Flood Susceptibility
Assessment for Coastal Villages of Southern Tamil Nadu: An Integrated GIS and AHP
Approach
Aswin S.K., Stephen Pitchaimani V. and Antony Alosanai Promilton A.
Disaster Advances; Vol. 18(6); 18-27;
doi: https://doi.org/10.25303/186da018027; (2025)
Abstract
Floods are among the most devastating natural disasters globally causing significant
loss of life, property damage and economic disruption across communities. This study
presents a comprehensive flood susceptibility assessment of the coastal villages
from Mookkaiyur to Tharuvaikulam in Southern Tamil Nadu, India, using an integrated
approach combining remote sensing, Geographic Information Systems (GIS) and the
Analytical Hierarchy Process (AHP). Ten critical parameters: geomorphology, rainfall,
slope, Topographic Wetness Index (TWI), land use/land cover, soil type, lithology,
Normalized Difference Vegetation Index (NDVI), distance from river and distance
from road, were analysed to develop a detailed flood susceptibility map of the region.
The study area spanning approximately 320 sq. km was evaluated using various data
sources including SRTM DEM, Landsat-8 imagery and meteorological data. The AHP method
assigned appropriate weightages to these parameters ranging from 18 for geomorphology
to 6 for NDVI.
The resulting flood susceptibility map reveals that 26.76% of the study area falls
under medium susceptibility, while 35.15% exhibits high to very high susceptibility
to flooding. The analysis identified that areas with very low slopes, high rainfall
and flood-prone geomorphological units combined with poor drainage characteristics
of Vertisols and black clay lithology are particularly vulnerable to flooding. This
study provides crucial insights for flood risk management and urban planning and
may be effectively applied to similar coastal regions for comprehensive flood risk
assessment.
