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1 Geologual recluucs Inc Page 3 Groundwater Monitoring Report Project No 770 2 . April 30,2003 point between the groundwater elevation and the bottom seal in the shallow well (MW- 5) g ( 5) • Measure the head in both wells used in the calculations • If the lateral distance between the well pair is greater than a few feet, then calculations must be made to correct the down-gradient piezometric head to account for the sloping water table between the wells The calculation considers the slope of the water table and the distance in a down-gradient direction between the two wells used in the calculations 1 Figures�A &2B show the location of the well clusters, MW-5/105 and MW-6/406, used for calculating vertical groundwater gradient in this report Table 1 includes Summary of ' Water Level and Gradients Water Table Wells, Table 2 includes Summary of Water Level and Gradients Deep Wells, Table 3 shows the calculated vertical gradients, and Table 6 contains the well construction details The inforination used in the calculations is shown below ' 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) I vertical distance) =vertical gradient] Vertical gradients were calculated for the MW-5/405 & MW-6/406 well pairs for both 0 quarter 2002 monitoring events The vertical gradient was positive (an upward direction) for the MW-5/-105 well pair on November 19 and negative (a downward direction) for the December 18 event The MW-6/406 well pair vertical gradients were the opposite of the MW-5/405 well pair for the two events These wells' gradients were negative (a downward direction) on November 19 and positive on December 18 Both positive and negative vertical gradients have been calculated for previous events Similar to the historical lateral directions, the direction of groundwater in the vertical plane also fluctuates at the site The magnitude of vertical groundwater flow direction ranged from—0 02 to 0 0097 for the last five monitoring events 1.2 Groundwater Sampling Procedure r On November 19, 2002, Don Light of Del-Tech Geotechnical Support Services mobilized to ' the site to measure depth to groundwater in the site's monitoring wells On December 18, 2002, Mr Light returned to the site to complete the quarterly groundwater r monitoring and sampling of the site's monitoring wells Before sampling was attempted the wells were sounded for depth to water and then a clear disposable bailer was used to . determine if floating product was present No free product was noted for the event however r r