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• <br />contour maps from the District indicate that ground water is currently <br />first encountered at elevations of -10 to -20 feet MSL in the site <br />area. The flow gradient is regionally to the southwest. <br />Water -level data acquired by EMCON during this investigation indicates <br />that current water levels in wells in the area range from elevations <br />of -19 to -27 feet MSL (see Table 2). The local gradient is,very flat <br />over most of the area, but appears to be generally to the west- <br />southwest (see Figure 4). Actual local flow direction conditions are <br />believed to be influenced by seasonal pumpage of irrigation wells. <br />No springs were identified on site or within 1 mile of the proposed <br />landfill site. The area was inspected by examining aerial photographs <br />and searching for vegetation reflective of springs. <br />B. SITE HYDROGEOLOGY <br />Ground water is found in site wells (G-1, G-2, W-1, and W-2) at depths <br />ranging from 124 to 156 feet (see Table 2). Ground water underlying <br />the proposed landfill site occurs under unconfined or partially con- <br />fined conditions within gravelly or silty sands. Static water levels <br />in Wells G-1 and G-2 are higher than levels at which ground water was <br />first encountered during drilling, indicating some limited confine- <br />ment. Boring G-3 was not converted to a well due to (1) lack of a <br />readily recognized water table above a depth of 170 feet (borehole dry <br />overnight), (2) borehole instability, and (3) use of a mud -rotary <br />drilling system, which concealed or temporarily sealed off water - <br />bearing zones. <br />Depth to ground water beneath the base of the planned landfill ranges <br />from 96 to greater than 118 feet. Capillary rise is estimated to be <br />less than 5 feet. This estimate is based on data in Lohman (1972) <br />correlating the height of capillary rise with the grain size of <br />unconsolidated soil. <br />PJ9 9390206.00D 10 <br />