Multi-hazard risk assessment in urban planning and development using AHP

Abstract

Many cities across the world are exposed to more than one hazards. Focus on only the most prominent natural hazards, or the most recent event can be dangerous, as many potential threats to urban development are not assessed. Even when multiple hazards in a given area is assessed, there is a lot of confusion on how to utilize hazard information in making decisions for urban land-use planning. This study is aimed to develop a method to utilize hazard maps in urban land-use decision making. The study has identified numerous applications of GIS-based multi-criteria decision model (MCDM) for land-use suitability evaluation. It has then tried to integrate multiple hazard maps, a product of multi-hazard risk assessment, into the model to generate suitability maps for further development. The used parameters were correlated using the Analytical Hierarchical Process (AHP), one of the MCDM tool and incorporated into the GIS environment, with a comparison between the cases with-and without-hazard considerations. The application of the proposed method was tested for Madang Province, Papua New Guinea for four land-uses, i.e., residential, industrial, commercial, and agricultural. The results of the model i.e., land-use suitability maps were spatially reflective of the model user's decisions and understanding. This model gave considerable results for the urban development plan. Furthermore, comparison of the model outputs with and without hazard considerations led to notable differences. For example, almost 1% of the study area was rendered unsuitable for residential development in the assessment without hazard consideration. Besides, approximately 14% of the study area were assessed as suitable for without-hazard consideration but less suitable for with-hazard consideration. Since the hazard maps represented patterns and locations of natural hazards, our approach of incorporating them could help highlight the gaps in risk recognition with future development in hazardous areas.