|
Monitoring Weli Destruction Report
<br /> Raymond Investment Corporation
<br /> 730 E.Channel Street
<br /> Stockton,California
<br /> Page 2
<br /> Quarterly monitoring events began in the fourth quarter 2004. The groundwater elevation in the
<br /> monitoring wells has ranged from approximately-13.5 to-21.0 feet below mean sea level(msl)or 29.5 to
<br /> 37.5 feet bgs.The general groundwater gradient for the Site has been approximately 0.005 ft/ft to the east-
<br /> I northeast,or 60 degrees east from true north.
<br /> ] Analytical constituents have rarely been detected at or above the laboratory reported detection limits in
<br /> {{ the groundwater samples collected from monitoring wells MW-1, MW-2, and MW-3R. On May 4, 2005,
<br /> _ TPH-G and TEPH-D were detected in the groundwater sample collected from MW-1 at concentrations of
<br /> 170 micrograms per liter(µg/L) and 110 jig/L, respectively. On August 16, 2005, TPH-G and TEPH-D
<br /> were detected in MW-2 at 92 µg/L and 82 µg/L, respectively. No other analytical constituents were
<br /> detected at or above the laboratory reported detection limits in the samples collected from those wells on
<br /> ` those dates.
<br /> I
<br /> MWA was installed on August 29, 2006. Soil borings were made on September 7, 8, and 28, 2006. The
<br /> installation and investigation activities were documented in the report titled Additional Soil and
<br /> Groundwater Investigation Report and Third Quarter 2006 Monitoring Report, dated January 2, 2007.
<br /> with some modifications. The report Conceptual Model titled Site
<br /> Groundwater monitoring continued wt p
<br /> 2008, dated October 31, 2008,.summarized data that had been collected regarding the Site to date and
<br /> f clarified existing data gaps. Soil samples were collected from borings, SB-12, SB-13, and SB-14,
<br /> monitoring wells MW-4D,MW-5, and MW-6 were installed, and soil vapor monitoring wells SV-4, SV-
<br /> 5, and SV-6 were installed in May and June 2010. Condor prepared the Monitoring Well, Soil Vapor
<br /> Well, and Soil Baring Installation Report to document the field activities and laboratory analytical results.
<br /> Monitoring well MW-7 was installed and sampled in April 2011. Condor prepared the Monitoring Well
<br /> MW-7 Installation and Groundwater Sampling Report, dated June 6, 2011 to document the installation
<br /> and laboratory analytical results. Groundwater monitoring continued until August 1,2011.
<br /> Condor prepared the Remediation Feasibility Report, dated August 25, 2011.The State Water Resources
<br /> Control Board Cleanup Fund (SWRCBCF) letter dated August 18, 2011 indicated that they had
<br /> i conducted a five year review and recommended that the SJCEHD consider the site for closure. The
<br /> SJCEHD letter dated December 9, 2011 directed that a site closure report be prepared. Condor prepared
<br /> j the No Further Action Request, dated April 6, 2012. The SJCEHD submitted the Case Closure Summary
<br /> dated Se ptember 13, 2012 to the Central Valley Regional Water Quality Control Board (CVRWQCB).
<br /> The CVRWQCB letter, dated October 11, 2012, indicated that they concurred with the recommendation
<br /> for closure. The SJCEHD letter, dated October 18, 2012, directed that a work plan for the destruction of
<br /> the monitoring wells at the Site be prepared.
<br /> Condor submitted the Monitoring Well Destruction Work Plan, dated November 20, 2012 to SJCEHD.
<br /> { The SJCEHD approved the work plan with modifications in their letter dated February 1, 2013. The
<br /> modifications directed by SJCEHD included the destruction of several monitoring wells by over-drilling
<br /> at locations where historic soil contamination had been identified. SJCEHD determined that MW-1,
<br /> MW-3R, and MW-7 qualified for pressure grouting and that the remaining wells would need to be over-
<br /> drilled.
<br /> 3.0 SITE PREPARATION
<br /> An encroachment permit was obtained from the City of Stockton Public Works Department for the
<br /> removal of MW-7, located in the sidewalk near the corner of Channel and Grant Streets. A well
<br /> destruction permit was obtained from the SJCEHD. Prior to initiating the fieldwork, the well locations
<br /> were marked with white paint and Underground Service Alert (USA) was notified five working days in
<br /> advance of the fieldwork to locate and identify underground utilities in the vicinity of the work area.Prior
<br /> I -
<br /> 4M
<br /> i1) CONDOR
<br />
|