Laserfiche WebLink
C. Background <br />The ground water problem at Santos Ranch, high ground water table <br />and possible pollution and contamination of the drinking water supply <br />for approximately five hundred (500) people and an elementary school, <br />all located four (4) miles west of Tracy California, is probably due to <br />natural geological formations and hydrological conditions made worse <br />by three irrigation project canals, local irrigated agriculture and urban <br />development without adequate provisions or facilities for storm drainage <br />management, sewage treatment and disposal, water supply pumping, <br />storage and distribution and other adverse impactors to the community's <br />water supply. Soil formations below Santos Ranch and surrounding area <br />are apparently layered—clay, sand, clay, sand, clay, sand, etc. which <br />allows for relatively easy lateral movement of ground water. The ground <br />water gradient at Santos Ranch is relatively flat when considered from <br />a water basin stand point, particularly the area north and east of Santos <br />Ranch. From Santos Ranch to Old River, approximately 12,000' to the <br />northeast, the ground water gradient is probably not more than one half <br />of one percent (0.5' per 100' of horizaontal reach). It is the writer's opinion <br />that ground water northeast of the Upper Main Canal is in a pooled <br />configuration --it moves very slowly under natural conditions. <br />Five hundred (500) people could be expected to produce about 50,000 <br />gallons of sewage per day. This amount of liquid, plus water from <br />surrounding irrigated agriculture and canal seepage could severely <br />aggrivate the already high ground water table. Agricultural fertilizer, <br />large animal wastes and recirculated sewage water could provide the <br />source for increased Nitrates and T.D.S. found in the domestic water <br />supply. <br />Although undocumented, biological contamination could occur because <br />of less than adequate filter soil due to the high ground water table. This <br />potential health hazard should be investigated throughly, particularly <br />in light of the school well failing to meet biological standards. <br />-4- <br />