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gsokgica!Technics Inc. Page 2 Groundwater Monitoring Report " y Project No. 662.2 January 27,2004 l 1.0 GROUNDWATER MONITORING r, 1.1 Hydrogeology of Site i � I The dominant soil type:in the upper 40 feet of the subsurface geologic soils investigated is sand, fine to course grained, interbedded with thinner units of plastic clay. The average groundwater elevation on November 21, 2003 was approximately 10.21 feet above MSL, which is about 29 feetbelow ground surface. This represents a decrease of 0.32 feet since the August 20, 2003.monitoring event. This is the lowest recorded groundwater elevation in the investigation and the'water table has fallen 6.16 feet since the February 2003 monitoring event. �1 A groundwater gradient was calculated for the event and the groundwater was found to flow S75°E at 0A013 ft/ft. Groundwater elevation and gradient data are summarized in Table 1, Appendix A. Gradient, direction is shown on Figure 2: Gradient Map, and Figure 3: Groundwater Gradient Rose Diagram: 1.2 Groundwater Sampling Procedure f On November 21, 2003, Don Light of Del-Tech mobilized to the site to conduct a groundwater monitoring of the four monitoring wells on site. I Before sampling was performed the wells were sounded for depth to water and then a clear disposable bailee was used to.determine if floating product was present. The wells were purged"of at least three well volumes of stagnant water using a dedicated Waterra check-ball f assembly and '/2 inch tubing. .Purging continued until'the temperature, conductivity, and pH of the groundwater stabilized (c10% variation between three readings) indicating that formation water representative of aquifer conditions was entering the well's. These water I quality parameters were measured at intervals of each well volume purged. Once purging was complete, a water sample was collected from the Waterra tube. Care was taken to minimize sample agitation. Once the sample container was filled and capped, the bottle was inverted, tapped, and checked for headspace bubbles. The sample container was identified and labeled with a unique designation, inserted into foam holders and placed in an ice chest cooled to 4°C for transport to the laboratory. All non-di d s osable sampling,equipment was decontaminated using a hot water washer and detergent before and between uses. Disposable gloves were used by the technician to collect all samples and were changed with each sample collection. f f E