Recession Analysis of Drought Flow Using Hele Shaw Model

This study presents recession analyses of drought flow from a sloping aquifer on a hillslope. The experimental part of the study uses a Hele Shaw model as a creeping flow model. The theoretical part applies the nonlinear Boussinesq equation with an open downstream boundary. The slopes of the recession curves on full-log paper at short times are the same whether the bottom slope of the aquifer is small or not. Conversely, those for the horizontal aquifer at long times are completely different from those for the sloping aquifer. The results have shown that the bottom slope generates a point of maximum water depth in the aquifer. The experimental data have also indicated that the water depth at the downstream end is not constant, but is a decreasing function of time.