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k <br /> By plotting the drawdown versus time for a <br /> monitoring well on a semi-logarithmic graph, a <br /> portion of the plotted curve will be linear. The <br /> storage coefficient and transmissivity of the <br /> aquifer can be determined by the following <br /> -- equation: <br /> 5 = 2.25 T to/(r2) <br /> where: to = Intersection at 0 drawdown on time axis <br /> of extended straight line portion of <br /> the graph <br /> and: <br /> T = 2.3 Q/(4 s) <br /> where: Is = Drawdown change over 1 log cycle of the <br /> straight line portion of the graph <br /> Equation 7 enables the calculation of T, which when <br /> substituted along with to and r in Equation 5, <br /> - yields B. <br /> The Cooper-Jacob solution is valid if u is less <br /> than or equal to 0.01. If r is relatively small, <br /> the condition will normally be met after one hour <br /> of pumping (Bouwer, 1978) . <br /> E 4.1.2 f- se og Rate-_o_t-_Fall <br /> } The in--situ hydraulic conductivity values can be calculated <br /> by means of tests performed in a single well or piezometer. <br /> The test is initiated by causing an instantaneous change in <br /> the water level in a well through a sudden introduction or <br /> f removal of a known water volume. The recovery of the water <br /> level with time is then observed. When water is removed, <br /> ' the tests are often called bail tests; if the water is <br /> added, it is known as a slug test. The procedure requires <br /> the use of a sensitive pressure transducer with the probe <br /> placed just off the bottom of the well. Water is then <br /> immediately introduced or removed from the well, and <br /> pressure readings are recorded versus time. <br /> Bouwer and Rice (1976) developed a procedure for estimating <br /> the hydraulic conductivity (R) based on the response of the <br /> well to a sudden change in the water table. The hydraulic <br /> �- conductivity can be calculated as follows: <br /> R = r•ln(R/r,)•ln(Yo/Yt)/(2L t) <br /> 10 <br />