JAMES M. THOMAS Research Professor Email: Jim.Thomas@dri.edu   Education Ph.D Hydrology / Hydrogeology University of Nevada, Reno M.A. Geology Indiana University, Bloomington B.A. Geology University of Vermont, Burlington

Professional Interests

Lake Tahoe clarity has been declining about 1 foot per year since the first clarity measurements in the late 1960’s. A major effort of my research has been providing decision makers and regulators with information to set policy on how best to restore Lake Tahoe clarity. This research includes nutrient and fine sediment loading to the lake from surface-water runoff and groundwater inflow to the lake. Research projects include evaluating the effectiveness of best management practices (BMPs), including both natural and engineered structures to remove fine sediment and nutrients from surface-water runoff. These studies also include (1) the evaluation of land use on runoff and the associated fine sediment and nutrient concentrations; (2) phosphorus adsorption on sediments beneath settling basins; (3) determining the source of fine sediments in watersheds with surface water flow into the lake.

My research in the Walker Lake basin focuses on the hydrology of the Walker Lake watershed including determining the hydrologic and dissolved salt budgets of Walker Lake. My research projects have also focused on groundwater flow to Walker Lake and groundwater flow and nutrient loading to Bridgeport Reservoir in the Walker Lake watershed. The Walker Lake basin is a unique internally drained watershed in the Great Basin of the western United States. The lake has no outlet, so the lake depends solely on surface water and groundwater inflow to maintain a hydrologic balance. Thus, the total dissolved salt (TDS) concentration of the lake depends on the amount of salt entering the lake from surface water and groundwater inflow and atmospheric deposition on the lake surface and the volume of water in the lake. Diversions of surface water in valleys upstream of Walker Lake for irrigation, beginning with the Bodie, California gold rush in the 1860’s when water was diverted to grow vegetables and beef for the nearby remote mining community, have resulted in the level of Walker Lake to steadily declined. The current volume of Walker Lake is about 80 percent of it’s volume in the 1800s. This dramatic reduction in lake volume has resulted in the lake salinity, TDS, increasing from about 2500 mg/l to 15,000 mg/l.

My research in southern and eastern Nevada has focused on regional groundwater flow system sources, travel times, and water budgets. The Death Valley flow system in southern Nevada and the White River flow system in eastern and southeastern Nevada encompass numerous valleys and hundreds of square miles with groundwater flowing beneath topographic divides and discharging at regional springs. Understanding the sources and amounts of groundwater in these regional flow systems and the time it takes groundwater recharged in mountainous recharge areas to flow to regional spring discharge areas is extremely important for water resource management in Nevada. Additionally, understanding the time involved in the potential radionuclide migration.

My research in West Africa has involved developing water supplies for rural villages in Ghana, Mali, and Niger. Rural villagers often lack a potable source of drinking water and non-potable sources of water often disappear during the dry season. Hand pumps are installed for village water supplies when successful wells are drilled. Developing reliable water supplies in rural villages also requires that the water is safe to drink. Water quality is a very important part of this project because high fluoride concentrations are often observed in the groundwater in these West Africa countries. This high fluoride, along with other trace elements such as arsenic, need to be treated to ensure that safe drinking water is being supplied to the villagers. Bacterial testing is also important to identify any wells with groundwater that is being contaminated from land surface sources so that the problem can be fixed.

JOURNAL ARTICLES

Coats, R; Gunter, M; Heyvaert, A; Thomas, J; Luck, M; 2008 (accepted).

Nutrient and sediment production, watershed characteristics and land use in the Tahoe Basin, California-Nevada. Journal of the American Water Resources Association.

Bohm, B.; Thomas, J.M.; Dahan, O.; Ralston, J.; Mckay, W.A.; 2007 (submitted).

Ground water chemistry evolution under unsaturated zone sulfate salt dissolution in a Great Basin lacustrine aquifer, western United States. Journal of American Water Resources Association.

Lutz, A.; Thomas, J.M.; Pohll, G.M.; Mckay, W.A.; 2007.

Groundwater resource sustainability in the Nabogo Basin of Ghana, West Africa. Journal of African Earth Sciences.

Winograd, I.J.; Fridrich, C.J.; Sweetkind, D.; Belcher, W.R.; Thomas, J.M.; 2005.

Comment on "Testing the interbasin flow hypothesis at Death Valley, California". American Geophysical Union, EOS. v.86. s.32. pp.294-297.

Dahan, O.; McGraw, D.; Adara, E.; Pohll, G.; Bohm, B.; Thomas, J.M.; 2004.

Multi-variable mixing cell model as a calibration and validation tool for hydrogeologic groundwater modeling. Journal of Hydrology. v.293. pp.115-136.

CONFERENCE ABSTRACTS

Carroll, Rosemary W.H.; Thomas, James; Sharpe, Saxon; 2007.

Water rights purchases using the current Walker Lake Total Dissolved Solid (TDS) model. Truckee River Symposium Headwaters to Terminus and Western U.S. Terminal Lakes: Research Needs for Policy Decisions. NWRA. Reno, NV.

Lutz, A.; Thomas, J.M.; Pohll, G.M.; Keita, M.; Apambire, B.; Mckay, W.A.; 2007.

Ground Water Resource Sustainability in the Bani Area of Mali. Albuquerque, New Mexico.

Sawyer, F.E.; Thomas, J.M.; Earman, S.; Carroll, R.; 2007.

Coupled mixing-cell and mass balance flowpath models of the Whiter River Flow System, Nevada. National Ground Water Association 2007 Ground Water Summit. Albuquerque.

Patterson, G.L.; Thomas, J.M.; 2006.

Carbon-14 groundwater analysis. Lawrence Berkley Laboratories.

Coats, R.; Gunter, M.; Heyvaert, A.C.; Thomas, J.M.; Luck, M.; Reuter, J.; 2006.

Water quality, watershed characteristics and land use in the Tahoe basin. Nevada Water Resources Association. Sierra Nevada College, Incline Village, Nevada.

Cablk, M.E.; Zhu, J.; Kratt, C.; Jasoni, R.L.; Young, M.H.; Thomas, J.M.; Arnone, J.A.; 2006.

Multi-scale remote sensing observations as a basis for estimating evapotranspiration across the eastern Great Basin Desert, Nevada, USA. AGU. San Francisco, CA.

Goddard, K.; Welch, A.; Thomas, J.M.; 2006.

BARCASS: An integrated, multi-agency hydrogeologic study of east-central Nevada. Nevada Water Resources Association. Mesquite, Nevada.

Bohm, B.; Thomas, J.M.; Dahan, O.; Ralston, J.; Mckay, W.A.; 2006.

Ground water chemistry evolution under unsaturated zone sulfate salt dissolution in a Great Basin lacustrine aquifer, western United States. American Geophysical Union. San Francisco, CA.

Sawyer, F.E.; Thomas, J.M.; Earman, S.; 2006.

A coupled mixing-cell and geochemical flow path model of the White River flow system, Nevada, USA. National Ground Water Association 2006 National Ground Water Summit.

Parra, A.; Stasenburgh, C.; Goldman, C.; Heyvaert, A.C.; Mihevc, T.M.; Thomas, J.M.; 2006.

Development of a long-term stormwater monitoring network for the Lake Tahoe Basin. NWRA. Lake Tahoe.

Sawyer, F.E.; Thomas, J.M.; Earman, S.; Carroll, R.W.; 2006.

Coupled mixing-cell and mass balance flow path models of the White River flow system, Nevada. American Geophysical Union Fall Meeting. San Francisco.

Lundmark, K.W.; Pohll, G.M.; Carroll, R.W.; Thomas, J.M.; 2006.

Regional Water Budget Accounting and Uncertainty Analysis Using a Deuterium-Calibrated Discrete State Compartment Model: White Pine County, Nevada, and Adjacent Areas in Nevada and Utah. American Geophysical Union. San Francisco, CA.

Thomas, J.M.; Deverel, S.; Decker, D.L.; Earman, S.; Mihevc, T.M.; Acheampong, S.; 2005.

Groundwater Evaporation From a Playa in Spring Valley, Nevada. American Geophysical Union Fall Meeting. San Francisco.

Patterson, G.L.; Thomas, J.M.; 2005.

Carbon-14 groundwater analysis. Lawrence Berkeley Laboratory.

Lutz, A.; Thomas, J.M.; Apambire, B.; Ayamsegna, J.; Mckay, W.A.; 2005.

Groundwater resource sustainability in the Nabogo Basin of Northern Ghana. San Antonio, Texas.

Ayamsegna, J.A.; Ampabire, W.B.; Thomas, J.M.; Lutz, A.; 2005.

Groundwater quality assessment, treatment, and monitoring in the Greater Afram Plains and northern region of Ghana. San Antonio, Texas.

Jones, T.; Thomas, J.M.; French, R.; Mihevc, T.M.; 2004.

Evaluation of effectiveness of three types of highway alignment BMPs for sediment and nutrient control. Crystal Bay, Lake Tahoe.

Complete Bibliography

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