Simulation and prediction of sediment loads using MUSLE–HEC-HMS model in the Upper Ewaso Nyiro River Basin, Kenya

Abstract

Sediment management in the river basins is a crucial issue that needs to be addressed. Sediment loads over time have been varying due to extensive changes in the climatic, biophysical, and anthropogenic activities carried out in the river basin. These changes threaten the natural sustainability of the basin and cause negative impacts on local, social, and economic development, including pastoralism, ranching, and agriculture. This study aimed at modeling the sedimentation rate in the Upper Ewaso Nyiro River Basin (UENRB) using the Modified Universal Soil Loss Equation (MUSLE) model and Hydrologic Engineering Center-Hydrologic Modeling System (HEC-HMS) model. The study utilized remotely sensed data for the UENRB: Landsat imageries, soil data, a digital elevation model, and rainfall data. The MUSLE parameters generated from the datasets included the practice factor, cover management, soil erodibility, topography, and precipitation for the years 1990, 2000, 2010, and 2020. The models were calibrated, and the simulated results indicated that the sedimentation loads varied in the various sub-basins as the years progressed from 1990 to 2020. In 2020, the highest river sediment load experienced in one of the sub-basins was 415,803.5 tons, while the lowest sediment load was 34,137.70 tons. It is essential to regulate the variables that aid in the variability of the sediment loads in the river sub-basins. Thus, there is a need to formulate a framework and concrete measures to ensure the river basin's protection and restoration, in line with Kenya’s Vision 2030.