ARCHIVED REPORTS_MONITORING WELLS INSPECTIONS, REPAIR AND REDEVELOPMENT REPORT

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1 1 �. sands and begins at the surface in areas not covered with fill. These materials appear to extend throughout the main body of Parcel III, and were encountered in borings MW-1, MW-4, B-2, B-3 and B-7 (Figures 4 and 5). The maximum recorded thickness of this zone was seven feet at the location of MW-4 (Figures 4 and 5). The fine grained materials are dry, primarily light brown to brown in color, 1 and commonly encountered with iron oxide staining, trace percentages of mica, and small diameter angular to subangular gravels. This zone grades into a brownish gray low plasticity silty clay with black y mottling and iron oxide staining along the eastern portion of Parcel III (Figures 4 and 5). 1 Underlying the sandy silt/silty sand zone is a dark gray, soft, moist, medium to high plasticity clay. This clay appears continuous throughout the main body of Parcel III and was encountered in borings MW-1, MW-4, B-7, B-3, and B-2 (Figures 4 and 5). The clay was also encountered in all borings and monitoring wells in adjacent Parcels I and R. However, this clay was not encountered along the conveyor easement in borings B-4 through B-6 which were advanced to a maximum depth of 10 feet bgs. The maximum recorded thickness of this clay is six feet at the location of B-3 (Figure 5). This clay commonly exhibited a peaty odor and contains trace amounts of organic material and hard white J' concretions. This clay zone grades into a sequence of silty clay and clayey silt interfingered with isolated lenses of silt and sand (Figures 4 and 5). The capillary fringe was generally encountered near the transition of this clay zone and the sequence of underlying materials. Total depth of the hand auger • borings occurred within the upper few feet of the transition between the clay zone and the underlying R materials (Figure 5). ' The zone comprising the sequence of materials underlying the clay zone is laterally discontinuous. -' The groundwater table extends into this zone. None of the monitoring wells installed during this investigation were advanced beyond this zone. This zone is predominantly brown micaceous silty clay and clayey silt. Discontinuous lenses of brown micaceous sandy clayey silt and gray micaceous sand are inter-fingered within this zone. 3.2 HYDROGEOLOGY _ The baseline investigation identified one saturated zone beneath the site. The zone is of varying lithology and appears continuous across the site. The zone appears unconfined and represents the water table beneath the site. The water table is encountered at approximately 12 feet below ground surface. The total thickness of the saturated materials was not determined during this investigation. • SAC28.013 December 20, 1991 6 J nr:_S .,._air.