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1 <br /> 1 COMPUTATION SHEET <br /> 1 PROJECT TITLE: Harney Lane Sanitary Landfill PROJECT NO. 939-01.11 <br /> DESCRIPTION: Ground-water Flow Velocity SHEET 1F 2 <br /> PREP. BY: M Capps DATE: 8/31/92 CHKD BY: DATE: 3/ 5Z <br /> 1 <br /> SUMMARY AND CONCLUSIONS <br /> 1 Ground water flow velocity calculations are prepared on a quarterly basis using <br /> ground water level data collected during quarterly sampling events. <br /> 1 Ground water flow during the third quarter of 1992 was generally toward the <br /> southwest. The flow gradient was determined to be 0.0041 ft/ft and the average <br /> linear velocity was calculated to be 0.000122 cm/sec or 126.78 ft/yr. <br /> 1 <br /> 1 PURPOSE <br /> The calculations are prepared quarterly for quantification of ground water <br /> flow conditions in the water bearing zone beneath the site. <br /> 1 METHODS <br /> A ground water contour map is prepared using ground water elevation data obtained <br /> from water level measurements and top of well casing data. The hydraulic gradient <br /> is determined from the map. The flow velocity is calulated using Darcy's Law. <br /> SOURCES OF DATA& EQUATIONS <br /> 1 Ground water levels are measured during the sampling event. <br /> Top of well casing data has previously been surveyed to 0.01 ft. <br /> 1 Darcy's Law is a standard equation used in ground water velocity calculations. <br /> V = Ki/n <br /> 1 V= average linear velocity <br /> K= hydraulic conductivity (determined from slug test of MW-4) <br /> i= hydraulic gradient <br /> 1 n = porosity <br /> ASSUMPTIONS <br /> 1 K= 0.009 cm/sec determined from slug test conducted in G-1 <br /> Monitoring Well G-1 is located at North County Sanitary Landfill <br /> & monitors similar soils at the equivalent stratigraphic horizon <br /> 1 of Harney Lane monitoring wells. <br /> i= 0.0041 ft/ft <br /> 1 n= 0.3 from porosity values of similar geologic materials <br /> 1 <br /> me/h:HLQp1 <br /> 1 <br />