HydroVisions | Summer 2021 by HydroVisions

VOLUME THIRTY SUMMER 2021

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2021 Summer Issue

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2021 Summer Issue

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 Water Replenishment District of Southern CA Tel: 562-921-5521 Erik Cadaret Water Systems Consulting Tel Office: 949-528-0960 x602 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.

2021 Summer Issue

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TABLE OF CONTENTS

President’s Message

Future of Water

The Geochemist’s Gallery

The 2021 WGC

Byron Alan Clark, P.E.

So, You’re Interested in ASR? Part II

Per- and Poly-fluoroalkyl substances (PFAS)

Wells and Words

Page 6

Page 16

Page 8

Page 18

Page 10

Page 22

Page 14

Page 26

Need To Know Where Your Water Infiltrates?

Page 30

THANK YOU TO OUR GRA DONORS

December 2020 - May 2021 William Sedlak, Thomas Harter, Richard Makdisi, Jason Duda, Eric Reichard, Dean Thomas, David Lipson, Mark Peterson, Julie Johnson, Mike Huggins, Nathan Hatch, Douglas Tolley, Joseph LeClaire, Gordon Osterman, Roger Masuda & Heather Jackson

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2021 Summer 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

Join us for two 60- to 90minute classes per day the week of July 12th.

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

geiconsultants.com 2021 Summer Issue

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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.

The sun is shining bright, the days are getting longer and GRA continues to advance resource management that protects and improves groundwater supply and quality through education and technical leadership.

President’s Message

Summer is almost here. With the change of the seasons we are enjoying more time outdoors and dreaming of long overdue summer vacations. We are also observing many positive signs that a return to in-person meeting may be an imminent possibility. GRA looks forward to safely gathering in the months ahead and reconnecting with our communities. Groundwater is in the spotlight as we prepare for conservation measures in the State of California. Alternative and emergency water supplies are critical components to our respective water resource portfolios, and many rely on groundwater to meet demand when precipitation and surface water supplies are dismal. As we face uncertainty from drought, we have a unique opportunity to advance innovation and creativity to address our most pressing challenges related to sustainable groundwater management and remediation. We have an opportunity to enhance the communities we support and integrate water resources management strategies that preserve our natural systems and watersheds.

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President’s Message

Our upcoming GRA events will connect our members to industry leaders and technical experts to help drive innovation and expand professional development. In addition, we will introduce and explore a myriad of groundwater management, monitoring, and remediation practices and technologies that will support sustainability and resilience. The 4th Annual GSA Summit is fast approaching on June 9th and 10th and is a unique virtual conference. The planning committee designed a collaborative 2-day event to spark direct engagement and build meaningful connections to regulators and fellow groundwater professionals that are navigating SGMA and Groundwater Sustainability Plan development and implementation. Our marquee, must-attend event, the 4th Annual Western Groundwater Congress (WGC) on September 13th – 15th in Burbank, CA, will bring a diverse and dedicated group of water resource and groundwater professionals to expand our minds and networks. The WGC is chaired by Lyndsey Bloxom, GRA Director, and will feature diverse tracks and panels to engage and spur interest from water resource professionals of all levels and backgrounds. Visit our website grac.org, engage with us on social media, or check your inbox for upcoming announcements and details on these great events. Get local and support your Branch! GRA Branches offer wonderful opportunities to take a field trip, network, and focus on regional priorities. Stay informed on the latest developments and technology though GRACasts and short courses to help advance your career. We are grateful for you, our members, sponsors, affiliates, volunteers, and leaders. We are looking forward to seeing you in Burbank this September!

Best Regards,

- Abigail Madrone, 2020 GRA President

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The Future of Water JOHN A. MCHUGH John A. McHugh, GRA Secretary, and Senior Hydrogeologist with Luhdorff & Scalmanini, Consulting Engineers

Future of Water was held February 23rd and 24th and is part of a GRA’s long tradition (over a quarter century) of providing the opportunity to learn. This event was GRA’s fourth fully virtual conference and second using VConfrenceOnline. We are adapting to bring our community together in these challenging times.

Future of Water

So here is a snapshot of the event by the numbers: • 2 half-morning dual track sessions • 2 keynote speakers • 9 Sponsors • 117 registered attendees Both private companies and public agencies attended the event. Below are the organizations with at least three attendees and the number of actual attendees. • DWR – 9 • Golder – 3 • GSI – Environmental – 7 • Mojave Water Agency – 3 • Monterey County Water Resources Agency – 3 • Montgomery & Associates – 4 • Self-Help Enterprises – 4 • Stantec – 3 • West Yost Associates – 4 • Woodard & Curran, Inc. – 3 It takes a village to have a successful conference. Smith Moore and Associates provided fantastic support. Logistics and planning were managed by our Administrative Director, Sarah Erck. During the conference, Abi Hauge assisted Sarah.

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Future of Water

The volunteers were anchored by my moderators: Adam Hutchinson, John Lambie, and Kate Richards. Additional support for planning and abstract review came from Rob Wilhelm and Lisa Campbell. Finally, Christy Kennedy made sure we were on track and was a driving force for obtaining sponsors. The people who made content, and provided financial support are all so important. A big thanks to the oral and poster presenters, sponsors, and attendees. Kim Baker, Elemental Excelerator, Day 1 Keynote & Rosemary Knight, Stanford University, Day 2 Keynote I was pleased with the highquality content. Day 1 Keynote speaker, Kim Baker, Director of Water Innovation Elemental Excelerator, explained how they are funding technical development in the water sector. Day 2 Keynote speaker, Rosemary Knight, Stanford University lead us on a tour from the recent past into the future of the application of “hydrogeophysics” a term she coined in 1985. Adam Hutchinson moderated two sessions – the first was a live panel discussion on water trading called: Shuffling the Deck: Water Budgets/Water Transactions in a Post SGMA World and the second was PFAS and Forever Chemicals. Kate Richards moderated Visualize Communication Using Powerful Tools. John Lambie moderated two sessions, Groundwater Science for the Future and Groundwater Resources in a Changing Climate. I moderated two sessions, Optimizing Current Infrastructure for Water Supply and Monitoring and Remote Sensing. The presentations were highly informative and entertaining. I can honestly recommend chairing a conference as it is good experience planning and collaborating with interesting and nice people. The speakers in my two sessions were very cooperative, allowing me to make suggestions to their presentations. I hope to work with them in the future. Speaking of future, the Future of Water is promising with so many bright and innovative practitioners.

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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 THREE In Part 1 of this series (Winter 2020 HydroVisions), I discussed a simple classification of naturallyoccurring hazardous substances (NOHS). In part 2 (Spring 2021 HydroVisions), I discussed the crustal and environmental distribution of arsenic including its speciation, relative toxicity, and bioavailability, particularly in groundwater. Dissolved element and element complexes can be readily delineated using redox (Eh-pH) diagrams (see Figure 2 in Part 2). Arsenic-contaminated groundwater typically contains soluble oxyanions that are extracted and/ or formed from the underlying aquifer’s alluvium or rocks adjacent to or surrounding the aquifer. These oxyanions generally exist in near neutral groundwater as arsenic acid ion (aka dihydrogen arsenate: HAsO42− and H2AsO4−).1

The Geochemist’s Gallery

1 Earlier versions appeared in the California Section of the American Chemical Society newsletter: The Vortex (February 2007 and September 2015 issues) at www.calacs.org.

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The Geochemist’s Gallery

Figure 1: Arsenic concentrations in California’s groundwater (2010). Source: State Water Resources Control Board. GeoTracker GAMA (Groundwater Ambient Monitoring and Assessment) Database at: http://www.waterboards.ca.gov/water_issues/ programs/gama/geotracker_gama.shtml.

For California’s Central Valley water providers, arsenic is a continuing problem (Figure 1). A conceptual model of arsenic in this region (Figure 2) suggests that several sources and factors are responsible for arsenic’s accumulation. Geogenic or naturally-occurring arsenic oxyanions result from chemical weathering of upland igneous and metamorphic rocks in the Sierra Nevada and western metamorphic belt adjacent to the Sierra Nevada. Such rocks also contain the Mother Lode mineralized gold belt, which have abundant sulfide-bearing minerals such as arsenic-bearing pyrite (FeS2) and arsenopyrite (FeAsS). These sulfide minerals weather in the surface and shallow subsurface resulting in oxidation that may be additionally enhanced or catalyzed by microbial activity: e.g., Acidithiobacillus ferrooxidans in reaction (1) below, causes waters to become more acidified and enriched in sulfate anions and heavy metals. Bacterial oxidation of dissolved ferrous cations (Fe2+) also results in iron oxide formation. However, reaction (2) may also occur, becoming important because As(V) is less toxic, less soluble, and adsorbs more efficiently than As(III) under acidic conditions:

(1) 4FeAsS(s) + 11O2(aq) + 6H2O(aq) ↔ 4Fe2+(aq) + 4SO42−(aq) + 4H3AsO3(aq) (arsenopyrite)

(oxygen)

(water)

(ferrous cation) sulfate anion

(arsenious acid)

(2) 2H3AsO3 + O2(aq) ↔ 2H2AsO4̶ + 2H+

Additionally, for reaction (2), arsenite oxidation is slow, particularly under acidic conditions, but it may be catalyzed by bacterial activity (e.g., Thiomonas sp.). CONTINUED ON NEXT PAGE

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Weathering of arsenic-bearing minerals also results in iron oxide coatings on sediment that both adsorb and release arsenic depending on subsurface geochemical conditions. For example, an increase in pH (resulting from weathering of silicate minerals by hydrolysis or cation exchange and calcite dissolution) may cause desorption of arsenic from iron oxides.

The Geochemist’s Gallery

Geogenic arsenic sources may also be mixed with anthropogenic sources such as previous applications of arsenic-containing fertilizers and/or pesticides/ herbicides. Once in Central Valley groundwater under more reducing environments, soluble arsenic may again precipitate as sulfides or be sorbed to clays. As groundwater tables decline in these zones, subsequent oxidation and pH increases can once again release accumulated arsenic.

The Geochemist Gallery

Figure 2: Conceptual model of arsenic cycling in California’s Central Valley groundwater Source: Welch et al. (2006): http://repositories.cdlib.org/jmie/sfews/vol4/iss2/art2.

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The stockpiles of chicken manure at large poultry farms are an example of how agricultural arsenic may enter the environment (i.e., groundwater). In 2006, in our efforts to obtain healthier diets by increasing our chicken consumption, the U.S. poultry industry produced about 9.1 billion broilers. To control avian infections and increase body weight, 70 percent of chickens were fed the arsenical food additive roxarsone [(4-hydroxy-3nitrophenyl) arsonic acid; C6AsNH6O6; Chemical Abstract Service (CAS) No. 121-19-7]. By itself, roxarsone is not significantly toxic and passes virtually unchanged through a chicken’s digestive tract. However, if one chicken could potentially excrete up to 140 grams per day of manure, the estimated industry-wide total, depending on the number of active chicken farms using roxarsone, might amount to about 12 billion to 23 billion kilograms per year. Researchers from the University of Arizona and U.S. Geological Survey (see ACS publication: Environmental Science & Technology, v.40, n.9, pp. 2951–2957) found that the resultant arsenic-laden manure was rapidly converted under reducing conditions to 4-hydroxyl3-aminophenylarsonic acid (HAPA), which then dissolved into water as soluble toxic arsenite [As(III)]. However, the National Chicken Council disagreed with this assessment, indicating that poultry manure was not linked to the leaching of arsenic to groundwater, suggesting that this issue may be only a “theoretical” concern. But scientists and regulators disagreed and, after further study, roxarsone usage in the U.S was voluntarily ended by the manufacturers in June 2011 and, in 2013, its use became illegal. In August 2011, roxarsone was banned in Canada and in 2012, Australia, discontinued its use in chicken feed. In a future article, I’ll continue this discussion with arsenic’s considerable impact to water resources and people in East Asia.

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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! Please save the date and plan to join us in Hollywood September 13-15, 2021, for the 4th Annual Western Groundwater Congress (WGC)! This year’s WGC will retain many of the engaging and educational aspects of past events with the addition of a bigger, more diverse planning team and an expanded technical program that aims to look forward, focusing on innovation and emerging challenges in our industry. Key Program Components will include: • Water Resources Exploration and Development • Groundwater Management • Contaminant Assessment and Remediation • Unique Challenges and New Opportunities • Diversity, Equity, and Inclusion in Groundwater • Academic & Student Research

REGISTRATION IS OPEN!

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Optimization of Remediation

The 2021 WGC: A Hollywood Blockbuster Sequel!

2020 Winter Issue

The WGC will also include numerous opportunities for networking and learning collaboratively! Workshops, panels, receptions, and interactive lunch events will provide opportunity for you to grow your network and expand your professional horizons. Our annual health initiatives, including the Darcy 5K Dash and 7-minute break-time workouts, will keep your energy up and your mind open. Please visit the event page for more information and feel free to contact the event Chair – Lyndsey Bloxom at lbloxom@ wrd.org with any questions or interest in event participation. GroundwaterX: A Workshop for Students Calling all GRA Student Members: You are invited to join fellow students at the 2021 WGC for GROUNDWATERx - a TEDx formatted workshop comprised of energizing networking and engaging presentations! This workshop will feature student and young professional speakers, each presenting highlights of their work or research for 3 minutes. Presentations will cover a wide variety of topics related to groundwater in California and beyond. This is a unique opportunity for students and professionals to network and discuss topics presented during the session. Who knows...You might find your future employer or employee at this event!

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Byron Alan Clark, P.E. Memorial 1976-2021 With great sadness and a deep sense of loss, Davids Engineering dedicates this tribute to our coworker and friend, Byron Alan Clark, who passed away on April 3, 2021. Byron was a highly talented and accomplished engineer who never lost sight of the forest for the trees, and always adhered to the principles of kindness and honesty as he conducted his work and imparted calm leadership. He led by example.

Byron Alan Clark

Byron dedicated his professional career to the advancement of agricultural water management, working in nearly all of California’s major, irrigated valleys, from the Shasta Valley on the CaliforniaOregon border to the Imperial Valley just north of the California-Mexico border. He was deeply committed to sound science, intellectual honesty, environmental sustainability, and held compassion for the people, organizations, and communities he worked for who rely on California’s agriculture industry and water resources. He provided nearly 20 years of service as a consultant to public- and privatesector clients and was recognized for his wide range of technical abilities, skilled project management, and clear written and oral communications. He was equally comfortable organizing and evaluating enormous land and water use databases and complex hydrologic models as explaining his work to laypersons in a way that they understood. His ability to listen carefully and understand clients’ concerns and needs was a foundational skill. During his too-short lifetime, Byron contributed greatly to water management in the state of California. The Sacramento Valley was always a special place to him. Byron’s connection to the valley began in his youth as he grew up in the small farming town of Willows, Glenn County, and it continued throughout his life, both professionally and personally. Byron became an Eagle Scout, was Valedictorian of the Willow’s High School class of 1994, and graduated from UC Davis with a degree in Biosystems Engineering. He joined Davids Engineering in 2006 as a project engineer and soon became a shareholder and part of the company’s leadership team.

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BYRON ALAN CLARK 2021 Summer Issue

As an engineer, Byron maintained an incredibly high standard of work. He brought an open-minded curiosity to each scientific problem, was data driven and highly creative. He wanted to see and understand every technical detail, but never lost sight of the big picture and why each project or task was important. He was dedicated to thoughtful data analysis and dissemination, helping clients and the community in making sound resource management decisions. He had an unmistakable passion for his work, and his leadership in agricultural water management will be missed. Among his many professional contributions is development of remote sensing (NDVI) based models for calculating crop water use without having to know crop type, calibrated using energy balance ET mapping. He applied the technique throughout the State for purposes of developing water budgets for irrigated cropland, wetlands, and riparian corridor environments. He expertly applied water budgets to advance agricultural and environmental water management. As a person, Byron was a warm, generous, and thoughtful man. He was appreciative and thankful of others, noting their unique skills and contributions. The people he worked with trusted not only the quality of his work, but also that he truly valued them and held their best interests in mind. He was always considerate and respectful and did everything with a deep kindness and consideration of others. After having his work reviewed by Byron, one colleague commented that Bryon likened his review to the tuning of a fine sports car. Byron told him that he’d only made a couple of adjustments and put a coat of wax on the machine, when in fact he had rebuilt the machine from the ground up while making his junior colleague feel good about it. Byron provided outstanding technical service and responsiveness to clients and developed longstanding relationships of shared purpose and mutual respect, trust, and friendship. Byron shared his experience and knowledge generously with colleagues. He was a long-time member of the Groundwater Resources Association of California (GRA), and attended many GRA meetings, symposia, and conferences. He was also an active member of the United States Committee on Irrigation and Drainage, the American Society of Civil Engineers, and served on many technical committees. Byron’s contributions to water management in California will long outlive him, and his calm and kind presence is greatly missed. Byron is survived by his father, Robert, his sister, Andrea, his wife, Cynthia, and his two sons, Wesley (12) and Oliver (10). If you would like to make a donation in Byron’s memory, Davids Engineering has set up a GoFundMe to raise funds for his sons’ education and development. We know that Byron valued education and was a life-long learner himself. The link can be found by clicking HERE.

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TREVOR KENT GEI Consultants

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

CHRIS PETERSEN GEI Consultants

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

Here it is, Part II in our 4-part series on Aquifer Storage and Recovery (ASR) systems and what to consider when starting or growing your program. If you missed Part I of the series, Aquifer Storage and Recovery, or ASR, is a process in which drinking water is injected, via a groundwater well, and stored in an aquifer for later recovery and use. For this article, we are going to focus on a few key hydrogeologic considerations for designing a successful ASR program. Now, this is a complex topic that would take more space than we have here to discuss. So instead, we are going to keep this high level and focus on some of the more foundational groundwater flow and chemistry considerations as it pertains to ASR. Ok, let’s dig in…

Recharge Project

So, You’re Interested in ASR? Part II – Knowing Your Local Aquifer

Before starting an ASR program, it is good develop a conceptual model of how your aquifer will respond to prolonged injection of drinking water. This understanding is usually supported with a pilot study using existing wells, or a pilot test well for small scale injection to observe aquifer response. In the initial phases of the conceptual model development, a few important hydrogeologic questions should be addressed, such as: What are the regional groundwater depths and elevations? So, You’re Interested in ASR?

What are the local groundwater flow paths and gradients? Do you know the chemical composition of the native groundwater and the injection water? Is the local aquifer impacted by nearby contaminant plumes, production wells, or other features?

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Through ASR operations, we are going to alter the aquifer hydraulics, such as water levels and flow gradients, near the injection site and create an injection mound or change in pressure head. The properties of the aquifer, including transmissivity, storativity, and hydraulic gradient, will determine the shape and size of the injection mound, and how quickly injected water will migrate away from the injection site (Figure 1). Using known or estimated aquifer properties, we can predict the effects of mounding on other groundwater users. Through careful evaluation of groundwater levels and gradients, it is important to verify that 1) adequate aquifer volume is available between the existing groundwater level and ground surface to store the targeted injection volume, accounting for the predicted water level rise around the injection well, and that 2) the predicted injection mound will not cause negative impacts, such as flooding low lying areas or complicating remediation of contaminant plumes. Additionally, it is important to understand the chemical composition of both the native groundwater and the injected surface water, and how a blending of these two waters will interact with the surrounding aquifer matrix (Figure 2). The Statewide ASR General Order requires that stored water meet drinking water standards, both while stored and when extracted and served as public drinking water supply; thus, evaluation of groundwater quality is essential. Three major types of chemical processes should be addressed by the design and evaluation of ASR operations: CONTINUED ON NEXT PAGE 2021 Summer Issue

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Precipitation/Leaching: Minerals may be deposited on the well screen and in pore space of filter pack/ aquifer or dissolve into the water, depending on changes in concentrations and/or aquifer conditions, such as pH and temperature. Oxidation – Reduction (Redox): These reactions occur due to changes in the electrochemical state of the water, such as when oxygenated water is injected into the aquifer system. Because redox reactions can dissolve minerals and change the composition or create precipitates that can plug the aquifer matrix and well screen/filter pack, understanding the potential for this process is critical. Biological Matter: Natural organic matter is present in surface water and can occur in an aquifer. Chlorine is commonly used as a disinfectant for drinking water and found in treated drinking water used during injection. The organic matter, both in the aquifer and the injection stream (such as conveyance piping), will react with the chlorine to form disinfection byproducts (DBPs). It is important to assess DBPs and ensure the concentrations remain below drinking water contaminant limits.

So, You’re Interested in ASR?

The potential for these chemical processes is not an ASR deal breaker by any means, rather they are things to consider in the understanding of how the aquifer system will change and how to design the program to manage the change. In some cases, the high-quality drinking water may actually dilute and improve groundwater quality. Simple geochemical modeling and analysis by an experienced geochemist will help identify potential concerns and reduce the level of uncertainty before proceeding with the next steps of an ASR program.

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Now that we’ve developed a conceptual model for your aquifer’s response to ASR operations, it’s time to begin the actual pilot test. It is important to monitor the hydrogeologic conditions discussed above to quantify any changes that occur during the pilot test, including: • Water levels in the test well and local observation wells • Injection flow rates • Well efficiency, generally measured by specific capacity (flow rate divided by feet of drawup/drawdown), which is important for both injection and extraction to track possible changes in well performance. • Chemical composition of the native groundwater and injection water • Particle load in the injected water – very fine particles that can adversely affect well performance and require special analysis (such as Silt Density Index test) to quantify. The pilot test data will be used to design proposed ASR operations, based on aquifer response, and can be used to better predict the impacts and benefits of full-scale ASR operations. This adaptive approach is key, not only for beginning an ASR program, but throughout long-term operations. A thoughtful monitoring program can help us address important questions about ASR operations: Are changes in water levels and well performance indicating we can store more water at a higher rate, or do we need to reduce flow to control the mounding? Is drinking water quality improved through mixing or are we seeing adverse reactions that could limit well performance and the ability to extract and serve the stored water? As an ASR program expands, continued evaluation is important to optimize the number, location, and operation of wells in order to achieve your storage goals and maintain a healthy ASR program. We hope this article has provided some clarity on the hydrogeologic aspect of designing ASR operations and the importance of pilot testing along with comprehensive monitoring for a healthy and successful program. Come back next quarter for Part III: ASR Program Costs.

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Per- and Poly-fluoroalkyl substances (PFAS) Prevalence, Sources and Release Types BRUCE MARVIN JOHN MERRILL

CHRISTINE PHAM

Per- and Poly-fluoroalkyl substances (PFAS)

Introduction: Per- and Poly-fluoroalkyl substances (PFAS) have received increasing attention from government, academia, and industry due to the persistence of this class of compounds. This article provides an overview of the prevalence, sources, and release types associated with PFAS in environmental media (water, air, and biota). PFAS are found in humans, animals, and water worldwide (Olsen et al, 2011 and Sedlak et al, 2018). Studies have detected PFAS in human blood serum, fingernails, and hair samples. Terrestrial livestock and game species have been shown to have concentrations of PFAS as well (Death et al, 2021). PFAS have been detected in polar ice, suggesting that PFAS can migrate long distances in the atmosphere (Muir, 2019). SFEI concluded that PFAS are ubiquitous in San Francisco Bay biota including fish, bird eggs, and harbor seals (Sedlak et al, 2018). As a result, defining background levels of

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Per- and Poly-fluoroalkyl substances (PFAS)

PFAS from non-point sources presents a challenge to groundwater professionals evaluating CERCLA liabilities and environmental due diligence assessments (see previous issue of HydroVisions.) Typical Uses and Applications PFAS are used in many industries that may or may not be sources of PFAS in the environment. Typical uses include fire retardants and fire suppression, food packaging, stain repellents, and vapor suppression systems. The US Environmental Protection Agency (EPA) issued an interim guidance for the management of PFAS wastes in December 2020 (Docket ID No EPA-HQ-OLEM-2020-0527). Aqueous film-forming foams (AFFFs) for firefighting have been used at airports, military bases, refineries, fuel terminals, hazardous waste disposal facilities, and kitchens. There are multiple types of firefighting foams, but the Class B-type typically contain a large fraction of PFAS compared to other types of fire suppressants. Accumulation of PFAS in soils may result from atmospheric deposition, use of PFAS-containing materials, industrial discharge, and/or storm water drainage. PFAS have been reported to concentrate in biosolids and landfill leachate through traditional operations. Textiles may also contain PFAS since fire retardants or durable water repellents are often applied to fabrics. Industry is working to reformulate fabric protective products, phasing out the use of long-chain PFAS such as PFOS and PFOA, which is an area of active research. Governmental and Industrial Activities and Industries EPA announced in 2021 that it is reproposing the Fifth Unregulated Contaminant Monitoring Rule (UCMR 5) to collect data on PFAS in drinking water. EPA is in the process of issuing final regulatory determinations for perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) under the Safe Drinking Water Act (SDWA). California is assessing PFAS in groundwater thru the Groundwater Ambient Monitoring and Assessment Program (GAMA). This program is assessing groundwater quality in public-supply wells and shallow aquifers. In addition, the State Water Resources Control Board is gathering information on the industrial uses of PFAS with a focus on non-drinking water media and has issued a series of water code section 13267 orders to four categories of facilities: airports, landfills, publicly-owned treatment works, and chrome plating operations. These orders direct owners to assess their past and current use of PFAS-containing materials and, in some cases, to prepare investigation work plans. Additional section 13267 orders are under development. Additional facilities that use PFAS include chemical synthesis and formulation, medical equipment manufacturing, fire training, while products that contain PFAS also include ski wax, floor polish, cosmetics, and lubricants (Sedlak et al, 2018). CONTINUED ON NEXT PAGE

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The wide-spread use of PFAS suggests that management of PFAS in the environment will likely follow processes the groundwater industry experienced with other emerging contaminants such as perchlorate and 1,4-dioxane. The part per trillion levels associated with PFAS numerical criteria lead to unique challenges. As with other classes of potential groundwater contaminants, releases can be intentional and/or accidental and take the form of point and non-point sources. Examples of PFAS point sources are wastewater discharges, and exhaust stacks from fume hoods. Most owners have stopped routine testing of systems that dispense AFFFs. Replacement of Class B foams containing PFAS with non-PFAS containing foams is underway. PFAS water treatment systems produce PFAScontaining waste streams that may not be accepted by California landfills. Incidental and non-point sources of PFAS in environmental media include land application of biosolids, municipal solid wastes, storm water and atmospheric deposition. Municipal solid waste contains consumer products that may include PFAS such as food packaging, clothing, furniture, and other personal care products. Storm water run-off can comingle with PFAS-impacted waters from multiple facilities which have unknown PFAS sources. Additional research is needed to protect groundwater resources and understand the local, state, and worldwide distribution of PFAS in environmental media. Conclusion

Per- and Poly-fluoroalkyl substances (PFAS)

The widespread use of PFAS has distributed PFAS in air, water, and soils throughout the world—and PFAS have been detected in humans, flora, and fauna ecosystems. Source identification will become increasingly important as environmental regulations continue to develop. Understanding PFAS sources will also help monitoring efforts and inform future management approaches.

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Per- and Poly-fluoroalkyl Groundwater Management substances (PFAS)

Release Types - Accidental, Incidental, and other Release Types

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References Death C., C. Bell C, D. Champness, C. Milne, S. Reichman, T. Hagen, Per- and polyfluoroalkyl substances (PFAS) in livestock and game species: A review, Science of The Total Environment, Volume 774, 2021, 144795, ISSN 0048-9697 Muir D., R. Bossi, P. Carlsson, M. Evans, A. De Silva, C. Halsall, C. Rauert, D. Herzke, Hayley Hung, R. Letcher, F. Rigét, A. Roos, Levels and trends of poly- and perfluoroalkyl substances in the Arctic environment – An update, Emerging Contaminants, Volume 5, 2019, Pages 240-271, ISSN 2405-6650, Olsen GW, Ellefson ME, Mair DC, Church TR, Goldberg CL, Herron RM, Medhdizadehkashi Z, Nobiletti JB, Rios JA, Reagen WK, Zobel LR. Analysis of a homologous series of perfluorocarboxylates from American Red Cross adult blood donors, 2000-2001 and 2006. Environ Sci Technol. 2011 Oct 1;45(19):8022-9. doi: 10.1021/ es1043535. Epub 2011 Apr 29. Sedlak M, R. Sutton, A Wong, D. Lin “Per and Polyfluoroalkyl Substances (PFAS) in San Francisco Bay: Synthesis and Strategy”. San Francisco Estuary Institute. Contribution No. 867, June 2018.

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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.

Well development programs and their importance: Part 2

Wells and Words

A well development (WD) program includes a pumping phase (P-phase) which is implemented once the mechanical/chemical WD program (summarized in Part 1) is completed on the well. The P-phase leads naturally into a pumping test program (step-drawdown [dd] and constant-discharge [Q]) to evaluate well performance and aquifer parameters. If hydraulic measurements are collected during the mechanical WD program, then this information can often be used to estimate the potential-capacity of the well so that a properly-sized test pump can be installed for the final step – “cleanup”. This clean-up phase can help to deliver a longlasting, optimal, efficient, and economically operating well to the client. The goal of this final WD phase is to continue to dislodge and remove fine-grained materials and residual drilling fluids around the well screen by backwashing and by deliberately over-pumping the well. Backwashing (a.k.a. rawhiding) is the WD method that uses the surging effect or reversal of water flow in a well to apply mechanical energy to remove fine-grained materials from the formation (and filter pack) surrounding the borehole and to help eliminate bridging. Backwashing effectiveness is dependent on the depth of the static water level (SWL) and the amount of water stored in the pump column above the SWL (deeper is better). Bridging of particles in the filter pack material (especially plate-like debris) can reduce efficient flow

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Wells and Words

Figure 1a. Vertical line-shaft turbine, circular orifice and pipe, and piezometer tube used for Pumpingphase of well development, Pierce County, WA (1970s).

of groundwater from the aquifer to the well. Hence, it is important to both pump and backwash water into the well to break-up and reduce bridging. One-way flow (i.e., only pumping) may reduce the well-efficiency as this material builds-up around the screen. Note that mechanical WD can be conducted in such a way (isolating packers) that isolates the applied energy to specific locations along the screened intervals. In contrast, P-phase WD unevenly distributes that “energy” along the entire screen length and tends to target those screened intervals that have the greatest permeability. One of two types of test pumps are usually selected and installed in the well for the final WD program: a variable speed (VS) line-shaft vertical turbine pump (preferred) or a VS submersible pump: air-lift pumps are usually used during the first phase of WD (see Part 1). The line-shaft turbine pump typically consists of a diesel engine and right-angle gear drive at the ground surface – see Figure 1a, a pump column and shaft, a multi-stage pump bowl assembly (impellers) below the water level, and a short column with a screened intake. The shaft is either watercooled (preferred) or oil-cooled. The line-shaft turbine pump can also be modified to allow “forceful” re-injection of water stored in the pump column by reversing the drive (back-spin). A check (or foot) valve2 cannot be installed above the pump assembly because its function (one-direction flow) will prevent the backflow of water from the column into the well. The submersible pump3 is an electric motor and pump assembly designed to fit in a well and operate below the water level and requires a generator for power. Pump selection may depend on the diameter of the well; small diameter wells (< 6-inch) are more likely to use a submersible pump. Backwashing with a submersible pump may not be as effective because the injection energy is dependent only on the depth of the static water level (SWL) and the amount of water stored in the pump column above the SWL.

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I usually recommend the installation of the test pump for the P-phase at about 150 feet below the SWL or 5 feet above the well screen (available dd), whichever is less. Caution: installing the pump within or below the screen can lead to a permanent loss of the pump and abandonment of the well due to sands and silts settling out of the overlying column of water and accumulating around the pump. Install a water level sounding tube alongside the pump column to a few feet above the intake to measure water levels and set a transducer, if available.

Wells and Words Wells and Words

Figure 1b. Circular orifice and pipe to measure discharge and sediment loading during Pumping-phase of well development, Pierce County, WA (1970s).

The discharge pipe should be equipped with a flow measuring device3 (in-line flow meter, a circular orifice and piezometer tube at the end of the discharge pipe [preferred – see Figure 1b], or a weir arrangement) to quantify the various discharges while developing with the pump. Note that in-line flow meters can report false readings due to settleable solids that are pumped out of the well and become lodged in the meter impellers. A circular orifice and piezometer tube work best, especially for high-capacity wells.

Wells and Words

Prior to turning the pump on, measure the SWL and during developmental pumping, measure the pumping water levels [PWL] frequently with concurrent notations of Q; and measure the total settleable solids [TSS] removed from the well using an Imhoff Cone: time-stamp this information. If the well is designed with a filter pack fill pipe, measure the filter pack depth before pumping, and periodically check that depth, especially if TSS is persistent. Initially, the pump should be adjusted (valved-back) so that the Q is relatively small with a small amount of dd (say about 20% of the design capacity of the well). Measure, observe, and evaluate the hydraulic response to pumping. I usually conduct a one-hour “mini-pumping test” at this low Q to become acquainted with the well’s “personality” and a preliminary estimate of the field Transmissivity which may provide an empirically goal for the specific capacity. Gradually and incrementally increase Q and continue to measure and record Q,

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PWL, and TSS in a methodical and systematic manner. Conduct a couple of backwashing events at these low-Q events to evaluate the well’s response and observe the TSS response. Gradually increase the discharge until the available dd is used while also periodically backwashing to dislodge fine materials from around the screened intervals; observe the impacts from backwashing (i.e., dd and sediment removal load). In the field, plot the Q versus dd graph which may indicate at what Q the well efficiency sharply decreases; and target that Q with additional backwashing. I usually recommend that the formal pumping test dd (prior to removing the test pump) and long-term operational dd be limited to either 100 feet or 2/3 the available dd (until historical well performance data are collected) or ½ the unconfined aquifer saturated thickness, whichever is less. Follow-on tasks include (1) a step-dd pumping test to evaluate the well performance and (2) a constant-Q test to evaluate the aquifer response and parameters.

1 The Roscoe Moss Company, 1990, Handbook of Ground Water Development, John Wiley & Sons, NY, 493p. 2 National Ground Water Association (NGWA), 2003, Illustrated Glossary of Ground Water Industry Terms: Hydrogeology, Geophysics, Borehole Construction, and Water Conditioning, NGWA Press, 69p. 3 Anderson, Keith, 1984, Water Well Handbook (fifth edition), published by the Missouri Water Well & Pump Contractors Assn, Inc., 281p. 4 Abbott, David W., Winter 2013, Tools in the Hydrogeologist’s field kit – The Imhoff Settling Cone, HydroVisions, a publication of the Groundwater Resources Association of California, Vol. 22, No. 4, pp. 15-16. 5 Driscoll, Fletcher, G., 1986, Groundwater and Wells, published by Johnson Division, St. Paul, MN, 1089p . 6 Abbott, David W., Summer 2015, Part 1 - Yield-Depression Curves for evaluating well development effectiveness or whether to rehabilitate a well, HydroVisions, a publication of the Groundwater Resources Association of California, Vol. 24, No. 2, pp. 10 to 11. 7 Kruseman, G.P. and N.A. de Ridder, 1990, Analysis and Evaluation of Pumping Test Data (second edition), International Institute for Land Reclamation and Improvement, Wageningen, The Netherlands, 377p.

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Need To Know Where Your Water Infiltrates? AHMAD-ALI BEHROOZMAND & MAX HALKJAER

Ahmad-Ali Behroozmand is a Senior Geophysicist at Ramboll in Emeryville, CA. He has extensive experience in conducting geophysical projects and has been involved in different groundwater-related projects in California. Max Halkjaer is a Senior Hydrogeologist and Geophysicist at Ramboll. Through his career, he has focused on geophysical methods and how these data are made an integrated part of hydrogeological investigations.

Well development programs and their importance: Part 2

The new 3D Geophysical imaging method, tTEM supports MAR projects Introduction This article addresses a key challenge for successful implementation of managed aquifer recharge (MAR) projects, that is where does most of the water infiltrates. The new 3D geophysical method, tTEM, has proven to be very valuable for the assessment of MAR sites. An example from our recent projects in California is presented below. The challenge for successful implementation of MAR projects

Need To Know Where Your Water Infiltrates?

When planning a MAR program, one of the main challenges is to assess the suitability of a site for water infiltration. In other words, it is crucial to know • what portions of the subsurface materials are of high hydraulic conductivity, • how good is the vertical hydraulic connectivity across the site, and • whether the volume of recharge can be enhanced by focusing at specific parts of the site where the geology is dominated by coarser materials. To address the above challenges, a cost-effective and detailed 3D characterization of the subsurface is needed in both shallow and intermediate depth intervals. A drilling program will not be cost-effective to provide detailed information over a broad area.

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Where Your Water Infiltrates 2021 Summer Issue

The tTEM geophysical imaging method A new towed time-domain electromagnetic geophysical method, tTEM, is a highly efficient method for fast, costeffective and high-resolution 3D imaging of the subsurface. The technique is ideally suited for different applications, including managed aquifer recharge, saltwater intrusion, aquifer vulnerability, geotechnical investigations, and other applications. The tTEM system, as shown in Figure 1, measures continuously while towed on the ground by an all-terrain vehicle (ATV). The method provides high-resolution electrical resistivity models of the subsurface, which can then be interpreted as subsurface geology. The interpretation is supported by borehole data and background knowledge of the site. The tTEM is advantageous over other geophysical methods for the following reasons: • Fast coverage – tTEM data are obtained continuously at speeds between 5 and 15 mph, which enables large areal coverage in a short time. • High resolution – both vertical and horizontal resolutions data which can be presented in 3-dimensional images that can be used to interpret ancient river systems, for example, or define vertical hydraulic connectivity. Figure 1 The tTEM system in operation at a study area in California. (a) The primary magnetic fields produced by the current in the transmitter (Tx) loop. (b) When the Tx current is abruptly turned off, eddy currents are generated in the subsurface, which then produce secondary magnetic fields that are measured with the receiver (Rx).

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During the past few years, Ramboll has conducted tTEM surveys across California to support implementation of the Sustainable Groundwater Management Act, SGMA, as well as for other applications. Here we present results from a MAR case study in Kern County where the challenge has been to achieve information about the sediments to a depth of 200 feet at existing and new infiltration sites west of Bakersfield. The project aimed at obtaining a solid understanding of the vertical hydraulic connectivity of the sediments, and to define new drilling locations. The high-density tTEM data have revealed several fluvial channels at different depths across the study areas. In each infiltration basin, the tTEM results provided a good understanding of where the water most likely infiltrates from the surface and how the vertical hydraulic connectivity varies across each study area. Moreover, the results revealed which areas are most prone to the highest infiltration rates when comparing basins.

Need To Know Where Your Water Infiltrates?

Figure 2 shows an example of the tTEM results from a new infiltration basin. The results show detailed structural variations across the basin. Units of fine and coarse materials, as well as buried paleochannels, are nicely mapped out at different depth intervals. Such information is critical when defining new drill sites as the interpretation of the geology could vary significantly depending on the

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Where Your Water Infiltrates

Case study

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borehole location and depth. Figure 2 An example of tTEM results at a new infiltration basin in Rosedale-Rio Bravo. Selected mean resistivity plan-view maps are shown at different depth intervals.

The tTEM method enables fast and cost-effective mapping of potential and existing recharge basins. Ramboll possesses a standard tTEM system. We have recently purchased an updated version which is easier to mobilize and provides an increased depth of investigation. The new system will soon be introduced in California. For more information about Ramboll’s Hydrogeophysical activities, please visit www. ramboll.com/hydrogeophysics

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