Flood Susceptibility Mapping in the Periyar River Basin of Kerala Integrating Gis-Ahp and Google Earth Engine

Abstract

In recent years, floods and flood-related natural disasters have increased frequently.  This study aims to identify flood-prone areas in the Periyar River Basin, which has been regarded as the lifeline for Kerala and Tamil Nadu using Multi-Criteria Decision Analysis (MCDA) and Analytic Hierarchy Process (AHP) methods . The parameters used for weighting and making the susceptibility map are drainage density, rainfall, slope, elevation, distance from the river, Topographic Wetness Index (TWI), soil, and LULC maps. SRTM DEM was used to construct the drainage network, drainage density, slope, elevation, TWI and distance from the river maps, as well as the Sentinel-2 LULC for land use and land cover map, IMERG GPM data for rainfall data, and FAO soil data to generate soil maps. According to AHP weights calculated and the weighted overlay method using ArcGIS Pro, the map is categorised into risk zones like Very High, High, Moderate, Low, and Very Low. Over 52% of the study area lies within moderate risk zones. The very high and high-risk regions cover an area of 4% and 14% of the total basin, in which 15.31% of the built-up regions are in very high-risk areas, and 42.15 % are in high-risk zones.

Keywords: Flood risk zone, remote sensing, AHP, Multi-criteria Decision Analysis, Google Earth Engine