ARCHIVED REPORTS_XR0007033 - Laserfiche WebLink

Home Browse Search

E11��t® Mr James Barton ' June 14, 2004 Page 2 ' USTs from the site Numerous soil and groundwater investigations of the Wards site were conducted and a remedial system (air sparging with vapor extraction) was installed to address the remediation of petroleum hydrocarbons present in soil and groundwater beneath the Wards site ' The remedial system was put into full operation in November 1999, and was in operation until December 2000 when the auto service center and remedial system were shut down due to Wards filing bankruptcy During its operation, the Wards remedial system removed approximately 8,000 pounds (lbs) of hydrocarbons Groundwater monitoring at the Wards site has been conducted since 1993 Groundwater monitoring activities for the Wards site and the Unocal site, for the most part, were conducted simultaneously and coordinated by the various consultants representing the two entities The former Wards site was redeveloped into a restaurant The former Wards building was demolished and the parking lot raised and resurfaced Well casing elevations and locations were ' resurveyed for all wells Former Unocal Station No 5098 was operated at 5606 Pacific Avenue, Stockton, California between approximately 1955 and 1985 In 1985, the station was closed and the USTs removed After completing soil and groundwater investigations Unocal excavated approximately 6,000 cubic yards of soil from the site in 1988 The excavated soil was aerated, and based on the analytical testing results associated with the aerated soil, 5,800 cubic yards of the aerated soil was reused on-site as fill, and 200 cubic yards transported off-site for disposal 4n August 25, 1989, the RWQCB issued a letter for the Unocal site confirming that the soil ' contamination at the site has been adequately cleaned up, but, that the extent of groundwater impact had yet to be defined Between 1992 and 1999, additional soil and groundwater investigations associated with the Unocal site were conducted ' San Joaquin Delta College (Delta College) operated a groundwater extraction well identified as the "Robinhood Irrigation Well" (RIW) (a k a Delta College Well) The RIW was located ' southwest of the intersection of Robinhood Drive and Pacific Avenue The RIW was installed in 1950 and was reported to be 322 feet deep with perforations in multiple zones beginning at depths as shallow as 40 feet below ground surface (bgs) According to the Water Well Driller's ' Report for the RIW, "no strata were sealed against pollution" Groundwater from the RIW was formerly used to irrigate portions of Delta College's campus Groundwater monitoring data for the site show that historical pumping of the R1W influenced and changed the natural direction of groundwater flow in the area from easterly, to south southwesterly, i e , towards the RIW Sampling of the RIW b Unocal and/or Wards for dissolved petroleum constituents began in 1997 P 9 Y and continued through June 15, 2000 In August 2000, Delta College students and staff complained of a gasoline odor from the water denved from the RIW As requested by the RWQCB, the RIW was taken out of service as of 6 00 AM August 22, 2000 and RIW was abandoned in August 2001 aIn February 2001, seven new wells (MW-18D, MW-23S, MW-23D, MW-24S, MW-24D, MW-25S, and MW-25D) were installed to assist in defining the vertical and lateral extent of hydrocarbon ,ilProjeclsk0694015098-293\FinahReports\5098 Work Plan doc Over 30 Years of Excelieoce in Environmental Services