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ppb MTBE Groundwater samples collected from monitoring well MW-11 contained 910 ppb ethanol and 059 ppb 1 ,2-dichloropropane Groundwater samples collected from monitoring well MW-12 contained 380 ppb TPH-G, 58,000 ppb ethanol, 066 ppb 1,2-dlchloropropane, 1 3 ' ppb PCE and 056 ppb chloroform For groundwater samples collected from monitoring wells screened below ' 100-feet bgs, groundwater samples collected from monitoring well MW-8 contained 1 8 ppb MTBE, 9 8 ppb ethanol and 1 3 ppb 1 ,2- I dlchloropropane Groundwater samples collected from monitoring well MW-10 contained 3,900 ppb TPH-D and 72 ppb TBA ' The only compound detected in groundwater samples collected from the drinking water well was 20 ppb 1,2-dichloropropane 9 . 0 GROUNDWATER ELEVATIONS AND FLOW ' The ground surface elevation and top of casing elevation of each new groundwater monitoring well and piezometer was surveyed relative t o mean sea level (msl) by Farley Surveying, Inc of Stockton, California o n April 15, 2000 The northing and casting location of the wells a n d piezometers were surveyed relative to the California Coordinate System The benchmark used for this survey was the USGS M1164-1960 brass cap ' at the southeast corner of Airport Way and West Yosemite Avenue The survey information is presented in Appendix G Depths to groundwater were measured in each well prior to sampling o n March 16, 2000 with an electric water level sounder Depth t o ' groundwater measurements are presented in Table Four, and groundwater elevation (potentiometric surface) contours are plotted on Figures 10, 1 1 and 12 On March 16, 2000, groundwater in the shallow zone (less than 19-feet bgs) appeared to flow primarily to the northwest beneath the site at a gradient of approximately 0 012-feet/foot If the anomalous high water level in piezometer P-4 and anomalous low water level i n piezometer P-5 are disregarded, the potentiometric surface will show an even more obvious flow to the northwest at a very flat gradient of 0 0007- feet/foot Groundwater in the 55 to 70-feet bgs zone flowed to the east at a gradient of 0002-feet/foot Potentiometric surface contours for the deeper zone (below 100-feet bgs) could not be plotted because three non- linear points in this zone would be required for contouring Potentiometric surface measurements in locations with monitoring wells screened at multiple depths (MW-5 and MW-11, monitoring wells MW-1 and MW-12, monitoring wells MW-6, MW-7 and MW-8, and monitoring Franks One Stop Report — May 2000 -12-