SITE INFORMATION AND CORRESPONDENCE

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Executive Summary GUARDINO & CRAWFORD 517 West Fremont Street, Stockton , California Guardino & Crawford Construction Company (G & C) is located at 517 West Fremont Street, Stockton , California , near the intersection of Lincoln and Fremont Street. G & C is a private construction company, currently operating , that was established in the 1970's . In September 1989 , one 1 , 000-gallon underground storage tank (UST), dispenser, and piping were removed from the site . During removal of the UST , petroleum-impacted (i . e . gasoline ) soil was encountered at the site . As a result of the impacted soil , the San Joaquin County Environmental Health Department ( SJCEHD ) issued a directive to investigate the full extent of petroleum contamination for this site . Based on the above SJCEHD directive , a subsurface investigation was performed at the G & C site . The investigation included drilling of ten ( 10) soil borings for evaluating soil conditions and eight (8 ) ground water monitoring wells ( MW- 1 through MW-8 ) for evaluating ground water conditions. Additionally, one soil vapor extraction (VW- 1 ) , one air sparging well ( IAS- 1 ) , one ground water extraction well (EW- 1 ) and four remedial observation wells (OB- 1 , OB-2 , OW- 1 and OW-2 ) were installed at the site for evaluating remediation alternatives . Due to the extent of petroleum-impacted soil and ground water at the site , the SJCEHD directed preparation of a Corrective Action Plan (CAP ) to mitigate petroleum -impacted soil and ground water for this site . As part of the CAP , ground water pump tests (April 2008) and soil vapor extraction and air sparging remediation feasibility testing were conducted at the site (June 2008) . Based on the pilot test results a Remedial Action Work Plan ( RAWP) was prepared in April 2011 . In the RAWP it was determined that in-situ air sparging and soil vapor extraction were the most effective remediation options for this site . In April 2011 the RAWP was submitted to the SJCEHD for approval . The RAWP proposes utilizing a 250-CFM catalytic oxidizer soil vapor extraction system to extract soil-gas vapor from the vadose zone . Additionally, a 10-horse power electric air compressor has also been proposed to inject air into the saturated zone to "strip" hydrocarbons from the ground water; "stripped" hydrocarbons have been proposed to be removed with onsite soil vapor extraction wells and the above referenced soil vapor extraction system . It is estimated that a period of 24 to 36 months will needed to perform the outlined remediation . All hydrocarbon recovery operations will be conducted via underground piping and remediation wells ; additionally, all extracted hydrocarbons will be completely treated through a catalytic oxidizer and under permit by the San Joaquin County Air Pollution Control District. Operation of the proposed SVE and IAS systems should not affect any public interest in any way. At the conclusion of corrective action , the G & C site hopes to satisfy the California Water Quality Goals , and will seek to obtain a ' No Further Action ' letter from the California Regional Water Quality Control Board .