A MULTI-CRITERIA GIS MODEL FOR SUITABILITY ANALYSIS OF LOCATIONS FOR DUMPSITES IN LILONGWE CITY.

The rapid urbanization of Lilongwe City, Malawi, has exacerbated solid waste management issues, as the existing dumpsite in Area 38 (Mtaya) is insufficient to accommodate the growing population. This study employs multi-criteria decision analysis (MCDA) utilizing Geographic Information Systems (GIS) to identify optimal dumpsite locations that ensure environmental sustainability and safeguard public health. The assessment involved key criteria including proximity to airports (1,000 m buffer), boreholes and waterways (500 m buffer), railways and roads (400 m buffer), slope gradients, soil characteristics (surface loamy sand and subsurface sandy clay loam), and land use/land cover (LULC). This was achieved through the integration of spatial datasets and the application of Analytic Hierarchy Process (AHP) weighting. The results indicate that 11% (45.88 km2) of Lilongwe's land is suitable for landfill sites, primarily located in the northern, southwestern, and southeastern regions. The designated areas adhere to international landfill placement regulations, characterized by non-productive barren terrain comprising 25 percent of the city and mild slopes of less than 5°, thereby minimizing the risk of leachate discharge. Soil types with restricted permeability safeguard groundwater, while proximity buffers reduce the likelihood of water source contamination and decrease transportation costs. The finding that only 11% of these results are suitable underscores the necessity of transitioning to constructed landfills equipped with leachate treatment systems, as recommended by Malawi's Environmental Affairs Department. The research demonstrates that data-driven spatial planning, utilizing GIS and remote sensing, can significantly mitigate environmental and health risks. Recommendations include on-site verification of proposed locations, community engagement in waste management initiatives, and additional studies that integrate climate resilience factors such as flood vulnerability. This study presents a replicable framework for sustainable waste management in rapidly urbanizing regions, emphasizing the need to balance ecological preservation with infrastructure development

The rapid urbanization of Lilongwe City, Malawi, has exacerbated solid waste management issues, as the existing dumpsite in Area 38 (Mtaya) is insufficient to accommodate the growing population. The assessment involved key criteria including proximity to airports (1,000 m buffer), boreholes and waterways (500 m buffer), railways and roads (400 m buffer), slope gradients, soil characteristics (surface loamy sand and subsurface sandy clay loam), and land use/land cover (LULC). The designated areas adhere to international landfill placement regulations, characterized by non-productive barren terrain comprising 25 percent of the city and mild slopes of less than 5°, thereby minimizing the risk of leachate discharge. The finding that only 11% of these results are suitable underscores the necessity of transitioning to constructed landfills equipped with leachate treatment systems, as recommended by Malawi's Environmental Affairs Department.

Lilongwe city of Malawi is located in the central region of Malawi at the latitude of 13.8500°S to 14.1000 and longitude of 33.6500°E to 33.9000°E precisely located within the Lilongwe district. It is the capital city of Malawi and the area is known for its high urbanization, high population and an increase in solid wastes which opts for a large and efficient disposal site. It has an elevation ranging from 983 meters to 1259meters and it is mainly comprised of flat plains with a total area of 403.343Km2 .

Traditional authority: Lilongwe City

District: Lilongwe

Coordinates: -13.9065, 33.7532