ARCHIVED REPORTS XR0011348 - Laserfiche WebLink

Home Browse Search

Geologwa(T'echnus Inc Page 3 Groundwater Monitoring Report {. Project No 425 2 August 12, 1999 ' Intermediate & Deep Wells The average groundwater elevation in the intermediate depth wells (MW-102, MW-105 & ' MW-107) was 72 59 feet above mean sea level The intermediate depth groundwater gradient was 0 0019 ft/ft flowing NWE The gradient in April 1999 is consistent with that of November 13, 1998 Table 2 of Appendix A summarizes the intermediate depth ' groundwater gradients and levels to date Table 2 also summarizes the groundwater level data from the deep well, MW-202 tFigure 2 is a map showing both the water table and intermediate groundwater gradients ' 1.1.2 Vertical Groundwater Gradients Vertical groundwater gradients were not calculated using MW-2 / 102 and MW-102 1 202 Floating product in MW-2 has prevented an accurate depth to water measurement for several monitoring events Vertical gradients were not calculated for those events This site has experienced both negative (downward) vertical gradients and positive (upward) vertical gradients Typically the negative vertical gradients are 175 to 2 times greater than gradients in a horizontal direction However, for April 28, 1999, the vertical gradients were positive at an order of magnitude greater than horizontal Refer to Table 3 of Appendix A for a summary of the vertical gradients calculated The groundwater elevation in MW-202 is 0 68 feet higher then the groundwater elevation in MW- 102 This indicates an upward flow of the deeper groundwater 1.2 Groundwater Sampling Procedure On April 28, 1999, Del-Tech Geotechnical Support personnel arrived on-site, opened the wells, and measured the depth to water with an electrically actuated sounding tape The water level reading was recorded to an accuracy of 0 01 foot In wells where free floating product was suspected, a clear disposable bailer was used to gauge the interface ' Stagnant water in the well casing was purged using a Centrifugal pump as recorded in the field logs (Appendix C) The rate of well purging was monitored The wells were purged of at least three casing volumes or until the groundwater parameters (temperature, conductivity, and pH) had stabilized (Appendix Q indicating that water, representative of actual aquifer conditions, was entering the well Groundwater parameter stabilization was characterized by ' three successive readings within 10% Before a sample was collected, the well's water level was allowed to recharge to at least 80% ' of its initial level All water removed from the monitoring wells and not used as a sample, t. was placed in a 55 gallon DOT (Department of Transportation 17-H) approved container that is properly labeled and temporally stored on-site i'