A numerical solution of two-dimensional free surface flow to ditch drains i
n homogeneous and anisotropic soils is presented. The differential equation
governing two dimensional ground-water flow in anisotropic soils is solved
by the alternating direction implicit (ADI) method of finite difference. I
n the approach the method is modified to make it applicable for curved boun
daries. This simplified approach does not involve any kind of smoothing or
linearization technique. The model solutions for ditch drainage with consta
nt replenishment and instantaneous drawdown are found to be in close agreem
ent with the finite-difference and finite-element solutions proposed by oth
er researchers.