ARCHIVED REPORTS_XR0011956 - Laserfiche WebLink

Home Browse Search

y SCSA—University Park Site Background Page 4 On August 10, 2004, a Condor representative was on Site to conduct the third quarter 2004 quarterly groundwater monitoring event. Field observations indicated that no separate phase petroleum, sheen or odor was noted in the groundwater recovered from the wells. The average depth to groundwater in the . monitor wells was 41.40 feet below the surveyed well collar measuring points (the measuring points are slightly below the ground surface). The average groundwater elevation measured in the monitoring wells decreased 2.50 feet between March 13, 2003, and August 10; 2004. The estimated,groundwater gradient for the Site on August 10, 2004, was 0.0023 ft/ft to the south. The groundwater gradient direction(south) is the southern-most gradient direction estimated for the Site during the brief monitoring history. Historic gradient directions have ranged from approximately due east to approximately due south. The Site water table elevation decreased relatively steadily from approximately 20 feet below' meansea level to approximately 24 feet below mean sea level during the Site monitoring history (December 2001 to . August 2004). The laboratory analytical results of the groundwater samples collected from MW-1, MW- 2, and MW-3 on August 10, 2004, were generally consistent with the historic laboratory analytical results. On November 10, 2004, a Condor representative was on Site to conduct the fourth quarter.2004 quarterly # groundwater monitoring event. Field observations indicated that no separate phase petroleum or sheen was found in any of the monitoring wells. Moderate to strong odor was noted in groundwater recovered from MW-2 and MW-3. The average depth to groundwater in the monitor wells was 42.76 feet below the surveyed well collar measuring points (the measuring points are slightly below the,ground surface). The average groundwater elevation measured in the monitoring wells decreased 1.36 feet between August 10, 2004 and November 10, 2004. The estimated groundwater gradient for the Site on August 10, 2004, was 0.0018 .ft/ft to the southeast. Historic gradient directions have ranged from approximately due east to approximately due south. The Site water table elevation decreased relatively steadily from approximately 20 feet below mean sea level to approximately 25 feet below mean sea level during the Site monitoring history (December 2001 to November, 2004). The laboratory analytical results of the groundwater samples collected from MWA, MW72, and MW-3 on November 10 and 11, '2004 were generally consistent with the historic laboratory analytical results. As the plan for Site development was modified and clarified during 2003, very aggressive and timely but less cost-effective Site remediation (over-excavation, as proposed in the above described March 3, 2003 work plan) was no longer considered necessary by the SCSA. Condor, on behalf of.the SCSA, proposed evaluation of Site source area remediation by pilot testing of air-sparging in combination with soil vapor extraction in a work plan dated September 15, 2004. In a letter dated November 8,,2004, Mr. Henderson r of the SJCEHD expressed concern with two aspects of the proposed approach and requested submittal of a work plan addendum by January 17, 2005, addressing his concerns. Concurrently, Site development ti plans continued to evolve such that a structure planned for the Site vicinity was to`be located well away from the Site contaminant source area and that a parking lot for the structure would'be built over the Site J source area. These considerations indicated the potential for consideration of less aggressive Site remediation techniques. i . As a result of the above considerations a meeting was held on December 17, 2004, with all concerned parties in attendance. As a result of the meeting it was agreed that Condor would prepare a work plan for additional groundwater investigation and feasibility evaluation of various remediation options for the Site. In an email transmission on January 6, 2005, to Mr. Henderson at the SJCEHD„,Condor requested an extension of the work plan submittal due date back to February 4, 2005. Mr. Henderson approved the extension in a return email on January 6, 2005. Condor subsequently prepared and submitted the Additional Groundwater Investigation and Remediation Feasibility Evaluation Work Plan, dated January. 25, 2005. The above-mentioned work plan was then submitted on February 7, 2005. The work plan was } conditionally approved in a letter received by Condor from the SJCEHD on April 8, 2005. Condor is currently waiting for SCSA authorization to begin the approved work. _ a