Intervention of Naraj Barrage: Its effects on sediment inflows into Chilika Lake, India.

Chilika Lake, Asia's largest brackish water lagoon, is located in the state of Odisha on the east coast of India. It was designated as a Ramsar site in 1981, being the first Indian wetland of international importance under the Ramsar convention. Siltation of the lake is become a major concern, because it is leading to various geomorphic changes that are affecting the shape and size of the lagoon, which receives a major silt load through the Daya and Bhargovi rivers (both being branches of the Mahanadi river) via the Kathajodi and Kuakhai rivers. The Naraj barrage was constructed at the mouth of the Kathajodi river to regulate its inflow, and also its silt load, into the lagoon. Two observatories are established in the Daya and Bhargovi rivers to determine the quantity of silt entering Chilika Lake through the rivers, with the bed load and suspended (total solids) being measured. Various effects of siltation in the lagoon because of the barrage are analysed in this study, to include the pre- and postconstruction situation. By considering different flood situations in the Mahanadi river, various alternate strategies for operation of the Naraj barrage were studied, with the goal of minimizing the siltation in Chilika Lake. These alternate operation strategies, and their potential effects on the inflow into the lagoon, are analysed and discussed in this report. [ABSTRACT FROM AUTHOR]