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-w <br /> "Mi <br /> �d <br /> Another term indicative of the water yielding capacity of an <br /> aquifer is its transmissivity or transmissibility. The <br /> transmissivity of an aquifer is the product of the hydraulic <br /> conductivity and the saturate,l thickness (B) , or: <br /> T - KB <br /> Of interest in understanding aquifer characteristics is the <br /> movement or yielding capabilities of the wager bearing <br /> formation. It is necessary to obtain values for one or more <br /> of the aquifer q properties to determine these parameters. <br /> Various techniques have been developed for obtaining values <br /> for these properties or <br /> parameters. <br /> The pump test technique is generally used to evaluate the <br /> hydraulic properties of aquifers. The results of this test <br /> 3 are used for predicting well yields, position of water tables <br /> and piezometric surfaces, and recharge rates of aquifers. <br /> $ Other techniques, such as the auger-hole and slug test <br /> methods (rate-of--rise techniques) , have been developed to <br /> measure the hydraulic Y gradient (K) of the soil profile in <br /> shallow ground water. <br /> i ,. With the pumped-well technique, often called pumping test-, <br /> hydraulic properties of the aquifer are determined by <br /> pumping a well at a constant rate and observing the <br /> drawdown of the piezometric surfaces or .rater table in <br /> observation wells at some di'3tance from the <br /> Pumped well. <br /> Two types of tests are used: the steady-state and the <br /> nonstead <br /> y-- or transient-state test. With the steady-state <br /> test, pumping is conducted for a sufficient period of time <br /> for the water levels in the observation wells to approach <br /> equilibrium. The equilibrium drawdown then enables the <br /> calculation of transmissivity (T) . With the transient <br /> pumping tests, the change in water level in the <br /> ' <br /> observation wells is measured <br /> determine the properties T and�S,�elatzon to time, to <br /> y <br /> Transient pumping tests are more commonly used than <br /> steady-state tests. Certain assumptions have to be made <br /> .11-1 calculating T and S from the pumping-test data, such <br /> as, the aquifer is homogeneous and isotropic. For the <br /> purposes of aquifer testing, only the transient-state <br /> 6 <br />