Laserfiche WebLink
E. Summary <br /> Based on BOD and hydraulic loading rates, 246 acres will have to be available <br /> for land treatment and disposal of daily wastewater discharges of 1 .5 million <br /> gallons. A total of 540 acres will be made available for the 1990 and future <br /> seasons. An additional 836 acres is under consideration for use after the <br /> 1990 season. <br /> IV. WATER QUALITY IMPACTS <br /> A. Groundwater Monitoring Wells <br /> QAP had a geotechnical consulting firm install three groundwater monitoring <br /> wells in 1985m. At that time it was determined that the local water table <br /> was about 70 ft below the ground surface. Well borings were terminated at <br /> about 90 ft. Results of analyses of well water samples are regularly sub- <br /> mitted to the RWQCB in compliance with order 88-094. During the 1989 season <br /> the water table in the monitoring wells dropped leaving them muddy during the <br /> later part of the harvest season". Current data does not indicate any <br /> declines in groundwater quality as a result of Q.A.P. operations . <br /> B. Sal inity`6' <br /> The local stratigraphy divides the components of the upper aquifer system into <br /> two units. The shallow groundwater which is impacted directly by the waste- <br /> water disposal operation already has a relatively high concentration of salts <br /> due to the agricultural practices of the area. Based on the regional average <br /> groundwater gradient it appears that the shallow groundwater will be only <br /> slightly affected by QAP irrigation practices. The primary source of ground- <br /> water for domestic, municipal and industrial uses is the preferred aquifer in <br /> the Laguna formation. This aquifer is not impacted directly by the percolate <br /> derived from irrigation. Hydraulic continuity between the shallow groundwater <br /> and the underlying groundwater in the Laguna formation is diminished by the <br /> presence of a region of low hydraulic conductivity separating the two. <br /> Evidence for the existence of an aquitard -comes from well log data. In <br /> addition water quality data indicates that groundwater in the Laguna formation <br /> is isolated from the shallow groundwater. Due to the local stratigraphy and <br /> regional geohydrology the land disposal of wastewater from the plant does not <br /> appear to significantly impact groundwater quality. Table 3 summarizes the <br /> differences in water quality with depth for nitrates and salinity. <br /> 6 <br /> RP050-L <br />