What is the Korean technology BMC is replicating in Mumbai at Rs 2,300 crore to prevent waterlogging?

Indian Express

3 days ago

To prevent waterlogging in low-lying areas of Mumbai's western suburbs, the Brihanmumbai Municipal Corporation (BMC) has come up with an ambitious plan of setting up 25 floodgates at various inter-tidal zones in the Mithi River for Rs 2,300 crore. The project is inspired by the flood control systems used by South Korea, especially in areas prone to immense flooding and tsunamis. The tender for the project is set to be floated in the next two months and the BMC has set a three-year deadline for completing the work.
What is the Korean technology for operating floodgates?
Like Mumbai, South Korea also experiences heavy rainfall and flash flooding during the rainy season. Its low-lying areas are susceptible to more flooding since the water comes rushing down from elevated regions to low-lying zones. Korea is also prone to tsunamis. Therefore, as a preventive measure, floodgates have been designed to prevent waterlogging in low-lying areas as well as intertidal zones.
These floodgates operate vertically, unlike conventional floodgates that open horizontally. Additionally, these gates have dewatering pumps that channel out surplus water which also helps in controlling the water pressure. A unique aspect of these floodgates is that the vertical gates give precise control on the water flow that allows both complete blockage and regulated release of water.
Why does Mumbai prefer this Korean technology?
The primary reason that this technology is preferred is because of the vertical alignment. Mithi River is narrow and will not allow the usage of horizontal floodgates. Therefore, these vertical gates will be useful since they will use lesser space and serve the purpose of water blockage. Another reason why these gates are preferred by the authorities is that they allow for precise control of the water flow which will allow civic officials to streamline the surplus water into holding tanks. This could be recycled later for non-potable usage as well.
How will these gates operate in Mumbai, and which areas will get respite?
Officials associated with the project said the gates will be installed in tidal zones starting from Mahim Creek and will stretch up to 8 km towards suburban Mumbai. During high tide in monsoon, these gates will be deployed and the inflow of water will be blocked. Meanwhile, a certain quantum of water will be pumped out, either into the sea or it could be transferred into holding tanks for reuse.
The officials said the installation of the gates will allow respite in areas including Bandra-Kurla Complex (BKC), Taximen's Colony in Bandra East, Dharavi, and Dadar.
'The project was first proposed in 2022. However, the design aspects were changed and a new structure has been proposed. The tenders have been approved and will be floated in the next one month. Last time, several international firms from countries like Korea, Japan and Germany had shown interest in this project,' the official said.