Modeling transient stream/aquifer interaction with the non-linear Boussinesq equation and its analytical solution

A new analytical solution of the non-linear transient groundwater flow equation subject to time variable river boundaries was used to simulate stream/aquifer interactions in an alluvial valley aquifer. The differential equations were solved using the method of decomposition. The mathematical model required relatively few parameters to simulate groundwater elevations: hydraulic conductivity, specific yield, and recharge.The model was physically based and could simulate the process of a flood wave propagation into an unconfined aquifer. The model was tested using observed water table elevations at three locations across a 2 km wide alluvial valley aquifer. The average daily deviation between observed and simulated water table elevations was approximately 0.09 m. The transient redistribution of water in the aquifer was simulated well with the model. The nonlinear form of the Boussinesq equation was shown to better simulate cases when the transmissivity of the aquifer could not be assumed to be a constant. (C) 1998 Elsevier Science B.V. All rights reserved.