A solution for urban flooding offered by JNTU-Hyderabad hit the sewage roadblock, when it was discussed threadbare at the recent round table meeting organised by GHMC.
The solution, based on a study by the university’s College of Engineering under Civil Engineering faculty member K.M. Lakshmana Rao, envisages diversion of the storm water to specially built water tanks with large capacities, and sale of the water to private tankers, through Build-Operate-Transfer mode.
The solution suggested reverse cambering of the roads, with 2.5% slope from the outer edge towards the centre of the road, so that the water is directed to the drain built at the median. Thus collected, the water may then be channelised to the water tanks built at vantage points in the city.
Water harvesting pits
The study also suggests water harvesting pits in government and private lands across the city, from which excess water can flow into the urban flood by-passes/storm water drains at the central medians.
In imitation of the chain-link tanks typical of Telangana, the study proposes diversion of excess storm water from one tank to the other, thereby conserving rain water for it to be commercialised.
Stagnation points
In total, the study identified 229 water stagnation points, covering nearly 780 square kilometres and suggested 636 water tanks — 385 on private lands and 251 on government lands. Solar panels on the tanks and bore-wells to pump the water are also advised. Further, it proposes over 2.7 lakh water harvesting pits and major storm water drains of 456 kilometres, and minor storm water drains of 1,092-km length.
Project cost
While the cost is still being worked out, GHMC affirms that implementation of the project on ground could cost about Rs. 5,800 crore. “Discussion on the project brought to fore that storm water would invariably be contaminated by sewage overflow, if the sewage is not treated and sewerage network is not strengthened. Commercialisation of sewage-mixed rain water is not a feasible solution,” says an engineering official from GHMC.
Reverse cambering, too, was refuted as a solution, as it goes against the norms prescribed by the Indian Road Congress. However, it was suggested that a pilot project may be taken up near one of the stagnation points to see the results, which was accepted.
The suggestions and objections, along with the study, will be sent to the government for future action, said the official.
Discussion on the project showed that storm water would invariably be contaminated by sewage overflow, if the sewage is not treated and sewerage is not strengthened.
GHMC engineering official
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