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' fa zcaf?ec(rn� Inc Page 3 Geog g ' Groundwater Monitoring Report Project No 770 2 April 11,2001 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 March 15, 2001, monitoring event, a vertical gradient was calculated for the MW- 5/MW-105 pair The vertical gradient was positive (an upward direction) and of slightly ' greater magnitude than the horizontal gradient of shallow wells MW-1 through MW-3 The vertical gradients calculated for two previous events are negative on August 28, 2000, and positive on December 29, 2000 Similar to the lateral direction, the movement of groundwater in the vertical plane also fluctuates at the site 1.2 Groundwater Sampling Procedure On March 15, 2001 Don Light of Del-Tech mobilized to the site to conduct groundwater monitoring of the seven 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 The wells were ' purged of at least three well volumes of stagnant water using a dedicated Waterra check-ball 40 assembly and '/z inch tubing Purging continued until the temperature, conductivity, and pH of the groundwater stabilized (<1 0% variation between three readings) indicating that formation water representative of aquifer conditions was entering the wells These water quality parameters were measured at intervals of each well volume purged ' Once purging was complete, a water sample was collected from the Waterra tube Care was taken to minimize sample agitation Once the sample container was filled and capped, the ' bottle was inverted, tapped, and checked for headspace bubbles The sample container was identified and labeled with a unique designation, inserted into foam holders and placed in an rice chest cooled to 4°C for transport to the laboratory ' L All non-disposable sampling equipment was decontaminated using a hot water washer and detergent before and between uses Disposable gloves were used by the technician to ' f collect all samples and were changed with each sample collection L A chain of custody document, listing all samples collected, accompanied the samples from field to laboratory, thereby providing a means to track their movement and insure their integrity ' L All water purged from each monitoring well and not used as a sample, was placed in a 55 gallon DOT approved container, properly labeled and stored on site until its proper irk, disposition can be arranged 1 .