Quantifying Sedimentation and Capacity Loss in Mwimba Reservoir, Malawi: A Baseline Assessment Using Bathymetric and GIS Analysis

Authors

  • Patsani Gregory Kumambala

    Agricultural Engineering Department, Lilongwe University of Agriculture and Natural Resources, Lilongwe P.O. Box 219, Malawi
  • Raphael Mathews Steven

    1. Agricultural Engineering Department, Lilongwe University of Agriculture and Natural Resources, Lilongwe P.O. Box 219, Malawi; 2. Training Department, Mwimba College of Agriculture, Agricultural Research and Extension Trust, Lilongwe P.O. Box 9, Malawi
  • Grivin Chipula

    Agricultural Engineering Department, Lilongwe University of Agriculture and Natural Resources, Lilongwe P.O. Box 219, Malawi
  • Lameck Fiwa

    Agricultural Engineering Department, Lilongwe University of Agriculture and Natural Resources, Lilongwe P.O. Box 219, Malawi
  • Lenard Kumwenda

    Agricultural Engineering Department, Lilongwe University of Agriculture and Natural Resources, Lilongwe P.O. Box 219, Malawi

DOI:

https://doi.org/10.30564/jees.v7i7.9061
Received: 12 March 2025 | Revised: 25 March 2025 | Accepted: 30 May 2025 | Published Online: 30 June 2025

Abstract

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 m³ was compared to the current volume of 72,966 m³, 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.

Keywords:

Sedimentation; Bathymetric Survey; GIS; Reservoir Management; Mwimba Reservoir; Malawi

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How to Cite

Patsani Gregory Kumambala, Raphael Mathews Steven, Grivin Chipula, Fiwa, L., & Lenard Kumwenda. (2025). Quantifying Sedimentation and Capacity Loss in Mwimba Reservoir, Malawi: A Baseline Assessment Using Bathymetric and GIS Analysis. Journal of Environmental & Earth Sciences, 7(7), 107–117. https://doi.org/10.30564/jees.v7i7.9061

Issue

Vol. 7 , Iss. 7 (July 2025): In Progress

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Article

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Copyright © 2025 Patsani Gregory Kumambala, Raphael Mathews Steven, Grivin Chipula, Lameck Fiwa, Lenard Kumwenda

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This is an open access article under the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) License.

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