Integrated GIS- and multicriteria-based methodology for siting municipal solid waste landfills: application to Riobamba (Ecuador)

Municipal solid waste management is a major challenge for spatial planning due to its links with population growth, changing consumption patterns, and associated environmental impacts. In settings where final disposal remains a structural component of the system, the limited capacity of existing sites and their proximity to end-of-life make it necessary to plan new alternatives. In this context, landfill siting is critical to minimize risks to soils and water resources, reduce social impacts, and ensure operational and economic feasibility.

This work develops and applies an integrated, adaptable, and replicable methodology based on Geographic Information Systems (GIS) and multicriteria analysis for selecting landfill sites using technical, environmental, and territorial criteria. The approach is applied to the city of Riobamba (Ecuador), a high-mountain Andean environment characterized by strong physical–environmental heterogeneity, where planning requires traceable and consistent technical support, particularly to avoid locating facilities in areas vulnerable from edaphic and hydrological perspectives.

The methodology is structured in four stages: (i) compilation of geographic information from local and global sources; (ii) processing, cleaning, reprojection, and standardization of layers to ensure spatial consistency; (iii) definition and classification of exclusion and inclusion criteria into categories and subcategories, incorporating a critical review based on regulations and the characteristics of the study area; and (iv) multicriteria evaluation through weight assignment to produce a suitability map and prioritize the most favorable areas.

The outcome is a transferable methodology that provides technical traceability to the selection process and can be adjusted to different territorial conditions and data availability. It is intended as a decision-support tool for spatial design and planning focused on soil and water protection, contributing to more transparent decision-making in integrated solid waste management.