TITLE:
Land Use and Land Cover Patterns on Water Quality at the Congo Dam Catchment Area in Freetown, Sierra Leone
AUTHORS:
Prince Tongor Mabey, Baimba Abdulai Koroma, Edmond Bockarie Ansumana, Mohamed Jalloh
KEYWORDS:
Land Use/Land Cover Change (LULC), Water Quality, Turbidity, Nutrient Enrichment, Deforestation, Urban Expansion
JOURNAL NAME:
Journal of Water Resource and Protection,
Vol.18 No.9,
September
28,
2026
ABSTRACT: This study examined the relationship between Land Use and Land Cover (LULC) changes and water quality in the Congo Dam catchment between 2004 and 2023. Geospatial analysis was conducted using Landsat satellite imagery and Geographic Information System (GIS) techniques to classify and quantify LULC changes. Water quality data were obtained from monthly monitoring of the Congo Dam reservoir from January to June 2023 and analyzed against World Health Organization (WHO) standards. Pearson’s correlation analysis was employed to evaluate the relationships between LULC variables and selected water quality indicators. The results revealed substantial vegetation loss, primarily through conversion to agriculture (3.74 km2) and settlements (2.59 km2), while water bodies remained relatively stable. Correlation analysis demonstrated that agricultural expansion exhibited the strongest positive relationship with phosphate concentration (r = 0.926, p E. coli (r = 0.835, p = 0.001). Conversely, water body stability exhibited weak and non-significant relationships with pH (r = −0.112, p = 0.734), calcium hardness (r = 0.094, p = 0.781), sulphate (r = 0.071, p = 0.824), and temperature (r = −0.236, p = 0.459). The study concludes that increasing agricultural activities, settlement expansion, and vegetation degradation significantly contribute to the deterioration of reservoir through elevated sediment, nutrient, dissolved solid, and microbial loads. It is recommended that watershed protection measures, afforestation programs, sustainable agricultural practices, and stricter land-use planning policies be implemented to reduce environmental pressures and safeguard the long-term quality of water in the Congo Dam catchment.