Clearwater Program Effluent Outfall Tunnel
The Clearwater Program’s Joint Water Pollution Control Plant (JWPCP) Effluent Outfall Tunnel Project is part of an extensive effort by the Sanitation Districts of Los Angeles County to analyze the needs of its Joint Outfall System to the year 2050. The outfall is envisioned to enhance the existing 8- and 12-ft tunnels with a new 37,000-lf, 18-ft ID post-tensioned concrete segmented lined tunnel. All tunneling work will be done from a single shaft. Structures located at the start and end of the tunnel will connect to the existing Ocean Outfall System facilities. Approval of plans and approval to advertise was scheduled for the April 11 Board of Directors meeting.
Mountain Tunnel Improvements
This project for the San Francisco Public Utilities Commission (SFPUC) involves 12 miles of rehabilitation of the 10-ft diameter, concrete-lined, horseshoe tunnel. Work includes concrete lining repairs, contact grouting, downstream valve control structure, large control valve installations, new tunnel adit, adit/portal improvements, tunnel siphon extension, water cut-off grouting, water discharge treatment, access roadway improvements, temporary staging area excavations and grading, and environmental mitigations. Most of the work will be 1,000 ft below ground surface and will be accessed via the downstream Priest Portal, and Adits 5/6 and 8/9 at intermediate locations along the alignment. Access will also be available 7 miles upstream via the 13.5-ft diameter unlined section of the tunnel from Early Intake. The project designer is McMillen Jacobs Associates (MJA) with AECOM as environmental consultant. Project design and environmental review has commenced, and both phases are anticipated to be completed at the end of 2019. Construction is scheduled for 2020 through 2026.
The Interlake Tunnel for the Monterey County Water Resources Agency comprises an 11,000-ft long, 10-ft diameter, gravity-flow tunnel and related structures that would divert water from Lake Nacimiento (Nacimiemto Reservoir) to Lake San Antonio (San Antonio Reservoir). The engineering firm EPC Consultants has been hired as Program Manager. McMillen Jacobs Associates and GEI Inc. have been retained for preliminary engineering and design services. Construction is scheduled to begin in Q3 2019. The estimated project cost is $80 million.
California Water Fix
The California Water Fix Program is a comprehensive effort to improve water conveyance in the Sacramento-San Joaquin Delta region. Key components of the program include a series of water conveyance tunnels that will allow for transport of up to 9,000 cfs of water directly from the Sacramento River to the major export pumping plants in the south end of the Delta. The program consists of three river intake structures, approximately 10 miles of 29-ft and 40-ft ID tunnels, and approximately 60 miles of 40-ft ID main conveyance tunnels, and a 9,000 cfs pumping facility located at the terminus of the main tunnels. The main conveyance tunnels will be configured in a parallel twin bore arrangement, with tunnel invert depth of averaging approximately 150 ft below ground surface. In addition to launching and receiving shafts, a series of ventilation/access shafts will be constructed along each tunnel reach. Tunnel design is anticipated to commence in mid-2019 with the first tunnel contracts being advertised for construction bids in mid/late-2020. Subsequent tunnel construction packages will be advertised on approximate 6-month intervals following the first contract award.
BART Silicon Valley Extension
The Santa Clara Valley Transportation Authority has a June 2018 deadline for completion of the project development for its 6-mile project into downtown San Jose, 5 miles of which would be subway construction, including four stations. The overall project is a 16-mile extension the Bay Area Rapid Transit system in the San Francisco Bay area. VTA is considering twin- and single-bore options for the subway section. A single bore would be on the order of 45 ft in diameter. Cost estimates are in the range of $5 billion. Project construction could begin in 2020 or 2021 according to preliminary plans.
DISTRICT OF COLUMBIA
Potomac River Tunnel Project
The Potomac River Tunnel is a component of DC Water’s long-term control plan (LTCP), also known as the DC Clean Rivers Project. The Consent Decree establishes schedules for construction of the Potomac River Tunnel and other CSO control facilities under the DC Clean Rivers Project, including a 2025 deadline to implement the project in its entirety. The Potomac River Tunnel will be located approximately 100 ft below ground.
NE Corridor Superconducting Maglev
The Environmental Impact Statement for the first leg of the Northeast Corridor Superconducting Maglev project is underway with the Record of Decision anticipated in 2019. Construction is planned for 2020. The first leg comprises 60 km from Washington to Baltimore, 75 percent of the alignment in tunnel, and three underground stations (Washington, Baltimore and BWI Airport). The total cost is over $10 billion. TBM tunneling is anticipated as a single bore with guideways (outside tunnel diameter approximately 15 m). Five or six TBMs are anticipated. Owner: TNEM/BWRR; Prime Consultant: Louis Berger; Tunneling subconsultant: Gall Zeidler.
Project Clear Tunnels
Metropolitan St. Louis Sewer District (MSD) has begun an ambitious program called Project Clear, a multi-billion dollar investment addressing wastewater overflows. The system improvements include construction of nine tunnels to control sewer overflows.
Upcoming tunneling components of Project Clear include (Project, Construction Begin, Construction Cost Estimate, Tunnel Length, Tunnel Diameter):
- Lower & Middle Des Peres Storage Tunnel, 2020, $631,000,000, 9 miles, 30 ft dia
- University City Sanitary Storage Facility, 2018, $40,000,000, 1,250 ft, 30 ft dia
- Lower Meramec Tunnel, 2018, $170,000,000, 6.8 miles, 8 ft dia
- River Des Peres Tributaries CSO Tunnel, 2024, $375,000,000, 12,144 ft, 20 ft dia
- Upper River Des Peres CSO Storage Tunnel, 2028, $226,000,000, 8,976 ft, 24 ft dia
Flushing Bay CSO
The New York City Department of Environmental Protection has begun drafting an RFP for design of 2.5-mile long, 25 million gallon CSO tunnel in Queens as part of a Long-Term Control Plan. The tunnel is expected to be 18-20 ft in diameter an estimated cost of between $670 million $829 million for the preferred alternative. Preliminary plans envision construction occurring from 2026 to 2035. DEP expects to initiate design in 2019.
Hudson Tunnel Project/Gateway
The Hudson Tunnel Project is a new two-track heavy rail tunnel along the Northeast Corridor from the Bergen Palisades in New Jersey to Manhattan that will directly serve Penn Station New York. It consists of three major elements: the Hudson Yards right-of-way preservation project, the Hudson Tunnel, and the rehabilitation and modernization of the existing North River tunnel.
A JV of WSP, AECOM and STV has been awarded the design contract. The tunnel contract, estimated at $12 billion to $13 billion, is envisioned to be a design-build including the Palisades Tunnel and Hudson Tunnel. Construction was expected to begin in 2019 but uncertainties regarding funding may impact the schedule. The original schedule projected both the new tunnel and the rehabilitated tunnel open for revenue service by 2028.
Second Avenue Subway – Phase 2
Design is underway for the Phase 2 of the second Avenue Subway. A joint venture of WSP and STV is working on the design for the project that extends the line northward from 96th Street to 125th Street – a total of 1.5 miles with three new stations. The alignment will use some existing tunnels originally built in the 1970s, in addition to new soft-ground TBM tunnels. The cost estimate for this phase of the project is $6 billion, with revenue service anticipated between 2027 and 2029.
NEORSD Project Clean Lake
Project Clean Lake for the Northeast Ohio Regional Sewer District (NEORSD) includes several major tunnel components to store and convey combined sewer overflows. The projects include:
- Westerly Storage Tunnel – 9,600 ft of 25-ft diameter tunnel. The design contract was awarded to a joint venture Mott MacDonald and MWH in fall 2015 and also includes a $28 million 46-ft diameter, 200-ft deep submersible Tunnel Dewatering Pump Station. The Westerly Storage Tunnel advertised for bid in Q4 2017, and in March was awarded to Jay Dee-Obayashi for $135 million. The Westerly Tunnel Dewatering Pump Station will bid in 2019;
- Shoreline Storage Tunnel – 15,300 lf of 21-ft diameter soft ground CSO tunnel. It is anticipated to bid in 2021;
- Shoreline Consolidation Sewer – 11,700 lf of 9.5-ft diameter soft ground tunnel. It is anticipated to bid in 2021;
- Southerly Storage Tunnel – 18,340 lf of 23-ft diameter CSO tunnel. It is anticipated to bid in 2024;
- Big Creek Storage Tunnel – 22,400 lf of 18-ft diameter CSO tunnel. It is anticipated to bid in 2029.
NEORSD Project Clean Lake
The Narragansett Bay Commission (NBC) has begun conceptual design of the third and final phase of its Combined Sewer Overflow Program. Phase III includes the Pawtucket Tunnel, NBC’s second CSO storage tunnel.
NBC completed the Providence Tunnel, a 16,500-ft long, 26-ft diameter CSO storage tunnel, in 2008 during Phase I of its CSO program.
The Pawtucket Tunnel will be approximately 13,000 ft long, 28 ft in diameter and located in bedrock about 200 ft below the ground surface. The contract to construct the Pawtucket Tunnel will include the launch and recovery shafts (which will become permanent access shafts), two to three drop shafts with connecting adits at existing outfall locations, and an underground shaft- or cavern-style tunnel pump station.
The program/construction manager for Phase III is Stantec and its teaming partner Pare Corporation. Construction of the Pawtucket Tunnel is anticipated to begin in late 2020 or early 2021.
Phase 2 Lake Travis Deep Water Intake
The Brushy Creek Regional Utility Authority (BCRUA) has embarked on a multiple year program to increase capacity and manage concerns associated with recent historic low water levels of Lake Travis. The program includes: a multiple level-screen deep water intake assembly and shaft extending about 70-ft below lake bottom; approximately 10,000-ft of 96-in. diameter tunnel to convey water by gravity from the intake to a new on-shore pump station (with a subterranean forebay, multiple individual pump wells and a 30 ft diameter wetwell extending about 300 ft below grade); and 3,000-ft of 84-in. diameter pressurized transmission tunnel. Final design is anticipated to begin in 2019, and construction is anticipated to begin in 2021 or 2022. BCRUA is currently acquiring easements for the project.
Hampton Roads Bridge-Tunnel
The HRBT Expansion project will build another bridge-tunnel and widen the four-lane segments of I-64 in Hampton and Norfolk to ease daily congestion between the Peninsula and South Hampton Roads, a corridor vital to Virginia’s economy. In December, the Virginia Department of Transportation issued an RFQ from interested firms. Responses were due March 2. Contract award for the $3.3 billion project is anticipated in early 2019, with project completion in 2024. Tunneled portions of the project are expected to be constructed with either immersed tube or bored methods.