HydroVisions | Summer 2022 by HydroVisions

VOLUME THIRTY-ONE AUGUST 2022

V.31

2022 Summer Issue th ANNIVERSARY

2022 Summer Issue

HYDROVISIONS is the official publication of the Groundwater Resources Association of California (GRA). GRA’s mailing address is 808 R Street. Suite 209, Sacramento, CA 95811. Any questions or comments concerning this publication should be directed to the newsletter editor at hydrovisions@grac.org 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 hydrovisions@grac.org

EXECUTIVE OFFICERS PRESIDENT R.T. Van Valer Roscoe Moss Company Tel: 323-263-4111 VICE PRESIDENT/SECRETARY Christy Kennedy Woodard & Curran Tel: 925-627-4122 TREASURER Rodney Fricke GEI Consultants Tel: 916-631-4500 DIVERSITY, EQUITY AND INCLUSION OFFICER Lyndsey Bloxom The Water Research Foundation Tel: 571-384-2106 IMMEDIATE PAST PRESIDENT Abigail Madrone West Yost Associates Tel: 530-756-5905 ADMINISTRATIVE DIRECTOR Sarah Erck Groundwater Resources Association of California Tel: 916-446-3626

DIRECTORS

Jena Acos Brownstein Hyatt Farber Schrek Tel: 805-882-1427 Erik Cadaret West Yose Associates Tel: 530-756-5905 Marina Delgiannis Lake County Water Resources Tel: 707-263-2213 Murray Einarson Haley & Aldritch, Inc. Tel: 530-752-1130 Todd Jarvis Institute for Water & Watersheds, Oregon State University Tel: 541-737-4032 Yue Rong Los Angeles Regional Water Quality Control Tel: 213-576-6710 Abhishek Singh INTERA Tel: 217-721-0301 Clayton Sorensen Balance Hydrologics, Inc. Tel: 510-704-1000 x206 John Xiong Haley & Aldritch, Inc. Tel: 530-752-1130

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 th commercial products, processes, or services, or the use of any ANNIVERSARY 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 Note

Wells and Words

Page 4

Page 6

The Geochemist’s Gallery

ISMAR11

Page 14

Page 16

Diversity, Equity, and Inclusion

Drought Conditions

Page 9

Page 10

GRA at the 60th Annual CESASC Convention

Growing Groundwater Grief in the Emerald Rectangle

Page 24

Page 26

WESTERN GROUNDWATER CONGRESS 2022

BUILT FOR CHANGE SEPTEMBER 19-21, 2022 | SACRAMENTO

PFAS & Co-Contaminants

Page 28

Western Groundwater Congress 2022

Page 32

Parting Shot

Page 34

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President’s Note The past 6 months have been amazing for GRA! After a phenomenal ISMAR11, we recently had one of the best Groundwater Law and Legislation Forum events ever. Many thanks to our event chair, longtime GRA Director Brad Herrema and to Chris Frahm and our friends at Brownstein Hyatt Farber Schreck. The Law and Legislation Forum agenda was filled with powerful and distinguished speakers such as keynote speaker Adel Hagekhalil, General Manager of Metropolitan Water District of Southern California, and the Chair of the State Water Resources Control Board, E. Joaquin Esquivel. Each of our presenters were extremely open and willing to take hard questions from the audience, and answered as fairly and truthfully as they could. I was truly pleased with the entire event. The following day we were given insight into the Reckoning with the Road Ahead at the 2022 GSA Summit. Chair Abhishek Singh and his team put on an amazing program in which presenters and attendees deliberated on how to translate our sustainability vision into action. My favorite session of the Summit was the closing panel, Coffee with DWR and the State Board, which provided attendees the amazing opportunity to have an open dialogue with Paul Gosselin, DWR Deputy Director of Sustainable Groundwater Management and Anthony Wohletz, Senior Engineering Geologist from the State Water Resources Control Board. These two outstanding programs also generated many new friends for GRA, and I would like to thank our first time and longtime sponsors and exhibitors for being a part our events. Your contributions are a huge portion of GRA’s success every year, and we couldn’t put on these events without your continued support! If you were not able to attend, there are breakdowns of each event on the following pages of this HydroVisions issue. So, you may be wondering, how does GRA plan to keep the success of the last six months rolling? The answer is the 2022 Western Groundwater Congress! Erik Cadaret and the planning team have been working nonstop since last year to develop one of the best WGC agendas ever, with the title Built for Change. Along with loads of information and networking time, we will be presenting three prestigious awards during the event: the Lifetime Achievement Award, Kevin J. Neese Award, and first ever Emerging Groundwater Professional Award. At our last meeting in June, the GRA Board of Directors voted unanimously for the recipients, who will be announced at the event in September. Thank you to Task Force Chair Clay Sorenson and his team for working so diligently on this project. Also, it wouldn’t be a WGC without great receptions. This year, we will proudly be celebrating GRA’s 30th Anniversary by travelling back in time to when the organization first started, with a 1990’s themed celebration! I can’t wait to see you all in September (or maybe sooner, virtually, at 101 Week).

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Finally, I know we are all incredibly busy right now. If I have learned anything in these past few months, it is to make sure you take time to slow down and be present. So please remember to stop and take a breath, enjoy time with your family and be thankful for all of the wonderful things you have around you (that you may not always notice from your office). I hope you and your families are all doing well, staying busy, and are able to enjoy a little summer vacation along the way.

R.T. Van Valer has worked for Roscoe Moss Company, a leading manufacturer of water well casing, screen and water transmission pipe, since 2001. R.T. currently serves as the Product Manager and Director of Human Resources for the company. In his 11th year with GRA, R.T. has previously served in multiple executive offices, chaired committees and twice chaired the Western Groundwater Congress.

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Wells and Words

Perforations, Slots, Louvers, or Screens (Steel or PVC) by David W. Abbott, P.G., C.Hg. Consulting Geologist

n my “book”, steel or stainless-steel wire-wrap screens are by far the superior product for water supply wells (especially for high-yield wells; even for low-yield water supply and small diameter monitoring wells) for several reasons, including: 1. The collapse, burst, and tensile (pull-apart) strength of steel versus PVC casing/screens: steel is simply stronger which allows for more effective and aggressive applied mechanical energy for various well development techniques for any diameter well. 2. Lower entrance velocities that can be achieved with wire-wrap screens because of the relatively greater open area for water transmission (up to 15% for perforations, slots, and louvers versus greater than ≈ 30% for wire-wrap screens for most slot sizes)1,2.

3. Wire-wrap screens provide greater exposed area

to encourage removal of fine-grained sediments (silts and clays) and drilling fluids during well development of the filter pack and of the borehole walls (including, if applied, the more effective distribution of chemical dispersants or acids). 4. Well-longevity, 5. Over-all economic costs to own and operate the well through its life-span.

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The primary advantage to using PVC is the lower costs to purchase and transport the pipe and for labor to install the pipe. Sometimes, PVC is recommended for monitoring wells because of groundwater quality issues. The higher the entrance velocity through the screened interval (wellintake), the greater the chance to mobilize silt and clay particles3 which can lead to undesired water quality changes that may not represent the groundwater quality from the actual aquifer (groundwater has zero turbidity) and, consequently, can accelerate water well deterioration and reduce the useful life-span of the well. Increasing the open area per foot of well screen reduces the entrance velocity. Recently, I reviewed about 80 CA DWR Well Completion Reports (WCR; dated from 1953 to 2019) for an area in Northern California from two adjacent Sections (2 square miles) of a Township/Range. I was disappointed at the absence of reporting the well-intake design and hydraulic information on the more recent WCRs. I was also surprised by the number of “failed” wells that were installed on several individual properties before a “successful” well was completed on that property. Most of the WCRs were for low-yield domestic wells and were constructed of 5- to 8-inch-diameter casing (95%) with about 65% of the wells constructed with PVC blank/slotted pipe; none had wirewrap well screens (not surprising!). Typical reporting for 6

the slots mentioned only the width (i.e., 3/32-inch) and did not identify the manufacturer. The length of the slot, the open area per foot of perforations, and the orientation (vertical or horizontal) were not reported on the WCR. This type of information is critical to evaluate the efficient transmission of groundwater from the aquifer system through the filter pack (if used), screen, and to the well pump. Without this information, it is difficult to evaluate the performance (poor or otherwise) of a water supply well and any suggested corrective actions, if needed. Hydraulic information was usually collected from 1- or 2-hour airlift pumping tests (clearly inadequate) that make it nearly impossible to measure the drawdown during the testing4. I suspect that the reported discharges are usually inflated to “impress” the well owner (and other drilling contractors). These wells were designed with slotted pipe (usually with unknown specifications on the total open area of the intake that were placed “essentially” from top to bottom leaving very little available drawdown (dd) for an appropriate (and recommended) level of dd in the well. This type of well design results in Pumping Water Levels (PWL) that are within the well intake which can impact inorganic (including bacterial growth) water quality due to cascading groundwater, which can shorten the well-longevity and reduce well efficiency. Permanent pump settings were typically at the bottom of the well (rather than above the well screen) in order to maximize the dd which leads to these inflated well yields. It seems that the adage “more is better” is taken literally when it comes to designing these long screen intervals5 and also over-rating the yield of the well. A standard parameter for proper and efficient well design is the available drawdown (ddavail), which is defined as the top of the screened interval minus the Static Water Level (SWL). The recommended PWL is 2/3 of the ddavail or 100 feet in wells tapping unconsolidated aquifers (or 50 feet in wells tapping fractured rock), whichever is less. The 2/3 of ddavail accounts for usually unknown seasonal water level fluctuations and hydraulic interference from unknown nearby pumping wells that can be resolved with a couple of years of weekly (preferred) or monthly date-stamped monitoring of the SWL, PWL, yield, and total volume of water pumped from the well. For an unconfined groundwater system (water table), the length of the well screen should be no more than ≈ 50% of the aquifer thickness. Note that the Transmissivity (T) is the product of the hydraulic conductivity (K) of the aquifer and the aquifer thickness (b) or T = K × b. Allowing a larger dd in an unconfined aquifer (more than 50% of the aquifer thickness) reduces the effective thickness of the aquifer which will further decrease T and the well-yield. The 100foot dd (50-foot in fractured rock) can be adjusted once some historical operating data have been collected from the well and calculations are performed to evaluate the 7

hydraulic pressure and its’ impacts on the collapse strength of the screened interval. In most cases, the 100-foot maximum PWL benchmark ensures that the down-hole hydraulic pressure does not exceed the collapse strength of the pipe. This rule of thumb is applied to standard-sized steel wells unless stronger steel pipe/screen is specified for the well with a deeper PWL. PVC casing has lower collapse strengths. Hydraulic differential of a pumping well is defined as the PWL in the well minus the water level outside of the well in the aquifer (measured and/or projected with an observation well) – the greater the hydraulic differential, the greater the pressure at the perforation/slot/screen intake. Inefficient wells exhibit significantly greater hydraulic differentials which can crush the screened interval. Drawing the PWL below the top of the screen allows groundwater to enter the well and cascade down the well mixing with air; aerating the groundwater and setting up local environmental conditions that can accelerate well deterioration by plugging the screen and promoting the growth of iron bacteria. This deterioration is particularly common with water wells that do not receive regular (annual) maintenance. PVC casing is inherently weaker than steel casing and does not always survive rigorous well development and rehabilitation methods without rupturing. Drilling contractors know this and usually do not spend sufficient time or apply enough mechanical energy during well development on PVC wells. The inference is that most PVC wells (including monitoring wells) are insufficiently developed which minimizes the well efficiency and reduces the achievable and maximum well yield. Incomplete well development can affect water quality pumped from the well. An efficient production well can reduce the cost to lift the water to the ground surface6 and provide better water quality which is more representative of the aquifer; and longer operating life-span. Yes, PVC casing is easier and cheaper to install than steel casing, but the weakness of PVC significantly reduces the amount of applied mechanical energy that should be used for effective well-development. Moreover, the lower open area of PVC perforations limits the reach of this mechanical and chemical energy into the filter pack and aquifer. Effective well development is necessary to correct the hydraulic damage due to drilling the boring. Usually, the greater the amount of mechanical energy applied during a development program: the more effective the program.

Continues on next page

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Slotted pipe, perforations, and louvered pipe have a significantly smaller open area than wire-wrap screens. The exception is PVC wire-wrapped screens, which has a large open area but is significantly more fragile than slotted PVC (I have installed only a couple of these wells during my career). Hand sawn or torch-cut perforations are not typically described in the WCRs. In fact, more recent WCRs do not have a place on the form for this information. Older WCRs had a section for describing the perforations that included:(a) length of perforated pipe installed, (b) perforations per row, (c) rows per foot, and (d) the dimensions of the slots, i.e., inch wide × inch long. The open area can be estimated using this information. This will be more fully discussed in a future Wells and Words installment. The installation of a water supply well is not just a “hole” in the ground but an “engineered” conduit into the groundwater system. Proper hydraulic testing and measurement of critical parameters are vital to the optimization of an operating well and proper groundwater management. Groundwater is a very valuable resource that can be damaged by the installation of water supply wells with poor design and engineering practices. Proper well design and operating parameters can: (1) protect the groundwater resource and minimize the number of wells or replacement wells that are installed in an area; (2) increase well-longevity; and (3) reduce overall operating costs of well ownership. 1 Driscoll, Fletcher G. (editor), 1986, Groundwater and Wells, Johnson Division, St. Paul, MN, see specifically Appendix 12.4, pages 948 – 949 which compares various Perforation, Slot, Louver, and Screen specifications.

2 In many cases also see the manufactures websites for well screen specifications. 3 Abbott, David W., Fall 2013, Why does groundwater have zero turbidity? -

Hjulströms Diagram and application to groundwater, published by Groundwater Resources Association of CA in HydroVisions, Vol. 22, no. 3, pp. 18-19.

4 Abbott, David W., Summer 2005, How is the yield or productivity of a

well judged?, published by Groundwater Resources Association of CA in HydroVisions, Vol. 14, no. 2, pp. 5 and 26.

5 Abbott, David W., Fall 2009, Tapping multiple aquifers with single-well

completion designs - Is this a good or bad idea?, published by Groundwater Resources Association of CA in HydroVisions, Vol. 18, no. 3, pp. 20-21.

6 Abbott, David W., Summer 2016, The nexus between energy and water wells or

why well development matters, published by Groundwater Resources Association of CA in HydroVisions, Vol. 25, no. 2, pp. 12-13.

David W. Abbott, P.G., C.Hg., Consulting Geologist, 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.

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Diversity, Equity, and Inclusion by Matt Pendleton, PG, CHg

he Groundwater Resources Association’s Diversity, Equity, and Inclusion (DE&I) committee sponsored the Environmental Career Fair which was co-organized by Mr. Matt Pendleton (Hydrogeologist, EKI Environment & Water, Inc. and GRA DE&I Committee member) and UCLA's DE&I Committee of the Department of Earth, Planetary and Space Sciences, University of California, Los Angeles (UCLA). The career building event was geared towards underrepresented student groups in the groundwater-related sciences and convened seven panelists from diverse ethnic and academic backgrounds and 16 students. The event was advertised to DE&I student groups and was held at the UCLA Luskin Conference Center. The half-day event was held on March 12, 2022, and included panel discussions, group-focused interview exercises, and oneon-one mock interviews. The student participants came prepared with their resumes in-hand and were giddy with nervous excitement to meet the industry panelists. After an initial panel Q&A, students mingled with panelists over refreshments and snacks, and then got to work! The meat of the event consisted of focused, 20- to 40-minute-long mock interviews and handwritten interview exercises. Every student had face-time with multiple panelists. The exercises and mock interviews were designed to get students thinking about their path and future career. The event was organized with the intent to create linkages between academia and the local participating industry organizations which benefit from employing recent graduates. According to Mr. Matt Pendleton, “there seems to be a lack of groundwater industry ties within the southern California universities and colleges, and that’s why we organized this event: to show students a sampling of the career pathways that exist and which are not often discussed in the academic setting.” As quoted from the post-event surveys, students “loved this experience” and “need these events to happen more often.” Furthermore, they said, “This was a fantastic event! The advice given was exactly what I was looking for and tremendously increased my understanding of the environmental industry.” This first-of-its-kind environmental careers event will surely be a career launcher for some of the participants, with the potential to shape the trajectory of students’ future careers. Similar events are being planned by the DE&I committee who will be using this event as a template to empower student careers, to promote diversity into the work force, and to enhance student interest in the groundwater sciences. Stay tuned for similar DE&I events at a branch near you! Mr. Matt Pendleton, PG, CHg, is a PhD student in the Department of Earth and Environmental Sciences at the University of Waterloo and was recently an environmental consultant at EKI Environment & Water, Inc. As a consultant, Matt specialized in environmental site investigation and construction stormwater compliance. He has supported development of corrective actions and regulatory negotiation for developers facing enforcement proceedings and penalties. Matt is a committee member of GRA’s Diversity, Equity, and Inclusion committee and is the Vice President of GRA’s Southern California Branch.

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Drought Conditions and Impacts in the Western United States – Part III by Todd Jarvis, Courtney Black, Abhishek Singh

he unrelenting grip of the drought on much of the western United States continues. 2020 to 2022 is the driest 3-year period on record in the Western U.S. over the last 1200 years, with the closest equivalent being the megadrought in the late 1500s1. Persistent La Niña conditions in the tropical Pacific since the summer of 2020 resulted in fewer storms to the southern United States, exacerbating drought impacts in the Southwest. Climate change has also played a role. The authors of a Nature Climate Change study estimate that approximately 42% of the soil moisture deficit experienced from 2000 to 2021 is attributable to human-caused climate change. As of May 2022, more than 70% of the Western United States was experiencing severe to exceptional drought conditions, with almost 40% in extreme to exceptional drought (Figure 1). California, Nevada, Arizona, Utah, Colorado, and New Mexico are classified as in severe to exceptional drought. Oregon added four counties to its “drought emergency” declaration, bringing half the state under the governor’s proclamation at the time of this writing. In Idaho, the water resources department issued an emergency drought declaration for 34 of 44 counties.

In the southwest, both Lake Powell and Lake Mead—the nation’s largest supply reservoirs—remain at historic low levels (approximately 25% and 30% capacity, respectively). In California, the Metropolitan Water District of Southern California imposed unprecedented outdoor water restrictions for the first time, impacting roughly 6 million Southern Californians who rely, in part, on imported State Water Project supplies. California’s largest reservoirs, Lake Shasta and Lake Oroville remain at “critically low” levels (50% and 70% of historical average, respectively) at the time of this writing. The drought is also having profound and long-lasting impacts on groundwater, which serves as critical supply when surface water supplies are depleted in dry conditions. Throughout the Central Valley, water levels were measured at all-time lows, even before the start of summer (Figure 2). The drought and on-going climate change will continue to impose unprecedented water supply challenges statewide and in the west. The first two articles in this series on the Western Drought reported on evolving drought conditions in California, Oregon, Washington, Nevada. This third article discusses the state of the drought in Utah and Colorado.

https://www.nature.com/articles/s41558-022-01290-z.epdf

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Figure 1

Figure 2

Figure 1 - Comparison of Drought Conditions in the Western United States between March 15, 2022, and May 17, 2022 (taken from https://droughtmonitor.unl.edu/Maps/CompareTwoWeeks.aspx ) Figure 2 - May 2022 Groundwater Conditions in California

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Figure 3: Drought Conditions in Utah

Utah Utah is the second driest state in the United States, yet water availability does not appear to be a deterrent to growth as it is also one of the fastest growing states. Groundwater-dependent communities like Oakley, Utah, have made national news because of a cap on growth due to lack of water. As of May, all of Utah was classified as being in the “severe drought” category, with more than half the state in “extreme drought” (Figure 3). According to the state drought monitor, the statewide snow water equivalent peaked at 12 inches, or about 75% of the median peak of 16 inches. Twenty-two of Utah’s largest 45 reservoirs are below 55% of available capacity. Statewide storage is 60% of capacity compared to 67% of capacity in 2021, and 47 of 63 monitored streams have below normal flows. In January 2022, the Governor released the first chapter of “Utah’s Coordinated Action Plan for Water” that is designed to meet the needs for agriculture, growing cities, and environmental concerns. Priority concerns include protecting Utah Lake from harmful algal blooms and spending millions of dollars on the state's crown jewel, the Great Salt Lake, to address continuing depletion from 20 years of drought. Statewide, critical supply projects are moving forward for permits and funding, despite the uncertainty of supply availability. For example, despite the declining water levels in Lake Powell on the Utah-Arizona border,

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the $2.2B Lake Powell Pipeline project is advancing, which is intended to deliver this supply over 140 miles to Washington County and St. George, Utah, where population growth is over 2.6% annually. However, the reality of the drought and climate change is setting in. The Southern Nevada Water Authority recently cancelled their Groundwater Development Project after spending $330M in planning and permitting. In May, The U.S. Bureau of Reclamation took the unprecedented step of holding back Lake Powell releases to downstream states as part of an emergency plan to protect the lake. If drought conditions persist, Utah may need to consider modifying their license plate motto of “Greatest Snow on Earth” to “Driest Lake in the US”.

Colorado Colorado is host to the headwaters of several major rivers that flow downstream, serving eighteen states and Mexico. Colorado has nine interstate compact agreements, where water originating in Colorado is allocated among Colorado, the downstream states, and Mexico. Water rights are administered using the prior appropriation doctrine (first in time, first in line for water), which recognizes the connection of surface water and groundwater. Alluvial groundwater that is hydrologically connected to a stream is administered alongside surface water through the prior appropriation system. Groundwater not connected to a surface water body (e.g., deep bedrock aquifers) is administered, depending on the location, through the Division of Water Resources or the Colorado Groundwater Commission. 12

Figure 4: Snow Water Equivalent

As of May 2022, Colorado is approaching 120 consecutive weeks of drought where there has been a US Drought Monitor ranking of “extreme” and/or “exceptional)”. In June of 2020, Colorado’s Drought Task Force and Phase 2 of the State Drought Mitigation and Response Plan was activated to respond to drought conditions. Phase 2 activated the Agricultural Impact Task Force, a group of stakeholders who meets regularly to address agricultural impacts and recommend mitigation. As conditions worsened in November 2020, the response was expanded to Phase 3, activating the Municipal Water Impact Task Force to coordinate and address water shortage challenges. Both groups remain activated as the state continues to experience extreme to exceptional drought.

the soil moisture deficit attributed to the last two dry water years, will likely impact runoff and streamflow from the melting snowpack. Statewide reservoir storage is about 77% of normal, although there is variation in site-specific storage throughout the state. Storage levels are generally highest on the east slope and lowest in southwest Colorado. Lower levels in southwest Colorado are partially attributed to emergency releases made from Blue Mesa Reservoir last fall to address hydropower production concerns at Glen Canyon Dam in Lake Powell. The NOAA Climate Prediction Center’s national 3-month climate outlook indicates the state will likely be warmer and drier than average through the end of August.

A substantial portion of Colorado’s water supply originates as snowpack. As of May 22, snow accumulation is well below normal statewide, with a snow water equivalent ranging from 4% to 76% of normal (Figure 4). Moreover,

https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor. aspx?west

References:

Williams, A.P., Cook, B.I. & Smerdon, J.E. Rapid intensification of the emerging southwestern North American megadrought in 2020–2021. Nat. Clim. Chang. (2022). https://doi.org/10.1038/s41558-022-01290-z

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.

Courtney Black is a Senior Water Resources Engineer with INTERA specializing in water resources planning, including conservation, drought, water supply and demand, and water rights.

Dr. Abhishek Singh is a Principal Engineer with more than 20 years of experience and is President of INTERA’s Water Resources & Supply Line of Business (LoB), where he leads and manages operations, business development, strategic planning for the lob across the United States. He has authored several technical publications and journal articles on groundwater modeling and calibration, stochastic optimization techniques, uncertainty and risk analysis, climate change, and emerging contaminants. Dr. Singh is also the chair of the GRA technical committee and serves on the GRA board of directors.

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The Geochemist’s Gallery Toxic Terra (Part 7) by William E. (Bill) Motzer

luorine is a naturally occurring (geogenic) element in rocks, soils, water, air, plants and animals. It’s the 13th most abundant element in the Earth’s crust, the most electronegative, and the most reactive of all the elements. Therefore, elemental fluorine (F0) by itself, does not occur but is largely found combined with other elements in inorganic minerals such as apatite (calcium fluorophosphate or CaFPO4) and in its solubilized state as ionic fluoride (F–). Figure 1

Toxicity and Epidemiology In low concentrations, fluoride is considered beneficial to human health; however, in higher concentrations it’s toxic. The term for fluoride toxicity is fluorosis, initially coined in 1925 to describe vegetation impacts from Swiss aluminum smelter emissions. Fluorosis is damage or deformity to human hard tissues such as teeth and bones. Dental fluorosis is an irregular calcification disorder of the enamel-forming process during childhood leading to pitted, eroded, and brown to black stained teeth. Skeletal fluorosis was first reported in France and Denmark in the early 1930s, from exposure by the mining and processing of the mineral cryolite (sodium hexafluoroaluminate or Na3AlF6). It is a crippling disease caused by over-mineralization of bones and joints resulting from long term or chronic exposure to high fluoride intakes. One study demonstrated a prevalence for neuro-medical indicators of fluorosis in population living in the Main Ethiopian Rift valley (Ayele, et al., 2022). Other recent research indicates that fluoride is not neurotoxic (Guth, et al., 2020).

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Figure 2

Human fluoride exposure can occur via inhalation, dermal contact or ingestion of food, beverages, and dental products. However, fluoride’s main exposure route is by water ingestion, largely from geogenic (natural) source dissolution in groundwater. Numerous studies have shown that regions with low fluoride groundwater concentrations (up to 0.5 mg/L) are often associated with increased dental tooth decay. In areas with fluoride concentrations of ~0.5 mg/L to 1.5 mg/L, tooth decay rates are much lower. Therefore, fluoride is now added to dental products, such as toothpaste where manufacturers may add it as sodium fluoride (NaF), monofluorophosphate (Na2PO3F), or stannous fluoride (SnF2). Many countries and U.S. States have implemented drinking water fluoridation programs. However, exposure to fluoride concentrations greater than 1.5 mg/L commonly results in fluorosis. Once absorbed in the human body, approximately 60% to 80% of fluoride is retained in the skeleton with bone concentrations typically ranging from 300 mg/kg to 7,000 mg/kg dry tissue weight, depending on exposure. This is because bones are largely composed of calcium (Ca) compounds, mostly carbonated hydroxyapatite [Ca5(PO4)3(OH)]. The process resulting in fluorosis is believed to occur as follows: 1.

F reacts with the stomach’s concentrated hydrochloric acid (HCl) to form weak hydrofluoric acid (HF), which is then absorbed by the gastro-intestinal tract, subsequently passing into the liver via the portal vein. F− is largely immune to phase 1 metabolic reactions. These are generally oxidation reactions, which are the body’s first line of defense, biotransforming harmful compounds into more easily excreted hydrophilic substances. –

HF now freely passes into the blood stream and is distributed to all tissues including the skeleton and teeth. The reaction of Ca2+ and HF forms insoluble calcium fluoride (CaF2) that must be cleared by the body, which concurrently leaches some of the calcium composing part of the bone’s matrix. This process results in increased bone density, but decreased bone strength. Resulting in fluorosis.

In unimpacted populations, fluoride blood levels are generally very low – approximately 0.04 mg/L; for impacted populations, concentrations range from 0.5 mg/L to 0.8 mg/L. Although fluoride is mainly retained in bones, there is a balance between blood concentrations versus excretion by the kidneys and partly by the skin through perspiration. Certain amounts of fluoride (studies estimate 15% to 50 %) remains in the ionic state; the remainder forms albumin bonds with calcium acting as a bond mediator. The lowest fluoride concentrations are in soft body tissues, generally ranging from 0.5 mg/kg to 1.0 mg/kg; however, 3 mg/kg to 50 mg/kg concentrations are not uncommon in epidermal tissues. Therefore, the main fluoride health issues are associated with bones and teeth. Recent estimates are that 1.7 million people in China and 1.0 million people in India suffer from some type of fluorosisderived disease such as skeletal fluorosis (Figure 2). Skeletal fluorosis also is a significant health problem for peoples in the East African Rift zone, including Ethiopia (Ayele, et al.,

2022). Worldwide, such diseases may affect more than 70 million people, severely limiting their ability to work and support families. In the next part of this series, I’ll discuss some of fluoride’s sources and geochemistry. * Note: This article is an update of an earlier version by Motzer (2016).

References Amini, et al., 2008, Statistical Modeling of Global Fluoride Contamination in Groundwaters: Engineering Science & Technology, v.42, n.10, p. 3662-3668. Ayele , B.A., Godebo, T.R., TekleHaimanot, R., and Yifru, Y.M., 2022, Neuro-medical Manifestations of Fluorosis in populations Living in the Main Ethiopian Rift Valley: Environ Geochemistry and Health, v. 44, n. 3, pp. 1129-1136. Fordyee, F.M., 2011, Fluorine Human Health Risks, in J.O. Nriagu (editor), Encyclopedia of Environmental Health: Elsevier, Burlington, MA, v.2, pp. 776-781. Guth, et al., 2020, Toxicity of Fluoride: Critical Evaluation of Human Developmental Neurotoxicity, in Epidemiological Studies, Animal Experiments and In Vitro Analysis: Archeological Toxicology, v.94, n.5, pp.1375-1415. Motzer, W.E., 2016, Toxic Terra – Part 5 (Fluorine): The Vortex, v. LXXVII, n. 2, pp.6-8, www.calacs.org.

Figure 1 - Map of worldwide probability occurrences of fluoride in groundwater. This map is a result of modeling accounting for groundwater flow and rock type parameters. Note the high probabilities in arid and desert regions. Source: Amini, et al., (2008). Figure 2 - Photo of human skeletal fluorosis in India. Source: https://www.pinterest.com/pin/466896686350201540/.

William E. (Bill) Motzer, PhD, PG, CHG, CPG is a somewhat semi-retired forensic geochemist. Formerly with Todd Groundwater, he has more than 40 years of experience as a Professional Geologist and more than 35 years of experience in conducting surface, subsurface, and environmental forensic geochemical investigations. His particular expertise is in stable and other isotopic “fingerprinting” and age dating techniques and water quality/ contaminant source identification geochemistry.

2022 Summer Issue

11th International Symposium on Managed Aquifer Recharge (ISMAR11) by Adam Hutchinson

RA hosted the 11th International Symposium on Managed Aquifer Recharge (ISMAR11) on April 11 to 15 in Long Beach, CA. Co-hosts included by the Arizona Hydrological Society (AHS) and the Orange County Water District (OCWD). GRA applied to host this event more than three years ago so it could be announced at the conclusion of ISMAR10 held in Madrid, Spain. Who knew what was going to happen in the world in the last three years! There were some nervous moments, but we are so delighted that we were able to host this event in-person at a great venue, the Long Beach Hilton Hotel. For many, it was the first in-person event they had been to since the start of COVID, and you could feel the excitement and energy of being together, face to face. Zoom can’t touch this! ISMAR11 was a multi-year effort and took a great team of people to pull it off.

Adam Hutchinson

Doug Bartlett

Sharon Magdal

Bob Bower

Felicia Marcus

Christy Kennedy

Jenn Swart

Sarah Erck

In all our work, we had three guiding principles:1) Share Knowledge, 2) Deepen Connections, and 3) Have Fun! We also were intentional about the structure of the event and introducing some new elements, such as: 1. A new policy and governance pre-conference workshop spearheaded by Sharon Megdal, University of Arizona. 2. A day-long general session that focused on the big picture of how MAR fits into achieving sustainability. This general session was designed to attract people new to MAR and those that are not specialists in this field. 3. Live streaming of the general session and key technical sessions, which was free to all outside of the USA. 4. Long lunch breaks to facilitate networking and connecting. 5. A fun night of entertainment with Sergio Vellatti and his big band.

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All of this would not have been possible without the generous support of our many sponsors and exhibitors. Thank you! Website Sponsors Wallbridge Gilbert Aztec Geo-Logic Associates Herman Bouwer Awards Lunch Sponsors Orange County Water District Todd Groundwater Dudek ACWA National Institutes for Water Resources (NIWR) City of Tucson MAR di Gras Evening Reception Sponsors INTERA Woodard & Curran In-Situ Brownstein Hyatt Farber Schreck West Yost MARathon Exhibitor Geo-Logic Associates GeoEngineers, Inc. Baski, Inc. WRD MARgarita Sponsor Torrent Resources

MARketplace Exhibitors Geoscience Support Services, Inc. American Aquifers California Department of Water Resources INTERA Incorporated Wildeye Aquaveo Ramboll Conference Bag Swag Sponsor Trussell Technologies, Inc. MARksman Sponsors GeoSystems Analysis, Inc. (Conference Bag Sponsor) Montgomery & Associates (Conference Lanyard Sponsor) Sonoma Water (Gourmet Water Station Sponsor) Eastern Municipal Water District (Lunch Sponsor) Irvine Ranch Water District (Lunch Sponsor) MARlin Wellness Sponsor EKI Environment & Water MARsh Field Trip Sponsor Valley Water

MARsh Field Trip Sponsor Peter Mock Groundwater Consulting, Inc. MARsh Field Trip Sponsor Water Replenishment District of Southern California MARvelous Exhibitor Johnson Screens HDR GEI Consultants, Inc. 3RValve LLC Roscoe Moss LRE Water Speakeasy Sponsors Rutan & Tucker, LLP Roscoe Moss World Access Sponsor Roscoe Moss American Institute of Hydrology (AIH) KWR Water Research Institute Wallbridge Gilbert Aztec Event Co-Sponsors Arizona Hydrological Society Orange County Water District

The response to ISMAR11 was tremendous. We had a truly international conference with representatives from 27 countries! Over 360 registered for the event. Check out these additional key facts:

Oral Presentations 115 Workshops 4

Field Trips 2

Exhibitors and Sponsors 44

Poster Presentations 6 Attendees 360

Countries Represented 27

Keynote Speakers

Herman Bouwer Award

Bruce Babbitt & David Kreamer

Peter Dillon

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ISMAR11

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ISMAR11

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ISMAR EVENING RECEPTION

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We had a truly international conference with representatives from 27 countries!

It is customary to hold pre-conference workshops at ISMAR, and ISMAR11 was no exception, David Pyne of ASR Systems, LLC and Russell Martin of Wallbridge Gilbert Aztec hosted a workshop on “Achieving Successful Groundwater Recharge and Recovery Through Wells”. Mike Milczarek of GeoSystems Analysis and Adam Hutchinson of Orange County Water District hosted a workshop on “State of the Art Techniques in Identifying and Characterizing Optimum Surface Spreading Groundwater Recharge Projects”. Sharon Megdal, Executive Director of the Water Resources Research Center of the University of Arizona, hosted the first ever workshop on “Meeting Water Management Objectives with Managed Aquifer Recharge: The Role of MAR Governance and Policy”. On April 12, we had a General Session that featured two keynote addresses and two panel discussions. The first keynote was given by Bruce Babbitt, former governor of Arizona (1978-87) and Secretary of the Interior (1993-2001) who spoke on “Leadership: A Key Ingredient for Addressing Water Management Challenges”. The second keynote was given by David Kraemer, Professor of Geoscience, University of Nevada, Las Vegas, who spoke on “Protecting the Invisible, Underground Pulse of the Planet: The challenges and what needs to be done”.

recharge. He authored more than 300 publications, including 12 book chapters and the textbook Ground Water Hydrology (McGraw-Hill, 1978). He was also a key driver in organizing numerous ISMAR events. And to top it all off, he was a genuinely great person that influenced and mentored many in the MAR community. The award is to be given to the person or agency that has significantly advanced the understanding or utilization of MAR. Nominations for the award were received and reviewed by past winners of the award and representatives from GRA and AHS. The 2022 Herman Bouwer Award was presented to Dr. Peter Dillon. Dr. Dillon epitomizes the spirit of the Herman Bouwer Award with his lifelong work and voluntary efforts making major advancements to science of MAR, through his world class research, mentoring, widely cited publications, and community outreach. Since the 1980s, Dr. Dillon has been at the forefront of cutting-edge MAR research to restore the natural equilibrium of groundwater systems that, at a global scale, are under ever-increasing pressure from extraction. Dr. Dillon co-founded the International Association of Hydrogeologists (IAH) working group in 1998 that became the IAH Commission on Managing Aquifer Recharge in 2001. Dr. Dillion remained co-chair of the Commission until

Two panel discussions were held that revolved around MAR. The first, moderated by Felicia Marcus, William C. Landreth Visiting Fellow, Stanford University; Former Chair, California State Water Resources Control Board, was on “MAR in California”. The second panel, moderated by Sharon Medgal, Director, University of Arizona Water Resources Research Center, was called “MAR in Action” and focused on MAR projects outside of California. Both of these panels offered a wide range of perspectives on how MAR projects and polices are currently working, and what challenges need to be overcome to increase MAR implementation in California and around the world. Between the two panels we broke for the Herman Bouwer Awards Luncheon. The late Dr. Herman Bouwer was one of the world’s leading researchers in water resources management, particularly in the area of managed aquifer

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2019. Dr. Dillon has produced well over 300 publications that have been cited more than 6500 times and currently has an h-index of 42. His role as lead author of a 2019 paper entitled ‘Sixty years of global progress in managed aquifer’ exemplifies his international leadership in the field of MAR. Before giving out the award, inaugural Herman Bouwer Award recipient, Robert Rice, who worked closely with Herman for 40 years, gave a short presentation on Herman as a scientist and as a friend. Dr. Dillon was not able to attend personally but received the award virtually and gave the audience a terrific, recorded presentation entitled: Managed Aquifer Recharge, Measure for Success and Growth! The final element of the general session is what we call ISMARx, which is a TED Talk-style series of short presentations given by students. Attendees enjoyed the rapid-fire introduction to a wide range of research being done by these students. After the presentations, the students and professionals spent time networking for mentoring and job opportunities. Several students were successful in getting interviews out of this process. The next two days of the conference consisted of four parallel tracks with a total of 23 sessions. Each session had five presentations with a lot of great content. If you attended the conference, you have access to the presentations and recordings (self-recorded presentations made by some presenters). For those that were not able to attend, you can visit the GRAC.com website to purchase access. On the last day of ISMAR11, we had two field trips: 1) Orange County Water District to see their recharge facilities and the Groundwater Replenishment System (GWRS) and; 2) Water Replenishment District of Southern California’s Albert Robles Center for Water Recycling and Environmental Learning and recharge facilities used to recharge the Central groundwater basin. Be on the lookout for information on the next Biennial Symposium on Managed Aquifer Recharge (BSMAR), to be hosted by the Arizona Hydrological Society (AHS) in 2024, and start making plans to attend ISMAR12 in 2025 in Cape Town, South Africa. Adam Hutchinson is the Recharge Planning Manager for the Orange County Water District in southern California. He has over 30 years water resources experience. In his 22 years at the District, he has worked as Director of Recharge Operations and as Senior Hydrogeologist. He has an undergraduate degree in Geology, a master’s degree in Hydrology from the University of Arizona. He is a Professional Geologist (PG) and Certified Hydrogeologist (CHG) in the state of California.

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GRA at the 60th Annual CESASC Convention by Yue Rong, GRA Director

RA was invited to speak at the 60th anniversary celebration of the Chinese-American Engineers and Scientists Association of Southern California (CESASC) on June 26, 2022. Founded in 1962 as a non-profit professional organization, CESASC has been promoting sciences and technologies among the American mainstream and the local minority community via its STEAM (science, technology, engineering, art, and mathematics) program. CESASC was recognized in “2019 Community Partner of the Year” by the Chinese American Elected Officials. Representing GRA, board member Dr. Abhishek Singh spoke at the daytime technical symposium on the subject of southern California water recycling and reuse. The presentation was an ‘eye opener’ to the audience, particularly to those who are not working in the water resources business. The message about the water resources conservation is very timely to current California drought conditions, particularly to grass water rationing implemented in Southern California. Dr. Singh also presented information about GRA and its mission, and spread the words to the local Chinese-American community. We thank Dr. Singh for his dedication and his own weekend time to speak at the conference.

Dr. Yue Rong (GRA board member, CESASC former president), Dr. Abhishek Singh (Speaker on groundwater resources, GRA board member), Dr. Wei Wu (Speaker on Robotics, USC professor), Dr. Yun Wang (Speaker on fuel cell for automobile, UCI professor), Dr. Liping Yan (CESASC former president), Dr. Jiachen Zhang (CESASC symposium panel moderator)

2022 Summer Issue

Dr. Yue Rong (GRA board member), Dr. Abhishek Singh (GRA board member), Moises Santillan (GRA Southern California Branch President)

YOUR FULL SERVICE MAR EXPERTS. From planning through operations, LRE Water is unique in our ability to provide comprehensive services related to MAR.

Cortney Brand, PG

Gary Gin, RG

Jackie Tappan, GIT

Lauren Handley, RG

Allan Foster, EI

Gary Burchard, RG

ROCKY MOUNTAIN | MIDWEST | SOUTHWEST | TEXAS 25

LREwater.com

2022 Summer Issue

Growing Groundwater Grief in the Emerald Rectangle by Todd Jarvis and Eddy Teasdale

he 2021-2022 drought continues to leave many well owners high and dry in the Klamath Basin, straddling the California-Oregon border. Water levels in wells, monitored by the US Geological Survey on both sides of the California-Oregon border have declined by 6 to 90 feet over the past 20 years, with sharp declines during the summer of 2021. Through funding provided by the Oregon Department of Human Services and support from the Klamath County and local irrigation districts, water supplies were trucked in and water tanks were provided to approximately 300 homes. The drought and related declines in available surface water led to studies by federal and state agencies of groundwatersurface water interactions in the borderlands to enable better understanding of groundwater pumping impacts to surface water availability during and following drought periods. The results indicated that a hydraulic connection exists between groundwater and surface water flows in some places and none in others, clearly indicating the need for site-specific studies to assess and quantify potential stream depletion due to pumping. The effects of groundwater pumping on streamflow depletion are predicted to last on the timescale of years to decades beyond the end of the current drought, indicating the need to better regulate pumping. However, in an effort to limit regulation, the predictive modeling analyses completed by state agencies have been challenged in Oregon courts by irrigators. The courts sided with state agencies, citing administrative law as opposed to technical arguments. Despite the water woes in the region, the cannabis industry

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is booming in northern California and southern Oregon. The legendary largest cannabis-producing region in the US of Humboldt, Trinity, and Mendocino Counties, the so-called “Emerald Triangle”, has morphed into the “Emerald Rectangle" as the cannabis industry has grown east into Siskiyou County, south into Lake County in California, and north into Josephine, Jackson, and Deschutes Counties in Oregon. Water use for cannabis has relied more on groundwater than surface water. The Cannabis Research Center at UC Berkeley reports well water use by cannabis farms is common statewide with more than 75 percent of permitted farms relying on groundwater. Many of the grows rely on wells located outside the boundaries of groundwater basins that are regulated by the 2014 Sustainable Groundwater Management Act (SGMA). In a recent study, a machine learning model suggested that 60 percent of unpermitted farms are likely using groundwater wells if they follow the same grow practices as the regulated industry. Groundwater use by cannabis cultivators represents an emerging threat to surface flows, so much so that Oregon has dedicated $5 million for oversight of water use and water rights. However, the cards are stacked against state regulators as the black market is estimated to approach over $2 billion in Oregon and approximately $8 billion in California. Conflicts related to cannabis and its associated groundwater use are manifold. Some farmers consider cannabis and hemp growing a blight to the identity of traditional agriculture. Despite cannabis legalization in 2014 by the state of Oregon, the tension between the black market and legal operations

Water use for illegal cannabis cultiviation is a media darling often referred to as "water theft", yet illegal water use could be extended to other cash crops. Rules and regulations are being developed to address when water is taken without prior approval because it clearly leads to conflict. Emerging conflicts focus on illegal use, but conflict in Siskiyou County, California surrounds how water is sold and transported to others who use it for cannabis grows. Lawsuits have been filed by residents in the Mount Shasta Vista community that allege groundwater depletion by cannabis growers. County ordinances have been passed that limit the quantity of water that can be hauled on county roads, which ultimately target the water purchaser.

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Combat hydrology may become a new niche of professional services.

remains in earnest. There are an estimated 1,000 illegal operations in a region of more than 4,000 square miles. However, detailed aerial mapping found 950 grows in an area less than 200 square miles in the Illinois Valley, of which 780 were illegal - a density 20 times greater. Illegal cannabis grows masquerading as hemp farms leased by unsuspecting landowners have led to land use violations in southern Oregon, costing landowners over $100,000 in fines. Water use practices by illegal operations is a challenge. The lack, as well as the use and misuse, of water data to support the regulation of groundwater management is a common source of conflict among scientists and engineers, and water use associated with cannabis and hemp is no exception. Water demand for cannabis and hemp is dependent on grow operations and irrigation practices . Indoor operations use an average of 121 gallons per square foot per year compared to outdoor facilities that average 11 gallons per square foot per year. Industry estimates of water used for cannabis cultivation in regulated settings varies from 5,000 acre-feet to approximately 14,000 acre-feet per year. Hemp and marijuana consume a fraction of the water consumed by cash crops like wine grapes, alfalfa, wheat, or corn. For example, a "joint" requires about 1 gallon of water while the water footprint of a glass of wine approaches 29 gallons. Closer to home, the water footrprint of California almonds averaged approximately 3 gallons per nut.

Additional consideration of cannabis regulations are in their infancy as Tribes enter the industry. Cannabis is grown and sold within their jurisdictions, and impacts to tribal water rights have become a concern. Within the expanding boundaries of the Emerald Rectangle, the Confederated Tribes of Warm Springs, Oregon and Elk Valley Rancheria in California serve as entrepreneurial leaders in the legal cannabis market. Groundwater is the preferred source for cannabis irrigation for legal and illegal cultivation in the Emerald Rectangle. As the phantasmagoric geometry and geography of cannabis and hemp farming continues to expand, the role of sustainablity of water resources, and in particular surface-groundwater interactions, will become a central focus. Combat hydrology may become a new niche of professional services. Eddy Teasdale has more than 25 years of experience, including 5 years in groundwater consulting with Luhdorff and Scalmanini Consulting Engineers. Currently, Eddy conducts and manages groundwater investigation, including groundwater resource and conjunctive use programs, and continues to support groundwater sustainability plan (GSP) implementation projects. He has worked in all major aquifer types (alluvial basins, volcanic, carbonate, and bedrock terrains). He is the president of the Northern Sacramento Valley GRA branch and is a member of the technical advisory committee for the Butte County Well Drillers Advisory Group. Eddy also teaches groundwater resources related classes for California State University, Chico, with a focus on groundwater management and development.

2022 Summer Issue

PFAS & Co-Contaminants by Jeff Hale, Jim Strandberg, Meeta Pannu, Raghavendra Suribhatla, Leila Saberi, Abhishek Singh

he last five articles in this PFAS HydroVisions series have summarized due-diligence, prevalence, release, source-types, monitoring, treatment, fate & transport modeling of per-and polyfluoroalkyl substances (PFAS). Part 6 of the series continues this discussion with focus on cooccurrence of PFAS with other contaminants, opportunities for building upon existing knowledge and implications for remediation. PFAS commonly occur in the presence of other environmental contaminants associated with related industries and activities. This association is exemplified by the California State Water Resources Control Board’s PFAS Investigative Orders, which required the investigation of PFAS at airports, landfills, chrome plating facilities, publicly owned treatment facilities, military installations, and petroleum refineries / bulk fuel terminals. Thus, when addressing PFAS contamination, it is important to consider the co-contaminant interactions, translatability of conceptual site models developed for other co-contaminants, and implications and synergies of prior and existing remedial measures for co-contaminants.

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CO-OCCURRENCE OF PFAS WITH OTHER CONTAMINANTS PFAS have been associated with multiple industries and commercial uses. As such, PFAS may occur in the presence of fuel hydrocarbons, metals, ethylene glycol, 1,4-dioxane, hexavalent chromium, chlorinated solvents (e.g., trichloroethene [TCE]) and volatile organic compounds [VOCs], among others) at several sites. Some examples follow. PFAS is used as a mist suppressant in the metal plating industry which is associated with hexavalent chromium and other metal contaminants. PFAS-containing aqueous film forming foam (AFFF) has been used where volatile petroleum products are used, stored, and refined. PFAS have also been identified in landfill leachate among numerous other contaminants known to occur in landfills, particularly 1,4-dioxane. In addition, PFAS from one source can potentially intersect contaminants originating from another, separate source(s).

TRANSLATABILITY OF EXISTING CONCEPTUAL SITE MODELS

COMPARISON OF PHYSICAL AND CHEMICAL PROPERTIES OF PFAS TO CO-CONTAMINANTS

Conceptual site models (CSMs) encapsulate the key physical and chemical processes controlling the fate and transport of contaminants from source to receptors, including hydrogeologic and geochemical controls. A CSM is typically used to identify data gaps specific to the contaminant through the site characterization process and to support remedial decision-making. Existing CSMs provide a good starting point for addressing PFAS contamination, as they may share key elements, including release history and site characteristics. For example, chlorinated solvents and PFAS may have the same source, similar groundwater migration pathways, and soilwater partitioning coefficients. However, for PFAS, additional elements must be considered when evaluating the adequacy of an existing CSM, including potential additional sources such as off-site releases, air emissions, leaching from soils, and surficial runoff; precursor transformation; retention in the vadose zone; impact of co-contaminants on PFAS sorption; past remediation activities; and potential additional receptors including biota.

Fate and Transport.

APPLICABILITY OF EXISTING MONITORING WELL NETWORKS Given that PFAS are typically retained in the vadose zone due to their surfactant property, soil and groundwater concentrations will vary with depth. As such, existing monitoring well networks capable of collecting depth-discrete samples are ideal for a detailed characterization. Additionally, redevelopment and/or multiple purges may be required to ensure samples are collected under low turbidity to obtain representative groundwater concentrations. Sampling frequency may also need to be adjusted to collect samples after precipitation events to evaluate potential leaching from soils, and infiltration of runoff containing PFAS.

Fate and transport of PFAS may be influenced by the presence of other contaminants. For instance, sorption of certain PFAS, such as PFOS, may be enhanced where the aquifer matrix is oil-coated due to the presence of non-aqueous phase liquids (NAPLs)1 . Such an example may occur in fire training areas where fuel hydrocarbons were ignited, and extinguished with PFAS-containing, aqueous film-forming foams. Other contaminants in the presence of PFAS may serve as proxy tracers for the migration of certain PFAS and can assist in differentiating the extent of a particular PFAS plume relative to background PFAS or co-mingled PFAS plumes. For instance, TCE released to groundwater from a source colocated with PFAS can encompass the expected nature and extent of PFAS. In this example, sorption of TCE is less than that of PFAS, leading to faster migration of TCE. In addition, TCE may occur as a DNAPL (dense non-aqueous phase liquid) with potential to penetrate deeper into the subsurface than would PFAS. Consequently, with similar release histories, TCE may be expected to circumscribe the extent of PFAS. Implications for Treatment and Remediation. Treatment and remediation strategies for PFAS will be influenced by co-contaminants present at a site, and technologies already being used at the site. • Granulated Activated Carbon (GAC) adsorption is a viable treatment technology for the removal of longchain PFAS but is less effective for short-chain PFAS. GAC removes co-contaminants like pesticides, nitrates, N-nitrosodimethylamine (NDMA) precursors2 as well as some chlorinated VOCs like TCE3. • Biochar is a carbon-rich porous solid synthesized by heating biomass. Biochar has been applied to removing organic contaminants and has shown potential for PFAS removal. • Air-sparging techniques to remove VOCs have had limited success with PFAS due to their low volatility. Sparging in turn may increase the mass of perfluoroalkyl acids (PFAAs) due to precursor transformation. • Incineration (destruction via combustion using heat) is one of the only technologies that can potentially destroy PFAS completely. Incineration of PFAS is currently an active area of research. • Remediation via pumping paired with appropriate above-ground treatment may be employed for multiple contaminant remediation.

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Ultimately, remediation of PFAS and co-contaminants may require a combination of multiple technologies for complete removal and destruction due to the potential for incomplete removal by a single technology. Co-contaminant Interactions. Co-contaminants can impact PFAS retention, mobility and potentially also transformation rates of precursors. Solid-phase sorption and air-water interfacial adsorption are known phenomena contributing to PFAS retention. In NAPL-contaminated source zones, significant PFAS sorption also occurs at the NAPL-water interface4. Conversely, the presence of PFAS as surfactants, may also impact the behavior of NAPLs in multiple ways. For instance, high PFAS concentrations (>100 mg/l) may result in changes to NAPL distribution through mobilization, and enhanced solubility. While such high PFAS concentrations have not been observed at legacy AFFF source-zone sites, they are relevant to new AFFF releases as well as for historicalrelease scenarios. Although the commonly known PFAS are relatively resistant to complete degradation, transformation of PFAS precursors to terminal products has been frequently reported in ambient environmental conditions. Currently, limited information is available regarding the effect of cocontaminants on PFAS transformation rates. References 1 Chen, H., Chen, S., Quan, X, Zhao, Y., and Zhao, H., 2009, Sorption of perfluorooctane sulfonate (PFOS) on oil and oil-derived black carbon: Influence of solution pH and [Ca2+], Chemosphere, v. 77, p. 1406-1411 2 David Hanigan, Jinwei Zhang, Pierre Herckes, Stuart W. Krasner, Chao Chen, and Paul Westerhoff. Adsorption of N-Nitrosodimethylamine Precursors by Powdered and Granular Activated Carbon Environmental Science & Technology 2012 46 (22), 12630-12639 DOI: 10.1021/es302922w 3 Kempisty DM, Summers RS, Abulikemu G, et al. Granular Activated Carbon Adsorption of Carcinogenic Volatile Organic Compounds at Low Influent Concentrations. J Am Water Works Assoc. 2020;1(2):10.1002/aws2.1128. doi:10.1002/ aws2.1128 4 qqVan Glubt, Sarah, and Mark L Brusseau. “Contribution of Nonaqueous-Phase Liquids to the Retention and Transport of Per and Polyfluoroalkyl Substances (PFAS) in Porous Media.” Environmental science & technology vol. 55,6 (2021): 37063715. doi:10.1021/acs.est.0c07355

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Jeffrey Hale, PGPA is the Practice Leader for Woodard & Curran’s Emerging Contaminants group. He provides consultation, strategy, and direction for challenging environmental and natural resources issues with emphasis on PFAS, emerging contaminants, complex sites, remediation, liability management, and environmental forensics. Manmeet “Meeta” Pannu, Ph.D., is a Senior Scientist in the Research and Development (R&D) 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 and managed aquifer recharge via in-situ adsorption and alternative methods to measure total PFAS in water samples. Leila Saberi, PhD is a Hydrogeologist at INTERA, LA, CA. Leila’s work focuses on groundwater flow and transport simulations using multi- and singlephase hydrological and reactive transport models including TOUGH, MODFLOW-MT3D, MODPATH, and MODFLOW-SURFACT. Additionally, she implements uncertainty and sensitivity analysis for model calibration and uncertainty quantifications in model simulations using tools such as PEST++ and PyEmu. The primary objective of these projects is to evaluate contaminant transport and seawater intrusion through the saturated and unsaturated zones to provide strategies for a comprehensive water quality and quantity management plan. Raghavendra (Raghu) Suribhatla, PhD, PE is a Senior Engineer and Technical Services Manager for INTERA’s California projects. He serves as modeling manager for water resources and recycled water projects in Southern California, and is the lead engineer for preparation of regulatory reports for seawater barrier projects in Los Angeles and Orange Counties. Jim Strandberg is a Senior Hydrogeologist/Project Manager at Woodard & Curran in Walnut Creek, CA. Jim is a member of the firm’s national emerging contaminants team and leads PFAS projects across the state.

Abhishek Singh, PhD, PE, is a Principal Engineer with more than 20 years of experience and is President of INTERA’s Water Resources & Supply Line of Business (LoB), where he leads and manages operations, business development, strategic planning for the lob across the United States. He has authored several technical publications and journal articles on groundwater modeling and calibration, stochastic optimization techniques, uncertainty and risk analysis, climate change, and emerging contaminants. Dr. Singh is also the chair of the GRA technical committee and serves on the GRA board of directors.

WAT E R B A N K I N G

uring times of emergency, leading to water supply disruptions, water banking projects provide important tools to augment supplies and safeguard customers from water shortages. This is accomplished by capturing low-cost water for recharge and underground storage during wet periods and recovering this water for later use during dry periods or emergencies. Irvine Ranch Water District’s water banking project, located in Kern County California, was established in partnership with the Rosedale-Rio Bravo Water Storage District. This project is engineered to provide enough water to replace IRWD’s imported water supplies during an emergency lasting up to 3 years. For more information visit IRWD.com/water-banking

2022 Summer Issue

WESTERN GROUNDWATER CONGRESS 2022

BUILT FOR CHANGE SEPTEMBER 19-21, 2022 | SACRAMENTO The 5th Annual Western Groundwater Congress will be September 19-21, 2022 at the Sacramento Convention Center & Hyatt Regency in Sacramento, CA. The theme for the Groundwater Resources Association's 2022 Western Groundwater Congress (WGC) is “Built For Change”. This year’s event will include Individual, Panel and Poster Presentations as well as Technical Workshops that cover the following subject areas: • Water Resources Exploration and Development • Groundwater Management • Contaminant Assessment and Remediation • Unique Challenges and New Opportunities Opening Keynote GRA’s Immediate Past President, Abigail Madrone, will be joined by previous Presidents and Board members from across GRA’s 30-year history, to explore how GRA has been “Built for Change” and how we’ve evolved with the groundwater industry since the organization was founded in 1992. We’re excited to announce that Vicki Kretsinger, Tom Mohr, and Brian Lewis - who were all charter members 30 years ago at the founding of GRA - will be panelists for our opening keynote session! Government and Public Agency Speakers We strive to make the WGC accessible and desirable for public agencies to participate and engage. We are excited to announce that we have 16 government and public agency speakers that will be present at the WGC to share their perspectives! 2022 Summer Issue

The agencies participating represent all regions of CA and include cities, utilities, state and federal agencies. The WGC program was built to ensure sessions have a diversity of speakers to facilitate dialogue between these public agencies and those representing the private sector, helping to build new and lasting connections across our industry. It is our hope that by building a program diverse in speakers and strong in public agency participation, attendees and speakers leave with a stronger understanding of the state and future of CA water resources management from the perspectives of project drivers, needs, and challenges - leading to new solutions and an industry that is truly Built for Change. • Zeno Levy, Jennifer Harkness - United States Geological Survey • Sierra Ryan - County of Santa Cruz • Yue Rong - California Regional Water Quality Control Board • Manmeet "Meeta" Pannu - Orange County Water District • Katherine Dlubac, Steven Springhorn, Ben Brezing, Chris Bonds - California Department of Water Resources • Scott Bradford - US Department of Agriculture - Agricultural Research Service, Sustainable Agricultural Water Systems Unit • Andy Campbell - Inland Empire Utilities Agency • Lisa Bilir - City of Palo Alto • Walt Delp, Gregory Norris - USDA Natural Resources Conservation Service • Edward C. Swaim - Bayou Meto Water Management District • Charles Johnck - Yuba Water Agency • Andrew Rich - Sonoma Water

Diversity, Equity, and Inclusion Sessions In 2020, GRA formed the Diversity, Equity, and Inclusion (DEI) Committee dedicated to improving DEI within GRA and groundwater communities throughout California and the western US. Throughout 2022, conversations and engagement on issues of inclusion and equity, diversity, and justice are being woven into all GRA events. This years’ 2022 WGC program will include a women in water workshop and a stakeholder engagement-focused track session. DEI focused workshop - Women Advancing Women for the Good of Water: Career and life lessons, perspectives, stories, and inspiration from current and emerging women leaders in water. Workshop description: This workshop will be facilitated by Abigail Madrone. The curated panel will be a combination of public and private sector emerging and established leaders. Following the panel discussion, break-out sessions will follow to facilitate more personal and safe dialogue amongst participants with GRA DEI Committee facilitators. Diversity, Equity, and Inclusion in Stakeholder Engagement Session Description: This session will be moderated and facilitated by Jena Acos. This session will feature a panel of speakers that will explore the overlap between increasing diversity in the water sector and meaningful stakeholder engagement and how these two goals can support each other. Following the panel discussion, the break-out sessions will follow to facilitate more focused dialogue amongst participants with panelists acting as facilitators.

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Parting Shot By John Karachewski

he University of California, Davis - Putah Creek Riparian Reserve is a 640-acre riparian and grassland ecosystem that runs along the southern edge of campus. Maintained and operated by the UC Davis Arboretum and Public Garden, the campus utilizes the Reserve for teaching and research purposes, wildlife and habitat protection, and community engagement. Most of the land is open to the public for recreational activities such as fishing, boating, swimming, and hiking. According to the State of California Wildlife Conservation Board, humans have removed, degraded, and disturbed 95% of California’s streamside habitat since the start of the Gold Rush (circa 1848). While the Reserve does have a history of disturbance and alteration by humans, this rare riparian ecosystem is being restored and now serves as inspiration for the ongoing Arboretum Waterway Maintenance and Enhancement Project. A brief history of the UC Davis Putah Creek Riparian Reserve is provided at: https://arboretum.sf.ucdavis. edu/blog/brief-history-uc-davis-putah-creekriparian-reserve. The history includes drought, habitat degradation, water rights, a non-profit group, lawsuits and a settlement, and a vision of a healthy environment and its value as a teaching resource. Prior to active management, the Reserve was a popular dump, illegal camping area, and destination for off-road recreational vehicles. Subsequently the university and many partners collaborated to establish the Reserve, build trails, remove invasive plants, reestablish native vegetation, and restore habitat.

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Prior to active management, the Reserve was a popular dump, illegal camping area, and destination for off-road recreational vehicles.

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Photographed by John Karachewski, PhD, from Pedrick Road bridge looking west into the Putah Creek Riparian Reserve on July 4, 2020. Photograph taken at 38.526765° and -121.803601°. Information for visiting the Reserve is available at: https:// arboretum.ucdavis.edu/putah-creek

2022 Summer Issue