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W 3•' - S 3-7 used to track time. NumerOUS flow readings were taken throughout [Ile test to control the flow rate. Nater levels were recorded using either an electronic sounder or a pressure transducer controlled by a data logger (In-Situ Hermit Model SE 1("B). The data from the data logger were subsequently downioaded to a portable field computer. Water levels were measured periodically in all of the other monitoring wells during the pumping test. The test consisted of three pumping steps plus recovery. Figure 3-5 shows' []te drawdown versus time in the pumping well,'CEX-1. Each pumping step lasted for hours. Du erg Tile row tile was step, the average pumping rate was about 7.5 gallons per minute (gp )• increased to 10.7 gpm for the second step,and subsequently increased again to 16.7 gpm for the third step. At the end of the 6-hour test, approximately 5 ft of drawdown was measured in TEX-1. Drawdowns as measured in the observation wells were insignificant. Specifically, a drawdown of approximately 0.1 foot was measured in ATR-4 and 0.03 ft was measured in ATR-2. There was no measurable drawdown in the other monitoring wells. In order to determine the horizontal conductivity of the saturated zone around TEX-1 the data collected from"IT--X-1 were analyzed by the generalized straight-line method of Cooper and Jacob modified for step-type variation of the discharge rate (1983)'. The assumptions and conditions of this method are: 1. The aquifer is of infinite areal extent. 2. The aquifer is homogenous, isotropic and of uniform thickness. 3. The gradient is nearly flat. 4. The aquifer is unconfined. 5. Flow to the well is in unsteadv state. ! 6. The aquifer is pumped at a variable discharge rate. 7. The pump well is fully penetrating. With the exception of condition (2) these assumptions are reasonably satisfied. However, the aquifer is thought to be anisotropic and heterogeneous and hydraulic conductivity valves will vary within the aquifer. Analysis of the data is shown on Figure 3-6. The two paraflel'lines drawn through the data have the same slope from which the transmissivity was calculated. The average transmissivity was calculated to be about 1,300 felday, assuming the saturated thickness of the age horizontal hydraulic conductivity is about 60 ft/day. Due aquifer to be about 23 ft. The aver to the heterogeneity of the aquifer and the presence of low permeable layers of silt,this hydraulic conductivity is probably accurate to an order of magnitude and represents the higher end. Thus, the aquifer around TEX-1 is thought to have a hydraulic conductivity between 6 and 60 ft/day. 'Kruseman,G.P.,DeRidder,N.A�, 1983,-Analysis-and Evaluation of Pumping Test Data,pg._-__ . 38, International Institute for Land Reclamation and Improvement ILRI, Wageningen, The Netherlands, 200 P.