Hyderabad: Possible design faults that did not factor in shifting of sand from under the foundations of the Lakshmi barrage at Medigadda on Godavari river, are believed to be the primary causes that resulted in subsidence of one of the 7 blocks of the barrage, making the entire structure useless with respect to storage of water for which it was designed.
For all practical purposes, Medigadda barrage for the next few years, would just be a structure without any real use as it can no longer hold any water – let alone the 16 TMCft it is supposed to store. “What we are seeing is a barrage which can no longer serve the purpose it was designed and built for,” authoritative sources told Deccan Chronicle.
This was also corroborated by the irrigation department which said until the actual problem is identified – which could take a while – and rectification is done if at all that is possible, the barrage will no longer be able to store any water.
Irrigation department sources who admitted that as it exists, the Medigadda ‘Lakshmi’ barrage is a write off for now, added that not all the news as bad. “The barrage is built in blocks, and only one of the 7 blocks is affected and that in a worst-case scenario, the block may have to be rebuilt from the ground up. The rest of the structure is safe,” the sources maintained.
One of the explanations that has come forth from the irrigation department, at least for now, is that the most likely problem for the sinking of Block 7 of the barrage was the shifting of sand from under the foundations due to the river water’s pressure and force.
However, this raises even more uncomfortable questions about the design and approvals by the irrigation department of the construction process, if this was indeed a system that with proven structural stability.
“If the foundation was anchored in sheet rock at the bottom of the river bed, then there should be no impact if sand shifts due to the river’s flow, or sudden flood,” the sources said.
They also said there were some concerns raised over the design of the pillars and foundations by one side during the construction, but this aspect could not be independently verified. The sources said even if the shifting of the sand was an issue, this possibility should have been factored in while finalizing the design.
Even as there is obscurity over what caused the disaster at Medigadda barrage, opposition parties have been clear on who is to be held accountable. Be it the Congress, or the BJP, they have been unequivocal in holding Chief Minister K Chandrashekar Rao responsible for Medigadda’s current plight.
According to TPCC president A Revanth Reddy, “the culprits are KCR and his family who looted one lakh crores along with the contractors. This is a fit case for a probe by Central Vigilance Commission. We are writing a letter to the EC to allow us to visit Medigadda and both KTR and Harish Rao should join us in our visit.”
He also questioned the silence on part of the BJP which keeps alleging corruption in the Kaleshwaram project execution but has not taken any action so far. “Amit Shah and Kishan Reddy should tour the area. The state government cannot say that the barrage was built by private companies and cannot shirk its responsibility,” he said.
On the other hand, BJP state president and Union Minister G Kishan Reddy who wrote to the Ministry of Water Resources to send a team of dam safety experts to took take stock of the situation, has questioned the government’s reluctance to let political leaders to inspect the damage.
“The developments have confirmed what engineers have for long been saying about the quality of construction of this project. The Chief Minister described the project as an engineering marvel. KCR ignored objections from engineers and pushed for construction and the result is there now for all to see,” he said.
In the past pump houses of the project were submerged owing to heavy floods and now a part of the project has sunk in. Lapses of projects are coming out one after another. Of the promised 400 TMC water the project was supposed to lift and help irrigate lakhs of acres so far only 150 TMC has been lifted in the last five years and released after heavy rains, he said.
The contracting firm, L&T Construction which built the barrage as per designs and specifications provided by the irrigation department, is learnt to have employed what is called a ‘secant’ foundation system – a hybrid model of piles driven into the sheetrock through a lattice kind of a network of a raft foundation which typically is an extended foundation designed to bear the load of a structure.
A dam safety experts team put together by the Government of India under the aegis of the National Dam Safety Authority is visiting the barrage on Tuesday for an inspection even as the state irrigation department has remained silent since the subsidence on Saturday evening except putting out a brief news release that L&T Construction, which built the barrage, would undertake any repairs at its cost. The same was echoed by L&T which put out a brief and terse statement that it was studying the problem along with irrigation department officials and further action will be taken after an inspection.
Right now, there is the normal flow of water from Pranahita river which is now being allowed to flow freely through the barrage and there is no question of any storage of water for the time being at Medigadda. The barrage was designed to store 16TMCft of water (16 times the water that is held in Hussainsagar lake which can hold 1 TMCft of water in the heart of Hyderabad city). It could have been the flood last year when 28.7 lakh cusecs (cubic feet per second) of water from Pranahita and Godavari buffeted the barrage which was designed to withstand 28.25 lakh cusecs of flow.
It was this flood and the backwash from it that also submerged the Lakshmi pump house near the same barrage raising questions about the project’s safety.
