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Hydrological impacts of land use and land cover change on the width of Bua River, Nkhotakota district, Malawi

2026Open accessUniversity of Malawi

In plain language

Changes in land use and land cover significantly alter the hydrology of the Bua River in Malawi. Satellite imagery from 2016, 2020, and 2024 shows that built-up areas and sparse vegetation expanded across the catchment, while forest cover, agricultural land, and surface water bodies declined. Concurrently, satellite measurements indicate that the width of the river widened over time. This widening corresponds to heightened surface runoff, increased sedimentation, and greater discharge, accompanied by reduced water infiltration and groundwater recharge. Because systematic river flow measurements on the ground have declined since 2010, tracking river width offers an effective proxy for monitoring water volume. The observed relationship between landscape degradation and altered river morphology demonstrates how spatial technologies can track hydrological shifts, providing a basis for sustainable catchment management and evidence-based land regulation.

Key takeaways

  • Between 2016 and 2024, the Bua River catchment experienced increases in built-up areas and sparse vegetation alongside declines in forests and agricultural land.
  • The width of the Bua River gradually increased over the study period, driven by heightened surface runoff, sedimentation, and river discharge.
  • Satellite-derived river width served as an effective proxy for water volume amidst a decline in ground-based hydrological monitoring in Malawi.
  • Human-driven land cover changes showed a direct positive relationship with river widening and altered river morphology.

Why it matters

Land degradation, deforestation, and settlement expansion threaten water resources by intensifying runoff and altering river structures. In regions where ground-level river monitoring infrastructure has deteriorated, remote sensing offers a reliable method to track hydrological changes. Understanding these catchment dynamics provides policymakers and environmental managers with the evidence needed to enforce land protection laws, promote afforestation, and safeguard future water supplies.

Commercialisation angle

The research demonstrates an applied, early-stage monitoring methodology combining Sentinel-2 satellite imagery and GIS analysis to assess river morphology where physical hydrological stations are absent. Environmental consultancy firms, spatial data analytics providers, and catchment management authorities could integrate this approach into remote watershed monitoring toolkits. Real-world adoption would require translating these analytical workflows into automated environmental surveillance services or decision-support platforms for resource regulators.

AI-generated from the published abstract. Always read the original work before citing.

Abstract

This study examined the impact of land use and land cover (LULC) changes on the width of the Bua River in Malawi, recognizing LULC change as a major environmental challenge with significant consequences for water and land resources. Deforestation, soil erosion, and agricultural expansion have contributed to land degradation, reducing both the quality and quantity of water. To monitor these dynamics, GIS and remote sensing techniques were employed, using Sentinel‑2 satellite imagery for 2016, 2020, and 2024. Classification and change detection analysis in ArcGIS 10.8 revealed that by 2024, the catchment experienced increases in built‑up areas and sparse vegetation, while water bodies, agricultural land, and forest cover declined. River width measurements, also derived from Sentinel‑2 data, showed a gradual increase in width over the study period, attributed to higher surface runoff, sedimentation, and discharge, alongside reduced infiltration and groundwater recharge. Given the decline in systematic river flow monitoring in Malawi since 2010, river width was used as a proxy for water volume. The study revealed that there is a positive relationship between LULC changes and river width variations. This suggests that human‑driven land use changes in the Bua catchment are closely associated with hydrological responses, particularly changes in river morphology. The findings align with broader regional studies that link forest loss and agricultural expansion to increased runoff and altered water availability. The study underscores the importance of integrating spatial technologies in environmental monitoring and highlights the urgent need for policymakers and stakeholders to implement effective land management policies. Ensuring sustainable land and water resource use requires active enforcement of legislation, promotion of afforestation, and regulation of settlement expansion. By addressing LULC challenges, Malawi can mitigate the negative impacts on river systems and safeguard water resources for future generations. This research demonstrates that combining GIS, remote sensing, and correlation analysis provides valuable insights into the interplay between land use dynamics and hydrological processes, offering a foundation for sustainable catchment management.

Research topics

  • Land Use and Ecosystem Services
  • Hydrology and Watershed Management Studies
  • Groundwater and Watershed Analysis

Read the original research

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DOI: 10.1007/s43832-026-00447-7

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