Modeling two-dimensional infiltration from furrows

Abstract

Numerical simulations were performed to study two-dimensional infiltration from furrows. The simulations were carried out using the models SWMS_2D, HYDRUS-2D and HYDRUS-1D. The first model was used to evaluate the individual effect of soil and furrow parameters on cumulative infiltration and deep seepage. Cumulative infiltration was found to be more sensitive to saturated hydraulic conductivity, wetted perimeter and furrow spacing than the other parameters for relatively long times, while cumulative deep seepage was more sensitive to the same parameters except to the furrow spacing. It was verified that two-dimensional cumulative infiltration can be approximated using one-dimensional models, for example HYDRUS-1D, by combining the vertical and horizontal infiltrations. The two-dimensional cumulative infiltration is underpredicted by no more than 35% using this calculation. When steady state is reached the steady infiltration rate may be linearly related to the depth of the furrow. As a result, steady infiltration rate is dependent only on type of soil, water depth in the furrow and furrow width. Broocks-Corey soil hydraulic parameters were matched to the van Genuchten parameters by four different procedures. The method based on matching sorptivities produced the closest results to the van Genuchten solution for one- and two-dimensional cumulative infiltration. However, cumulative deep seepage was not accurately simulated. The SCS infiltration parameters were also matched but using an inverse problem methodology. The parameters obtained described cumulative infiltration reasonably well.