The magnitude of the Kerala catastrophe could have been minimised if the agencies involved in reservoir management had used a technically sound approach in the opening of the dam gates, said Professor Nayan Sharma, a dam expert and former professor at IIT Roorkee.
In an exclusive interview with Firstpost, Sharma, who visited a number of dam sites in the southern state along with a dam break analysis team formed by the Kerala government in 2011, said that there should be a proper inquiry on why no technically sound method was followed while opening up the dam gates.
“It is a known scientific reality that no gate of any dam with a full reservoir should be opened all of a sudden. It should be opened gradually within a long span of time to prevent flooding. But in the case of Kerala, it was seen that the gates of 35 dams were opened at the same time, which resulted in the massive flood,” he added.
On 15 August, after rainwater brimmed 35 out of 39 dams in Kerala, gates of these dams were flung open, wreaking havoc in the state.
He added that instead of following a technically sound reservoir management system, the authorities waited for the dam reservoirs to be full before opening their gates.
"There are technically sound methods to open gates of dams. If followed, it could have prevented the the catastrophe to a great extent. But the way the government decided to open the gates of 35 dams at the same time, it does not seem that any technically sound method for managing the reservoirs is used in Kerala,” he explained.
Sharma, who is currently working as an honorary professor at Nottingham University in the United Kingdom, further asserted, "It was a wrong decision to open all the dam gates in one go on the part of officials of the dam management authorities and they should be held responsible for it."
Significantly, anti-dam activists have been attributing catastrophic floods to big dams for a long time. But Sharma said that dams themselves are not the cause of flooding, but faulty water resource management of the dams is.
“A dam can be multi-purpose. One of such purposes could be flood control. But then, the proportion of usage of reservoir water in various purposes should be balanced to meet the demands in changing circumstances,” he asserted.
He added that in a sound reservoir management system, the dam authorities should ensure that reservoirs are empty before the monsoon begins.
“To decide upon opening and closing of dam gates, it is now a global norm to use Global Precipitation Measurement Mission data provided by NASA about rainfall. It does not seem such data was used in Kerala,” he said.
Providing a series of suggestions as to how to prevent such a catastrophe in Kerala, he said that the reservoir management system requires rigorous review by experts. The system also needs to be re-claibrated with changing environmental conditions.
Suggesting an overall study about the performance of the dams, he said, “Have the dams outlived their lives? Do the dams have enough flood cushion? Should it be increased? Do the dams have modernised early warning system to evacuate the people living in lower reaches before the gates are opened? These questions are to be inquired into in a time-bound study.”
He also cited the example of France, where several existing dams were renovated using a new technology called 'Piano Key Weir’ to increase storage capacity, a mission in which he also participated.
He also suggested that a detailed Catchment Area Treatment system should be adopted to restore the rivers by removing encroachments in river bed, adding that conservation techniques should be applied in the hills to prevent further sedimentation in the rivers.
Sharma, who was also a part of a global team constituted by European Commission to gauge the effect of climate change in Danube and Brahmaputra river, attributes global warming to the sudden increase in rainfall.
“Rise in temperature has triggered change in air circulation pattern, which in turn has caused erratic monsoon behavior. The sudden increase in rainfall in Kerala can be surmised to be a result of it,” he added.
“But in 1924, that amount of rainfall was received in four months and this time around, it was received in around just two and a half months. Heavy rainfall is a cause of the flood," he said.
Significantly, in the last one decade, various states including Bihar, Uttarakhand, Jammu and Kashmir, and Assam have suffered floods of a similar magnitude. Sharma said that apart from global warming, massive quarrying, mining encroachment of river beds, unfavourable agricultural practices and deforestation have resulted in destabilisation of rivers by way of pouring massive silt in them.
“Apart from stopping such practices, the states can also use Flood Monitoring Information System to prevent the menace of deluge. After a massive flood occurred in Bihar due to overflow of the Kosi river, the state government used this system as a preventive measure. In this system, the river is monitored in real-time basis from Patna and any possible breach in the embankments is prevented by immediate measures,” he added.
Sharma, who was also a member of a high-level expert committee formed by the ministry of water resources for a study on the Kosi river, said that though the state government is fighting tooth and nail to prevent flooding in the Kosi river, a possibility of similar floods cannot be ruled out in the near future due to massive deforestation and encroachment in the river in its upper reaches in Nepal.
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Updated Date: Aug 22, 2018 20:09:38 IST