The Use of LAPSUS Model to Estimate the Runoff and sedimentin the Kakhk paired catchment of Gonabad

In this research introduced the LAPSUS model as a runoff, erosion and sediment model in Iran. This model for the first time has operatedin Iran at Kakhk paired catchment of Gonabad. LAPSUS model is a Landscape Evolution Model that can estimate the runoff, erosion and sediment at the four stage include: calculate the effective rainfall, runoff routing, calculate the capacity of sediment transport and calculate the rate ofsediment transport. The input to the models include DEM, amount of rainfall, runoff coefficient, convergence factor, discharge and slope exponent, erodibility and sedimentation potential factors.The result showed that the LAPSUS model is able to show runoff, erosion and sediment as a raster maps for each rainfall event. The result showed LAPSUS model has a normalized RMSE of 3.5 percent for runoff and 2.6 percent for sediment. Also,Coefficientof Determinationis 99 percent for runoff and 97 percent for erosion and sediment. On this basis, due to limited and available inputs, this model can be introduced as a runoff, erosion and sediment model in Iran.