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Gealog i al Teckntcs IHC Page 2 Groundwater Momtormg Report Protect No 724 2 May 17, 2004 iflow component of shallow groundwater gradient were mixed for this quarter Well pair MW-41104 exhibited a downward flow that is consistent with past events ' Nine new monitoring wells were installed at the site in December 2003 and this report details the inclusion of these wells into the quarterly monitoring schedule The data from these new wells indicate that the plume appears to extend to the east of the site It is not known whether or not contaminated properties to the northeast of the site have contributed to the groundwater plume 1 1.0 GROUNDWATER MONITORING 1 1A Hydrogeology of Site The site's monitoring wells are screened through various levels of the aquifer as shown in Figure 14 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 March 2004 monitoring event are as follows "AC-fWater table wells screened 25 to 50 ft bgs 0 007 ft/ft flowing S63°E Intermediate wells screened 42 to 64 ft bgs 0 002 ft/ft flowing S80°E ti ^+ —Deep wells screened 65 to 80 ft bgs 0 002 ft/ft flowing S84°E* $t *M W-104 not❑tili7ed for gradient detennmation due to deeper well screen(87 5—90') Figures 2, 3 & 4 show the respective gradient directions for the shallow, intermediate and deep wells, respectively The data for well MW-104 are omitted in Figure 4 contours due the well's deeper screened interval 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 to the east-northeast for all three aquifer intervals for this monitoring event ' The average elevation of groundwater in the water table wells site was –21 95 feet MSL (below mean sea level) or approximately 37 feet below grade surface This elevation ' represents an increase of 1 17 feet since the November 2003 monitoring event The water level has risen significantly at the site since October of 1992 when groundwater was –39 feet MSL 1