Evaluation of Stream Depletion Considering Finite Stream Width, Shallow Penetration, and Properties of Streambed Sediments

Commonly used methods for estimation of pumping-induced stream depletion are based on a series of idealistic assumptions about the stream-aquifer interface. In many cases, however, these assumptions are not consistent with field conditions. In order to obtain stream-depletion estimates that are based on assumptions more appropriate for conditions often faced in the field, a new analytical model is proposed. This model, which incorporates the effects of finite stream width, shallow stream penetration, and a low permeability streambed, is based on the Dupuit assumptions and a steady-state representation of flow across the streambed. A general solution for stream depletion is developed in Laplace space and numerically inverted to obtain stream depletion as a function of time. In two special cases, the Laplace-space solution can be analytically inverted to obtain closed-form expressions. This solution is used to assess the impact of finite stream width, shallow stream penetration, and a low-permeability streambed on stream depletion estimates