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I Gealagiral%cluctcsl�u Page 2 Groundwater Monitoring Report Project No 724 2 February 13, 2006 The data continues to indicate that the plume appears to extend to the east of the site It is not known whether or not contaminated properties to the northwest of the site may be contributing to the groundwater plume This possibility is being investigated by installing CPT (cone penetrometer testing) bonngs to the east of the subject site Four CPT borings were installed on January 10 - 12, 2006 and a report on this work is forthcoming I 1.0 GROUNDWATER MONITORING 1.1 Hydro Bolo y of Site g g ' 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 November 2005 monitoring event are as follows Water table wells screened 25 to 50 ft bgs 0 0022 ft/ft flowing S79°E Intermediate wells screened 42 to 64 ft bgs 0 0036 ft/ft flowing N78°E Deep wells screened 65 to 80 ft bgs 0 0021 ft/ft flowing S74°E* 'BMW -104 was not utilized for gradhent deternunation 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 range of groundwater flow directions for the three respective horizons The groundwater flow direction was northeasterly or southeasterly for all three aquifer intervals for this monitoring event ' The average elevation of groundwater in the water table wells site was -22 41 feet mean sea level (msl) This elevation represents a decrease of 1 13 feet since the August 2005 ' monitoring event ' 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