Amidst a severe water crises, Bangalore Metro Rail Corporation Limited (BMRCL) has called a tender to implement Rain Water Harvesting (RWH) projects in Bengaluru to ensure that the rain falling on Namma Metro’s elevated concrete tracks is used to recharge the groundwater table.
BMRCL officials said that the tender has been called to dig RWH pits below the viaduct along the metro alignment of Line 1 (Purple Line) and Line 2 (Green Line), and stations.
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At present, the metro spans 73.75 km, of which 65.01 km is elevated and has the potential to harvest rainwater. There are 65 stations; however, rainwater harvesting systems have been implemented only in select stations.
“We are planning to initiate rainwater harvesting at an estimated cost of ₹65 lakh. The potential for rainwater harvesting to replenish the groundwater table along metro lines is significant, which is why we have called a tender to initiate the process now,” a BMRCL official said.
At present, rainwater harvesting for groundwater recharge is solely accessible along the metro line connecting M.G. Road and Baiyappanahalli metro stations (Reach 1). The BMRCL has built 3,000 litre-capacity underground tanks on both sides of every second metro pillar between M.G. Road and Baiyyappanahalli metro stations. In-built pipes carry rainwater from the duct to the tanks on the medians.
In June-July 2023, a survey conducted by the NGO ActionAid India revealed the absence of rainwater harvesting facilities along the Green and Purple lines of BMRCL.
According to its report: “A total of 1,189 pillars were surveyed. Across the 41 km stretch examined, it was observed that there were no rainwater harvesting structures in place to collect rainwater for groundwater recharge.” The report recommended that BMRCL take up RWH initiatives along the Green, Purple, and Pink lines.
A BMRCL official said, “We have initiated the tendering process for implementing rainwater harvesting systems along the existing lines. Separate tenders will be called for upcoming lines, and those under construction.”
