Laserfiche WebLink
20 STEP DRAWDONVN TEST <br /> A three step, well performance test was performed in EW-1 On August 29, 2001 the first stem <br /> was performed at a nominal flow rate of 3 GPM On October 31 2001 two stepped rates were <br /> performed at a nominal flow rates of 6 and 12 GPM The three steps were conducted at mean <br /> flow rates as maintained by DOLETm Flow Regulators of the indicated nominal flow rates The <br /> following table lists the nominal flow rate, the mean flow rate, the end of step drawdown, and the <br /> duration for each step of the step drawdown test The sum of two nominal flow rates from two <br /> DOLE valves ar e indicated as appropriate <br /> Step Nominal Mean Drawdown Step <br /> Flow Rate Flow Rate (Ft ) Duration <br /> (GPM) (GPM) (minutes) <br /> 1 3 2 56 073 40 <br /> 2 6 5 65 279 30 <br /> . 3 12 11 01 11 10 90 <br /> The interpretation of the step drawdown test is provided in Figure 1 This graph is a double <br /> logarithmic plot showing the water level drawdown versus the discharge rate The step <br /> drawdown test data points are represented by the three filled circles <br /> Drawdown in a pumped well is made of two components aquifer loss (drawdown caused by <br /> resistance to laminar flow in the aquifer) and well loss Well loss is the drawdox n required to <br /> overcome the resistance to turbulent flow in the vicinity of the well through the screen and <br /> filterpack, and within the well if the pump is tightly fit Anisotropic aquifer stratification can <br /> also affect tlus relationship The total drawdown is represented by the following equation <br /> D = BQ } CQP <br /> where D = drawdown in the pumped well in YI <br /> Q = flow or discharge rate in GPM, <br /> BQ = aquifer loss, <br /> CQP = well loss, <br /> and B, C, and P are coefficients <br /> H 20GE01, A GROUNDWATER CONSULTANCY <br />