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0 Wodward•Clyde Consultants Mr. James T. Allen December 10, 1987 page 2 2) Continous measurements of groundwater levels in two monitoring wells was reduced to one monitoring well . 3) The location of the monitoring well to be continously measured was changed to MW-3 (the downgradient well ) . 4) A Hermit Enviromental data logger was used in place of a Stevens Chart Recorder to measure groundwater levels in MW-3. 3. Monthly groundwater samples were collected from MW-1 and MW-3. Monthly samples were taken from MW-3, the downgradient well from the removed sump area, in place of MW-4 (phone conversation with DHS on 7 September 1987) . The groundwater samples were submitted to California Analytical Laboratories, Inc. (CAL) in West Sacramento. The samples were analyzed for total copper (Cu) , total lead (Pb) and total dissolved solids (TDS) . Summary of analytical results received from CAL are shown in Table 1 (Attachment 1) . None of the results for Cu, Pb or TDS exceed the Federal Drinking Water Standards of 1.0 mg/l , 0.05 mg/l and 1,000 mg/l respectively. Field measurements of pH, temperature and conductivity were taken during the monthly sample exercise from the two monitoring wells , MW-1 and MW-3 (Table 1) . The results taken from the field measurements and the analytical laboratory do not indicate that contamination has migrated from the removed sump area. 4. Tidal gage data for the Port of Stockton was obtained by DHS and sent to Woodward-Clyde Consultants (WCC) . The Tidal Gage Data obtained from the Sacramento District of the Corps of Engineers for the Port of Stockton gaging station reported daily maximum and minimum water elevations (Attachment 2) . Comparison of the water levels from the tidal gage and the groundwater levels for MW-3 determined that the direction of groundwater flow is away from the Sacramento River (effluent) during the water level measurement period. Generally, the water level in the Sacramento River was six feet higher than the groundwater level in MW-3 (Attachment 3) . 5. The supplemental lithology section requested was completed as shown in Attachment 4. All of the lithology sections (Remedial Investigation and new submittal ) are included (Attachment 4) . A silty clay layer underlies the entire site. The vertical migration of water through silty clay where lenses of silty sand and sand layers exist are unlikely. Water will move through the soil with the highest permeability (silty sand and sand) and will migrate laterally through the silty sand or sand layer. In addition to the above, DHS requested that a map of all existing wells within one mile of the site be prepared (Attachment 5) .