Professional Experience

July 2001 - present

Hydrologist, HydroFocus, Inc., Davis, CA

• Numerical modeling to evaluate the effects of land retirement on groundwater levels and drainflow - Western San Joaquin Valley, California.
• Data collection and analysis of groundwater and water quality conditions related to subsidence mitigation strategies - Sacramento-San Joaquin Delta, California.
• Data collection and analysis of groundwater and surface water conditions related to agricultural reuse of treated wastewater - Ironhouse Sanitary District, Oakley, California; City of Lathrop, California.
• Numerical modeling and Geographic Information System support for a regional groundwater-flow model of the Westside Basin - San Francisco and San Mateo Counties, California.
• Use water quality characteristics to determine water sources - Nevada County, California.
• Estimate future land subsidence using a Geographic Information System - Sacramento-San Joaquin Delta, California.

1987-2001

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

• Conducted groundwater modeling investigations with emphasis on the use of Geographic Information Systems to manage model input data and display model output.
• Integrated Geographic Information Systems into projects including database creation, data analysis, and map creation.
• Performed duties of Geographic Information System Coordinator for the California District of the U.S. Geological Survey which included representing the District on Geographic Information System matters, responding to requests for spatial data and information, and acting as a resource to co-workers.
• Collected and compiled geohydrologic and water-quality data.
• Evaluated and interpreted data using Geographic Information Systems, statistical, and other appropriate analytical methods to determine hydrologic conditions and develop an understanding of groundwater-flow systems.
• Wrote technical reports describing study results and performed peer review of reports written by colleagues.

1985-1987

Hydrologic Technician, U.S. Geological Survey, Sacramento, CA

• Conducted geohydrologic and groundwater quality investigations - western San Joaquin Valley, California.
• Directed development of a regional Geographic Information System database - South San Francisco and Peninsula Area, California.
• Directed data collection, database development, data analyses, and report writing.
• Constructed groundwater-flow models - western San Joaquin Valley and South San Francisco Bay areas, California.

Academic Background

Bachelor of Science, 1982, Forest Resource Management, Humboldt State University, Arcata, California

Awards and Honors

U.S. Geological Survey Performance Award: 1987, 1988, 1989, 1990, 1993, 1998, and 1999

Relevant Publications

Groundwater-Flow Modeling

Leighton, David A., and Phillips, Steven P., 2003, Simulation of groundwater-flow and land subsidence in Antelope Valley, California: U.S. Geological Survey Water-Resources Investigation Report 03-4016, 118 p.

Hydrogeology of the San Francisco Bay Area

Fio, John L., and Leighton, David A., 1995, Geohydrologic framework, historical development of the ground-water system, and general hydrologic and water-quality conditions in 1990, south San Francisco Bay and Peninsula area, California: U.S. Geologic Survey Open-File Report 94-357, 46 p.

Leighton, David A., Fio, John L., and Metzger, L.F., 1995, Database of well and areal data, South San Francisco Bay and Peninsula area, California: U.S. Geological Survey Water-Resources Investigation Report 94-4151, 47 p.

Geochemistry, Salt Migration, and Water Quality

Deverel, Steven 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 2007]. Article 2.

Fio, John L., and Leighton, David A., 1994, Effects of ground-water chemistry and flow on quality of drainflow in the western San Joaquin Valley, California: U.S. Geological Survey Open-File Report 94-72, 28 p.

Leighton, David A., Deverel, S.J., and Macdonald, Janet K., 1992, Spatial distribution of selenium and other inorganic constituents in ground water underlying a drained agricultural field, Western San Joaquin Valley, California: U.S. Geological Survey Water-Resources Investigation Report 91-4119, 73 p.

Monitoring

Carlson, Carl S., Leighton, David A., Phillips, Steven P., and Metzger, Loren F., 1998, Regional water table (1996) and water-table changes in the Antelope Valley Ground-Water Basin, California: U.S. Geological Survey Water-Resources Investigations Report 98-4002, 2 sheets.

Kerr, Barry D., and Leighton, David A., 1999, Extensometer, water-level, and lithologic data from Bacon and Bethel Islands in the Sacramento-San Joaquin Delta, California, September 1987 to August 1993: U.S. Geological Survey Open-File Report 98-631, 12 p.

Leighton, David A., and Fio, John L., 1995, Evaluation of a monitoring program for assessing the effects of management practices on the quantity and quality of drainwater from the Panoche Water District, Western San Joaquin Valley, California: U.S. Geological Survey Open-File Report 95-731, 25 p.