Two‐Dimensional Analysis of Furrow Infiltration

Abstract

A recently developed two‐dimensional finite element transient water‐flow model was used to simulate infiltration by furrow irrigation with a shallow water table. Suggested applications are primarily those that focus on unsaturated zone water flow. Field soil measurements were used to compare field‐measured with simulated infiltrated water for two‐layered soil systems. Simulated and measured infiltration were fairly close for one irrigation event, but significantly different for another. To further investigate the causes of discrepancies between simulated and measured infiltration, we also applied the water‐flow model to simulate the influence of variable soil and flow characteristics on infiltration in a furrow. We simulated infiltration for varying water levels in the furrow, for water‐filled and dry adjacent furrows, studied the effect of a surface seal on infiltration, and compared homogeneous with heterogeneous soil profiles with preferential flow regions. Lateral water movement was found to be insignificant, and the influence of a variable furrow water level was almost completely described by the changing wetted perimeter. Introduction of a spatially variable hydraulic conductivity in the two‐dimensional soil domain resulted in an immediate response of the water table to ponded infiltration.