Experts express concern over diversion of fresh water from Odisha’s Brahmani river

It could pose a grave threat to the famous mangrove vegetation in Odisha, they say

A crocodile looks inside the Bhitarkanika National Park in Odisha. File.

Environmentalists on Friday expressed concern over the massive diversion of fresh water from the Brahmani river basin, which could pose a grave threat to the famous mangrove vegetation in Odisha.

Bhitarkanika — a notified Ramsar wetland — is spread over 195 sq. km and is home to 62 mangrove species. Besides, 1,600 salt water crocodiles crawl on the mudflats of the Bhitarkanika mangrove forest.

Mangroves grow in brackish water. Proportionate fresh water flow from the Brahmani river basin and the Kharasrota river keep the salinity level of the water along the shore down. The brackish water becomes ideal for the mangroves to grow and stay healthy.

The Wildlife Society of Orissa (WSO), an environmental pressure group, had drawn public attention on the excess water allocation for industries, which is likely to reduce fresh water discharge to the sea.

“The Talcher-Angul coal mines, steel and power plants as well as the Kalinganagar steel and power hub are drawing enormous quantities of fresh water from the Brahmani river,” said Biswajit Mohanty, secretary, WSO.

“The total live storage capacity [LSC] of the Rengali reservoir is 4,400 million cubic metre [mcum]. Rengali canals require 3,450 mcum. Large industrial users are likely to draw 454 mcum from the Samal barrage in Angul district. An additional 414 mcum shall be drawn from the Kharasrota [distributary of the Brahmani river] at the Jokadia barrage to meet the water needs of the Kalinganagar industrial complex,” Mr. Mohanty said.

“Thus, against an available 4,400 mcum of fresh water stored by the Rengali reservoir, 4,318 mcum that is almost equal to the available water supply shall be withdrawn from the river,” he said.

According to the WSO secretary, 105 million litres, as per government claims, would be withdrawn for the mega drinking water project.

Mr. Mohanty said, “The reduction in water flow would lead to drastic changes in the water regime of the Bhitarkanika mangroves. The Sunderbans mangrove forest was drastically affected after the Farraka barrage was commissioned.”

Stating that the lack of normal flow of fresh water would increase saline ingression upstream, the WSO secretary said it would affect the local flora and fauna as well as the livelihoods of the farmers and fishermen dependent upon the Brahmani and the Kharasrota.

Besides, there could be a quantum increase in the man–crocodile conflict since the estuarine crocodiles would leave the core sanctuary area and migrate upstream once salinity increases, he said.

“The State government has not yet revealed how it plans to ensure adequate flow of fresh water in the Kharasrota and Brahmani rivers that feed Bhitarkanika once the Rengali canals start drawing water,” Mr. Mohanty said.