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' 0 ' Mountain House Storm Water Detention Basin Page 6 WKA No. 6504.05 October 7, 2005 the shallow wells ranged from 104.61 feet msl to 109.85 feet msl. The depth-to-groundwater in the deep well (MW4) was 19.89 feet bgs (98.25 feet msl). Groundwater elevations for each monitoring well are summarized in Table 1. Groundwater flow based on calculated groundwater levels in the shallow monitoring wells is to the northeast at a gradient of 0.01 feet/feet. 5.3 Site Groundwater Quality Conditions A summary of general groundwater quality conditions are presented in Table 3. Appendix D ' includes the laboratory report for the September 14, 2005 sampling event and a copy of the Chain-of-Custody. The data suggest that the quality of the groundwater sample collected from the deeper well (MW4) is lower than the samples collected from the shallow wells. ' 6.0 SUMMARY tGroundwater monitoring wells were installed on September 12, 2005 to obtain groundwater parameter monitoring data to support the design of the proposed storm water detention basin. ' Due to the fine-grained nature of the sediments encountered during well construction activities, an accurate depth of the groundwater table could not be determined. As a result, the deep monitoring well screen interval was installed to bracket first water, which was encountered at 59 feet bgs. The rationale for the screen intervals for the shallow monitoring wells was based on the approximate depth of excavation for the proposed storm water detention basin. The water levels in the shallow monitoring wells eventually stabilized at a depth ranging from 12.24 feet bgs to 16.20 feet bgs (104.61 feet msl to 109.85 feet msl) as determined during the September ' 14, 2005 monitoring event. Although the screen intervals for the shallow monitoring wells do not cross the groundwater table, the elevations measured in these wells can be used as an indication of the groundwater table at the site. WALLACE•KUHL R11"11d, ur &ASSOCIATES INC.