Aquifer Parameters from Drawdowns in Large-Diameter Wells: Unsteady Pumping.

An optimization method is proposed for estimating transmissivity, storage coefficient, and effective well radius from drawdowns in large-diameter wells. Unsteady pumping is considered; any variation in pumping discharge can be accounted for. Pumping and residual drawdowns can be analyzed simultaneously using the new method. The application of the method is illustrated through the examples of prior studies. The new method reliably estimates the parameters. For the examples considered, the estimates of transmissivity and effective radius of well are more accurate than the estimate of storage coefficient. The proposed method is superior to the prior method because it is objective, more quantitative, and more general. [ABSTRACT FROM AUTHOR]