Assessment of Flood Risk in the High Rainfall Coastal Area of Cuddalore Taluk, Southeast India, Using GIS-Based Analytic Hierarchy Process Techniques

Abstract

Flooding stands as the most prevalent and financially burdensome natural disaster impacting nations worldwide. This study focuses on flood risk assessment within the Cuddalore taluk, aiming to leverage Geographic Information System (GIS)-based Analytic Hierarchy Process (AHP) techniques for analyzing flood hazards, vulnerabilities, and risks in the region. Seven key causal factors—elevation, slope, drainage density, river distance, rainfall, soil, and geology—were utilized to construct the flood hazard map. Results indicate that the taluk encompasses very low, low, moderate, high, and very high flood hazard zones, covering 7%, 22%, 34%, 25%, and 12% of its total area, respectively. Additionally, a flood vulnerability map was generated using five spatial layers: land use/cover, population density, distance to road, literacy rate, and population under the age of 6. Integration of the flood hazard and vulnerability maps facilitated the creation of a comprehensive flood risk map. The findings reveal that within the Cuddalore Taluk, zones classified as very low, low, moderate, high, and very high flood risk constitute 51%, 6%, 12%, 18%, and 12%, respectively. While the majority of the coastal region faces susceptibility to flooding within the very low, low, and moderate ranges, select areas are at risk of high and very high flooding. Disseminating flood hazard, vulnerability, and risk maps to relevant authorities is imperative for raising awareness regarding flood-prone locations. The coastal regions, along with adjacent areas, predominantly fall under the category of very high-risk zones, necessitating effective mitigation strategies. Specific locales such as Pillayarkuppam, Cuddalore, Tiruvandipuram, Kayalpattu, Nellikuppam, and Punjimangattuvalkkai demand focused efforts to mitigate high flood risks. Conversely, areas with very low and low flood risks, including Vadakuthu, Neyveli T.S., Sorathur, Panruti, Aierpali, and Pewndur, require preservation measures. Additionally, zones such as Arunam and Mettukuppam, exhibiting moderate flooding risks, warrant attention for preservation efforts in their immediate surroundings.