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<p>Municipal solid waste disposal is a global problem that is associated with continuous population growth and urban expansion especially in developing countries. City planners find it challenging due to lack of accessible, open source and automated tools for evidence-based landfill site selection. Bulawayo, Zimbabwe’s second-largest city, faces acute solid waste management challenges from the Ngozi Mine landfill which is now overcapacity and has exceeded its lifespan often resulting in frequent fires. This study seeks to identify suitable landfill sites in Bulawayo using an open-source and script-based hybrid GIS and Fuzzy AHP approach within R to support sustainable waste management. Eleven environmental, economic, and social criteria from Shuttle Radar Topography Mission, Landsat 8, WorldPop, Diva GIS, Open Street Map, Food and Agricultural Organisation, and Bulawayo City Council were processed and analysed in QGIS (30&#xa0;m resolution), and weighted via Fuzzy-AHP in R. Weighted overlay produced suitability maps and candidate landfill sites that were validated and ranked using CR, ROC-AUC and OAT sensitivity analysis in R. The results indicate the following area distributions: not suitable (2,940.75&#xa0;ha, 5.36%), less suitable (24,633.68&#xa0;ha, 44.92%), suitable (27,011.96&#xa0;ha, 49.25%), and more suitable (257.95&#xa0;ha, 0.47%). Six candidate sites, each exceeding 15 hectares, were identified as viable alternatives for addressing Bulawayo’s waste management challenges, with Site C emerging as the top-ranked option (defuzzified score: 0.224) based on its superior performance across 11 weighted criteria. Model robustness was confirmed by a consistency ratio of 0.037 (&lt; 0.1 threshold), an AUC of 0.854 from ROC validation, and a high Spearman rank correlation (mean ρ = 0.922) in sensitivity analysis, ensuring reliable rankings above ± 30% weight perturbations. Bulawayo City Council should immediately prioritize Site C development through phased implementation integrating residential/industrial buffers and urban growth modelling, and pilot geotechnical investigations across all sites to establish slope risk thresholds specific to Bulawayo soils. The findings from the study provide researchers, urban planners and local authorities with a scientifically grounded basis for sustainable waste management policy and site allocation through enhancing reproducibility, automation and cost reduction relative to ArcGIS-based methods, thereby advancing both industry practice and methodological knowledge.</p>

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Landfill Site Selection in Bulawayo, Zimbabwe: Integrating Fuzzy-AHP and GIS Within An R-Based Decision Support Framework

  • 期刊论文

  • 发表日期：

    2026年2月26日

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  • Norman Karimazondo,
  • Narissara Nuthammachot,
  • Warangkana Jutidamrongphan

摘要

Municipal solid waste disposal is a global problem that is associated with continuous population growth and urban expansion especially in developing countries. City planners find it challenging due to lack of accessible, open source and automated tools for evidence-based landfill site selection. Bulawayo, Zimbabwe’s second-largest city, faces acute solid waste management challenges from the Ngozi Mine landfill which is now overcapacity and has exceeded its lifespan often resulting in frequent fires. This study seeks to identify suitable landfill sites in Bulawayo using an open-source and script-based hybrid GIS and Fuzzy AHP approach within R to support sustainable waste management. Eleven environmental, economic, and social criteria from Shuttle Radar Topography Mission, Landsat 8, WorldPop, Diva GIS, Open Street Map, Food and Agricultural Organisation, and Bulawayo City Council were processed and analysed in QGIS (30 m resolution), and weighted via Fuzzy-AHP in R. Weighted overlay produced suitability maps and candidate landfill sites that were validated and ranked using CR, ROC-AUC and OAT sensitivity analysis in R. The results indicate the following area distributions: not suitable (2,940.75 ha, 5.36%), less suitable (24,633.68 ha, 44.92%), suitable (27,011.96 ha, 49.25%), and more suitable (257.95 ha, 0.47%). Six candidate sites, each exceeding 15 hectares, were identified as viable alternatives for addressing Bulawayo’s waste management challenges, with Site C emerging as the top-ranked option (defuzzified score: 0.224) based on its superior performance across 11 weighted criteria. Model robustness was confirmed by a consistency ratio of 0.037 (< 0.1 threshold), an AUC of 0.854 from ROC validation, and a high Spearman rank correlation (mean ρ = 0.922) in sensitivity analysis, ensuring reliable rankings above ± 30% weight perturbations. Bulawayo City Council should immediately prioritize Site C development through phased implementation integrating residential/industrial buffers and urban growth modelling, and pilot geotechnical investigations across all sites to establish slope risk thresholds specific to Bulawayo soils. The findings from the study provide researchers, urban planners and local authorities with a scientifically grounded basis for sustainable waste management policy and site allocation through enhancing reproducibility, automation and cost reduction relative to ArcGIS-based methods, thereby advancing both industry practice and methodological knowledge.