Abstract
Type curves for the general nonlinear flow based on the exponential flow law were derived with the application of the Boltzmann transformation to the groundwater continuity and flow-law equations. The initial and moderate portions of these curves are very significant for the estimation of aquifer parameters. Recently, nonlinear flow-type straight-line expressions were derived on the basis of exponential flow law instead of the linear Darcy law. A procedure of hypothesis testing for the flow- regime linearity has been developed. Using this procedure, it was concluded that any straight line for late time-drawdown data on semilogarithmic paper does not necessarily guarantee the accurate application of the classical Jacob methods, but confirms the flow is radial. A dimensionless time-drawdown plot should be used for the identification of flow regime. If the dimensionless time-drawdown plot for the late time-drawdown data fits a straight line with the same slope as the Jacob straight line, then the underlying flow regime is linear. Otherwise, the flow regime is nonlinear. Once the flow regime is nonlinear, the necessary equations should be applied for the estimation of parameters such as the storability, turbulence exponent, and transmissivity. The methodology has been applied successfully to field data. (Author 's abstract)