Modelling groundwater changes due to fluctuating dam discharge

In this contribution, two numerical methods are used to predict the free surface changes in a sand bar due to fluctuations in river stage. One is a fixed-mesh, finite-element seepage formulation including Biot's consolidation theory, and the other is a boundary element method solution of the Laplace equation. Both models give overall predictions that are in good agreement with field data recorded at an instrumented sand bar in the Colorado River subjected to stage fluctuations from operation of the Glen Canyon Dam. The boundary element method appears to offer significant advantage in data preparation and computational times over the finite-element method for the problem studied in this paper.