While delivering a lecture at the Centre for Social Studies on Monday evening, Dr Desai said the flood in 1968, when the dam was under construction, was the most critical natural flood, but the situation has changed now with regulated flows.

Nobody seemed to have made use of satellite pictures, which clearly showed that it was going to rain heavily in the dam's catchment areas, only five per cent of which falls in Gujarat. The catchment area of the reservoir was spread over 62,000 sq km.

He said a model was prepared 20 years ago which was supposed to help authorities to keep a tab on the inflow of water by taking into account the average rainfall figures in the catchment areas. Dr Desai, who was also deputy director of Central Water Commission for close to a decade, visited the dam a couple of days ago and found that the same model was being used.

This was evident from the fact that everything went wrong with the model. The warning issued at 6 am on September 15 that a flood of 2500 MCM was developing and would reach Surat within 40 to 50 hours was also not useful as water level started galloping by the same evening, he said. The control room is at Gandhinagar, when it should have been either at Ukai or Surat.

The benchmark of 96-feet danger level at the Hope Pool was fixed by British collector Theodore Hope and was still followed though it had become irrelevant with the passage of time. He recalled that in 1968 the rate of discharge was as huge as 15 lakh cusecs but the water level 102 feet, the level reached in 1994 with only half the discharge. The Chowk Bazaar area was under 14-feet water then.

He said water could be stored in the dam even up to 351 feet in emergency as its height was 365 feet. That would mean that about 100 villages in the upstream would be under two-feet water, besides damage to crops. While crop damages could always be compensated, loss of human life and damage to properties worth hundreds of crores could have easily been averted.

A known opponent of the weir-cum-causeway at Singanpore, he said the structure had increased the chances of siltation.

Experience tells us that the crucial time to monitor was only a 16-day period up to September 15, but unfortunately all senior officers at the dam were absent when they were needed most. With advance releases the flood water could have been managed.

He suggested setting up of a committee that would have besides government representatives experts and prominent persons. The committee should be empowered to take decisions like how much water to be released from the dam and not politicians, who are technically not qualified. He also suggested making of road maps based on flood marks and red marks on sign boards indicating water level on particular roads.

Dr Desai said yet another public interest litigation would be filed in the Gujarat High Court on the issue.