To improve rainwater harvesting in government buildings, the Public Works Department has issued a circular to its officials to ensure recharge pits were constructed before the onset of the northeast monsoon.
According to officials, of the nearly 50,601 government buildings constructed and maintained by the department, nearly 50,385 buildings have RWH structures.
The department maintains buildings of nearly 60 departments, including the Governor’s residence, judges quarters, PHCs, memorials and so on. In July-end, the PWD Buildings Chief Engineer wrote to the officials of the division in various regions to execute the project in government buildings even if they have an RWH system. The PWD designed a new recharge pit using stone jelly and sand that could enable quicker rainwater percolation. It could be constructed in a few hours and would cost a minimum of ₹20,000, officials said.
“We have designed a recharge pit that could be constructed in any size and suitable for all soil conditions. The recharge pits could be dug up to any size using building materials. On large campuses, it could be built at every 10 metres. Similar structures could be provided along road corners,” said an official.
The 4ft-5 ft deep pit would have an inner layer of 40 mm broken stone jelly and filled with 20 mm broken stone jelly on the sides above it and then a small layer of sand. The structure needs to be covered on sides with concrete slabs to protect it from damage and free flow of rainwater. In areas with clayey soil, a borehole with half a feet diameter for a depth of 10 feet could be dug beneath the structure, an official said. “We have designed and tested the structure in our research lab. It enables nearly 70-80% of rainwater percolation,” the official said.
While most of the buildings constructed in recent decades have structures to harness rainwater, some of the buildings built about 50 years ago are yet to be provided with the facility, sources said. Land revenue, School Education, Animal Husbandry and Health and Family Welfare are some of the government departments that have a large number of old buildings.
Of the 14,020 buildings built 40 years ago, nearly 216 buildings do not have RWH structures. PWD officials said some of these heritage buildings did not have the structures due to lack of space.
The department has now created a cell in which PWD engineers would assess and monitor the provision of RWH and their maintenance in government buildings.
Article source: https://www.thehindu.com/news/cities/chennai/pwd-wants-recharge-pits-in-all-govt-buildings-before-monsoon/article29037412.ece