Simulating Hydraulic Behavior of an Agricultural Drain Based on Experimental Data

Abstract

Simulation models have been used in a limited fashion to describe and characterize soil water flow in saturated conditions as an approach to optimize drainage design parameters. The dynamic hydraulic behavior of an ideal drain can be characterized by a drain intake resistance factor, solving a two-dimensional equation, including humidity retention functions, by a numerical method based on the finite-element analysis tool, describing time variations of streamline magnitudes and direction, water flow radial velocities, relative soil water content, and pressure head profiles throughout the drainage process. Two drainage pipe extraction areas of 7.85 and 39.47 cm2 m−1 were simulated, with the drainage system embedded in a homogeneous and isotropic quartz sand under constant and variable discharge conditions. Simulation results indicate that the water entrance resistance factor must be considered in the design of a drainage network because the hydraulic behavior on the agricultural drain depends on its geometric characteristics.