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The land surrounding QAP has never been irrigated by water from surface sources. Groundwater has been the exclusive source of irrigation water supply. Plans have been prepared to obtain more surface water for the entire county (2) to offset overdraft of the groundwater basin. However, it is unlikely that surface sources will come on line anytime soon. Present Irrigation Practices at QAP Figure 2 shows the area presently irrigated with wastewater from the plant. Fields 1, 2 and 3 are in permanent pasture. The Bozzano and Alpine fields have mixed field crops with a small section of walnuts. Wastewater is blended with fresh water prior to application to the land. Dilution of wastewater prior to application is carried out for a number of reasons including cooling, adjusting overall pH levels, improving solids distribution and meeting irrigation quantity requirements. The ratio of fresh water to wastewater is not constant. On average, approximately 350,000 gallons of wastewater per day are blended with 100,000 gallons of fresh water prior to being applied to the permanent pasture in fields 1, 2 and 3. The permanent pasture totals 42 acres and is cared for by QAP personnel . The pasture is cut and baled three to four times per year. Average yield per cutting is two tons per acre. The 42 acres of pasture have been recently converted from surface irrigation to a sprinkler system to conform to the new operating plan. The use of sprinklers for wastewater application may reduce or eliminate the need for dilution in the future. The Alpine and Bozzano fields which together comprise 126 acres are operated by private farming concerns. Wastewater is discharged to these fields only at their regular irrigation interval . Full flow from the plant is directed to these fields whenever irrigation is in progress. Surface irrigation is practiced in the Alpine and Bozzano fields. Consequently, the ratio of fresh water to wastewater is much higher because of the greater overall water requirements for surface irrigation. In the Bozzano field dilution ratios vary from 4 to 9 parts of fresh water to one part wastewater. This would correspond with the addition of approximately 1 .4 to 3.15 million gallons of fresh water to 350,000 gallons of wastewater on a daily basis when water is diverted to the Bozzano field. The Alpine field may be switched to sprinkler irrigation next season, in which case it would be operated in a manner similar to fields 1, 2, and 3. GROUND WATER HYDROLOGY General Figure 3 shows the general geohydrology for eastern San Joaquin County. The Halocene alluvium and Pleistocene era sediments labeled as the Victor formation are evident in the well logs for the monitoring wells included in the appendix. The Victor formation is heterogeneous in outcrop and in the subsurface. It is generally coarser grained than the underlying Laguna formation. Groundwater 1-3 RP033-L