The TBM is set in the bottom of the riser shaft to be launched for the 6,000-ft. (1,829 m) tunnel.
It’s been 50 years since the Monroe County Water Authority (MCWA) in upstate New York first considered construction of a water treatment plant taking water from Lake Ontario to customers in its eastern service area.
Now, at last, the East Side Water Supply Project (ESWSP) is becoming a reality.
The original plan was put aside in the late 1970s after a cooperative effort between the city of Rochester and MCWA increased the latter’s available water supply. Now, however, constructing a new facility is considered to be the most cost-effective way to deal with aging infrastructure and increasing demands on the system.
As Richard Metzger, Monroe County Water Authority executive engineer, pointed out, the benefits of the new facility include:
• Enhancing water supply security for the authority’s six-county service region,
• Increasing reliability of treatment and transmission should man-made or natural disasters occur, and
• Meeting the region’s long-term supply needs as well as those for future growth and economic development.
In addition, during the three years it will take to complete the job, the project is expected to boost local construction employment by an estimated 500 full-time jobs each year.
The East Side Water Supply Project is one of the region’s most expensive public works venture, with a price tag of $150 million. Funding sources include a $17.75 million grant from the American Recovery and Reinvestment Act of 2009 (ARRA) under the Green Infrastructure project criteria as applicable to the Drinking Water State Revolving Loan Fund (DWSRF). The New York State Environmental Facilities Corporation administers the fund for the New York State Department of Health (NYSDOH) and is financing an additional $17.75 million of the project cost. The project also has received a $5.76 million grant from the U.S. Environmental Protection Agency (USEPA).
The project calls for construction of an intake tunnel, filtration and treatment facilities, a pumping station and pipelines. When completed in 2013, the plant will withdraw 50 million gal. (189 million L) of water a day from Lake Ontario.
Based in Forth Worth, Texas, Southland Contracting Inc., (SCI) was awarded the $35 million intake tunnel contract on Jan. 10, 2010.
“This project for the Monroe County Water Authority includes one 45-foot diameter shaft 170-feet deep; 6,000 linear feet of 8-foot tunnel under Lake Ontario; six 60-inch drilled pump shafts 100-feet deep; 220 linear feet 12-foot main pump adit tunnel; and a marine intake in 60-feet of water and outfall 33-feet deep, both in Lake Ontario,” said Kent Vest, project manager of Southland Contracting Inc.
Work began in February 2010, with an anticipated completion date of January 2012.
A 9.5-ft. (2.9 m) diameter double shield rock tunnel boring machine (TBM) is currently at work mining the 6,000 linear ft. (1,829 m) tunnel under Lake Ontario. Manufactured by Southland Contracting, the TBM began work in December 2010. Featuring 24 cutters, it is capable of removing as much as 100 ft. (30.5 m) of rock a day, which is collected on rail cars and hoisted up the riser shaft by a Terex 150-ton (136 t) crawler crane. In similar fashion, those working on the tunnel reach their job site via a cage suspended from a Grove 28-ton (25 t) rough-terrain crane sitting on the surface more than 170 ft. (52 m) above them.
“The 45-foot diameter 170-feet deep riser shaft was excavated by drill-shoot and has been completed. During shaft excavation, the 220 linear foot main pump adit tunnel was excavated by drill-shoot and is now also completed. The six 60-inch drilled pump shafts have been drilled and connected to the main pump adit, while the intake and outfall shafts have been drilled and 96-inch/24-inch final linings have been set and tremie grouted in place,” Vest said.
The remaining work on the project includes:
• Completion of the intake tunnel;
• Excavation and connection of the outfall adit and intake adit tunnel to the marine shafts that were drilled;
• Installation of a 4-in. (10.2 cm) shotcrete liner in the tunnel;
• Installing 58,000 linear ft. (17,678 m) of HDPE chemical feed lines to the intake structure, which will be installed in the crown of the tunnel for Zebra Mussel control and raw water sampling;
• Installation of 3,000 linear ft. (914 m) of 24-in. (61 cm) DIP in the invert of the tunnel, routing backwash water generated in the water treatment process to the marine outfall; and
• Cast-in-place concrete in the riser shaft, 40-ft. (12.3 m) D finished concrete wall, intermediate walls and deck, along with installation of the four sluice gates.
Marine work yet to be completed includes erecting a precast intake crib structure over the intake shaft, which is located a mile from shore in 50-ft. (15.2 m) deep water; flooding the tunnel and removing the bulkheads; and installing the diffuser on the backwash pipe, located 3,000 linear ft. (914 m) from shore in 45-ft. (13.7 m) deep water.
Several subcontractors are working on the job, including BIDCO Marine Group Inc., of Buffalo, N.Y. (marine diving), and ATS Drilling Company Inc., based in Fort Worth, Texas (shaft drilling, marine and land). In addition, two local companies are involved: Ramsey Constructors Inc., headquartered in Rochester, N.Y. (site work), and the John W. Danforth Company of Victor, N.Y. (mechanical piping). The design consultant was Brierley Associates LLC, of Syracuse, N.Y., and Nothnagle Drilling Inc., of Scottsville, N.Y. (handled blasting).
Southland Contracting Inc. is a specialist in wet utility installation and excavation of tunnels ranging from 30-in. (76 cm) diameter to 50-ft. (15 m) wide and more than 30-ft. (9 m) high. The company designs and manufactures its own TBMs, which allows it to provide tailor-made equipment to deal with a wide variety of site conditions.
Its past projects include the Kansas River Tunnel in Johnson County, Kan., which involved installation of 1,440 linear ft. (439 m) of 8-ft. (2.4 m) diameter tunnel, and drainage improvements for the city of Lubbock, Texas, for which the company installed 11,950 linear ft. (3,642 m) of 88-in. to 96-in. (223 to 244 cm) diameter tunnel. Current contracts include the Bi-County Water Tunnel, which consists of 5.3 mi. (8.5 km) of 120-in. (305 cm) diameter deep rock tunnel, for the Washington Suburban Sanitary Commission, as well as construction of a 3.5-mi. (5.6 km) long tunnel for the San Francisco Public Utilities Commission, a particularly difficult job involving excavation up to 700 ft. (213 m) underground and extensive tunnel reinforcement and dewatering due to working conditions. CEG