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Cleo(oy eaLTechnws Inc Page 3 Groundwater Monitoring Report Project No 724 2 March 13,2001 Figure 2 shows the location of the well pairs used for calculating vertical groundwater 1 gradient in this report MW-4/MW-104, MW-6/MW-106, and MW-7/MW-107 Tables 1 & 2 show a Summary of Water Level and Gradients Slope and Bearing and Table 3 shows the calculated vertical gradients The information used in the calculations is shown below 1 Vertical gradient calculation formulas are as follows • vertical correction for gradient [(gw gradient slope) x (distance) = vertical correction] • vertical head [(head of deep well) - (head of shallow + correction) = vertical head] • vertical gradient [(vertical head) / vertical distance) = vertical gradient] For the January 4, 2001 event, the vertical gradient for the MW-4/MW-104 pair was negative (downward) and equal to the horizontal gradient 0 0014 ft/ft In well pairs MW- 6/MW-106 and MW-7/MW-107 the vertical gradient was positive (upward) and approximately double the magnitude of the horizontal gradient 1.2 Groundwater Sampling Procedure On January 4, 2001, Del-Tech Geotechnical Support personnel arrived on-site, opened the wells, and measured the depth to water with an electrically actuated sounding tape The water level reading was recorded to an accuracy of 0 01 foot In wells where free-floating ' product was suspected, a clear disposable bailer was used to gauge the interface No free- floating product was observed during this monitoring event Stagnant water in the well casing was purged using a dedicated Wattera pump as recorded in the field Iogs (Appendix Q The rate of well purging was monitored The wells were purged of at least three casing volumes until the groundwater parameters (temperature, ' conductivity, and pH) had stabilized (Appendix Q This indicated that water, representative of actual aquifer conditions, was entering the well Groundwater parameter stabilization was characterized by three successive readings within 10% ' Before a sample was collected, the water level was allowed to recharge to at least 80% of the initial level All water removed from the monitoring well and not used as a sample was ' placed in a 55-gallon DOT (Department of Transportation 17-H) approved container that was properly labeled and is temporally stoied on-site A dedicated Wattera pump was used to collect each sample Extreme care was exercised while collecting samples to prevent agitation of the water contained in the bailer Water samples were transferred into 40-m1 VOA vials preserved with hydrochloric acid in a manner that nimimizes sample aeration during transfer of the