Investigation of Geomorphometric Parameters to Simplify Water Erosion Modelling (a Case Study: Emamzadeh Watershed, Iran)

Abstract

In recent decades, water erosion potential has been recognized as a severe threat against soil sustainability and water resources. The present study was conducted to investigate the relation between geomorphometric parameters and soil type to simulate water erosion in the Emamzadeh watershed located in the northeast of Khuzestan Province. The primary and secondary geomorphic parameters, including slope, plan curvature, profile curvature, flow length, flow accumulation, flow direction, and stream power index (SPI) calculated based on the digital elevation model (DEM). The water erosion measured using available data and laboratory analyzes, then it was predicted with water erosion prediction project (WEPP) model. Our results revealed that the measured soil erosion does not show any relation with geomorphic parameters, while some of the geomorphometric parameters depicted a significant relation with WEPP model’s predictions. A model with an excellent explanation coefficient obtained using multivariate linear regression to predict water erosion. The geomorphometric parameters application allows an estimation of erosion based on simple linear models (R 2 : 0.934, sig: 0.000). Moreover, for SPI, the total curvature was -0.794, plan curvature was -0.658, and profile curvature was 0.746. Therefore, there was a relation between curvature and SPI. Our results showed no specific relation between sediment transport index (STI) and water erosion. The low amount of STI represents the sedimentation areas in the watershed. Generally, application of geomorphometric parameters simplify the soil erosion prediction.