Los Angeles to San Francisco
Sepulveda Transit Corridor Project
Metro is making strides to improve travel between the San Fernando Valley, the Westside and Los Angeles International Airport (LAX). The natural barrier created by the Santa Monica Mountains means that most people traveling between these areas are funneled primarily onto the I-405 Freeway, already ranked as one of the most traveled urban highways in the nation. More than 400,000 people travel through this area every day to commute to work, school, and other destinations along the freeway and beyond.
In Fall 2019, Metro completed a two-year Feasibility Study (Study) evaluating a number of alignments and station locations for a range of high-capacity rail transit alternatives between the San Fernando Valley and LAX with connections to existing and planned Metro bus and rail lines, including the East San Fernando Valley, Orange, Purple, and Expo Lines. The study findings will be the basis for future environmental analysis and project refinement, expected to begin in mid-2020. Given the mountainous terrain, tunneling is being considered for part of the alignment.
The Sepulveda Transit Corridor is part of the Measure M expenditure plan, with approximately $5.7 billion for new transit service to connect the San Fernando Valley and the Westside, scheduled to open by 2033-35. Approximately $3.8 billion is allocated to extend that service from the Westside to LAX with a 2057-59 opening date.
On Oct. 31, 2019, Metro issued a Request for Proposals (RFP) seeking assistance from the private sector to jointly develop plans for the Sepulveda Transit Corridor Project. Metro’s RFP seeks a pre-development agreement (PDA) with up to two private sector proposers to assist in the planning and design of this mega-project. Once project development is complete, the private sector project developer would have an opportunity to submit a proposal to build and operate the line, potentially accelerating construction and improving project performance.
Los Angeles to San Francisco
California High-Speed Rail
The California High-Speed Rail Authority is planning a rail link from Los Angeles to San Francisco that will allow passengers to complete the journey in just 2 hours and 40 minutes. Work is currently underway in the Central Valley.
Tunnels will be required in the north across the California Coast Range between Gilroy and Merced; and in the south in the Tehachapi Mountains between Bakersfield and Palmdale, and the San Gabriel Mountains between Palmdale and Burbank.
The alignments currently under consideration involve between 45 to 50 miles of tunnels that range in length from several thousand feet to over 20 miles, some of which are over 2,000 ft underground. The target revenue service date for the Merced-Fresno-Bakersfield segment is 2028-29, per the Authority’s Draft 2020 Business Plan that was released Feb. 12.
The draft plan calls for the environmental clearing of the entire Phase 1 system between San Francisco and Los Angeles/Anaheim in the next 18-24 months, allowing the process of right-of-way acquisition to proceed. The 2020 draft business plan outlines Phase 1 costs ranging from a low of approximately $60 billion to a high of approximately $100 billion, assuming a 2033 project delivery date.
WSP is serving as the Authority’s Rail Delivery Partner (RDP).
Mountain Tunnel Improvements
This project for the San Francisco Public Utilities Commission (SFPUC) involves 11 miles of rehabilitation of the 10-ft diameter, concrete-lined, horseshoe tunnel, which was completed in 1925. 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, the construction of a new 1,075-ft Adit Tunnel at Priest Reservoir to improve maintenance access, 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. The project is currently in the bid phase, which is scheduled to close May 7. The advertised value of the project is between $133 million and $143 million.
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 benefits of the project include increased surface water storage, increased water supply and reduced flooding downstream of Lake Nacimiento by diverting water into Lake San Antonio that would otherwise flow out to the ocean. The project also includes a spillway modification at Lake San Antonio to add an additional 41,500 acre-feet of water storage. The engineering firm COWI North America has been hired by the agency as Program Manager for the project. McMillen Jacobs Associates has been retained for preliminary engineering and design services for the projects. Tunneling with EPB single-pass lining technology is envisioned. Design-build SOQ is scheduled for Q1 2020. Construction is scheduled to begin in Q3 2020 following a local election to secure project financing. The estimated project cost including the tunnel and spillway modification is approximately $123 million.
The Department of Water Resources (DWR) announced on Jan. 15 that it would initiate the preparation of an Environmental Impact Report (EIR) for the Delta Conveyance Project. The tunnel project through the Sacramento-San Joaquin Delta will protect water supplies from sea-level rise and saltwater intrusion into the Delta. Additionally, the project will help to reduce the risk associated with earthquakes, improve water supply reliability, and reduce impacts on local Delta communities and fish. The project, originally envisioned to include twin tunnels, is being redesigned as a single-tunnel option under Gov. Gavin Newsom, who took office in January 2019.
BART Silicon Valley Extension
The $5.5 billion, 6-mile BART Silicon Valley Phase II Extension includes 5 miles tunnel constructed by a single, large-bore TBM on the order of 45-ft in diameter. The extension includes four stations (three underground). The overall project is a 16-mile extension of the Bay Area Rapid Transit system in the San Francisco Bay area. A joint venture of HNTB and WSP agreed to a four-year, $88.3 million program management contract with the owner, Santa Clara Valley Transportation Authority (VTA). Mott MacDonald/PGH Wong was awarded a general engineering consultant contract in January 2019. Current plans are for construction to occur from 2022-2028.
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, 24,000 lf and 18-ft ID, will be located approximately 100 ft below ground. CSOs captured by the Potomac River Tunnel would be conveyed to the Blue Plains Advanced Wastewater Treatment Plant.
The B&P Tunnel is a planned replacement of the existing B&P Tunnel, which is an integral portion of Amtrak’s Northeast Corridor. The new tunnel would replace the low speed, two-track brick arch tunnel, built in the 1870s with four, new single bore, high speed tunnels. The estimated construction cost is $5 billion, with a construction duration of a decade. The project is on Amtrak’s priority list, along with four other mega-projects – thus awaiting funding.
The FRA and MDOT issued the Final Environmental Impact Statement (FEIS) in November 2016 and the Record of Decision (ROD) was released March 2017.
Northeast Corridor Superconducting Maglev
The process for approving the Environmental Impact Statement (EIS) under the National Environmental Policy Act (NEPA) has been paused, according to the project website. The plan for the first leg of the Northeast Corridor Superconducting Maglev comprises 60 km from Washington to Baltimore, approximately 75 percent of the alignment in tunnel, and two underground stations (Washington, BWI Airport) and one at-grade station (Baltimore). The total cost is over $10 billion. TBM tunneling is anticipated as a single bore with guideways (outside tunnel diameter approximately 15m). As many as eight or nine TBMs are anticipated. Owner: TNEM/BWRR; Prime Consultant: WSP (formerly Louis Berger); Tunneling subconsultant: Gall Zeidler.
Redundancy Tunnel Program
The Redundancy Tunnel Program for the Massachusetts Water Resources Authority (MWRA) will allow reliability of vital drinking water system that was impacted by 2010 main break that resulted in an estimated impact of $310 million per day. The two main components are:
- Northern Tunnel – 4.5 miles long, 10-ft dia., 200-500 ft deep
- Southern Tunnel – 9.5 miles long, 10-ft dia., 200-500 ft deep
The construction duration is estimated to last between 17-23 years, with construction beginning around 2026. The cost estimate is $1.475 billion.
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
- Lower Meramec Tunnel, 2020, $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.
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 joint venture of WSP, AECOM and STV has been awarded the design contract. The tunnel portion of the contract, estimated at $13 billion, is envisioned to be a design-build contract including the Palisades Tunnel and Hudson Tunnel. Currently the project is hold pending finalizing funding sources.
The Hudson Tunnel Project is part of the Northeast Corridor Gateway Program, a series of strategic rail infrastructure investments designed to improve current service and create new capacity. The Port Authority of New York and New Jersey (PANYNJ) currently serves as the project sponsor, but the project is a joint undertaking that also includes Amtrak and New Jersey Transit (NJ TRANSIT).
The existing North River Tunnel, opened in 1910, is owned by Amtrak. NJ TRANSIT and Amtrak operate approximately 450 trains each weekday through the tunnel that carry over 200,000 daily passenger trips. The North River Tunnel presents reliability challenges due to damage from Superstorm Sandy in 2012, as well as the overall age the tunnel and the intensity of its current use. Significant delays to a large number of trains occur when problems arise.
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.
Water Tunnel No. 3 Shafts
The NYC DEP will be constructing two shafts, 600 ft deep, in Queens. The project includes four large-diameter riser pipes in each shaft. The project will require ground freezing. Documents for bidding were expected to be ready by March 2020.
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:
- 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.
ALCOSAN CSO Tunnels
The Allegheny County Sanitary Authority (ALCOSAN) is designing a tunnel program to control combined sewer overflows (CSOs) as part of a consent decree with EPA. The $2.8 billion system improvement program is expected to include tunnel segments to store and treat overflows. The improvements are slated to be complete by 2026. The tunnels include: Ohio River Segment (1.9 miles, 12-14 ft in diameter, $84 million); Allegheny River Segment (3.6 miles, 12-14 ft in diameter, $136 million); and Monongahela River Segment (4.5 miles, 12-14 ft in diameter, $152 million). Additionally, the program will include interceptor and consolidation sewers, dewatering pump station and treatment plant improvements. Plans unveiled in September call for tunneling to begin on the Ohio River in 2023, with the others to follow.
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.
Mechanical fit out of the tunnel pump station will be performed under a separate contract. Construction of diversion structures, gate and screening structures and consolidation conduits at existing outfall locations will be performed under separate contracts as well.
The launch shaft and tunnel pump station will be located at NBC’s Bucklin Point Wastewater Treatment Facility in East Providence, Rhode Island. The alignment will be parallel to the Seekonk River and Blackstone River, and end near the border of Pawtucket and Central Falls, Rhode Island. An 8,800-ft long, 10-ft diameter conveyance tunnel, which will connect to the Pawtucket Tunnel, is planned to begin after the Pawtucket Tunnel is completed. 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.
Dallas Area Rapid Transit (DART) is well underway with planning and preliminary design of the D2 Subway, which will provide a second light rail alignment through downtown Dallas. The targeted opening date for the design-build project is 2024.
Thirty-four borings have been completed since 2016, providing data on conditions up to 120 ft below grade. These borings have revealed the rock types of Austin Chalk (limestone) and Barnett Shale (shale). Upon completion of soil and rock testing, additional evaluations will be performed to help DART determine the most appropriate method(s) to construct the tunnel, stations, and station access portals.
The project budget was $1.3 billion as of October 2016. The project includes 1.3 miles of alignment below grade (2 miles total) and three underground stations (four total).
Flood Control Tunnels
The Harris County Flood Control District is set to receive a federal grant of $320,000 to study the feasibility of building deep tunnels to divert storm water to the Houston Ship Channel, the Houston Chronicle reported on Feb. 20. The four-month study would determine whether the tunnels would be practical and cost-effective in the district’s flood-protection strategy. The district got a $2.5 billion flood bond approved last summer.
Early discussions have the tunnels at least 20 ft diameter and 150 ft deep moving water from upstream bayous to the ship channel, in some cases a distance of 30 miles.
The San Antonio Water System (SAWS), a public utility owned by the City of San Antonio, Texas, is in the process of selecting a consultant for its W-6 Upper Segment: Hwy 90 to SW Military Drive Sewer Main Project.
The estimated $150 million project involves approximately 27,000 lf of 10-ft diameter tunnel to host the new 90-in. FRP gravity sewer pipe. The project also includes installation of about 2,300 lf of 60-in. gravity sewer pipe via open cut. The tunnel depth will vary along the alignment with depths of up to 130 ft. The project includes five launching/receiving shafts with additional smaller access shafts. Geotechnical data is being gathered as design proceeds.
This project is part of SAWS’ compliance with the EPA Consent Decree. The depth and extent of tunneling is beyond that of past sewer projects at SAWS. SAWS invites capable tunnel contractors local, national, and international to submit proposals when the project is advertised in spring of 2020.
The goal is to complete 100% Contract Documents by February 2020, so SAWS can advertise in March 2020. The objective is to award the construction contract in June 2020. Estimated construction duration is a maximum of 36 months.
Alexandria Renew Enterprises (AlexRenew) has put forth a plan to address the discharge of combined sewage to Alexandria, Virginia’s waterways that includes a storage and conveyance tunnel system. The Tunnel System is the largest component of the program with an estimated construction cost of $293 million and capital cost of $345 million. The tunnel is envisioned to be a 12-ft diameter, 11,500-ft long and 120-ft deep soft ground tunnel, with three shafts ranging from 35 to 50-ft in diameter. The Tunnel System and other controls need to be in place by July 1, 2025, per state law.
The Tunnel System Project will be procured through a two-step Fixed-Price, Design-Build process. A Request for Qualifications (RFQ) was issued on June 7, 2019. The board expects to approve the contract in November 2020 with NTP in December 2020.
West Seattle and Ballard Link Extensions
Sound Transit is planning for new extensions to its Link Light Rail system including:
West Seattle to Downtown: which includes a potential 0.5 to 1-mile tunnel under West Seattle neighborhood with 1 new potential underground station, and
Ballard to Downtown: which includes 7.1 miles of new LRT service, and nine stations. Plans call for a 3.3-mile tunnel alignment, and six underground stations with two mined pedestrian connections to existing stations. Additionally, a potential 1-mile tunnel under Lake Washington Ship Canal and one new potential underground station could be included.