Laserfiche WebLink
r October 24,2001 <br /> Job Number: LG01-320 <br /> Page 4 <br /> available ground-water information collected for the site and nearby area. <br /> Table 2. <br /> Summary of Available Ground Water Information. <br /> Date,Description,Source Groundwater Depth Notes <br /> October 10,2001,one 17-foot,on-site soil Not encountered. No ground water found to a depth <br /> boring,Neil O.Anderson&Associates, of 17 feet. <br /> r Inc. <br /> Fall 1998,San Joaquin County Ground About 80 feet in depth. Ground water gradient 6.25 ft/mi <br /> r Water Map.Plates 2 and 4. flowing east to east-southeast <br /> Spring 1999,San Joaquin County Ground About 63 feet in depth. Ground water gradient 3.6 ft/mi <br /> Water Map.Plates 3 and 5. flowing southeast. <br /> r <br /> The existing on-site water well presently serves the residence on the property (Plate 1). <br /> No ground-water sample was collected from the well due to a problem with the well surface <br /> casing/seal as described by Mr. Ted Norgard R.E.H.S., SJC PHS-EHD. Mr. Norgard indicated <br /> that when the well is properly repaired and he is notified, we can collect a water sample from the <br /> r <br /> well and submit it to an analytical laboratory for DBCP and nitrate testing. <br /> The presence of nitrates and DBCP are not uncommon in shallow ground-water aquifers <br /> in San Joaquin County and other parts of the Central Valley. Nitrate in ground water originates <br /> from agricultural fertilizers, livestock waste, and untreated septic tank waste. Nitrate is mobile <br /> and often accumulates in the shallow ground-water zones. In the early 1900's, natural levels of <br /> r nitrate in ground water were measured in 43 wells throughout the Sacramento Valley by Bryan? <br /> It was thought that ground water at that time was close to "natural"conditions. Based on the <br /> work by Bryan, it is estimated that under natural conditions, groundwater concentration of nitrate <br /> r is no more than about 3 mg/L-N (that's about 13.5 mg/L as NO3). Areas having 5.5 mg/L-N <br /> (that's about 24.8 mg/L as NO3) or more are those in which nitrate concentrations may be <br /> increasing.3 <br /> r <br /> r, Z Bryan,K., 1923,Geology and ground-water resources of Sacramento Valley of California:U.S. <br /> Geological Survey Water-Supply Paper 495,285p. <br /> _ 3 Hull,L.C., 1984,Geochemistry of Ground Water in the Sacramento Valley,California:U.S.Geological <br /> Survey Professional Paper 1401-B. <br /> r <br /> rotaro <br /> 1 <br /> Y <br /> O `'1 <br /> �1r0� <br />