MWRA - The MetroWest Water Supply Tunnel

Facts about the MetroWest Water Supply Tunnel

Purpose:

To enhance the security, capacity and reliability of the water system that serves 2.3 million people in 40 communities

Total Program Budget Set in 1995:

$728 million

Total Program Estimated Completion Costs:

$665 million (includes design, construction management, construction
and other support costs)

Awarded construction:

8 contracts valued at over $506 million in construction costs

Length of tunnel:

17.6 miles – roughly the distance from Rte. 495 to Rte 128, parallel to the Mass.Turnpike

Installing forms for concrete lining 2001-2002

Diameter:

Mined at 16 feet, finished at 14 feet

Depth:

200-500 feet deep

Years to Complete each phase of construction:

Excavating Shafts: 1 year
Mining: 2 years
Lining: 2 years
Line Shafts: 1 year
Piping, connections and disinfection: 1 year

Construction schedule and duration:

Construction work took place over a 7-year period with over 6 million man-hours worked. Work proceeded 24 hours per day on 3 shifts, 5-6 days per week with no fatalities.

Mining:

3 machines, each valued at over $7 million, were used to mine the tunnel

3 major working shafts: (Southborough,
Framingham and Weston)

9 connections to water facilities and communities

Under five communities:

Marlborough, Southborough, Framingham,
Wayland, and Weston

Wye intersection 235 feet below the Mass. Turnpike tolls at Rte. 128

Average production rate:

57.1 feet per day

Total rock excavated:

1, 025,000 cubic yards

Kinds of Rock Excavated:

Granite, gneiss, shist, quartzite and others

Total Amount of Concrete Used for Lining:

184,722 cubic yards

Concrete Production Rate:

154 cubic yards per day

Average production for lining:

77 lineal feet per day

Project coordinated with:

Treatment Facilities at Walnut
Hill (Marlborough) and Covered
Storage at Norumbega

Reservoir (Weston)
capacity:

450 million gallons per day

Amount of water needed to fill the tunnels and shafts:

105.5 million gallons

Disinfected with:

42,000 gallons of sodium
hypochlorite (chlorine)

Total Number of People Who Worked on the Project:

1,907

Maximum Number of People Working at One Time:

598

Unions on the Job:

Tunnel Workers Local 88, Operators Local 4, Electricians Locals 103 and 96

Schedule:

Broke Ground late 1996

Finished construction on schedule in Spring 2003

Final Testing and Disinfection in Summer/early Fall 2003

Memorandums of Agreement with Communities:

Weston
Wayland
Framingham
Southborough

Designers:

Sverdrup/Jacobs Civil Inc.

Construction Management Team:

Stone and Webster Massachusetts Inc., a Shaw Group Co.
Parsons Brinckerhoff Construction Services Inc.
Regina Villa Associates
Hager GeoScience
H2O Engineering Consulting Assoc.
DMC Engineering
Judith Nitsch Engineering
Revet Environmental

Major Contractors:

Shea/Traylor/Healy
Modern Continental/Obayashi
Barletta Heavy Division