ARCHIVED REPORTS_1981 - Laserfiche WebLink

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drawn from the Arroyo -Seco, Laguna and Mehrten formations. The groundwater obtained from these formations is continually being recharged by percolation from surface waters which originate in the Sierra Nevada or adjacent foot hills. Based on information in the San Joaquin County Conservation Element, the site is located in an area of none to slight recharge. In the shallower bore holes drilled to define the hydrogeologic setting at depths extended to 110 feet below the present ground surface or _about Elevation five feet below sea level (U.S.G.S. Datum) no perched water condi- tions were observed. The deeper exploration drill hole intercepted ground- water at 137 feet below the present ground surface or about Elevation 32 feet below sea level (U.S.GS . Datum). Water level was also measured in an adjacent well across from the western property boundary and was found to be at approxi- mately 30 feet below sea level. Seasonal groundwater measurements are compiled by the San Joaquin County Flood Control and Water Conservation District. These seasonal measurements indicate well water levels in the study area at between Elevation 20 to 30 feet below sea level. During the last five years, water table elevation has decreased approximately ten feet in the general area and this is average for the County. Predominant groundwater movement, determined by these seasonal measurements, is from northeast to southwest. The groundwater in the eastern portion of San Joaquin County is almost without exception of excellent quality for all present beneficial uses. The total dissolved solids content of water sampled from irrigation wells ranges from 120 to 550 parts per million and averages about 200 parts per million. In general, the domestic wells analyzed were found to contain water conforming to the standards for chemical substances in drinking water set by the U.S. Public Health Service. The nearest wells with groundwater quality data available are located on and near the existing Harney Lane Landfill site, approximately one mile west of the proposed site and northeast of the site near the corner of Kettleman Road and Clements Road. Groundwater sampled from four wells in the area of the existing Harney Lane site in 1980 are_ included in the following Table. Water quality was also sampled from the exploration drill hole (TW -1) which intercepted groundwater and further substantiates that underlying groundwater is of potable quality (see Table 5). To summarize the data shown in Table 5, groundwater beneath the site is of excellent quality and suitable for domestic use without special treat- ment. ,20