Assessment of Flood Potential Ranking of Subwatersheds: Adayar Watershed a Case Study
Flooding may be caused due to a combination of heavy rain, blockage in the channel, development along the stream channel and urbanization in the upstream of the watershed. The assessment of the extent of flooding in a watershed is essential for its sustainable development. The flow contribution to the river from upstream areas outside the city limits are generally neglected in the downstream flood management. The present study focuses on the Adayar watershed, Chennai. It emphasizes on identification and prioritization of flood source area by coupling Unit Flood Response (UFR) technique and HEC-HMS, considering the spatial distribution of the rainfall. The results indicate that Manimangalam sub-watershed ranks first in production of peak discharge. As a flood mitigation strategy, recharge zones are identified in order to reduce the severity of flooding. The outcome of the study would help in formulating policy guidelines and intervention strategies.