摘要
Sedimentation in reservoirs is a significant challenge that affects water storage capacity and operational efficiency.This study establishes a baseline sedimentation status for Mwimba Reservoir in Kasungu,Malawi,five years after its commissioning in 2017,using an integrated bathymetric survey and Geographic Information System(GIS)analysis.A bathymetric survey conducted in March 2022 collected depth measurements at 507 points along 23 transects,which were used to construct a Triangulated Irregular Network(TIN)model in ArcGIS for accurate volume calculations.Sediment concentration was determined from seven water samples using the filtration method.The original design volume of 89,200 m^(3)was compared to the current volume of 72,966 m^(3),indicating an 18.2% loss in capacity over the five-year period.Statistical analysis using a one-sample T-test confirmed that this reduction is significant(p=0.013).The annual sedimentation rate was estimated at 1.25 tonnes per year,and the reservoir’s projected operational life is 27.5 years if no intervention is undertaken.Despite a relatively low sedimentation rate compared to other regional reservoirs,targeted sediment management and further catchment analysis are essential.This study provides critical baseline data for future sediment monitoring,management,and conservation planning for Mwimba Reservoir and similar small water bodies in Sub-Saharan Africa.
基金
the Agricultural Research and Extension Trust of Malawi and the Centre of Excellence of Transformative Agriculture Commercialisation at Lilongwe University of Agriculture and Natural Resources for supporting this study.
