Westside Basin Groundwater Model

Over the last 7,000 years, tidal wetland conditions in the Sacramento-San Joaquin Delta has led to the formation of organic deposits, with plant material accumulating under anerobic conditions as sea levels rose. Subsidence of Delta land began in the late 1800s as wetlands were cleared and dewatered for agricultural practices on peat soils. This has led to a decrease in elevation to as much as -9 meters MSL, with islands protected by a vast network of man-made levees that are increasingly destabilized by subsidence.

Today’s Delta not only comprises hundreds of thousands of acres of farmland, but also provides a portion of the drinking water for nearly two-thirds of the California’s population. Subsurface processes – seepage and siphoned irrigation water recharge – dominate the subsided delta hydrology, and heightened levels of dissolved organic carbon (DOC) in irrigation drainage is a key water quality issue. Problematic DOC levels in Delta export waters arise due to disinfection byproduct (DBP) formation such as trihalomethanes (THMs). The connectedness of channel water, groundwater, and irrigation infiltration and drainage on Delta islands highlights the need for evaluating and mitigating water-quality problems associated with subsidence. Rice cultivation and transitioning land use back to a permanent wetland state are proven ways to mitigate subsidence.

Hydrofocus developed groundwater-flow and solute transport models in attempt to address the following questions related to subsidence and implementation of subsidence mitigation practices in the Sacramento-San Joaquin Delta: (1) How do the groundwater-flow and drainage systems interact to influence island drainage volumes and drain dissolved organic carbon (DOC) concentrations and loads?; (2) How will future subsidence affect drainage volumes, DOC loads, and seepage onto islands?; (3) How will land-use changes to mitigate subsidence affect seepage, drain flow, and DOC loads?; (4) How can seepage and water-quality effects from drainage, restoration, and rice cultivation in Delta islands be minimized?

This project answered the above questions by using pre-existing data and modelling, collecting additional chemical and physical data on Twitchell Island, and developing and refining groundwater flow and solute transport models. Data was collected on three areas of the island. Drain flow, groundwater level, and aquifer-parameter data were collected from wells and drainage ditches in 2000 – 2003, and 2009 – 2013, and analyzed for inorganic and organic constituents. Steady-state and transient groundwater-flow models were developed using concepts and data from a conceptual model from Deverel et. Al (2007) for processes that result in temporal and spatial variability in DOC and THMFP drain loads. Subsidence-mitigation effects were simulated using a solute-transport model (MT3DMS) coupled with the groundwater-flow models for (1) present-day practice with subsidence and sea-level rise, and (2) seven alternative land-use scenarios. Model simulation results suggest that water quality concerns are alleviated through hydrologic controls (e.g. maintaining higher groundwater levels in drainage ditches to near the land surface for wetlands and rice) to minimize export of DOC and DBPs.

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Marc Olds - Resumé

Qualifications

Marc joined HydroFocus in May of 2019. Before that, he worked with the USGS California Water Science Center. On the HydroFocus team, Marc primarily assists with the development of hydrologic models, water quality analysis, and subsidence evaluation. His specialties include GIS, data management, and programming solutions.

Marc holds a Bachelors of Science in Hydrology from the University of California, Davis. Marc is currently working towards a Masters of Science in Soil Science at UC Davis focusing on the development of advanced tools for soil classification.

Professional Experience

2019 to present

Assistant Hydrologist, HydroFocus, Inc. Davis, California.

Nick Christen - Resumé

Qualifications

Nick Christen’s background is in meteorology and climate science. He holds a Bachelor of Science degree in Earth Science from San Francisco State University. His undergraduate research there included statistical analysis of high-resolution precipitation model forecasts and simulations. In 2018, he joined the HydroFocus team where his focus includes biometeorology and quantification of greenhouse gas (GHG) fluxes and net ecosystem carbon balance of systems. He has over six years of experience collecting, processing and analyzing field data and procuring high quality datasets. Other areas of his work include developing maps in ArcGIS Software, digital imagery analysis, groundwater and land surface elevation measurements, and water quality data collection.

Professional Experience

2024 to Present

Ecosystem Scientist, HydroFocus, Inc. —Davis, CA

  • Deploy and maintain eddy-covariance towers for micrometeorological monitoring
  • Quantify net ecosystem carbon balance related to land use studies in the Sacramento-San Joaquin Delta and Northern California
  • Collect, process, and analyze field data
  • Utilize Geographical Information Systems to create maps for project field sites and well monitoring reports
  • Design, build, and test custom gas chambers for gas measurements in various ecosystems

 

2021 to 2024

Associate Ecosystem Scientist, HydroFocus, Inc. —Davis, CA

2018 to 2021

Hydrolocal Technician, HydroFocus, Inc. —Davis, CA

2017-2018

Data Analyst, StormGeo Shipping — Sunnyvale, CA

  • Data processing, customer service, and software support for ship routing weather display software on board vessels and in client offices

Academic Background

  • Bachelor of Science, 2016, Earth Science, San Francisco State University.

Thesis title: Statistically evaluating high-resolution model precipitation forecasts and simulations in the San Francisco Bay Area

 

Resumé

Steven Deverel - Resumé

Qualifications

Steven Deverel has over 30 years of hydrologic problem-solving experience in the western United States.  Dr. Deverel analyzes groundwater systems, quantifies chemical and physical processes in soils and groundwater, and evaluates groundwater- and surface-water quality.  He is a registered Professional Hydrologist certified by the American Institute of Hydrology, a California licensed Professional Geologist and a Texas licensed Professional Geoscientist.

Dr. Deverel:

  • Conducts surface and groundwater quality assessments.
  • Develops models to evaluate water movement and solute transport.
  • Quantifies chemical and physical processes in the saturated and unsaturated subsurface.
  • Applies statistical techniques to analyze land and water resources.
  • Determines water sources using geochemical and age-dating techniques
  • Evaluates subsidence and subsidence mitigation

Professional Experience

February 1996 to present

Consulting Hydrologist in Private Practice and Principal Hydrologist and co-founder, HydroFocus, Inc. since January 1998—Davis, CA

Recent example experience includes the following.

  • Hydrologic analysis and modeling of proposed development. 
  • Groundwater hydrologic and quality analysis related to agriculture.
  • Expert witness for groundwater contamination litigation which includes extensive data collection and groundwater flow and solute transport modeling.   
  • Provided expert testimony in Delta island flooding litigation on subsidence-related causes of levee failure.
  • Geochemical analysis and groundwater and heat flow modeling of stream aquifer interactions in agricultural watersheds in northern California. 
  • Evaluation of subsurface flow and seepage.  Used water isotopes and modeling to determine effects, rates and nature of leakage.
  • Evaluation of groundwater supply, flow and quality in relation to land and water management practices in various locations in California.
  • Evaluation of processes affecting water quality—Sacramento-San Joaquin Delta.  Field data collection and modeling to estimate organic carbon, mercury and salt load for different wetland and agricultural water management practices.
  • Measurement and modeling of subsidence in the Sacramento-San Joaquin Delta.
  • Consulting hydrologist for agricultural coalitions in the Central Valley, California.
  • Evaluation of subsidence mitigation strategies—Sacramento-San Joaquin Delta, California.  Field data collection and modeling to evaluate water quality effects (including mercury) of different wetland management strategies for stopping and reversing the effects of subsidence.

1994 to 1996

Senior Hydrologist, Hydrologic Consultants, Inc.—Davis, CA

Consulting assignments included the following:

  • Evaluated sea water intrusion, nitrate contamination and flow of groundwater and nitrate movement in unsaturated zone—Salinas Valley, California.   
  • Analyzed water supply and quality issues—Santa Ynez Valley, California.
  • Developed water resources element of city General Plan—City of Lompoc.
  • Advised California Department of Water Resources on issues relating to subsidence in organic soils—Sacramento-San Joaquin Delta.
  • Quantified geochemical processes and groundwater flow for gold mining operations—northern Nevada.

1991 to 1994

Supervisory Hydrologist, U.S. Geological Survey—Sacramento, CA

Assistant District Chief: Guided hydrologic research, investigations and data collection programs throughout California:

  • Supervised and planned research of land- and water-management effects on subsidence and carbon fluxes—Sacramento-San Joaquin Delta.
  • Facilitated interactions among diverse projects and personnel.
  • Developed and maintained projects investigating processes affecting land and water resources.
  • Communicated research results to the resource management community and other audiences using published reports and oral presentations.
  • Established long range research and data collection activities.
  • Responsible for over 100 employees and an annual budget of over $11 million.

1984 to 1991

Research Geochemist, U.S. Geological Survey—Sacramento, CA

Project leader: Directed studies of processes affecting constituent mobility and transport.  Evaluated transport processes in aqueous and gaseous phases.  Conducted regional, subregional and local scale studies.  Guided an interdisciplinary team that integrated multi-scaled data:

  • Defined water and solute movement to agricultural drainage systems.
  • Identified processes affecting trace element mobility in soil and water.
  • Evaluated and implement statistical methods.
  • Directed hydrologic study of water quality, carbon fluxes and subsidence in organic soils—Sacramento-San Joaquin Delta:
    • Identified processes affecting subsidence.
    • Related carbon fluxes from organic soils to subsidence and global carbon balance.
    • Developed water and land management strategies for reducing subsidence.
    • Determined water management effects on drainage water quality.

Academic Background

  • Ph.D., June 1983, Soil and Water Science, Department of Land, Air, and Water Resources, University of California at Davis
  • Bachelor of Science, December 1979, Agricultural Science and Management, University of California at Davis
  • Instructor, “Ground-water Solute Transport Concepts”, USGS Denver Training Center, 1988-1993
  • Lecturer, Department of Land, Air, and Water Resources and Associate in the Experiment Station, University of California at Davis, 1988-1992
  • Post-graduate dissertation, thesis and oral examination committee member for University of California, Davis Hydrologic Sciences graduate students, 2001-present

Professional Affilications

  • American Geophysical Union
  • American Institute of Hydrology - registered Professional Hydrologist
  • California Groundwater Resources Association
  • International Association of Hydrogeologists

Relevant Publications

Vadose-Zone Hydrology, Biogeochemistry and Subsidence

Deverel, Steven J.; Bachand, Sandra; Brandenberg, Scott J.; Jones, Cathleen E.; Stewart, Jonathan P.; & Zimmaro, Paolo. 2016. Factors and Processes Affecting Levee System Vulnerability. San Francisco Estuary and Watershed Science, 14(4). jmie_sfewss_33460. Retrieved from: http://escholarship.org/uc/item/36t9s0mp

Deverel, Steven J., Ingrum, T., Lucero, Cl, and Drexler, J.Z., 2014, Impounded Marshes on Subsided Islands: Simulated Vertical Accretion, Processes, and Effects, Sacramento-San Joaquin Delta, CA USA. San Francisco Estuary and Watershed Science 12(2). jmie_sfews_12893. http://escholarship.org/uc/item/0qm0w92c.

Jaclyn A. Hatala, Matteo Detto, Oliver Sonnentag, Steven J. Deverel, Joseph Verfaillie, Dennis D. Baldocchi, 2012, Greenhouse gas (CO2, CH4, H2O) fluxes from drained and flooded agricultural peatlands in the Sacramento-San Joaquin Delta, Agriculture, Ecosystems and Environment , 150,1-18.

Cathleen Jones, Gerald Bawden, Steven Deverel, Joel Dudas, Scott Hensley, 2011, Characterizing land surface changes and levee stability in the Sacramento-San Joaquin Delta using UAVSAR  radar imagery, IGARSS2011 Proceedings

Deverel, S.J. and Leighton, D.A., 2010, Historic, recent and future subsidence, Sacramento-San Joaquin Delta, California, USA, San Francisco Estuary and Watershed Science, 8(2)  http://www.escholarship.org/uc/item/7xd4x0xw

Drexler, Judith Z., de Fontaine, Christian S., Deverel, S.J., 2009, The legacy of wetland drainage on the peat resource in the Sacramento-San Joaquin Delta, California, USA, Wetlands, 29, 372–386

Deverel, S.J., Thomas, J., Decker, D., Earman, S. and Mihevc, T, 2005, Groundwater evaporation estimates using stable isotope and chloride data, Yelland Playa, Spring Valley, Nevada, Desert Research Institute Division of Hydrologic Sciences, DHS publication 41219

D.A. Cohen, S.J. Deverel, L.A. Johnson, 1998, Feasibility Study of Differential SAR Interferometry for Subsidence Monitoring  in the Sacramento-San Joaquin Delta, IGARSS'98 Proceedings , pp1629-1631

Deverel, S.J., Wang, Bronwen and Rojstaczer, S.A., 1998, Subsidence in the Sacramento-San Joaquin Delta, in (Borchers, J.W., ed.) Proceedings of the Joseph Poland Subsidence Symposium, Association of Engineering Geologists, Special Publication No. 8, Star Publishing, Belmont, California, pp. 489-502.

Deverel, S.J., Rojstazcer, S.A. 1996, Subsidence of agricultural lands in the Sacramento-San Joaquin Delta, California:  Role of aqueous and gaseous carbon fluxes, Water Resources Research, 32, 2359-2367.

Rojstazcer, S.A. and Deverel, S.J., 1995, Land subsidence in drained histosols and highly organic mineral soils of California, Soil Science Society of America Journal, 59:1162-1167.

Rojstaczer, S.A. and Deverel, S.J., 1993, Time dependence in atmospheric carbon inputs from drainage of organic soils, Geophysical Research Letters, 20, 1383-1386.

Fio, J.L., Fujii, R. and Deverel, S.J., 1991, Evaluation of selenium mobility in soil using sorption experiments and a numerical model, western San Joaquin Valley, California, Soil Science Society of America Journal, 55, 1313-1320.

Rojstaczer, S.A., Hamon, R.E., Deverel, S.J. and Massey, C.A., 1991, Evaluation of selected data to assess the causes of subsidence in the Sacramento-San Joaquin Delta, California, U.S. Geological Survey Open File Report 91 -193.

Fujii, Roger, Deverel, S.J. and D.B. Hatfield, 1988, Distribution of selenium in soils of agricultural fields, Western San Joaquin Valley, California, Soil Science Society America Journal, 52, 1274-1283.

Deverel, S.J., L.D. Whittig and K.K. Tanji, 1986, Sulfate reduction and calcium carbonate equilibria in a Central California histosol, Soil Science Society of America Journal, 50, 1189-1193.

Tanji, K.K., and Deverel, S.J., 1984, Simulation modeling for reclamation of sodic soils, in  Soil salinity under irrigation-processes and management, Shainberg, I., and Shalhevet, J., eds., Springer-Verlag, Berlin

Groundwater Geochemistry and Quality

Deverel, S.J., Goldberg, S. and R.  Fujii, 2012, Chemistry of trace elements in soils and groundwater In Tanji et al (eds) Agricultural Salinity Assessment and Management Manual, American Society of Civil Engineers. Manual 71, 2nd edition.

Deverel, S.J., Leighton, David A. and Finlay, Mark R., 2007. Processes Affecting Agricultural Drainwater Quality and Organic Carbon Loads in California's Sacramento-San Joaquin Delta. San Francisco Estuary and Watershed Science. Vol. 5, Issue 2 (May), Article 2. http://repositories.cdlib.org/jmie/sfews/vol5/iss2/art2

Deverel, S.J., Fio, J.L., Dubrovsky, N.M., 1994, Distribution and mobility of selenium in groundwater in the western San Joaquin Valley of California in Selenium in the Environment, Benson, S. and Frankenburger, W. (eds).  Marcel Decker, New York.

Dubrovsky, N.M., Deverel, S.J. and Gilliom, R.J., 1993, Multiscale approach to regional groundwater quality assessment: selenium in the San Joaquin Valley, California in Regional Ground-water Quality (Alley, W.M, editor), Van Nostrand Reinhold, New York.

Deverel, S.J. and Fio, J.L., 1991, Groundwater flow and solute movement to drain laterals, western San Joaquin Valley, California. I. Geochemical assessment, Water Resources Research, 27, 2233 - 2246.

Deverel, S.J. and R.  Fujii, 1990, Chemistry of trace elements in soils and groundwater In Tanji et al (eds) Agricultural Salinity Assessment and Management Manual, American Society of Civil Engineers.

McNeal, J.M., Feder, G.L., Wilbur, W.G. and Deverel, S.J., 1990,  Environmental concerns related to selenium in the Western United States in   Proceedings of a U.S. Geological Survey Workshop on Environmental Geochemistry (Doe, B.R., ed.) U.S. Geological Survey Circular 1033.

Deverel, S.J. and S.P. Millard, 1988, Distribution and mobility of selenium and other trace elements in shallow ground water of the western San Joaquin Valley, California, Environmental Science and Technology, 22, 697-702.

Deverel, S.J. and Roger Fujii, 1988, Processes affecting the distribution of selenium in shallow groundwater of agricultural areas, Western San Joaquin Valley, California, Water Resources Research, 24, 516-524.

Fujii, Roger and S.J. Deverel, 1988, Mobility and distribution of selenium and salinity In groundwater and soil of drained agricultural fields, western San Joaquin Valley, California: In Jacobs, L.W. and others (ed.), Selenium in Agriculture and the Environment: American Society of Agronomy, Madison, Wisconsin, Special Publication no. 23, pp. 195-212.

Deverel, S.J., Gilliom, R.J., Fujii, Roger, Izbicki, J.A., and Fields, J.C., 1984, Distribution of selenium and other inorganic constituents in shallow ground water of the San Luis Drain Service Area, San Joaquin Valley, California: A preliminary study, U.S.  Geological Survey Water Resources Investigation Report 84-4319.

Deverel, S.J., 1985, Selenium in the San Joaquin Valley of California In 1984 National Water Summary, U.S.G.S. Water Supply Paper 2275.

Statistics

Deverel, S.J., 1989, Geostatistical and principal-component analysis of ground-water chemistry and soil-salinity data, San Joaquin Valley, California, In   Ragone, S. (ed.) Regional characterization of water quality, International Association of Hydrologic Sciences Publication no. 182  pp. 11-18.

Millard, S.P. and S.J. Deverel, 1988, Non-parametric statistical methods for comparing two sites based on data with multiple non-detect limits, Water Resources Research, 24, 2087-2098.

Ground Water Hydrology

Deverel, S.J. and Gallanthine, S.K., 1989, Distribution of salinity and selenium in relation to hydrologic and geochemical processes, San Joaquin Valley, California, Journal of Hydrology 109, 125-149.

Deverel, S.J., 1988, Geohydrologic aspects of water-quality problems of the San Joaquin Valley, California, Proceedings on Planning Now for Irrigation and Drainage, Irrigation and Drainage Division, American Society of Civil Engineers, Lincoln, Nebraska, July, 1988 pp. 694-699 (invited paper).

Fio, J.L. and Deverel, S.J., 1991, Groundwater flow and solute movement to drain laterals, western San Joaquin Valley, California, II. Quantitative hydrologic assessment, Water Resources Research, 27, 2247 - 2257.

Fio, J.L. and Deverel, S.J., 1990, Interaction of shallow ground water and subsurface drains: Implications for selenium transport and distribution in the western San Joaquin Valley, Groundwater, 28,788-789.

Sustainability

Deverel, Steven J.; Bachand, Sandra; Brandenberg, Scott J.; Jones, Cathleen E.; Stewart, Jonathan P.; & Zimmaro, Paolo, 2016. Factors and Processes Affecting Delta Levee System Vulnerability. San Francisco Estuary and Watershed Science, 14(4). jmie_sfews_33460. Retrieved from: http://escholarship.org/uc/item/36t9s0mp

Deverel, Steven J.; Lucero, Christina E.; & Bachand, Sandra. 2015. Evolution of Arability and Land Use, Sacramento–San Joaquin Delta, California. San Francisco Estuary and Watershed Science, 13(2). jmie_sfews_27914. Retrieved from: http://escholarship.org/uc/item/5nv2698k

Deverel, S.J., 2012, Impacts of irrigation in California, USA and relevance for the Brazilian semi-arid region (in Portuguese), ITEM, Irrigação e Tecnologia Moderna, Publication of the Brazilian Association of Irrigation and Drainage

 

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