WORK PLANS FILE 1 - Laserfiche WebLink

Home Browse Search

Stantec November 28, 2011 Page 3 of 5 Assessment Report and Fate and Transport Model, which also presented calculations of the lateral migration of dissolved MtBE in groundwater. Per the request of the SJCEHD, groundwater monitoring and sampling is coordinated with a former Exxon site (currently a USA Gasoline station) immediately east of the 7-Eleven site. On July 22, 2004, SECOR submitted a proposal for a Field Test Program for Evaluation of Oxidation Capacity of Groundwater to the California Regional Water Quality Control Board (CRWQCB). The CRWQCB conditionally approved the proposal in a letter dated October 4, 2004. On July 27, 2004, SECOR submitted a Work Plan for Additional Offsite Assessment to the SJCEHD. The work plan was approved by the SJCEHD in a letter dated August 23, 2004. The work plan proposed the installation of two offsite groundwater monitoring wells (MW-9 and MW-10), advancing three offsite soil borings (GP-1 through GP-3), two offsite CPT borings (CPT-2 and CPT-3) and one onsite CPT boring (CPT-1). Between April 26 and April 28, 2005, SECOR supervised the installation of oxygen injection well 1-1 and the advancement of soil borings GP-1, GP-2, and CPT-1 through CPT-3 by Gregg Drilling and Testing. With the exception of 4.0 micrograms per liter (Ng/L ) of MtBE in CPT-3 (CPT-3-70') the lateral extend of deep groundwater contamination was defined to the northeast and east. The lateral limits of shallow contamination in soil and groundwater was defined to the north, west, and southwest of the site. Proposed groundwater monitoring well MW-10 could not be installed due to the presence of underground utilities around the proposed location. Access to install proposed well MW-9 was not granted by USA Gas, therefore MW-9 was not installed. SECOR submitted the Additional Site Assessment and Site Conceptual Model report to the SJCEHD on September 30, 2005 summarizing the well installation and boring advancement activities. On December 2 and 16, 2005, SECOR conducted oxygen capacity testing into well 1-1 as outlined in the July 22, 2004 Field Test Program for Evaluation of Oxidation Capacity of Groundwater. A report, Results of Oxygen Injection Feasibility Pilot Study, summarizing the results of the test was submitted to the CRWQCB on May 9, 2006. On June 15, 2007, SJCEHD requested submittal of Correction Action Plan (CAP). The CAP was submitted to the SJCEHD on October 12, 2007. The SJCEHD requested a CAP addendum in a letter dated January 4, 2008. SECOR submitted the CAP Addendum to the SJCEHD on March 19, 2008. The SJCEHD approved the CAP Addendum on July 9, 2008. On June 1, 2008, SECOR International Inc. became Stantec Consulting Corporation (Stantec). Onsite oxygen injection wells (1-2 through 1-5)were installed on December 30 and 31, 2008 and January 8, 2009. Between March 9 and 31, 2009, conveyance conduits were installed, leading from oxygen injection wells 1-2 through 1-5 to a single subsurface well vault. On April 16, 2009, Stantec submitted a Well Installation and Subsurface Trenching Report to the SJCEHD. On April 17, 2009, all of the site groundwater and newly installed remediation wells were professionally surveyed in relation to existing site features. 14117 11-30 Report.doc