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' 13 July 2001 • AGE-NC Project No 96-0232 ' Page 2 of 15 ' operated at the site, ground water pump-and-treat operation and maintenance procedures for the site were outlined in Final Remediation Plan, dated 31 August 2000,prepared by AGE and approved by the RWQCB by letter dated 05 October 2000 2 1 GROUND WATER PUMP AND TREAT OPERATION ' The ground water pump and treats stem was designed to operate at a maximum flow rate of 25 ' gallons per minute (GPM), requiring ground water extraction from selected wells on alternating weekly shafts The first shift consisted of wells located in the south trench-brie (EW-2, EW-4, EW-6 and EW-9) and the second shift consisted of wells located in the north trench-lane (EW-5, EW-7, ' EW-8 and EW-10) Each extraction well was adjusted to extract ground water at a flow rate of approximately 5 to 6 GPM, the discharge of treated water (effluent) to the Coldam ditch was adjusted at a flow rate of approximately 23 GPM Field notes of ground water pump and treat ' operation and maintenance activities are in Appendix A Based on effluent flow meter readings (Appendix A), approximately 2,395,645 gallons of treated water were extracted and discharged to the Coldam ditch during the second quarter 2001 under RWQCB General Order 5-00-119 for discharge to surface waters of ground water from cleanup of petroleum fuel pollution Since initiation of the ground water pump and treat remediation system on 20 November 2000, a total volume of approximately 5,875,416 gallons of MTBE-impacted water has been treated and discharged to the Coldani ditch An RWQCB waste water discharge (NPDES permit no CAG915001)permit for discharge to the Coldani ditch was issued to Flag City Chevron ' by the RWQCB by letter dated 06 November 2000 2 2 GROUND WATER PUMP AND TREAT SAMPLING PROCEDURES Samples of ground water pump-and-treat influent and effluent water were collected from valved rsampling ports located upstream and downstream the remediation system Receiving water sampling stations are located in the Coldani ditch approximately 50 feet upstream (R-1) and 80 feet downstream (R-2)of the point of discharge, R-1 and R-2 locations were approved by the RWQCB during a site inspection on 22 November 2000 Grab water samples were collected from influent, intermediate, effluent and receiving water locations utilizing 1-later amber bottles and 1-gallon plastic dugs without a sample preservative and 40-m1 EPA-approved VOA vials containing 0 5 ml 18%hydrochloric acid as a sample preservative ' Care was taken to ensure that visible air bubbles were not present in the vials after filling and capping Ground water sample containers were labeled with a sample designation, date, time, and • sampler's initials Advanced GeoEnvironmental,Inc