Mumbaikars must brace for flooding at the first monsoon shower, thanks to the illegal dumping of metro excavation debris into the sewage and drains choking the pipelines. The slurry and muck excavated for the Colaba–Seepz underground metro line are a major cause for the shrinkage of the capacity of drains and stormwater pipes - clogging is being caused by the illegal discharge of debris by the contractor, Dogus-Soma JV. A month-long investigation by The Free Press Journal into the process of dumping and disposal of Mumbai Metro silt, slurry and muck has led to the discovery of a shocking illegal network of six-inch pipes underground, which pump slurry into BMC drains and nullahs at Worli, choking the drainage system.
In blatant violation of environment norms, metro tankers have been dumping slurry and muck at secluded spots in the Vikhroli and Wadala mangroves under the cover of darkness.
The 33.508km, underground Mumbai Metro Line 3 tender specifies that the contractor must use the muck and debris generated for the landfill at JNPT Terminal 4, minor ports in Maharashtra and the filling of abandoned quarries in Raigad and Thane districts outside Mumbai limits. Documents accessed by The Free Press Journal specify that the contractor DogusSomas JV has to deploy dumpers and tankers for 591 trips daily, from metro sites to outside Mumbai limits for the dumping of the waste generated for Rs 347 crore and additional payments of Rs 1.6 crore for transport by sea route.
Mumbai metro silt, slurry and muck near Nehru Sion center BMC nalla in Worli | FPJ
Water-logging due to choking of pipes | FPJ
6 inch underground pipes to pump the slurry into BMC drains | FPJ
6 inch underground pipes to pump the slurry into BMC drains | FPJ
The rules stipulate that the dumping sites should not be ecologically sensitive areas, should be free of pristine habitats and shall not be in the channel of small streams flowing through the dumping sites. A quick check of Vashi and Airoli Mumbai Entry Point Toll centre records showed an average of just eight tankers and trucks exiting and entering daily for the dumping of metro debris outside Mumbai (of the required 591 trips daily).
The Mumbai Metro Rail Corporation Ltd (MMRC) agreed to pay Rs 372 crore to Dogus-Soma JV for environmental clearances, transportation cost (via road & sea) to dispose of the excavated debris, muck and slurry removed by the giant tunnel boring machines (TBMs) at metro sites. An MMRC spokesperson, responding to a detailed questionnaire, admitted that a few cases of violation of illegal disposal of slurry had been brought to their notice and the civil contractor had terminated the contract with the transportation subcontractor and a financial penalty had been levied on the contractor.
“The Mumbai Metro underground rail network is supposed to dispose debris, muck and silt generated from station excavation and tunnelling activities outside Mumbai to MIDC Mahape, Kalwar-Bhiwandi, Dhapode, Mankoli as approved by the Government of Maharashtra and responsibility of muck disposal was with the contractors” reads the MMRC mail.
Disposal of Metro silt, slurry and muck | FPJ
Disposal of Metro silt, slurry and muck in Sion | FPJ
The debris is used for the land-filling of JNPT Terminal 4 and minor ports at Rajauri Creek, Raigad. The underground metro construction activity involves tunnelling, cut-and-cover, foundation, fill and embankment, generating about 5.40 mm3 of debris and muck. According to the MRCC, the disposal is done by transporting sub-contractors engaged by the respective civil contractors and is not disposed of into any water bodies or any environmentally sensitive locations. Activist Ankush Kurade had raised objections against the malpractice of of illegal discharging the muck and slurry generated from metro sites into the BMC rainwater drainage canals (SWD Nallah) on the Eastern Express Highway at Vikhroli and the National Sports Club (NSC) Nallah, posing a threat to the protected mangroves.
“I had demanded a criminal complaint against the Mumbai Metro authorities and the contractors Dogus Soma JV for dumping muddy silt and slurry illegally. Mumbai Metro has been giving lame excuses of terminating the sub-contractors employed by Dogus Soma JV while the illegal dumping into BMC drains continues brazenly without fear,” Kurade had alleged.
The Brihanmumbai Municipal Corporation (BMC) had objected to the unauthorised dewatering of the grey slurry from the construction site at the Nehru Science Centre Metro Station RMC plant into the NSC nallah. The BMC had sent repeated letters about the unloading of the illegal slurry into the nallah by metro contractors, causing environmental harm to mangroves and marine life. Environmentalist Stalin Dayanand echoes the objection of the dumping of debris in stormwater channels, which reduces the carrying capacity of the channel.
“It will cause flooding of nearby land masses and the toxic silt dumped into urban rivers contaminates marine life and environment. The mangroves of Mumbai and Thane are choking because of the illegal dumping by infra contractors,” he explained. Residents of the Mahalaxmi Racecourse Stable employees’ quarters adjacent to the Nehru Science Centre metro site are the worst affected, as the slurry water daily floods their homes. “Our complaints to Mumbai Metro and BMC of the daily flooding of our homes with dirty water and slush falls on deaf ears.
6 inch underground pipes to pump the slurry into BMC drains | FPJ
Water-logging due to choking of pipes | FPJ
We had eight children slip in the slush and get injured, while two elderly people got fractures,” complained resident Shivbaran Singh. Mumbai Metro assistant general manager Rohit Tilak, defending the contractor DogusSoma JV, insisted the slurry and silt is treated through sedimentation and centrifuge process before discharge as per rules. Dogus-Soma JV project manager Navlesh Kumar refused to speak with The Free Press Journal on the illegal dumping of muck and slurry in nallahs and mangroves, saying that he was not authorised to speak with the media and directed this reporter to meet the MMRC Corporate Communication team for details.
A ground visit to the Mumbai Metro site at Worli and the Nehru Science Centre revealed the dirty game of illegal dumping continuing unabated, through an extensive network of underground high-pressure pumps into BMC drains and nallahs, choking the drainage pipes with a thick layer of heavy sediment and grey slurry for outfall into the open seas.
