A research project of the Indian Institute of Technology (IIT) Madras has helped the Chilika lake in tripling the population of Irrawaddy dolphins.

A team of researchers conducted geotechnical, hydraulic and satellite imagery studies and developed a dredging methodology with minimum impact on the lake’s ecosystem.

The process of dredging consists of excavation of the materials from the bottom, removal of the loosened materials to the dredge vessel and ultimately transportation of the materials to the placement area.

The IIT’s intervention also benefited the over two lakh fishermen living in 132 villages as it resulted in a seven-fold increase of fish catch and tourists to coexist with the lake ecosystem, the team claims.

IIT Madras Professor of Department of Ocean Engineering R Sundaravadivelu said the Chilika lake’s highly-productive ecosystem supports the livelihood for fishermen and also acts as drainage for the Mahanadi river basin.

“The lake was in a degraded condition and included in the threatened list by Ramsar Convention in 1993. This warranted urgent action for restoration of the lake,” he said.

The geotechnical, hydraulic and satellite imagery studies showed the spit of Chilika is constantly changing. Among other things, the studies also showed the Chilika lake mouth located originally near Sipakuda in 1800 has gradually shifted in the last 200 years towards the northern side to Arkhakuda,” he said.

The IIT Madras team developed the dredging methodology identifying the location of dredging along with disposal and selection of suitable dredger with minimum impact on the ecosystem.

“Based on the outcome of this successful hydrological intervention, the flood inundation and freshwater weeds are reduced. The hydrological intervention restored the lake ecosystem and ameliorated the biodiversity. The fish production increased seven-fold and the population of highly threatened Irrawaddy dolphin increased,” Sundaravadivelu said.

“The enhancement of fishery resources and the increase of population of Irrawaddy dolphin promoted ecotourism which immensely benefited the local fishers,” he said.

Restored at a cost of Rs 10 crore by opening the mouth and other related works in six months, the lake is now off the threatened list (Montreux record). The Chilika Development Authority has developed an Ecosystem Health Report Card and periodical monitoring of salinity, fish and dolphin, freshwater weeds, birds and other biological parameters are being carried out.