Mapping and Spatial Analysis of Waste-Dumping Sites in the Tilé Watershed, N’Zérékoré, Guinea: A GIS-based Contribution to Sustainable Urban Waste Management
Alpha Oumar Kalissa
*
University of N’Zérékoré, N’Zérékoré, Guinea.
Ansoumane Sakouvogui *
Higher Institute of Technology of Mamou, Mamou, Guinea.
Alsény Bah
University of N’Zérékoré, N’Zérékoré, Guinea.
Aboubacar Sangaré
University of N’Zérékoré, N’Zérékoré, Guinea.
Aboubacar Cissé
University of N’Zérékoré, N’Zérékoré, Guinea.
Amadou Baïlo Baldé
University of N’Zérékoré, N’Zérékoré, Guinea.
*Author to whom correspondence should be addressed.
Abstract
Background : Inadequate solid-waste management poses a serious environmental and public-health challenge in many African cities. In N’Zérékoré, the problem is particularly visible in the Tilé watershed, where informal waste-dumping sites occur close to homes, roads, and the watercourse.
Aim : This study mapped and characterised dumping sites in the Tilé watershed, N’Zérékoré, Guinea, and examined their spatial distribution to inform local solid-waste management planning.
Methods: A systematic inventory was conducted from 6 May to 17 June 2026 across nine neighbourhoods. Active dumping sites were georeferenced using a Garmin 65 GPS receiver, and site boundaries were digitised and analysed in QGIS 3.44.9. Site areas and proximity to dwellings, roads, and the Tilé watercourse were assessed. Kernel density estimation and Global Moran’s I were used to identify concentrations and evaluate spatial clustering.
Results: The survey identified 199 active dumping sites. Of these, 120 (60.3%) were small, 54 (27.1%) were medium-sized, and 25 (12.6%) were large. A total of 170 sites (85.4%) were within 50 m of dwellings, 128 (64.3%) within 50 m of roads, and 50 (25.1%) within 50 m of the watercourse. Five areas of relatively high concentration were identified in Dorota 1, Wessoua, Gbanghana, Mohomou, and Nakoyakpala. Global Moran’s I indicated statistically significant positive spatial autocorrelation (I = 0.42; p = 0.001).
Conclusion: Dumping sites were unevenly distributed across the watershed, with substantial proximity to residential areas and the watercourse. These findings provide a spatial basis for prioritising collection services, identifying suitable designated collection points, and monitoring affected neighbourhoods.
Keywords: Solid-waste management, informal dumping, geographic information systems, spatial clustering, kernel density estimation, Global Moran’s I, urban watersheds, proximity analysis