CHENNAI: The Tamil Nadu government on Monday approved rainwater harvesting guidelines, directing departments, district collectors and local bodies to build, restore and maintain harvesting structures across the state in a coordinated, time-bound manner with immediate effect. The guidelines cover systems to capture rooftop runoff and channel surface water into groundwater recharge structures.
The Municipal Administration and Water Supply (MAWS) Department’s November 2 order requires departments to draw on existing administrative and financial provisions or district contingent plans. It, however, sets no completion deadline.
While rainwater harvesting has been mandatory for new buildings under the Tamil Nadu Combined Development and Building Rules, 2019, the guidelines detail methods suited to different premises, roof areas and soil conditions.
Filtered rooftop runoff can be stored in sumps, while surplus water can recharge groundwater through percolation pits, wells and defunct borewells. Separate methods are prescribed for individual houses, apartments, industries and institutions.
In industries and institutions, excess water and surface runoff can be diverted into recharge wells and trenches along the periphery, while campuses with sufficient space can develop percolation ponds in low-lying areas.
For roads, parks, open spaces and public places, the guidelines recommend recharge wells, filter strips, permeable pavers, percolation ponds and sponge parks.
The MAWS department will remain the nodal agency for coordinating implementation.