Sediment yields estimation and identification of their sources in lake Tanganyika basin: a case Mulongwe sub catchment - Uvira City DRCongo

Soil erosion /sedimentation are immense problems that have threatened water resources development in the Tanganyika basin, particularly in the northwest of Lake Tanganyika (Mulongwe sub catchment in Uvira City). This study was conducted in Mulongwe sub catchment (DRCongo) to set up and calibrate SWAT model, to estimate the sediment yields from the sub catchment and identify the sediment sources. The required input data for this study were Digital Elevation Model (DEM) with spatial resolution of 30x30m, Land use/cover and soil map for the year 2004. Eight types of land use/cover were determined and two types of soil in the study area. The hydro meteorological observations were set up around the Mulongwe sub catchment. Stream flows and sediment loads were monitored from two years 1999 and 2004 at Mulongwe gauging site on the main Mulongwe River. Sediment sources were determined by fing printing method and water chemistry. Model performance evaluation statistics for calibrating daily stream flow and sediment were satisfactory with NSE and R2 greater than 0.62 and 0.71 respectively. For the validation the NSE and R2 were also greater than 0.56 and 0.63 respectively. Sediment erosion rate were in the range of 0.17-5.23tons/ha/yr with average of 0.53tons/ha/yr and average amounts of 6,096tons/yr for sediment yields. The sediment sources should be the weathering of rocks, tectonic effects and anthropogenic activities in the study area.