The study aimed to analyze the drivers of sedimentation in the Nkhata River catchment in Nkhatabay district, Malawi, where an increase in sediment deposition poses significant challenges to Northern Region Waterboard’s water supply infrastructure. Specifically, it aimed to analyse land use land cover changes, as well as to investigate sediments generation and transportation factors in Nkhata River’s catchment. A quantitative research design was used which involved collecting 2013 and 2023 imagery from Landsat 7 and 8, digital elevation models and soil and climate databases. Land use land cover classification of land Landsat images was performed using a Multi-Layer Perceptron neural network model to performed change detection analysis. Sediment generation and transportation factors were investigated using the Revised Universal Soil Loss Equation (RUSLE) model, which estimated soil loss and sediment yield based on factors such as rainfall erosivity, soil erodibility, slope length and steepness, land cover, and management practices. Key findings revealed significant LULC changes over a decade, with grassland decreasing from 493.72 hectares to 318.86 hectares, built-up and bare land increasing from 463.76 hectares to 642.93 hectares, and tree vegetation decreasing from 463.76 hectares to 388.41 hectares. The sediment yield for areas producing 0-2 tons per hectare per year decreased from 94.02% in 2013 to 90.55% in 2023, while areas yielding more than 8 tons per hectare per year increased from 0.83% to 1.17%. The cover and management practice factor (C factor) and the slope length and steepness factor (SL factor) were identified as major drivers to sediment yield. The study therefore concluded that maintaining vegetative cover is crucial for reducing erosion and recommended reforestation, soil conservation practices, community engagement, regular monitoring, and advanced modeling techniques to improve sediment yield predictions and management. This research demonstrates the effectiveness of GIS and remote sensing in hydrological studies of small and ungauged catchments and highlights the importance of integrated catchment management practices to mitigate sediment-related challenges.
Keywords: Land Use Land Cover, RUSLE, Sedimentation, GIS and Remote Sensing
