Evaluation of integrated KW-GIUH and MUSLE models

In this study, the Kinematic Wave-Geomorphologic Instantaneous Unit Hydrograph-Modified Universal Soil Loss Equation (KW-GIUH-MUSLE) model was tested for its sediment yield estimation potential on the Kengir watershed in Iyvan city of Ilam Province, Iran. The runoff factor was calculated for six storms during 2000. The spatial distribution of soil erodibility factor was taken from the attribute data pertaining to the soils of the study area. The topographic factor (LS) was calculated by multiplying the length (L) and slope (S) factor from the created maps. On the other hand, cropping management and erosion control practice factors, for different land use, were taken from the satellite based land use/land cover attribute data and geographic information system (GIS), respectively. Subsequently, all the parameters were substituted in the KW-GIUH-MUSLE in order to derive event-wise sediment yields. Sediment yield at the outlet of the study watershed was simulated for 6 storm events spread over the year 2000 and validated with the measured values. The percent deviations between the sediment yield measurements and observations vary in the range of-22.50 to 5.83%. The high coefficient of determination value (0.99) indicates that model sediment yield predictions are satisfactory for practical purposes. Key words: Sediment yield modelling, geographic information system (GIS), kinematic wave-geomorphologic instantaneous unit hydrograph-modified universal soil loss equation (KW-GIUH-MUSLE), storm event, Kengir watershed