Mazda Kompani-Zare - Desert Management Department, School of Agriculture, Shiraz University, Shiraz ۷۱۸۸۶, Iran.
Hongbin Zhan - Department of Geology and Geophysics, Texas A&M University, College Station, TX ۷۷۸۴۵-۳۱۱۵, USA

The credibility range of Dupuit-Forchheimer assumption in prediction of steady-state flow to an infinite horizontal drain in an unconfined aquifer is studied by utilizing analytical element method together with Genetic Algorithm. The functionality of the flow rate in respect to different hydraulic head of the constant-head boundary, drain radius, drain elevation, and distance to the constant-head boundary is also studied. It is found that Dupuit-Forchheimer assumption is credible in the distances more than 1.8 times of drain elevation from the drain where the distance between the drain and the costant head is about 10-12 times of drain elevation.

Analytical element method; Water table; Horizontal drain; Dupuit-Forchheimer; Genetic Algorithm