Modeling Flood Risk for an Urban CBD Using AHP and GIS

 Abstract—The Central Business District (CBD) of a city is the activity center of the city, typically locating the main commercial and cultural establishments, as well as acting as the center point of the city's transportation network. Flood risk assessment for a CBD is crucial for proper city planning and maintenance. In this study, we model the flood risk for the CBD of Tuguegarao City, which is located in northern Philippines. To accomplish this, we identified important flood-related factors whose data are either easily available or may be collected through some automated process that we developed. We then surveyed experts to gather their estimation of the importance of the identified factors, and then used the AHP to determine the consistency of the expert judgments as well as the relative weights of each factor. These factor weights from the AHP were applied to the gathered data, and a Quantum GIS software tool was used for visualization, producing a geo-hazard map that is color-coded representing 5 levels of estimated flood risks. Using such a GIS weighted overlay analysis map as guide, the city and municipal councils, planning agencies and other stakeholders can act to prepare for potential flooding or, better yet, proactively promote appropriate land-use policy that will minimize threat to lives due to flooding.