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8820101-R COT-7 subsurface environment and the extent of soil and groundwater. f contamination. Recommendations .for additional investigative activities are given later in this ,report. H dro eolo ical Conditions The regional geology in the vici•nity of the site was described previously in the aforementioned Hydrotech report dated, .lanuary 7, 1988. Observations made during drilling revealed that silts and Silty clay dominate the subsurface in the southern portion of the site (i.e. Borings MW-1 and . MW-2) while sandy silt appears to prevail beneath the., northeasternportion of the site (MW-3). . A silty sand zone was encountered in Borings MW-1 and MW-2 at depths of approximately 20 to 30 feet and 20 to 25 feet, respectively. The location of the water table was difficult to determine during drilling. as only Boring MW-2 displayed obvious signs of groundwater at 'approximately 50.5 feet below grade. Groundwater in Boring MW-3, which was drilled first, was assumed to be at a depth of 43 feet due to the soils becoming moist at that depth. It was originally thought that the first groundwater 4 ' may actually be perched because the soils in MW_3 became-damp again at 47 feet. Due to the RFP specifying a maximum -well completion depth of 50 feet, the apparent water being located at 43 -feet, the absence of iobvious contamination in 'the soil samples 'and only 20 feet of extra wel� casing on hand, it was decided to complete, MW-3. at 50, feet. and extend the ' other two wells to a depth of 60 feet. The location of the water table in Boring M-1 was also very difficult to determine, as all so-il samples, E ' regardless of depth, appeared to have minimal moisture content (i.e. damp). No indications-of free groundwater were noted in any of the samples. ' - Determination of the groundwater gradient was precluded by the absence of groundwater in MW-3. It appears that the few inches of groundwater at the S 10