DITCH DRAINAGE THEORIES FOR HOMOGENEOUS ANISOTROPIC SOIL

The problem of seepage of steady rainfall or irrigation recharge into a homogeneous and anisotropic soil medium, drained by equally spaced d itch drains overlying a barrier, is solved, Two general cases of the p roblem are considered: (1) ditch drains dug down to an impermeable bar rier; and (2) ditch drains dug down to a gravel substratum. The propos ed solutions are exact in the sense that they are based on potential t heory and account for the surface of seepage. The validity of the prop osed solution for the first case is tested by comparing the midway wat er-table heights obtained from it for some specific drainage situation s with the corresponding upper and lower theoretical bounds of Youngs. The accuracy of the proposed analytical model for the first case is f urther tested by comparing the midway water-table height obtained from it for a specific drainage situation with the corresponding height ob tained from other numerical work.