FIELD DOCUMENTS - Laserfiche WebLink

Home Browse Search

K L E I N F E L D E R 4 ACTIVITIES CONDUCTED ' On October 17 and 18, 2007 Kleinfelder measured water levels and collected groundwater samples from the existing onsite monitoring wells (MW-1 r, MW-2r, MW-6r, MW-25, MW-26, and MW-27), and the off-site upgradient monitoring well (MW-5). The information gathered was used to estimate the groundwater flow direction and gradient, and to evaluate the potential impact of former site operations to groundwater. Monitoring well MW-3r could not be located during this sampling event. ' 4.1. MEASUREMENT OF WATER LEVELS ' In order to assess the groundwater gradient at the time of sampling, water level measurements were made in each of seven monitoring wells. Plate 2 shows the locations of the groundwater monitoring wells. The water levels were measured prior to ' purging and sampling of the monitoring wells. The depth-to-water was measured in each well according to the protocol described in Appendix A, Section A-4.1. The depth- to-water measurements were then converted to relative groundwater elevations with ' respect to mean sea level by subtracting them from the surveyed casing elevations. The resulting groundwater elevations were used to develop groundwater contours and t to assess the groundwater flow direction and gradient at the time of sampling. This information was then used to assess which wells represent upgradient and which wells represent downgradient groundwater conditions. ' 4.2. GROUNDWATER SAMPLING ' Kleinfelder collected seven groundwater samples from six on-site wells and one off-site monitoring well. The wells were purged and sampled using disposable bailers and ' submersible pumps as described in Appendix A, Section A-4.2. The water purged from the wells was not contained. ' After collection, the groundwater samples were labeled, logged on a chain-of-custody, and immediately stored in an iced cooler. The seven samples were transported under chain-of-custody control to Kleinfelder's office and then transported by courier in a sealed container to Test America of Morgan Hill, California for chemical analysis. Test America is certified by the California Department of Health Services to perform the requested analyses. 20-3978-03.MN7/STOSR117 February 1,2008 0 2008 Kleinfelder Page 11 of 19