ARCHIVED REPORTS XR0002718 - Laserfiche WebLink

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04. s during the early portion of this century. Although UST's have been identified beneath the sidewalks of other streets in Stockton, research to date has not confirmed the presence of UST's beneath Harding Way. ' It should also be noted that the property located directly north of the site, beneath what is currently Harding Way,was identified as part of a canal on some of the early Sanborn maps (see Appendix A). The canal was located along the south side of North Street; North Street was renamed Harding Way sometime prior to 1950. GeoAudit has been unable to locate information concerning the backfilling of this canal or the subsurface structures that may be located beneath Harding Way (i.e. the presence of UST's). 3.0 SITE ASSESSMENT ' 3,1 Initial Investigation ' In June 1990, Youngdahl &Associates (Y&A) performed a site investigation by drilling soil borings on the site. Drilling and sampling was reported to be difficult because of many underground pipes. Samples collected during this investigation indicated-that petroleum hydrocarbon impacted soil was present on the property at very shallow depths. One sample was collected from a depth of 15.5 feet in the area of the former fuel tank cluster (sample 6-2A). No petroleum hydrocarbons were detected in this sample. Analytical results of the Y&A investigation are summarized in Table 1. A map of the sample locations is included in Appendix B. ' 3.2 Excavation of Hydrocarbon Impacted Soil ' On February 6, 1991, WHF began re-excavating the site with using a backhoe. Trenching and sampling were also conducted at this time. No petroleum hydrocarbons were detected in the former fuel tank area. However, the product lines to the fuel island had not been ' removed, and one of those lines contained approximately 10 gallons.of fuel. The fuel was drummed on-site and the product lines were disposed of. as hazardous material. Hydrocarbon impacted soil was encountered intermittently in areas.near the former fuel ' islands. This soil was excavated and stockpiled on site. During excavation, a previously unknown fuel island was discovered at the northwest corner of the property. Petroleum hydrocarbons were detected in a narrow zone of soil about 4 feet wide and three feet thick, near the surface; the impacted zone narrowed to the west and north as the depth increased. All impacted soil to a depth of 22 feet was removed and ' stockpiled on site. Excavation was terminated at 22 feet due to equipment limitations. During excavation at the site, several buried pipes were encountered near the north ' boundary of the property. It was determined that these pipes extended out beneath, or extended from, the sidewalk (and potentially Harding Way) in the vicinity of MW-4. These � 1