The Greater Chennai Corporation (GCC) will launch a rainwater harvesting (RWH) campaign in all 15 zones of the city on Monday, ahead of the northeast monsoon. The campaign, scheduled till October 9, will focus on various aspects of rainwater harvesting in public spaces and private buildings.
The GCC has identified about 89,000 buildings in the city without RWH structures. Some are said to have faulty structures. The civic body will ask owners of such buildings to restore these structures before the monsoon.
Corporation Commissioner Gagandeep Singh Bedi said, “All buildings should have facilities for rooftop rainwater harvesting. The GCC has put up 200 sunken wells in the city and silt catch pits and renovated waterbodies. In terms of silt catch pits, around 20,000 already have RWH structures. And now, we have gone for desilting of silt catch pits, which is the interface between the roads and the stormwater drains.”
Groundwater quality
Many residents’ associations have informed the civic officials about groundwater depletion and seawater intrusion in various neighbourhoods over the past few years.
V. Rajagopal, a resident of Anna Nagar Western Extension, said though awareness campaigns and surveys by government agencies were good initiatives, the drive to inspect RWH structures in buildings should be intensified. They should also check the stormwater drain network to minimise waterlogging and link it to the nearest waterbody, he added.
Former Corporation floor leader V. Sukumar Babu said the Corporation should develop RWH structures in more public spaces instead of asking residents to create structures during a pandemic when people were facing economic difficulties.
Geetha Ganesh of the AGS Colony Residents’ Welfare Association said, “About 80% of houses in our colony are independent residences. We have enough space around them for groundwater percolation. Before 2015, groundwater used to be saline and the total dissolved solids (TDS) level used to be more than 3,500 parts per million. Now, water quality has improved with rainwater being harvested in houses and in two large parks and a playground.”
Comprehensive report
In a fortnight, the Metrowater would also bring out a comprehensive report on the survey done on the status of rainwater harvesting in the city. It is also considering a proposal to make the report accessible to the public.
So far, volunteers roped in by the agency have covered nearly 8 lakh buildings in the city as part of the RWH awareness campaign launched at the end of August. Nearly 2,000 members of self-help groups (SHGs) were employed for the campaign.
There are nearly 10.91 lakh buildings in the 35,000 streets of the city. Metrowater officials said volunteers would collect various details, including the type of buildings and wells, presence of water and sewer connections, and the status of RWH structure maintenance.
Besides testing water quality in buildings, nearly 3.5 lakh samples were collected from various areas to test other parameters, an official said.
Data collated from the survey forms were being analysed, and the information would be compiled into a book. Based on the outcome of the analysis, the water agency would intensify its campaign and strengthen interventions for optimum harnessing of rainwater.
For instance, TDS level in water was found to be higher in some streets, and the survey analysis would help identify specific reasons and solutions.
The report would help identify old, ageing pipelines and improve infrastructure. Data could help identify buildings that either do not have RWH structures or maintain them poorly, the official added.