ARCHIVED REPORTS_XR0006946 - Laserfiche WebLink

Home Browse Search

' solvent-impact to ground water was reported from the First Water Zone, low to moderate fuel component and chlorinated solvent-impact was reported from Second Water Zone,Third ' Water Zone and Primary Aquifer Zone from P-7,P-8,P-9 and P-10 Results of the December 2000 CPT investigation were reported in Cone Penetrometer Testing Site Investigation - Fourth Quarter 2000, dated 07 February 2001, prepared by AGE ' • March 2001 -Ground water extraction well EW-1 and ground water observation well MW-6 were installed at the site for performance of a ground water pumping test Soil borings EW-1 ' and MW-6 were advanced vertically to depths of 45 feet below surface grade(bsg) Boring EW-1 was single-completed as a 6-inch diameter ground water extraction well and MW-6 single-completed as a 2-inch diameter ground water observation well with screen intervals between 20 and 45 feet bsg Soil and ground water samples were not collected during this investigation Results of the March 2001 investigation were reported in Ground Water Aquifer Pumping Test Report-Second Quarter 2001,dated 15 May 2001,prepared by AGE ' • April 2001 -A ground water aquifer pumping testing was performed at the site to assess the general ground water aquifer characteristics and to assess aquifer response to ground water ' extraction utilizing wells EW-1, MW-1, MW-2, MW-3 and MW-6 at a constant pumping rate of 6 gallons per minute,purged ground water was containerized on-site in a 6,500-gallon poly tank(Baker tank) From data collected during the pumping test, a transmissivity value ' was calculated at 955 W/day,a storativity value calculated at 0 032,a hydraulic conductivity value of 0 013 cm/s and a radius of influence projected at 140 feet utilizing a semi- logarithmic plot of draw-down versus distance Results of the March 2001 investigation ' were reported in Ground Water Aquifer Pumping Test Report- Second Quarter 2001,dated 15 May 2001, prepared by AGE • January 2002 - initiate interim ground water purnp-and-treat remediation at the site by continuously extracting ground water from well EW-1 The extracted ground water was routed through a ground water treatment system consisting of granular activated carbon ' (GAC)and Sunsolve® Following treatment,water was discharged underground via 2-inch diameter PVC piping to the City of Manteca sewer system, discharge piping is connected to a sewer manhole located approximately 25 feet south of the pump-and-treat system Interim ' ground water pump-and-treat operation and maintenance procedures for the site were outlined in AGE's Interim Remediation Work Plan - June 2001, dated 21 June 2001 ' 24 REGIONAL GEOLOGIC SETTING 1 ' The property is situated within the Great Valley Geomorphic Province of California, a large, elongate, northwest trending, asymmetric structural trough The Great Valley Province has been filled with thick sequences of sediment ranging in age from Jurassic to Recent,creating a nearly flat- lying alluvial plain,extending from the Tehachapi Mountains in the south to the Klamath Mountains in the north The western and eastern boundaries of this province are comprised of the California ' Coast Range and the Sierra Nevada, respectively Rocks composing the basement complex of the province have not been completely defined but are believed to be metamorphic and igneous in origin The northern and southern portions of the Great Valley Province have been designated the 1 Advanced Geal;nviroomental,Inc 1 1 1