The civic body is planning to modify the size of the city’s stormwater drains to accommodate any sudden huge quantum of rain the city is likely to receive during monsoon.
With advice from expert hydrologists from the Netherlands, the Chennai Corporation officials are finalising a design that will withstand a rainfall of up to 68 mm per hour.
They analysed rainfall data from 1980 to 2011 and calculated the highest rainfall intensity (68 mm per hour) recorded in the city in the past 30 years.
Previously, the Corporation had designed stormwater drains equipped to handle just 32 mm rainfall per hour, in a bid to reduce dimension and cut costs.
“The new canals will be larger. They will drain water during very heavy rains too,” said an official.
Senior hydrologists have played a role in recommending design aspects to improve drainage network in the city.
Hydrologists in the Netherlands have developed expertise to cope with drainage problems in flat terrain similar to that of Chennai.
Experts associated with World Bank visited Ripon Buildings on Wednesday to finalise the design and 40 packages for the stormwater drain project.
They visited Cooum and Adyar watersheds, covering 270 km of drains and canals, and recommended various aspects pertaining to improving the drainage.
The Corporation will have to evict more residents along the canals to create larger drains. It will finalise the number of households to be evicted next week.
Work on operation and maintenance of the drainage network will be included for the first time in the bid document. This initiative is expected to prevent mixing of sewage in stormwater drains.
