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��$_��rt��.ERCUG$A'�'IOI�T�%�, , ■7T ��R�;� �■{:� � ��T�., �:�>3: ,,, t ,...' V� � Al Ave.i i M h �°° , )»^R33h�P" .-miiv pe 3�N�}4�.JT+ .L 1�JLON B 1�ST�t R�k3'�{ry$4`C 6@Y'w$ayl y■1/R/ :S 7,„,___g i� _ ,.,°...»w b..oAE..0 eec2k?i §E�.�c��se s6 as,z t4a� ,.•„Ag:�3 ,....zaa nes :�� 5�.>.,�$ - 42 INCH DEEP PERC 7.2 FOOT DEEP PERC �16 FOOT DEEP PERC RATE IN MIN/INCH .RATE IN MIN/INCH RATE IN MINIINCH INFILTRATION RATE IN CM/HR,CM/SEC ANp MIN/IN + 25 min/in 7.9 min/in 4.6 min/in 3.54 cm/hr,0.00098 cm/sec,43 min/in D. GROUNDWATER INFORMATION Groundwater depths and elevations are illustrated on maps published by the San Joaquin County FIood Control and Water Conservation District. The 2000 Lines of Equal Depth map illustrates the groundwater depth under the subject properties to be approximately 140 feet below grade. The Lines of Equal Elevation map show the groundwater to be at an elevation of-3 feet MSL and the directional flow to be southwest, which is the direction of flow of the Mokelumne River. The groundwater gradient, as determined by the Lines of Equal Elevation Map, is (0 to -10e groundwater ft/ft. Based upon studies with similar groundwater gradients, the velocity of the 7,920 = 0.00126 groundwater under the subject prope J p p rty can be roughly estimated to be the 60 feet/year. For comparison purposes, the Lines of Equal Elevation map of 1992 show the water table elevation to be -3 feet MSL. Therefore, the water table has dropped approximately six feet (3 feet to -3 feet) in the last decade. Groundwater elevation is important since there must be sufficient distance between the bottom of the proposed seepage pits and the highest anticipated depth to groundwater for sufficient treatment of the septic effluent to occur. This is generally accepted to be five feet in leachline trenches and ten feet in seepage pits. Obviously, a great distance exists between the seepage pits to be installed and the static water table depth. Unfortunately, no well Iogs were available from EHD of wells near the subject site, so the underlying lithology could not be examined. It is assumed there are clay strata down to the groundwater. Clay strata can have an attenuation effect on the nitrate concentration in underlying groundwater. GROUNDWATER ANALYTICAL TEST RESULTS A water sample was obtained for analysis from the water supply line to the IOOF building. This water originates from the single well that serves the town of Clements. As noted in the Table below, the underlying groundwater has a very low nitrate concentration of 5 ppm (as nitrate). Water analyses for the Clements well for the past 20 years is found in Appendix F and shows variability in the nitrate concentration over this period of time, although all tests results are below 5 ppm. These concentrations may be considered "background," or naturally occurring concentrations. Given the relatively recent vineyard plantings in this locale, monitoring of the nitrate concentration in this well over an extended period of time will prove interesting. Higher nitrate concentrations may occur many years from now given the intense vineyard plantings. 6 CF4sney Consu,(ilB