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c7afogua(rdotx Inc Page 2 ' Groundwater Monitoring Report Project No 724 2 . March 29,2005 1.0 GROUNDWATER MONITORING 1.1 Hydrogeology of Site The site's monitoring wells are screened through various levels of the aquifer as shown in Figure 13 The wells' construction details are indicated in Table 7 Horizontal Groundwater Gradients Due to there being monitoring well sets at three different depth intervals (water table, ' intermediate & deep), three different horizontal gradients were calculated, one for each interval The calculated gradients for the January 2005 monitoring event are as follows ' Water table wells screened 25 to 50 ft bgs 0 0071 ft/ft flowing S53°E Intermediate wells screened 42 to 64 ft bgs 0 0030 ft/ft flowing N50°E ' Deep wells screened 65 to 80 ft bgs 0 0042 ft/ft flowing N46°E* *MW-104 was not utilized for gradient determination due to deeper well screen(87 5—90') Figures 2, 3 & 4 show the respective gradient directions for the shallow, intermediate and Mdeep wells, respectively The data for well MW-104 are omitted in Figure 4 contours due the well's deeper screened interval, and monitoring wells MW-106 and MW-110 are not used for ' contouring in Figure 3 due to anomalous data Tables 1, 2 & 3 in Appendix A contain the historical groundwater elevations and gradients for the shallow, intermediate and deep wells respectively ' Figures 5A, 5B and 5C, Groundwater Gradient Rose Diagrams, illustrate the historical groundwater directions for the three respective horizons The groundwater direction was easterly for all three aquifer intervals for this monitoring event The average elevation of groundwater in the water table wells site was --24 43 feet MSL (below mean sea level) or approximately 39 1 feet below grade surface This elevation represents a decrease of 0 3 feet since the November 2005 monitoring event The water level has risen significantly at the site since October of 1992 when groundwater was—39 feet MSL The rose diagram included in Figure 5A shows that the water table groundwater gradients at this site are consistently towards the east In Figure 5A, arrows labeled 22 and above were measurements made after November 2000 Since additional wells were installed in November 2000, the groundwater direction has had a more southerly component suggesting that the earlier measurements were biased due to the spatial orientation of fewer wells The ' rose diagram included in Figure 5B shows that the intermediate aquifer gradients at this site have been consistently to the east for the last eleven events The rose diagram included in