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f # ' r- i# 5 RM WIN I'd P Julian Munoz WEISSASSOCLSTES 15 October 1487 11 Based on the flow rates during well development, anticipated flow rates for wells MW-1. MW-2 and MW-3 are 0.3-0.5, 3-4 and 5-6 gallons per minute (gpm), respectively. The low flow rate seen in MW-1 may be due to silting of the annular space adjacent to the screened interval in this well. Flow rates of MW-2 and MW-3 are within expected ranges for the soil type screened in these wells. Water removed from the wells was directed to a 10,000-gallon tank temporarily stored at the site. Since analytic results (discussed below) for the ground water samples were below detection, the development water that was temporarily stored in the 10,000 gallon tank was discharged to the storm sewer system. Water Sam2ling and Analysis Water samples were collected from the wells within 2 hours of the end of development. Samples were collected in steam-cleared teflon bailers and were then decanted into 40-ml glass vials. The vials were immediately sealed with a teflon-lined cap, labeled and refrigerated until delivery under I cht;in-of-custody procedures to B&C. Water samples were analyzed at B&C for TFHC by CC/FID and for BTX by EPA Method 602, gas chromatography/photo ionization detection (GC/PID). Analytic results for samples from all three wells were below the detection limits of 1 ppm for TFHC and 0.5 ppb for BTX. Copies of laboratory analytic reports are included in Attachment C. GROUND WATER GRADIE14T Top-of-casing (TOC) elevations for monitoring wells were surveyed by Nick Clayton-.._..of_....PL..._.on__.25...Augusti. 1987. The datum elevation for the survey was the _......_ centerpoint of the storm sewer manhole located 15 ft north of the tank pit excavation. A USGS topographic map of the Stockton West guadrange indicates that the elevation of this manhole is approximately 7 ft above mean sea