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  California Water Science Center

Ground Water: Cycle I Activities (1991 - 2001)

Retrospective Analysis
The review and analysis of existing ground water-quality data provide a historical perspective on ground water quality in the Study Unit and are used to assess strengths and weaknesses of available information and to evaluate initial priorities for study design.

Reference:
Domagalski, J.L., 1997, Pesticides in surface and ground water of the San Joaquin-Tulare Basins, California: Analysis of Available Data, 1966 through 1992: U.S. Geological Survey Water-Supply Paper 2468, 74 p.



Ground Water Study Design

The study design for ground water focuses on assessing the water-quality conditions of major aquifers in the Study Unit with emphasis on the quality of recently recharged ground water associated with present and recent human activities. The sampling design is based on the need to examine ground-water quality at different spatial scales. Study-Unit Surveys are used, in conjunction with an analysis of available data, to broadly characterize ground-water quality across the Study Unit. Land-Use and Flow-Path Studies are done at intermediate and more local scales, respectively, to build an understanding of causal relations and processes. The Land-Use and Flow-Path Studies are directed, for the most part, toward the effects of human activities on ground-water quality. Low-Intensity Phase Sampling is intended to meet the objectives of trend assessment to identify, describe and explain current and future changes and trends in water quality.

Summary of ground-water sites with data on this web page: Site Information

References:
Gilliom, R.J., Alley, W.M., and Gurtz, M.E., 1995, Design of the National Water-Quality Assessment Program--Occurrence and distribution of water-quality conditions: U.S. Geological Survey Circular 1112, 33 p.

Koterba, M.T., Wilde, F.D., Lapham, W.W., 1995, Ground-water data-collection protocols and procedures or the National Water-Quality Assessment Program: Collection and documentation of water-quality samples and related data, U.S. Geological Survey Open-File Report 95-399, 113 p.



Study-Unit Survey

The Study-Unit Survey was designed to provide a broad assessment of the water-quality conditions of the most important present and future ground-water resources of the study unit. Instead of a regional-scale survey of ground-water quality covering the entire study unit, the Study-Unit Survey focused on the eastern alluvial fans, which account for most of the ground-water use in the study unit.

Map showing location of study unit survey sampling sites

Data collected:
Thirty domestic wells were sampled for major chemical constituents, nutrients, pesticides, volatile organic compounds, trace elements, and radon in 1995.

Selected data available for downloading:
Study-Unit Survey Wells:
Site information
Nutrients: view data | download data
Insecticides: view data | download data
Herbicides I: view data | download data
Herbicides II : view data | download data
VOCs I: view data | download data
VOCs II: view data | download data

Reference:
Burow, K.R., Stork, S.V., and Dubrovsky, N.M., 1998, Nitrate and pesticides in ground water in the eastern San Joaquin Valley, California: Occurrence and trends: U.S. Geological Survey Water-Resources Investigations Report 98-4040, 33 p.



Land-Use Studies
The purpose of the ground water Land-Use Studies was to assess the concentration and distribution of water-quality constituents in recently recharged ground water, and then to examine the natural and human factors affecting the quality of shallow ground water underlying various land uses. The Land-use Studies in the San Joaquin-Tulare Basins focused on the effects of three agricultural land uses: 1) wells located in vineyards were sampled in 1993, 2) wells located in almond orchards were sampled in 1994, and 3) wells located in areas which rotated corn, alfalfa, and vegetables were sampled in 1995.

Map showing location of land use survey sites

Data collected:
Twenty domestic and 10 monitoring wells in each land-use study were sampled for major chemical constituents, nutrients, pesticides, volatile organic compounds, trace elements, and radon.

Selected data available for downloading:

Domestic Wells located in Vineyards: (Site information) Monitoring Wells located in Vineyards: (Site information) Domestic Wells located in Almond Orchards: (Site information) Monitoring Wells located in Almond Orchards: (Site information) Domestic Wells located in areas which rotated corn, alfalfa, and vegetables: (Site information) Monitoring Wells located in areas which rotated corn, alfalfa, and vegetables: (Site information) Reference:
Burow, K.R., Shelton, J.L., and Dubrovsky, N.M., 1998, Occurrence of nitrate and pesticides in ground water beneath three agricultural land-use settings in the eastern San Joaquin Valley, California, 1993-1995: U.S. Geological Survey Water-Resources Investigations Reports 97-4284, 51 p.



Flow-Path Study
The primary objectives of the Flow-Path Study were (1) to characterize the spatial and temporal distribution of water quality in shallow ground-water systems in a particular land-use setting, and (2) to increase understanding of the natural processes and human influences. The Flow-Path Study of the San Joaquin-Tulare Basins was located on the Kings River alluvial fan in the eastern alluvial fan physiographic region.

Map showing location of the Flow Path Study in the San Joaquin basin
Data collected:
Twenty wells installed at 6 sites along an approximate ground-water flow path beneath the vineyard land-use setting were sampled in 1994-95 for major chemical constituents, nutrients, pesticides, volatile organic compounds, radon, transformation products of 1,2-dibromo-3-chloropropane (DBCP), and constituents used to estimate the date when ground water was recharged.

Selected data available for downloading:

Flow-Path Study Wells: (Site information) Reference:
Burow, K.R., Panshin, S.Y., Dubrovsky, N.M., VanBrocklin, David, and Fogg, G.E., 1999, Evaluation of processes affecting 1,2-Dibromo-3-Chloropropane (DBCP) concentrations in ground water in the eastern San Joaquin Valley, California: Analysis of chemical data and ground-water flow and transport simulations: U.S. Geological Survey Water-Resources Investigations Report 99-4059, 57p.


Low-IntensityPhase Sampling

Five wells of the Vineyard Land-Use Study were resampled in July of 1999, 2000, and 2001 as part of the low-intensity phase (1997- 2001). Major inorganics, nutrients and pesticides were analyzed for in all three years. Trace elements were analyzed for in 2001.

Site information
Major inorganics: view data | download data
Nutrients: view data | download data

Pesticide and trace element data not yet available


Alternate methods of obtaining data

NWISWeb Data for Nation: Online Searchable database of USGS data

NAWQA Data Warehouse: Online Searchable database of NAWQA data

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Page Last Modified: Tuesday, 14-Jun-2011 14:06:05 EDT