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APPENDIX G <br /> GROUNDWATER DIRECTION AND FLOW RATE CALCULATIONS <br /> The groundwater monitoring network consists of seven monitoring wells and a piezometer. Two <br /> water-bearing zones are monitored. To monitor the shallow,perched aquifer,MW-4, MW-5, SB-1 <br /> and PZ-1 are used. Well SB-1 was originally installed to provide additional water level data. SB-1 <br /> was added to the monitoring well network on December 2, 1996. Piezometer PZ-1 was added July <br /> 30, 2003. Water elevations taken at these four points are used to define the direction and gradient of <br /> groundwater flow in the vicinity of the Corral Hollow Sanitary Landfill. The average groundwater <br /> velocities in this water bearing zone were calculated using the following equation(Darcy's Law): <br /> V= Ki <br /> n <br /> V=maximum linear velocity <br /> K=permeability <br /> i =hydraulic gradient <br /> n =porosity <br /> K= 8.1 lx 10-5 centimeters per second(cm/s) <br /> = 83.69 feet per year(ft./yr) <br /> i =0.0054 foot per foot (ft/ft)northwesterly <br /> i = 0.0069 foot per foot (ft/ft)southwesterly <br /> n =0.30 <br /> The northwesterly groundwater flow velocity of 1.51 ft/yr from well SB-1 to MW-5 was calculated <br /> as follows: <br /> V= 83.69 ft/yr(0.0054 ft/ft) = 1.51 ft/yr <br /> 0.30 <br /> The southwesterly groundwater flow velocity of 1.94 ft/yr from well SB-1 to MW-4 was calculated <br /> as follows: <br /> V= 83.69 ft/yr(0.0069 ft/ft) = 1.94 ft/yr <br /> 0.30 <br /> The hydraulic conductivity was determined with a slug test in well MW-4 to be 8.11 x 10-5 cm/s in <br /> the perched water-bearing zone beneath the landfill. The hydraulic gradient in the northwesterly <br /> direction was calculated by dividing the difference in groundwater elevations between contour lines <br /> 231.5-ft and 230.5-ft by the distance between lines measured in the direction of groundwater flow <br /> (280 feet). An average porosity value of 0.30 was used,based on published porosity values for <br /> similar geologic materials. <br /> The deep water-bearing zone is monitored by wells MW-1,MW-2,MW-6 and MW-7. Wells MW-1 <br /> and MW-2 were dry. MW-6 and MW-7 were installed this quarter and water elevations were used <br /> to calculate groundwater flow and generate a groundwater contour map. The average groundwater <br /> velocity was also calculated using the equation based on Darcy's law: <br /> Corral Hollow Landfill G-1 Department of Public Works/Solid Waste <br /> 4T"Qtr/Annual 2003 Groundwater Monitoring County of San Joaquin-January 28,2004 <br />