Bhubaneswar, Sept. 15: Lakhs of flood victims in Orissa may not be aware that human failings are as much to blame for their plight as cruelty of nature.

With a little more gumption on part of engineers managing Hirakud dam over Mahanadi and better coordination between Orissa and Chhattisgarh, the magnitude of the calamity could have been reduced.

Engineers operating the dam-cum-reservoir failed to anticipate the heavy inflow from the upper catchment area of Mahanadi, around 85 per cent of it falling in Chhattisgarh.

So, when rainfall of 201.97 millimetres was recorded in the upper catchment area between September 6 and 9, the engineers were forced to make heavy discharge downstream from the reservoir by opening more gates.

While of the 64 sluice and 34 crest gates, only 16 were open on September 6, 14 more had to be opened the next day. The number went up to 53 on September 8 and it was further increased to 59 the next day.

What made the heavy discharge from Hirakud all the more imperative was that Bango dam on river Hansdeo, one of the tributaries of Mahanadi in Chhattisgarh, released 1.77 lakh cusecs of water in three phases on September 9, further adding to the inflow into the Orissa reservoir. Hirakud dam superintending engineer Nilkantha Das says the first round of discharge from Bango was without any warning.

“We came to know about it from our men at the Champa gauge and discharge station, about 90 km downstream of Bango, and immediately alerted our government. However, the discharge from the dam continued,” said Das.

Chief engineer, Mahanadi basin, Chhattisgarh, Hemraj Kutare said: “I, too, did not know about it (the discharge) initially as Bango reservoir is managed by another chief engineer. But as the inflow was heavy, there was too much pressure on the dam.”

Together this created a situation where around 11 lakh cusecs of water was entering the Hirakud reservoir on September 9 and 9.70 lakh cusecs was being discharged through the 59 gates. High floods in the downstream of Hirakud were thus a foregone conclusion.

The unpredictability of the rainfall also has a bearing on the operation of the reservoir, which is guided by a rule curve framed by a CWC appointed committee in 1988. The curve, premised on the experience of high rainfall in July and August and less rainfall between September and October, prescribes the upper and lower reservoir levels of 627 feet and 619 feet, respectively, on September 1.

The engineers managing Hirakud have been criticised for keeping the reservoir level on the higher side at 624 feet. Das said it was done keeping in mind that Hirakud also had a kharif command area of 1,59,000 hectares to irrigate apart from generating 307.50 MW of hydel power.

“Before the floods it was a drought like situation in the command area. Farmers would have suffered had we brought the reservoir level down,” said Das.

Hirakud dam’s retired chief engineer, Sudhakar Patri made a fervent plea for revisiting the rule curve, which appears to have become obsolete considering the changing rainfall pattern and new challenges of flood management before the engineers.

“Instead of prescribing two reservoir levels as the rule curve does for the sake of flexibility, we should have only one which would cause less confusion and allow the engineers more freedom of decision,” said Patri.

However, the greater need is to reduce the unpredictability of release from dams and reservoirs on Mahanadi and its tributaries in Chhattisgarh as it decreases the flood cushioning ability of Hirakud.

Also, proper coordination between the two states regarding flood management appears to be going haywire despite assertions of water resources secretary Suresh Mohapatra, who said things were working fine between the two states.

Nilkantha Das said: “The information that we get from Chhattisgarh side sometimes takes a week to reach us.”