The Surya Regional Water Supply Project has achieved a milestone by completing the tunnelling work of the Tungareshwar tunnel recently. The 4.6 km long underground tunnel for crossing the Tungareshwar wildlife sanctuary is now finished. The internal finished diameter of the tunnel is 2.85 meters. The water will be channeled through this tunnel to the Chene Master Balancing Reservoir (MBR) and distributed to MBMC.
"The tunnel excavation was carried out using a modern Tunnel Boring Machine by constructing two shafts of 10 meters in diameter at the inlet and outlet for lowering of the TBM. The tunneling scope of the Surya project involves a total of 4 tunnels. One tunnel in phase-I and the other three tunnels are in phase-II. The tunnel in phase 1 at Mendhwankhind is ready for water supply" said an official.
MMRDA overcomes challenges during Tungareshwar Tunnel construction
An extensive geotechnical investigation was meticulously carried out in preparation for the ambitious Tungareshwar Tunnel. This comprehensive study involved drilling boreholes, plunging as deep as 200 meters, to gain a profound understanding of the subsurface conditions. The maximum overburden of the tunneling is 192 m. The construction phase posed formidable challenges, particularly with the creation of a 55-meter-deep inlet shaft, where the rock conditions were exceptionally hard. To overcome this, the drill blast method was employed, adhering rigorously to stringent quality and safety standards.
According to a senior official, The construction process included the formation of a back shunt, extending up to 50 meters, and a front shunt, reaching depths of up to 10 meters, both executed through the drill blast method. Notably, the geological conditions in this region displayed a remarkable variation, transitioning from the formidable basalt rock to the more manageable murram.
Undeterred, the project continued, culminating in the construction of the Tungareshwar tunnel in a single drive, spanning an impressive 4.6 kilometers at a depth of 55 meters. The progress efficiency for this stretch is 30% more compared to the previously completed tunnel of Mendhvan, as we gained expertise from our previous work. Throughout this endeavor, paramount emphasis was placed on ensuring the highest levels of safety and quality standards, a testament to the dedication and expertise of the MMRDA's project team.
"We have reached a significant achievement by successfully completing the tunneling of the 4.6 km long Tungareshwar Tunnel. Currently, the focus is on preparing for the interconnection of the tunnel with the MS pipeline, with a priority on safety measures, including pressure grouting to address any potential water leakages at segment joints. Upon the successful commissioning of the Tungareshwar Tunnel, the Mira Bhayandar Municipal Corporation stands to benefit immensely, as it will gain access to a substantial water supply of 218 million liters per day from the Surya Regional Water Supply Scheme. This substantial water supply will effectively meet the drinking water needs of approximately 16 lakh residences in the MBMC area. This achievement represents a significant step toward addressing the water demands of this region," said Dr. Sanjay Mukherjee, IAS, Metropolitan Commissioner, MMRDA.
MMRDA's ambitious Surya Regional Water Supply scheme
MMRDA, renowned for its infrastructure development, is now venturing into its first Water Supply Project for the Western sub-region of MMR. This ambitious project aims to address the acute water scarcity in the rapidly growing urban agglomerations of Vasai-Virar and Mira-Bhayandar. With a growth rate surpassing 50 percent, these areas require a significant increase in their daily water supply capacity. The Surya Regional Water Supply Project, undertaken by MMRDA, intends to meet this demand by enhancing the water supply capacity to over 403 MLD.
The project involves lifting raw water from Kawadas pick weir located downstream of Surya Dam in Vikramgad Taluka. The raw water will be lifted through vertical turbine pumps from the intake structure and further conveyed through underground pipelines up to the Water Treatment Plant located at Suryanagar, where it will undergo treatment. In the treatment process, the water from the cascade aerator oxidizes iron by reducing dissolved gases. The water then flows to the filter house through reactor clarifier units for further treatment. Once treated, the clear water is transferred to the Break Pressure Tank (BPT) for distribution. From there, the treated water will be supplied in bulk to the Kashidkopar reservoir in Vasai-Virar city and the Chene reservoir in Mira-Bhayandar through underground pipelines by gravity. After commissioning, Vasai-Virar City Municipal Corporation will receive 170 MLD of bulk water, the en route 44 villages in Palghar district will receive 15 MLD of bulk water, and the Mira-Bhayandar Municipal Corporation will be supplied with 218 MLD of water.