Soil erosion shrinks capacity of Hirakud reservoir in Odisha

Odisha Sun Times Bureau
Ib Thermal (Jharsuguda), Apr 13:

The safety of the Hirakud dam, the longest major earthen dam in Asia built on river Mahanadi at Burla in Odisha’s Sambalpur district in 1953, has become a major issue.

While rapid industrialisation on the banks of river Mahanadi has polluted the river water, the capacity of the reservoir has shrunk alarmingly due to massive soil erosion raising serious questions on the longevity of this multi-purpose dam.

Since the inauguration of the dam in 1956-57, around 4000 acres of reserve forest and 51,000 acres of village forest have been destroyed leading to massive soil erosion.

While mushrooming of industrial units near the reservoir area in Jharsuguda district and rampant open cast coal mining in the nearby areas of Belpahar, Lakhanpur, Lilari and Samaleswari have resulted in the massive destruction of forest cover along the reservoir area, use of forest land for construction of roads and railway track and construction of ash pond for Ib Thermal Power Plant have also largely contributed to the soil erosion.

According to reports, the state government has acquired land at Tilia panchayat near the reservoir for construction of an ash pond for the third and fourth hydropower units of the Odisha Power Generation Corporation (OPGC). Besides, the land for construction of an ash pond of Ind Barath Power Project at Sahajbahal has been acquired at Kurmimal near Ib river bank. If the construction of this ash pond begins, there is every possibility that the eroded soil would mingle in Ib river and be later carried to the reservoir.

This apart, rampant quarrying in the Patara forest  and vast submerged area near the reservoir has posed a serious threat to the dam.

The reports said more than 45 percent of forest spanning 32 sq km along the reservoir area in Sambalpur and Jharsuguda districts has been destroyed during the period from 1930 to 1975.

Though the state government has taken measures to stop soil erosion by taking up plantation in 12 percent area around the reservoir, it is not enough to stop the volume of erosion at present.

As per a survey conducted in 1991, the volume of soil erosion in Mahanadi delta per year is 12.90 million tonne of which 7.92 million tonne of soil enters into Hirakud reservoir.