WORK PLANS - Laserfiche WebLink

Home Browse Search

A.Vorster/5 October 1990 2 property is located north of Grant Line Road to the west of the Kuden property. The Pombo property is located along the south side of Grant Line Road,starting at the southwest corner of the intersection of Corral Hollow and Grant Line Roads. The southern edge of the Kuden property was the site of a leak in Chevron Pipe Line's east-west trending fuel-product transmission pipeline running along the north side of Grant Line Road. The pipeline leak occurred in April 1987, and was the result of a puncture that occurred during the installation of shallow (about 25 ft deep) dewatering wells, DW-1 through DW-3, that were drilled along the pipeline route in preparation for the installation of municipal utilities. Further information regarding the installation of the dewatering wells was not available to WGR as of the date of this workplan. According to a June 1987 report to Chevron by Dames and Moore (D&M) of San Francisco, California, approximately 870 barrels of unleaded premium gasoline and diesel fuel were released into the surrounding soils as a result of the puncture. Chevron estimated that about 90% of the spilled fuel consisted of gasoline and about 840 barrels were recovered. Approximately 100 cubic yards of obviously contaminated soil were excavated and removed. Subsequently, D&M installed three groundwater monitor wells(MW-1 through MW-3) outside of the estimated area of the spill (Figure 2). D&M determined the groundwater flow direction to be to the northeast. In May 1989, WGR conducted a soil vapor survey (SVS) on the three properties to the west of Corral Hollow Road and to the north and south of Grant Line Road. Total volatile hydrocarbons (TVH),at a concentration of 210 parts-per-million by volume(ppmv),were detected in the soil near Grant Line Road near the west end of the area that D&M estimated to be impacted by the release. TVH, at concentrations up to 11 ppmv, were detected in two vapor points on the south side of Grant Line Road on the Pombo property. On 2 and 3 May 1989, WGR collected groundwater samples from domestic supply well SW-1 (Figure 2). Hydrocarbons and related compounds were not detected in the groundwater samples from the well. On 3 and 11 May 1989, WGR staff collected groundwater samples from monitor wells MW-1 through MW-3,installed by D&M,three dewatering wells designated DW-1 through DW-3, installed for the city near the site of the pipeline leak, and one non-operating domestic well designated SW-2 (Figure 2). The groundwater samples from monitor well MW-3 and dewatering well DW-3 were nondetectable for all compounds analyzed. Total purgeable petroleum hydrocarbons (TPPH) at a concentration of 1,200 part-per-billion (ppb), were present in the groundwater samples from dewatering well DW-1,located near the western extent of the spill area; in addition, other aromatic hydrocarbons were detected, including up to 410 ppb benzene. Lower concentrations of benzene were detected in the groundwater samples from wells MW-1 and DW-2. Oil and grease were present in the groundwater samples from wells MW-1, MW-2 and SW-2. 107W 1 OCO.va