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I1 III 1 The soil and groundwater results from MW-1 adjacent to the former gasoline UST indicated nondetectable levels of hydrocarbons in the shallow ,oil and groundwater As a consequence, no remedial action is scheduled at this time in thus area 2.0 SITE DESCRI;TION The UST excavation is in rear of the DPC facility as shown on the Site Map (Figure 2) The yard restroom which is currently unused is approximately four feet north of the excavation as shown, on Figure 3 The excavation was partially backfilled with soils from the original UST excavation and is presently open to an average depth of three feet The DPC. yard around the excavation is a covered by a asphalt pad A soil berm has been placed around the excavation to reduce surface water flow into the excavation Soil stockpiled from original excavation are located as shown on Figure 2 and are placed on plastic and are covered with plastic One monitoring well and two piezometers are located near the excavation as shown on Figure 3. Overhead power lines run to the north of the restroom Buned water and sewer lines also run to the plant from the restroom All subsurface structures are shown on Figure 3 A site health and safety plan is included as Appendix A Prior to excavation, buried utilities will be marked by the Plant Manager Soils in the shallow zone consist of a silty sand with some areas of coarse sand and gravel Water depth at the time of UST removal was approximately 12 feet but • during the investigation the groundwater level recorded at approximately 9 feet 3.0 PIAN FOR SOIL REMOVAL AND BACKFILLI'.JG Brunsing Associates, Inc (BAT) proposes to excavate soils containing elevated concentrations of hydrocarbons and soils backfilled at the time of UST removal Excavation will be guided by an on-site mobile analytical laboratory to remove all soils until hydrocarbon concentrations are less than 20 parts per million (ppm) 3.1 Excavation Size s Based on previous analytical results and the proposed soil cleanup criteria of a maximurn hydrocarbon level of 20 ppm, it is estimated that 450 cubic yaids will be excavated from the former UST pit Initially, the excavation will remove all soil within the former excavation to a depth equivalent to the groundwater surface, approximately nine feet Excavation is not anticipated to significantly extend beyond the lateral limits of the existing UST pit Excavation will take place in the area shown in Figure 3 The sides of the excavation will be sloped only as required to maintain stability of the excavation walls As described in the Health and Safety Plan (Appendix A), no personnel will enter the excavation at any time I 2 BRUNSING ASSOCIATES, INC ��+�