Wetting patterns estimation under drip irrigation systems using an enhanced empirical model

The wetting pattern is an important factor to consider when designing and managing a drip irrigation system. The dimensions of the pattern are imperative in selecting the right spacing between emitters and the suitable distance between laterals. We conduct laboratory experiments with surface drip irrigation involving two soil textures (sand and clay), two discharge rates, and two soil profiles (homogeneous and layered-textural). An empirical model was developed to estimate the vertical and horizontal advance of the wetting front at different application times. The empirical model includes estimation of the wetted radius at the soil surface and the depth of the wetting pattern as a function of application time, emitter discharge, soil bulk density, initial soil moisture content, saturated hydraulic conductivity, and the proportions of sand, silt and clay in the soil. We follow the same procedure in developing empirical formulas for predicting the wetted radius at different soil depths, to estimate the full shape of the wetting pattern. The proposed model predicts the full wetting pattern with acceptable accuracy and performs well in replicating published experimental data.