A Parametric Analysis of Infiltration Equations in Saturated and Unsaturated Conditions and the Effect of Land-Use Changes on them: A Case Study of Kamyaran City, Iran

Infiltration is one of the most important parameters of hydrologic cycle. To prevent soil erosion and to utilize water resources, soil infiltration characteristics should be determined. The present study aimed to determine the effect of land-use changes on infiltration and then to choose the best infiltration model of each land-use. Field experiments were conducted in 3 various landuses including pasture, agriculture and garden land-use. Then, agriculture and garden land use engender from pasture land-use, in 5 various tensions (0, 3, 6, 10, 18 cm-H2O) and 3 replication. Infiltration models of Kostiakov, Lewis Kostiakov, Horton, Green- Ampt, Philip and SCS were evaluated. Simulation cumulative infiltration and infiltration rate were compared with the observation data using relative error (RE) and root mean square error (RMSE) parameters. The results indicated that land-use changing from pasture to agriculture or garden leads to an increase in infiltration rate and cumulative infiltration. The comparison of infiltration models indicated that in pasture and agriculture land-use, Kostiakov and Philip models have higher accuracy than other models, but in garden land-use, Horton and Kostiakov models were better than the other ones.