“Flood inundation mapping of upstream region in the Adyar River basin: Integrating hydrologic engineering centre's river analysis system (HEC-RAS) approach with groundwater considerations”

Abstract

Chennai, the capital of Tamil Nadu, has grappled with recurrent devastating floods, notably in 2015 and 2021, originating from the upstream of the Adyar River basin. These events have profoundly impacted the city's growth sectors. The regions both upstream and downstream of the Adyar basin, covering Chennai and Chengalpattu districts, face increased vulnerability to severe riverine flooding due to rapid urbanization. The interplay of extensive urban development and river overflow during monsoon seasons has created conditions conducive to substantial flooding, necessitating the development of an effective flood model. This study utilizes digital elevation data and unit hydrograph analysis to estimate flood return probability water levels for various recurrence intervals, including the 10-year and 100-year events. Moreover, it investigates flood inundation, specifically in the Somangalam area, providing insights into the extent of water spread. To comprehensively address the flood dynamics, the study incorporates considerations for groundwater interactions. The overarching objective remains to identify the most vulnerable zones within the Adyar River region prone to flooding. Accurate identification of these vulnerable areas is crucial for policymakers and stakeholders to devise proactive planning and early warning measures, enhancing disaster preparedness and resilience in the face of potential flood disasters. This approach aims to safeguard the well-being of Chennai's residents and promote sustainable development in the region.