Assessing the risks of soil erosion and small reservoir siltation in a tropical river basin in Mali using the swat model under limited data condition

Abstract

This article presents a modeling-based assessment of soil erosion and small reservoir siltation risks in a middle-sized river basin in southern Mali, West Africa. An integrated watershed model, the Soil and Water Assessment Tool (SWAT), was applied to simulate the watershed hydrology and the sediment detachment and transport processes on land and in streams. According to the estimated land sediment yields and the reservoir lifespans, we concluded that soil erosion and reservoir siltation risks in the study river basin are not significant. The limited data availability posed challenges to the application of the SWAT model and lead to uncertainty in this study. The data available only allows for calibrating and evaluating the SWAT-Banifing model in hydrologic simulation. However, it was found with the hydrologically-calibrated SWAT model that the river system in the Banifing River basin is dominated by the combined baseflow and lateral flow. The low surface runoff intensity provides a possible causal and physical explanation for this study's findings, which were arrived at under circumstances in which there is a lack of monitoring data on sedimentation processes. © 2011 American Society of Agricultural and Biological Engineers.