India's Hirakud dam: Disaster in the making

By Ranjan K Panda Sambalpur

[...]

The Mahanadi drains an area of around 141,600 sq km and has a total course of 858 km. The river flows through the states of Chhattisgarh and Odisha, and the Hirakud dam is the only major flood control system on the river, as well as in Odisha. The Hirakud reservoir spread over 746 sq km – almost half the size of Delhi – is the largest dam in the country. Inaugurated in 1957, the dam was intended to control floods in the Mahanadi delta, with irrigation and power generation as incidental benefits.

Government engineers and supporters of the dam claim it successfully moderated 24 out of 30 potential floods. However, these claims are doubtful. Our ground observation tells us the dam has been unsuccessful in flood management. By its very design, the dam cannot control high floods as it has the capacity to intercept only 16% of the Mahanadi’s total flow at its location. Independent studies have indicated the dam’s failures in just two decades after it became functional; our observations further show that the issues have been compounded because of its faulty design, ineffective flood management operations, and other factors such as climate change-induced disturbed rainfall distribution in the river basin.

A contributing paper to the World Commission on Dams noted, “India’s Hirakud Dam was first justified in the name of flood control, yet extreme floods in the Mahanadi Delta between 1960 and 1980 were three times more frequent than before Hirakud was built.” The flood impact in the region has increased post the dam construction, and from four flood-affected districts in the 1950s, almost all districts in the Mahanadi basin are now flood-prone. In the first decade of the 21st century, floods occurred in five years, and the dam can be blamed during on at least four instances. The dam has failed to control any floods since 2008.

[...]