SU0002694 SSNL - Laserfiche WebLink

Home Browse Search

Water analysis: The water table elevation varies from approximately 30 fejt above sea level at the south cast corner of the site to approximately 0 feet above sea level at the north west corner of the site. The depth to the water table from the surface increases from south to north. The depth being approximately 95 feet below the surface at the south east corner of the site to a depth of approximately 130 feet at the north west corner of the site.The ground water gradient is to the north west. This information was taken from data published by the San Joaquin County Flood Control And Water Conservation District titled Groundwater Report, Fall, 1994. The water quality varies slightly in the area,as referenced from water sample results at appendix IlI- A-D. Water sample test results that were taken near the site and at the site read as follows: Location: Sample# Test: Nitrate TDS Abandoned domestic well at site- TV] 13 mg/L 224 mg/L DW#I at sit,first test- TV2 13 mg/L 192 mg/L Abandoned irrigation well- TV3 13 mg/L 224 mg/L Domestic well,ECK Ranch, south west to the site and water gradient relative.to the site- TVW-1 9 mg/L 256 mg/L Domestic well, to Ranch, north east to the site and water f gradient relative to the site- TVW-2 I 1 mg/L 356 mg/L Domestic well,Taro Ranch, upgradient to the site TVW-3 13 mg/L 237 mg/L DW#i at the site,second test- TVW-4 13 mg/L 218 mg/L OID irrigation well, downgradient to the site- TVW-5 10 mg/L 154 mg/L The water quality changes only slightly as it travels under the facility,reference water sample TVW-3 1 to the TVW4 sample,appendix I11-13. Note that the water at the OID irrigation well has a slightly better test results. This could be due to extensive pumping which is drawing from high quality upgradient water which in turn dilutes the nitrates and TDS contents. Based only on the test results from six wells and the fact that we are not sure what depths from which the water samples have been collected,it is impossible to conclude with any degree of accuracy the source of the contaminates that are affecting the water quality. There are three major artificial water influences to the water table in the area: { First, there are a number of rice fields.They have a constant head of water during the summer growing season forcing elements down into the soil profile. Considering that there is no appreciable wet-dry cycle during the rice growing season and the constant wetting of the soil from winter rains,there is a constant flow of surface water penetrating into the water table. Consequently,any mobile elements, including nitrate,will be carried down to the water table given long periods(years)to farming rice. Second;the Farmington Reservoir. This body of water is approximately I mile to the north east,north cast gradient to the site,and at the same water table elevation contour line. This force of water into the upper aquifer will influence any plumes in the down gradient direction to travel faster and wider than naturally. Third;the Woodward Reservoir_This body of water is approximately 2 miles upgradient from the site. It will have a greater influence to the shallow aquifer that passes under the site. Considering the potential i permeability rate in the area,there can be as many as 35,000 acre feet of water that percolates into the ground water.This force of water into the upper aquifer will also influence any plumes in the down gradient direction to travel faster and wider than naturally This soil analysis is based on criteria from the Agricultural Waste Management Field Handbook, fart 651,and Sail Survey of San Joaquin County, California. e Western Design/David Avila I999 13