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City of Stockton • French Camp Landfill Groundwater Investigation - 0 P-4k Task 1 — Development of Revised Program j ts� A proposed expansion of the monitoring well network at the French Camp Landfill was transmitted to Bill Marshall of the CVRWQCB in a document dated May.2.' 1996. This proposal provided the basis of the discussion at the May 23,1996 meeting. The proposed program will be revised,under Task 1,to incorporate the decisions reached at the May 23 meeting. Activities to be conducted under this task include review of historical disposal facility information and aerial photographs to define the limits of the waste,and preparation o1'a revised plan depicting well locations and describing future monitoring activities. The plan will be reviewed by the CVRWQB prior to the initiation of field activities. Task 1 Deliverables CDM will prepare a transmittal,for submittal to the CVRWCB, describing the proposed expanded detection monitoring well network at French Camp. The correspondence will include a figure depicting proposed well locations and a description of the program objectives. Task 2— Installation of Monitoring Wells A Health and Safety Plan will be prepared for the French Camp Landfill drilling and sampling operations prior to the initiation of the field work. The plan will consist of an identification of hazards associated with these tasks in accordance with OSHA29 CFR 1910.120. A clear description of protocols to be followed to assure worker safety during both drilling and sampling operations will be included. Figure 1 indicates the location of the seven proposed monitoring wells,CDM-6A;CDM-7A,B;CDM- 8A;CDM-9A,B, and CDM-10A. Figure 2 depicts typical well construction details which are subject to revision based on actual field conditions and depths to groundwater. The objectives for each well are provided below. Monitoring Wells CDM-6A and CDM-7A.B: Monitoring wells CDM-6A and CDM-7A,B will replace well MW-5 as the background wells in the monitoring network. The objective is to place these wells in a location which accurately monitors local groundwater conditions,but is not impacted by surface water bodies or landfill contaminant sources. These wells will provide data characterizing upgradient groundwater quality to use as comparisons with downgradient wells to assess whether the waste management unit is impacting groundwater in accordance with California Code of Regulations,Title 23,Chapter 15,Article 5. Monitoring wells CDM-6A and CDM-7A will be screened in the first encountered groundwater estimated to occur approximately 20 to 25 feet below ground surface. Fifteen feet of well screen will be set below the water table,and five feet above,to account for water level fluctuations.CDM-7B will monitor the deeper aquifer with 10 feet of well screen. The deeper aquifer is defined as the first water bearing zone encountered below the uppermost aquifer with a minimum 5 foot separation by a clay or low permeability layer between zones. Monitoring Well CDM-8A: Monitoring well CDM-8A will replace existing well MW-4 in monitoring the northern portion of site downgradient of the waste footprint. Existing well CDM Camp Dresser&McKee 2 w96%250OXM