ABSTRACT
The techniques discussed for analyzing pumping-test data from unconfined aquifers fall into three fundamental types of increasing sophistication: Equilibrium Methods, Nonequilibrium Methods, and Delayed-Yield Nonequilibrium Methods. Equilibrium Methods is the older steady-state radial flow equations are used in practice because of their simplicity. Delayed-Yield Nonequilibrium Methods is the most accurate techniques for analyzing pumping-test data from unconfined aquifers involve a multiple curve-matching approach originally proposed by N. S. Boulton. This combines a match of early data to a Theis curve, and later delayed-yield data to a second curve set. The Theis method was introduced, pumping-well analyses were based on an assumption of equilibrium or steady-state radial flow to the pumped well. In modern practice the most frequent application of the steady-state well equations is to derive, or confirm, permeability and transmissivity values for an aquifer in the fairly frequent case where it is not convenient to shut down an existing well to conduct a test.
