The aim of this research was to measure wetting front (WF) advances under various conditions using a physical model. WF advance, along with its distribution in soils, is an important parameter in drip irrigation. It is influenced by many factors, including land slope, emitter discharge and soil texture. The effects of these factors were investigated by constructing a physical model (60 cm wide, 120 cm high and 160 cm long). Experiments were conducted using two heterogeneous soils, three land slopes (0, 10 and 20%), three emitter discharges (2, 4 and 8 l/h) and a constant volume of irrigation water (24 l). The results indicated that, on sloping lands, the wetted area of the WF advance downstream from the emitter was, on average, 20–62% greater than that upstream from the emitter. With an increase in land slope, the wetted depth under the emitter decreased by 3–18%. When the land slope was changed from 0 to 10% and then again from 10 to 20%, the maximum radius of the WF increased, on average, by 32, 44.8 and 77.5% for discharges of 2, 4 and 8 l/h, respectively.
