten outcrop by Nimbus Dam in Fair Oaks. Hydrogeologic Overview of the Mehrten Formation The Mehrten Ranch is in the northeastern portion of the Eastern San Joaquin Subbasin of the San Joaquin Valley Groundwater Basin. The primary freshwater formations include Pleistocene-Holocene alluvium, Modesto and Riverbank Formations, and floodbasin deposits; the Late Pliocene-Pleistocene Laguna Formation; and the Miocene-Pliocene Mehrten Formation (DWR, 2003). The limit of aquifers that supply fresh groundwater to wells is generally considered to be in the basal Mehrten Formation. CONTINUED ON NEXT PAGE 2021 Winter Issue

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Mehrten Ranch and Mehrten Formation Field Trip

The Mehrten Formation crops out at ground surface near Camanche Reservoir and extends to approximately 1,600 feet depth near Stockton (ESJGA, 2019). The natural hydraulic gradient in the groundwater system is generally westward from areas of recharge in the upper Sierra Nevada foothill alluvial fans toward the valley trough.

The Mehrten Formation consists of two distinct units: volcaniclastic, andesitic sands (aquifers) (Figure 8) interbedded with brown to blue clays, and layers of dense, tuff breccia (aquitards) (Figure 9).

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The Mehrten Formation aquifers, commonly referred to as “black sands” on driller’s logs, have moderate to high permeability and can yield large quantities of groundwater to wells. Recent modeling in the South American Subbasin to the north suggests the transmissivity of the Mehrten Formation is approximately 70,000 feet2/day, with a hydraulic conductivity of about 50 feet/day (SASB GSP Public Draft, 2021). Municipal wells constructed within the Mehrten Formation commonly exceed 1,000 feet in depth and can yield over 1,000 gallons per minute. Localized water quality impairments may exist (i.e., elevated arsenic, manganese, and methane gas concentrations); however, the groundwater quality of the Mehrten Formation is overall good and suitable for public water supply. The Mehrten Formation is undoubtedly an important source of drinking water to municipalities in the Sacramento region and eastern San Joaquin Valley, including the City of Sacramento, Sacramento County Water Agency, and the City of Galt, who operate and maintain deep production wells completed in the Mehrten Formation that provide potable water to communities. References Busby, C.J., DeOreo, S.B., Skilling, I., Hagan, J.C., and Gans, P.B., 2008b, Carson Pass–Kirkwood paleocanyon system: Implications for the Tertiary evolution of the Sierra Nevada, California: Geological Society of America Bulletin, v. 120, p. 274–299. Curtis, G.H., 1954. Mode of Origin of Pyroclastic Debris in the Mehrten Formation of the Sierra Nevada: University of California Press, Berkeley and Los Angeles, p. 453-501. DWR, 2003. California’s Groundwater, Bulletin 118. Eastern San Joaquin Subbasin 5-21.65 summary. DWR, 2021. Dams within the Jurisdiction of the State of California. Division of Safety of Dams, California Department of Water Resources. Tabular document. 28 p. Eastern San Joaquin Groundwater Authority (ESJGA), 2019, Eastern San Joaquin Groundwater Subbasin – Groundwater Sustainability Plan, November 2019. Piper, A.M., Gale, H.S., Thomas, H.E, and Robinson, T. W. 1939. Geology and Ground-Water Hydrology of the Mokelumne Area, California. USGS Water-Supply Paper 780. SASB, 2021. South American Subbasin Groundwater Sustainability Plan – Public Draft, June 18, 2021. Wagner and Saucedo, 1990. Reconnaissance geologic map of the Milford 15-minute quadrangle, Lassen and Plumas counties, California. Division of Mines and Geology Open File Report OFR 9008. Scale: 1:62,500.

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ISMAR 11 is Coming! April 11 - 15, 2022, Long Beach

Drought Conditions and Impacts in the Western United States

We are excited to give you an update on next year’s 11th International Symposium on Managed Aquifer Recharge (ISMAR 11). ISMAR is the world’s preeminent symposium on managed aquifer recharge (MAR). With the continued unsustainable overuse of groundwater in many areas of the world, MAR has become more important than ever in recovering depleted aquifers and developing resilient groundwater supplies for the future. The first ISMAR was held in Anaheim in 1988 and now returns to California after more than three decades of being hosted in locations all over the world. ISMAR 11 is being hosted by the Groundwater Resources Association of California (GRA), the Arizona Hydrological Society (AHS), the International Association of Hydrogeologists (IAH), and the Orange County Water District (OCWD). ISMAR 11 is going to be different than prior symposia. We will still have pre-conference workshops on surface and subsurface recharge. We will still have multiple tracks of technical presentations and post-conference field trips. We will still have networking opportunities, exhibitors, poster sessions and receptions. What is new is that we are dedicating a full day to the big picture of how MAR fits into groundwater sustainability. In fact, the theme of ISMAR 11 is “MAR, a Bruce Babbitt served as the 16th governor of Arizona key to sustainability.” Kicking off the from 1978 to 1987, and conference is a keynote address on as President Bill Clinton’s leadership in water by former Arizona Secretary of the Interior from Governor and Secretary of the Interior 1993 to 2001. Bruce Babbitt. He will be followed by Dr. David Kreamer, professor of Hydrology at the University of Nevada, Las Vegas and current president of IAH. To dive into the policy and governance issues related to MAR are two curated panels, one moderated by Felicia Marcus focused on MAR in California and

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April 11, 2022 Subsurface Injection and Recovery Recharge Workshop David Pyne Russell Martin Surface Spreading Recharge Workshop Mike Milczarek Adam Hutchinson Meeting Water Management Objectives with Managed Aquifer Recharge: The Role of MAR Governance and Policy Sharon B. Megdal Workshop Details - Click Here

2021 Winter Issue

11TH INTERNATIONAL SYMPOSIUM ON MANAGED AQUIFER RECHARGE APRIL 11-15, 2022 | HILTON, LONG BEACH

www.ismar11.net the other by Dr. Sharon Megdal focused on MAR in Arizona, Israel and other areas. Dr. Megdal is also offering a preconference workshop on the role of MAR governance and policy in meeting water management objectives. You won’t want to miss this event. So, whether you are a MAR veteran, someone new to MAR, a policy maker or board member, there is something for you at ISMAR 11. We will also have opportunities for students to present and be part of running the event. Students, be sure to reach out to your local GRA branches for scholarship funding to attend. ISMAR 11 will be held at the Hilton Long Beach, which is a tremendous venue that is close to multiple restaurants and other attractions. ISMAR 11 will run from April 11-15, 2022. To register go to ismar11.net. Thanks to the sponsors that are already on board! Excellent opportunities are still available for other sponsors to partner with us in presenting this amazing event. See the website for sponsorship opportunities. See you there!!!

PRELIMINARY AGENDA (subject to change) April 12, 2022

April 13, 2022

April 14, 2022

General Sessions

4 Concurrent Tracks

Keynote 1

Session Topics Include:

Bruce Babbitt, Former AZ Governor, and Sec. of Interior

ASR

Keynote 2

MAR-Geophysics

MAR-Emerging Contaminants

David Kreamer, UNLV, President of IAH Panel 1:MAR in California Moderator: Felicia Marcus Panel 2 MAR in Action Moderator: Sharon B. Megdal Herman Bouwer Awards Luncheon IAH Plenary Session

FLOOD-MAR

International MAR

MAR-Integrated Water Management

MAR-Environment

MAR Engineering & Design

MAR-Water Markets

Reception

Networking

Poster Session

Gala

Networking

April 15, 2022 Water Replenishment District of Southern California Albert Robles Learning Center Orange County Water District Surface Recharge System and Groundwater Replenishment System Field Trips Details - Click Here Post-Conference - Geophysics Workshop Ahmad-Ali Behroozmand Max Halkjaer John Jansen Timothy K. Parker Workshop Details - Click Here

ISMARx Workshop A series of short presentations by graduates and young professionals to showcase their research.

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GRA Parting Shot JOHN KARACHEWSKI

John Karachewski is a geologist for the California EPA (DTSC) in Berkeley. He is an avid photographer and often teaches geology as an instructor and field trip leader.

This telephoto image shows Mount Whitney (center) and the Alabama Hills (foreground) along the eastern slopes of the Sierra Nevada range. The mountains and the foreground hills are separated by the Sierra Nevada Frontal Fault, which is the first of the Basin and Range normal faults heading east from the Pacific Coast. The rocks are Late Cretaceous (82 to 83 Ma) Whitney granodiorite and Alabama Hills granite – a result of magmatic intrusions into the edge of the North American crust during Mesozoic subduction. Despite their common lithology, the ‘granites’ on either side of the fault look strikingly different. Mount Whitney is the highest mountain in the contiguous United States with an elevation of 14,494 feet. The high peaks have been sculpted by glacial and physical weathering processes. In contrast, the Alabama Hills at an elevation of 5,300 feet have not been glaciated and have experienced prolonged chemical weathering. Thermal expansion and contraction coupled with exfoliation allows the Alabama Hills granite to weather into spheroidal forms. There are two tree-lines on the Sierras’ eastern front: an upper one defined by colder temperatures and a lower one defined by aridity. The Alabama Hills are also in the rain shadow of the Sierra Nevada. Beginning in 1920, Hollywood filmmakers began to film in the Alabama Hills for its rugged scenery. Since then, over 400 movies and television shows have been filmed here, especially westerns. Photographed at the Eastern Sierra Visitor Center near the town of Lone Pine on March 12, 2017, by John Karachewski, PhD. The GPS coordinates for the photograph are 36.578450° and -118.056032°. For additional information refer to: https://www.fs.usda. gov/recarea/inyo/recarea/?recid=20698

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HYDROVISIONS

HYDROVISIONS 2021 Winter Issue | Authors

Azita Assadi, M. Sc., P. Geo. (Canada) is a technical committee member at the Groundwater Resources Association of California (GRAC). She is a Hydrogeologist with over 20 years of consulting experience in water resources and soil/groundwater management in Canada and internationally. Todd Jarvis is on the Board of Directors for the Groundwater Resources Association of California (GRAC) as the first out-of-state member from Oregon. He can be reached at the Institute for Water & Watersheds at Oregon State University water.oregonstate.edu. He has ridden over 67,000 kilometers on his Vespa. Chris Bonds, PG, CHG, Senior Engineering Geologist, California Department of Water Resources Rodney Fricke, PG, CHG, Senior Hydrogeologist, GEI Consultants, Inc. Julie Garofalo, PG, CHG, Associate Hydrogeologist, Wood Rodgers, Inc. Dr. Brian Hausback, Professor of Geology, California State University Chris Petersen, PG, CHG, Principal Hydrogeologist, GEI Consultants David Von Aspern, Environmental Specialist 3, Sacramento County Environmental Management Department Bruce K. Marvin, P.E. is a Senior Principal at Geosyntec Consultants in Oakland, CA. Bruce works on PFAS, remediation, and redevelopment projects nationwide. He was co-chair of the GRA Technical Committee and a co-author of several Interstate Technology and Regulatory Council guidance manuals on DNAPL, chemical and biological remediation methodologies. He is an advisor to research teams at two universities investigating PFAS remediation technologies. John Merrill is an Engineer at Geosyntec Consultants in Oakland, CA. John works on PFAS projects nationwide involving site investigation and remediation, litigation support, environmental due diligence, and applied research. Funded by the U.S. Department of Defense, he is helping develop lines of evidence to assess the effectiveness of PFAS remedial technologies. Balaji Seshasayee, P.E. is a Project Engineer at Geosyntec Consultants in Chicago, IL. Balaji works on groundwater treatment solutions for PFAS and other emerging contaminants, including technology evaluation, treatability testing, and treatment system design. His experience includes the analysis and design of fixed-bed adsorbers as well as other unit processes for water treatment. Manmeet “Meeta” Pannu, Ph.D., is a Senior Scientist in the Research and Development Department of Orange County Water District (OCWD) at Anaheim, CA. Meeta is currently completing research at OCWD related to PFAS. These projects include evaluation of GAC, IX, and alternative adsorbents to remove PFAS from groundwater during wellhead treatment. Meeta also works on managed aquifer recharge evaluating in-situ adsorption and alternative methods to measure total PFAS in water samples. John Karachewski is a geologist for the California EPA (DTSC) in Berkeley. He is an avid photographer and often teaches geology as an instructor and field trip leader. David Abbott is a Geologist with 45+ years of applied experience in the exploration and development of groundwater supplies; well location services; installation and design of water supply wells; watershed studies; contamination investigations; geotechnical and groundwater problem solving; and protection of groundwater resources. William E. (Bill) Motzer, PHD, PG, CHG, is a somewhat retired Forensic Geochemist Abigail Madrone, Business Development Director with West Yost. Throughout her 20 year career, Abigail has served and supported groundwater and water resources management through groundwater monitoring and analysis, project and program management and public outreach and education. Jim Strandberg, PG, CEG, CHG. Mr. Strandberg, senior hydrogeologist with Woodard and Curran, has 30 years of experience providing environmental and water resources consulting services to private- and public-sector clients. He is experienced in managing multidisciplinary groundwater, soil, sediment, and surface water studies and field investigations for water resources, groundwater remediation, and litigation support projects. He holds a Bachelor of Science degree in Geology from UC Davis and a Master of Science degree in Civil Engineering, Water Resources specialization, from Stanford University.

44 HYDROVISIONS

2021 Winter Issue

Photo: Ryan Gibeault, Geotechnical EIT, San Diego, California | Friant-Kern Canal Middle Reach Capacity Correction Project, Friant Water Authority

Solving California’s Complex Water Reliability Challenges 2021 Winter Issue

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