Analyses of Drought Flow in Recession Period

This study presents a downstream boundary condition for the nonlinear Boussinesq equation (NBE) in an unconfined rectangular aquifer using experimental results, which is often caused by drought flow in a recession period. It is possible to obtain a semianalytical solution for NBE using a series expansion method. The semianalytical solutions are compared with the numerical and experimental results. Their agreement between the semianalytical and numerical solutions and the semianalytical and experimental ones is satisfactory.