Unsteady State Groundwater Flow in Unconfined Aquifer Under Changing Conditions in Water Levels

Abstract

Generalized solution of linearized Boussinesq equation is derived to approximate the nature of ground water flow due to changes in water levels in two ditches bounding an unconfined aquifer. In this research a mathematical model is developed for two flows. In the first case, a sudden change in the water level occurs in the two bounding ditches simultaneously, while in the second case, a sudden change in water level in one ditch is followed by a gradual rise in water level in the other ditch.

Closed form analytical solutions are obtained for the two cases by solving governing equations using eigen value eigen function method. A numerical example problem is presented in which head values are computed at various places in the aquifer at given time intervals and the results plotted.