SR 06:208 - Laserfiche WebLink

The groundwater basin includes several aquifers consisting of water-bearing gravel layers separated by impervious clay layers. Directly under flat portions of the Planning Area sits the greatest amount of usable groundwater in the main water basin. Figure VII-2 shows the location of water resources in the Planning Area, including surface water resources and the main groundwater basin. See the Public Facilities Element for discussion of water supply, water storage, and water distribution along with related policies and programs. Water Quali(y Both Zone 7 and the City of Pleasanton have in place extensive water-quality mortitoring programs that they have continually updated and refined over the last decade. Neither agency has detected any significant levels of volatile organic compounds or contaminants in the water supply. In addition, Pleasanton's water quality has complied with all federal and State drinking water-quality standards. Although the City and Zone 7's water are both in compliance with all water-quality standards, some people consider the local groundwater to have lower quality water than surface-water resources. This is because local groundwater contains total dissolved solids averaging from 400 to 550 milligrams per liter (mg/l) and has higher amounts of naturally occurring minerals such as calcium and magnesium than water from other sources. Although these minerals are harmless at the levels present in the groundwater, after the winter months the summertime well water sometimes has a noticeable change in taste, odor, and/or washing characteristics. See Water Supply in the Public Facilities Element for additional discussion of water odor, taste, and hardness. Within the Planning Area, the Regional Water Quality Control Board has characterized the Arroyo de la Laguna, Arroyo de Las Positas, Arroyo del Valle, Arroyo Mocho, and Alameda Creek as impaired by diazinon14 Diazinon is a pesticide used on a variety of agricultural crops and formerly used on residential gardens and lawns. As of December 31, 2004, the EPA no longer pemllts its sale for non- agricultural uses. Diazinon is highly toxic to birds, mammal, honeybees and other beneficial insects, freshwater fish, and invertebrates. It affects plasma, red blood cells and brains in humans, especially children. In addition, diazinon is one of the top causes of bird-kill incidents. 15 Diazinon is a non-point pollutant within the Planning Area. Continued mortitoring for diazinon and other pollutants of concern should be performed to help define the non-source pollutant problems within the Planning Area. Water quality protection from diazinon can be achieved through source control and through increasing public education and the awareness of agricultural users. 14 Impaired surface waters are those which are known to not meet applicable Clean Water Act water quality standards or which require implementation of control programs to maintain compliance with applicable water quality standards. 15 US Environmental Protection Agency, hllpJL\1<yvw.cpa.govi$stici.dcsJopidiazinoni.s:ummat:y.htm. "Pesticides: Organophosphates," March 20, 2006. ('.on as EJement, CC 082906, dean VII-11 City Council 8/29/2006