Mumbai: CRZ nod to install rake screen at Worli pumping station

However, the authority deferred a proposal by the state’s harbour engineering division to beautify Dadar beach with stepped ghats, an immersion ramp, staircases to connect the promenade, a play area, and an approach staircase from Dnyaneshwar Udyan side for accessibility to the beach

The Maharashtra Coastal Zone Management Authority (MCZMA) has given coastal regulation zone (CRZ) clearance for the installation of large mechanical screens to remove floating material and trash at a nullah connected to the Lovegrove stormwater pumping station at Mumbai’s Worli.

The MCZMA has deferred a proposal by the state’s harbour engineering division to beautify Dadar beach. (HT archive)

The installation of the heavy-duty mechanical screens, proposed by the Brihanmumbai Municipal Corporation (BMC), will ensure plastic waste or other trash does not choke the pumping station that is crucial to pump water from south-central Mumbai into the Arabian Sea during monsoon.

The details were revealed on Friday as MCZMA published the minutes of its October 27-28 meeting.

In two other significant decisions, the authority deferred a proposal by the state’s harbour engineering division to beautify Dadar beach with stepped ghats, an immersion ramp, staircases to connect the promenade, a play area (consisting of two volleyball courts, sandpits etc), and an approach staircase from Dnyaneshwar Udyan side for accessibility to the beach. The proposal was deferred due to a lack of clarity on the CRZ status of proposed activities.

The second decision involved rejecting the clearance for a passenger jetty and allied facilities proposed by the Maharashtra Maritime Board (MMB) at Guhagar beach in Ratnagiri district citing turtle breeding near the project site. MMB was asked to look for an alternate site for the project. Similar jetty projects were deferred for Mumbai, Thane, Palghar, etc due to a lack of details submitted by MMB.

Another project proposed by BMC involving carrying secondary treated sewage from Ghatkopar to Deonar for developing a 600 tons per day waste to energy project for generating 4-megawatt power from Deonar was deferred due to lack of information from BMC.

BMC’s rake screen project would also ensure the primary treatment of trash entering this station, the proposal said. A similar screen was installed at the Irla pumping station and Lovegrove (2015) would be the second one. There are six pumping stations in Mumbai. Each pumping station gets excess rainwater from the drains and nullahs diverted to them at the time of high tide. Flood gates at the mouth of these drains are kept closed during high tide to ensure excess water does not enter the city. The pump pushes this excess water and releases it from a height into the sea. However, in the case of excess trash, it chokes these floodgates slowing down the pumping of excess rainwater further adding to flooding.

P Velrasu, additional municipal commissioner (projects), BMC said, “The stormwater drains discharging into the Lovegrove pumping station carry lots of waste material, plastic, and other floating material. Currently, these materials affect the operation of pumps by clogging the operation well. This delays the operation of pumps as de-clogging takes time and pumps cannot be operated during that time. So, these mechanical rakes will remove all such waste and floating material and are most efficient for water pumps during monsoon, especially during heavy rain to avoid floods.”

The height of the mechanical rake screen would be 28.8 m while the width would be 31 m.

“Our clearance pertained to allowing the construction of columns in the concrete wall within the nullah where the screen would be placed to stop floating trash. This will also result in a reduction in water pollution in the Arabian Sea. With this CRZ nod, the project has been recommended to the state environment impact assessment authority for final clearance following which BMC can commence construction,” said a senior MCZMA official. He added that such projects were important to address the flooding woes of the city.

Mumbai has been built on land that connected seven islands in the early 19th century but a robust flood management system has been in the making for several years now. However, its need was felt most on July 26, 2005, when 944mm rain lashed the city in 24 hours. This monsoon, too, four extreme weather events led to waterlogging across all chronic flooding spots.

State environment minister Aaditya Thackeray said the city’s flooding problems stem from a larger canvas. “Mumbai’s geography has changed over the years. The city’s rain days have reduced from 120 to about 72 in the past four or five years, albeit the volume of rain has increased. Run-off areas have also gone up and water percolation is much lower. These factors have created an imbalance,” he said.

After 2005, the BMC worked on improving the sewage network under the Brihanmumbai Stormwater Disposal System (Brimstowad) project, which established the need for pumping stations in Mumbai.

“Haji Ali, Love Grove, Worli, Britannia, Irla and Gazdhar Bandh pumping stations have been completed and Mogra Nallah and Mahul pumping stations will soon be established. Each pump can take out almost 6,000 liters of water per second. The storm-water drain size was increased from 25 mm per hour to 50 mm per hour rain pushing out capacity,” said Thackeray.

He pointed out the Mithi River had become narrow and shallow because of illegal construction. “BMC has worked on the Mithi extensively,” he said.