ABSTRACT
The Adyar watershed is a part of the Chennai basin which is affected by stormwater floods during the north-east monsoon period. A flood susceptibility map and a one-dimensional steady flow model have been created to reduce the severity of flooding in the study area. Sentinel-2 (2021) and ASTER-GDEM satellite data have been analyzed separately. ALOS-PALSAR Digital Elevation Model data have been used and rived data for 1D steady-flow flood simulation. Rainfall trend variability has been studied for 20 years in three districts of Tamil Nadu. Flood conditioning parameters like slope, elevation, drainage density, rainfall, Topographic Wetness Index, Normalized Difference Water Index, Normalized Difference Vegetation Index, land use/land cover, distance from the river, distance from the road, among others, were used in the multi-criteria decision analysis. Finally, the influence of river channel modifications through encroachment has been studied to justify the flood scenario in the watershed. The recommendation and community action plan for flood relief are also given in the conclusion. A detailed community interaction meeting was conducted in the flood-affected areas and the derived action plan to check the level of acceptability was discussed. The outcome of the present study will aid planners and decision-makers in formulating strategies to reduce food insecurity in this region.
