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REVISED PUMP TEST PLAN The presence of the two groundwater zones A and B and the presence of the monitor wells MW I through MW5 which are screened across both zones, complicates the performance of a pump test at this site Of major concern is the location of MW 1 in relation to RWIA and RW I B and the MW6 cluster With monitor wells completed across both zones pumping from one zone will cause flow up or down the cross zone well from the non pumped zone Upon further modeling of the probable outcome of the interaction of the cross zone wells during pumping at the site, it is our opinion that the closest cross zone wells MW1, MW2 and MW3 should be destroyed prior to the pump test and the de-watering of the upper zone Because the modeling was only preliminary a simple analog model of the interaction of pumping from RWO 1 A and the cross-zonal flow in MW I was developed The flow up the well is driven by the difference in head between the two groundwater zones Even in two inch casing, the anticipated flow between the two zones is significant with even a slight difference in head From the Hazen-Williams Formula, for anticipated flow in a pipe Q=0 432CiD263S'14 Q= ft3/s Ci= Coefficient dependent on surface roughness approximately 120 D= pipe diameter in feet S = head lose in feet per feet of pipe For a 2-inch pipe with a differential of 0 01 feet per the 3-foot clay Iayer that separates the zones the flow in the pipe would be 13830 gallons per day D=2/12=0 167 S= 0 1/3=0 033 Q=0 432*120*0 167263*0 0033'14=0 0214 ft3/sec =1 284 cfm = 9 604 gpm or 13830 gpd From the above it can be assumed that flow between zones in MW 1 would be sufficient to equalize the head between the two zone even in response to significant pumping at RW01 The preliminary model used the distance draw down equation to calculate the response to pumping The equation was solved for three instances I The response of the upper zone from pumping RW01A 2 The response of the upper zone to the flow of water from the lower zone to upper zone at MW 1 3 The drawdown of the lower zone in response to flow from the lower zone to the upper zone in MW 1 While running the model the flow parameter in MW 1 between the two zones was adjusted so that the groundwater elevation for both the A and B zone were equal, as the zones responded to pumping at RW I A 1 Rev Pump Test Plan- Appendix A, 1/10/02