KOZHIKODE:On Friday, when Chief Minister Oommen Chandy will finally commission the Japan-aided water supply project, the Kerala Water Authority (KWA) will not only be meeting the water requirements of the Corporation and several panchayats, they will also be showcasing a great engineering feat, which made this scheme possible.
While the people were agitated over the decreasing water table in their area, the engineers in the Kerala Water Authority were sweating it out to ensure that they complete the project that would provide continuous water supply to hundreds of households for the next 15 years. It took them eight years to complete the project after it was started in 2006.
There was a time when everybody had given up hopes and the funding agency, Japan International Cooperation Agency (JICA), was disappointed and did not want to fund the project any further, says K G Harshan, project director, KWA, who remained unperturbed by all the criticism throughout.
Even after two years, the project was heading nowhere, but already Rs 50 crore had been spent on laying the pipeline and constructing the treatment plant. The biggest hurdle was to construct the water treatment plant. There were huge rocks, about 6 to 7 m below the ground as well as above. The challenge was to blast the rocks, which was just adjoining the dam.
But the Dam Safety Authority did not give permission to blast the rocks as it would lead to cracks in the dam. After much convincing, they did controlled blasting and finally the treatment plant was laid.
Another biggest challenge was to construct the intake tank, from where the water from the river can be pumped to the treatment plant. The surface was rocky and uneven. It demanded digging of the surface up to 20 m. But the dam was just 22 m away from the area.
Our hurdles increased when the Dam Safety Authority went against the plans, recalls Harshan. It was then that Professor Sundar Vadivelu came as a messiah and suggested constructing a floating well, that can be placed in the middle of the river near the dam. It is no more in prevalence as in such projects the tanks are constructed in the banks.
“It was no ordinary job. They began constructing the tank near the banks by first concreting the base by laying flex sheet. Then they slowly raised the side walls, which were 45 m thick. They used 1.25 m shutter to construct the side wall, which they slowly pushed to 0.5 m, without moving it out. They poured the concrete mix and repeated the procedure until it got to a height of 16 m,” he says.
Explaining the science behind it, he says, during the process, the water was let out of the dam to construct the structure near the bank of the river. Once the dam shutters were closed, the water level rose. The buoyancy of the water pushed the tank above the ground level and then using the ropes they pushed the tank into the middle of the river. It was done carefully as any mistake would tilt the tank down.
While a place was chosen near the dam, they found huge silt accumulated below the dam. Then, using the mud pumps the silt was removed and it was stopped only after they found the plain surface. Later, using the underwater concrete, the place where the tank would be placed was made.
Then with the help of underwater divers, the tank was drilled. About 54 holes were drilled through the tank to fit into the concrete. Six openings were also made in the intake well, from where the pipe can be connected that would take the water to the treatment tank, when water is at various levels.
But during these processes, the biggest challenge was the escalating cost of material and labour. People had to be brought from North India to work for the project, he adds.
He says that to pump water out of the tank they have used four 750 horse power pumps and two 650 horse power pumps, which would take water to the treatment plant from the intake well. For supplying water, 20 reservoirs have been constructed.
The pipeline has been laid in such a way that minimum use of power will be required, as the water from the treatment plants will be taken through the gravitation, he adds.
While Harshan is busy with his colleagues for the inaugural ceremony, he heaves a sigh of relief and feels more confident after having completed the work.
SCADA Technology Used for the First Time in State
The Kerala Water Authority has utilised a unique technology called Supervisory Control and Data Acquisition (SCADA), for the first time in Kerala, by which the flow of water, the pressure in the pipeline, leakage and blocks can be monitored and controlled from the central office.
The high-tech equipment will acquire data, communicate and store it to help the controller take immediate steps.
It is controlled by telemetric system. Once the message is sent from the control room, the valves will automatically take the command for letting the water in and out of the tank. The water level can be controlled and monitored. Even supply can be ensured. In case the communication cannot be sent, it can be monitored manually.