Laserfiche WebLink
+ 1 <br /> BACKGROUND <br /> The area of the Highiet/Monterosso property addressed by this plan (the "project area") is located <br /> adjacent to West Byron Road. Pipelines, operated by CPL and other oil companies from <br /> approximately the early 1900s to the late 1950s, ran parallel to the northern edge of the <br /> Highiet/Monterosso property along West Byron Road (Figure 2). These pipelines carried crude <br /> oil and Bunker C oil and were buried at a depth of approximately 3 feet below ground surface. <br /> Since 1988, soil and groundwater investigations have been conducted at the Highiet/Monterosso <br /> property on behalf of the Sunboro Development Corporation and CPL. The investigations have <br /> been reviewed by the PHS-EHD. The results of these investigations indicate that limited amounts <br /> of petroleum hydrocarbons are present in subsurface soil along the northern edge of the property <br /> that fronts West Byron Road, apparently the result of releases from the pipelines. The petroleum <br /> hydrocarbons appear similar to those found at the Dividend property (APNs 238-02-10113114), <br /> located northwest of the Highiet/Monterosso parcel. The petroleum is likely degraded crude oil <br /> or Bunker C. Sample locations where petroleum-affected soil on the Highiet/Monterosso <br /> property was encountered are shown on Figures 2 and 3. <br /> The petroleum hydrocarbons have been reported to be present in soil in 4 of the 29 borings <br /> drilled at the site, at concentrations up to 1100 parts per million (ppm). The affected soil occurs <br /> between the depths of 5 and 15 feet. The lateral distrib tion of petroleum hydrocarbons in soil is <br /> limited and does not appear to extend more than 50 fee L southeast of the property boundary. <br /> The subsurface soil at the project area is predominantl silt and clay, with isolated sandy lenses, <br /> to a depth of at least 20 feet. The water table is about 7feet below ground surface. Based on the <br /> groundwater investigations performed to date, shallow groundwater beneath the site has not been <br /> affected by the degraded crude oil. It has been determined by the PHS-EHD that the degraded <br /> crude oil is not a threat to groundwater quality. It should be noted that shallow groundwater <br /> beneath the project area is prohibited for use as dames is or municipal supply by the City of <br /> Tracy for reasons unrelated to the presence of degraded crude oil. <br /> KAWPDOCSIC34991S0ILPLAN.DOC(WORD) 2 <br />