IIT Madras researchers propose wall at Ennore Creek to prevent floods in Chennai

Researchers at the Indian Institute of Technology (IIT) Madras have studied flooding in and around Chennai and have proposed the construction of ‘Straight Training Walls’ at the mouth of Ennore Creek in order to minimise the flood risk significantly on its upstream.

The study focused on extreme storm surge scenarios and high tide levels along with flooding in the river. It found that heavy siltation in the creek mouth and narrow opening in the mouth posed a flood threat to the areas adjoining the river.

The study was commissioned by Kamarajar Port (formerly Ennore Port) in Chennai to propose solutions to reduce flooding around Kosasthalaiyar riverbanks. It was undertaken by professors K Murali, SA Sannasiraj and V Sundar, faculty in the Department of Ocean Engineering, IIT Madras.

“Based on the expertise and experience of the Department of Ocean Engineering, IIT Madras, the rResearchers working with training of river mouths, the proposal has been made to construct a pair of training walls extending perpendicular from the shore up to a water depth of -5m on either side of the creek,” SA Sannasiraj, was quoted in an IIT-Madras press release.

In the history of flooding in and around Chennai, the three creeks — Adyar, Cooum and Ennore — remain as major bottlenecks due to sand bar formation at their mouths, this results in significant flooding over the settlement along its banks, impact on coastal villages, disruption in fishing activity, industrial network on the upstream, road encroachments and illegal waste disposal.

“Several earlier attempts that were made for prevention/reduction of sand bar formation at Cooum mouth by constructing a pair of training walls have not yielded the required outcomes due to various reasons,” Prof K Murali said, adding, “Fixing a lower crest elevation much less than required allows the sand moving along the coast termed as ‘littoral drift’ pass over it and deposit in the mouth. These serve as lessons to be learnt from the past mistake.”

The Ennore creek is located about one km southward of the Kamarajar Port at Ennore, Chennai. Historical imagery showed that the inlet width varies seasonally, depending on the net longshore sediment transport rate due to waves that vary monthly and with the occurrence of cyclones as well as rainfall, the release added.