Efficiency Evaluation of Different Infiltration Models in Different Land Uses and Soil Classes using Rainfall Simulator

Infiltration is one of the most important soil physical variables and basic data in rainfall–runoff models for water loss determination in watersheds. Its measurement is، however، time consuming and costly. For this reason، soils infiltration rates determination by different models is always a serious concern to researchers. In this research، a single event precipitation was measured using rainfall simulator during a 90-minute rainfall for determination of the best infiltration equation in watershed scale. The parameters of five infiltration models namely Kostiakov، Green-Ampt، Horton، NRCS and Philip، were estimated by sum of squared error optimization for four different land uses and three soil textures of sandy clay loam، loam، and sandy loam. The cumulative infiltration rates estimated from the different models were compared using eight different statistics. The results showed that the Kostiakov and NRCS models had the highest priority score and the most permanent trend for accurate estimating of cumulative infiltration rate in different land uses whereas the Horton model was situated in the next position. Overall، the empirical models (Kostiakov، NRCS and Horton models) had the more realistic efficiency than the physical models (Green-Ampt and Philip models).