Los Angeles

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.

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.

In March 2021, Sepulveda Transit Corridor Partners (Bechtel) was awarded a $69.9 million contract to further develop its proposed heavy rail transit solution concept. More than 60% of the partner team’s proposed heavy rail concept would travel underground, with the remainder of the line traveling primarily in an aerial section. A Valley-to-Westside trip would take just under 20 minutes according to the team’s proposal. The team’s estimated costs for constructing this proposed solution is $10.8 billion.

LA SkyRail Express was awarded a $63.6 million contract to further develop its proposed monorail concept that would be an aerial alignment primarily within the I-405 right-of-way between the Valley and Westside. Proposed travel times via monorail are estimated at 24 minutes. The LA SkyRail Express team’s baseline proposal cost for building the monorail concept is $6.1 billion.

In August 2021, Metro issued Notices to Proceed to the two teams to officially begin project development. Metro held an environmental review phase with project scoping from Nov. 30, 2021, and through Feb. 11, 2022, with more than 3,000 comments received. In June 2022, Metro released a Scoping Summary Report which provides more information about feedback received from the public during the project’s recent scoping period. According to the report, heavy rail and underground alternatives received support.

Metro and the PDA teams will consider the comments received during scoping as they continue to develop the project alternatives and advances to preparing a draft environmental impact statement.
Web: https://www.metro.net/projects/sepulvedacorridor/


Delta Conveyance
The Delta Conveyance Project for the Department of Water Resources (DWR) includes a tunnel through the Sacramento-San Joaquin Delta that is designed to 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.

In July 2022, DWR released a Draft Environmental Impact Report. After consideration of public comments submitted on the Draft EIR and issuances of a Final EIR, DWR will determine whether to approve the proposed project. The comment period is scheduled to close on Dec. 16, 2022.
Web: water.ca.gov/

San Bernardino

Ontario Airport Tunnel
The San Bernardino County Transportation Authority (SBCTA) has partnered with Ontario International Airport (ONT) to develop transit solutions for today’s and tomorrow’s passengers while ensuring the neighboring communities experience reduced congestion throughout the region.

This project, an innovative approach of tunneling, will create a subsurface transit connection between the Cucamonga Metrolink Station and ONT terminals. The Cucamonga Station is the closest to ONT on the San Bernardino Line and has consistently represented one of the higher number of boardings in the Metrolink system. The project sets the foundation for the privately funded Brightline West electrified high-speed rail connection between Las Vegas and Cucamonga Metrolink Station, as well as the zero-emission West Valley Connector bus rapid transit service coming in 2025.

Operated and maintained by Omnitrans, the project will feature a bi-directional system where passengers traveling to and from ONT will be transported in autonomous, zero-emission vehicles on an “on-demand” basis and developed under the Federal Transit Administration (FTA) Fixed Guideway requirements.
Most passengers departing from and arriving to ONT use I-10, which parallels the Metrolink San Bernardino Line from downtown Los Angeles to San Bernardino. I-10 is currently the most used segment of freeway in San Bernardino County, carrying some 270,000 vehicles per day.


The current reference design considers a 24-ft inner diameter single bore tunnel to accommodate a single travel lane in each direction. A center dividing wall would be constructed to separate the two travel lanes. Cross passage doors would be provided in the center wall at 800-ft spacing for emergency egress, per NFPA 130.


The proposed project includes three passenger stations. One station would serve the Cucamonga Metrolink Station, and two stations would serve ONT within the existing parking lots located across from Terminals 2 and 4. The proposed Cucamonga Metrolink Station would be approximately 18,000 sq ft in size and located in the northwest corner of the existing Cucamonga Metrolink Station parking lot. A vehicle maintenance facility and operations control center would be integrated at Cucamonga Station. The two stations proposed at ONT would be located at-grade and would connect to their associated tunnel portals along Terminal Way via an at-grade connection. The proposed stations would be approximately 10,000 sq ft and entirely located within ONT right-of-way.


The proposed system will be operated using automated transit network (ATN) vehicles capable of providing on-demand dispatching of vehicles (individual and platooned) to carry passengers directly to their station without other station stops. These ATN vehicles will be fully ADA compliant, and feature level boarding and luggage accommodations for airport passengers.


Following the RFQ period, SBCTA will shortlist at least two design-build teams for a 10-month preconstruction (Phase 1) period, leading to selection of a single design-build team to proceed to final design, construction, and O&M (Phase 2). The Phase 2 contract will also include a one-year (minimum) transitional operations period at the conclusion of construction and system start-up, testing, and commissioning.

A stipend for each shortlisted design-build team is included in the Phase 1 budget.
The two-stage model allows SBCTA and selected contractors to collaborate as an integrated team during the preconstruction phase. This collaborative approach promotes innovative ideas to benefit the project cost and schedule. Areas for potential project innovation include tunnel sizing, tunnel boring machine logistics and operations, and vehicle technology selection.
According to the preliminary schedule, design-build construction is set to begin in 2024 with operations by 2027. RFQs are being accepted through Jan. 26, 2023.

Web: gosbcta.com/project/ontloop-rail-to-air-tunnel-connection

San Diego

San Vicente Energy Storage Facility
The San Vicente Energy Storage Facility is one of the most promising pumped energy storage solutions in California. The energy storage project is under consideration by a partnership of the San Diego County Water Authority and the City of San Diego. As proposed, the project could store 4,000 Megawatt-hours per day of energy (500 Megawatts of capacity for eight hours), which is enough energy to provide approximately 135,000 homes with power.

The potential project would create a small upper reservoir above the San Vicente Reservoir, along with a tunnel system and an underground powerhouse to connect the two reservoirs. The powerhouse is proposed to contain four reversible pump turbines. During off-peak periods – when power is inexpensive and renewable supplies from wind and solar facilities exceed demand – turbines will pump water to the upper reservoir where it will act as a battery of stored potential energy. During high energy use, the system will discharge energy as water from the upper reservoir flows downhill through the turbines. The exchange between the two reservoirs will not consume water and is closed-loop.

The reservoir is near major electricity transmission interconnection facilities, which will allow the project to play a central role in integrating solar and wind energy from across the Southwest for use in San Diego County.

The preliminary schedule indicates that construction could begin by 2027.
Web: sdcwa.org/projects/san-vicente-energy

San Jose

BART Silicon Valley Extension
The $6.9 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.

At its May 5, 2022, regular board meeting, the VTA Board of Directors voted unanimously to authorize the General Manager/CEO to execute the first in a series of construction contracts for the BART Silicon Valley Phase II (BSVII) Project. This first Contract Package for the Tunnel and Trackwork (CP2) is a Progressive Design Build Contract with Kiewit Shea Traylor (KST), a Joint Venture, in the amount of $235,000,000.
Contract Package (CP2) will be carried out in stages with Stage 1 activities including investigation of innovations, engineering and design, open book cost estimates, and the work schedule. Stage 1 activities are anticipated to occur from May 2022 through approximately December 2023, setting the stage for major construction (Stage 2) which includes boring the tunnel under downtown San Jose.

In November 2022, an independent study by world renowned tunneling experts, confirmed the single bore tunnel design is the right approach to deliver the project.
Web: vta.org/projects/bart-sv/



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 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.

Contract Award/Start Construction is anticipated to begin in 2023, with Operations beginning by March 23, 2030 (Consent Decree Milestone).

Web: dcwater.com/projects/potomac-river-tunnel-project



B&P Replacement Tunnel
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.

In June 2022, Amtrak kicked off the procurement phase for the $1+ billion Southern Approach construction package, which is the first of three major construction contracts for the B&P Tunnel Replacement Program in Baltimore. Amtrak has issued a Request for Letters Of Interest (LOI) to the industry, indicating that this portion of the program will be completed under a Construction Manager At-Risk (CMAR) delivery approach.
Contractors interested in serving as the CMAR were to complete the LOI by Aug. 31 in order to be eligible to receive the RFP (Request For Proposals) that were to be issued for this portion of the project later this year.
Construction contracts of subsequent portions of the program will be procured separately. Amtrak continues to advance design, property acquisitions, and preparations for other smaller construction projects associated with the B&P Tunnel Replacement Program, which will transform the Northeast Corridor in West Baltimore. The Program includes nearly $5 billion of construction, and after receipt of new federal funding, Amtrak will be ready to complete early construction activities.

Web: bptunnel.com/


Northeast Corridor Superconducting Maglev
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.

The Draft Environmental Impact Statement (DEIS) has been released but has been paused to review project elements and determine the next steps, according to the project website.

Owner: TNEM/BWRR; Prime Consultant: WSP (formerly Louis Berger); Tunneling subconsultant: Gall Zeidler.

Web: bwmaglev.info

Ellicott City

Extended North Tunnel
Howard County public works officials said they expect to complete design of the tunnel this year, with construction starting as soon as possible. The project, known as the Extended North Tunnel, will be about 5,000 ft long, 18 ft in diameter and run up to 100 ft underground, just north of Main Street. County officials announced that it had secured funding for the project in May.
Howard County has already broken ground on two other major flood mitigation projects – the H7 and Quaker Mill ponds. Both projects are expected to be completed in the next year and will retain nearly 7.5 million gallons of storm water combined.



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. A CDM Smith-led team was awarded a $15.7 million, 3.5-year contract in September 2020 to develop and evaluate tunnel route alternatives, deliver environmental impact reports, conduct geotechnical investigation and evaluation and prepare a preliminary design report.


St. Louis

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, 2027, $640,000,000, 8.6 miles, 30 ft dia
  • River Des Peres Tributaries CSO Tunnel, 2028, $178,000,000, 3.1 miles, 17 ft dia
  • Upper River Des Peres CSO Storage Tunnel, 2032, $188,000,000, 2.6 miles, 22 ft dia

Web: msdprojectclear.org/


Las Vegas

Horizon Lateral
The Horizon Lateral will provide a critical second water transmission pipeline to ensure reliable service to nearly a million existing customers.

The approximately $1.6 billion project will ensure continued, reliable water service to existing customers while supporting the community’s future water needs and the regional economy. The targeted in-service date is approximately 2030.

With pipelines as large as 120 inches in diameter, the Horizon Lateral will bolster system dependability and capacity for the area, which currently relies upon a single transmission pipeline known as the South Valley Lateral (SVL). The SVL, in service since 1999, is projected to reach capacity within the next 10-15 years and currently lacks critical redundancy or back-up facilities to service the region in case of system outages or emergencies.

A Feasibility Study indicated the project could include 7 to 8 miles of TBM tunneling.
Web: snwa.com/our-regional-water-system/horizon-lateral/index.html


New York

Hudson Tunnel Project/Gateway
A joint venture of WSP, AECOM and STV has been awarded the design contract. The tunnel portion of the contract, estimated at $16 billion, is envisioned to be a design-build contract including the Palisades Tunnel and Hudson Tunnel. The Hudson Tunnel Project is currently in the environmental review process and is on 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 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.

In December 2021, The last major step in the federal regulatory process for the Hudson Tunnel Project has been completed with the U.S. Army Corps of Engineers’ permit issuance for construction within the New Jersey Meadowlands and Hudson River, the Gateway Development Commission announced.

In July 2022, Gov. Kathy Hochul of New York and Gov. Phil Murphy of New Jersey signed an MOU. The MOU outlines sources, uses, and timing of funding on behalf of New Jersey and New York for Phase One Gateway Projects: Portal North Bridge and the Hudson Tunnel Project. Signing this MOU advances the Gateway Program to its next phase, which will detail the parties’ responsibilities with respect to delivery of the Hudson Tunnel Project and move forward in the federal project review.

Web: hudsontunnelproject.com

New York

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. In January 2022, the project advanced into Engineering phase of the federal Capital Investment Grants (CIG) program.
Web: web.mta.info/capital/phase2_sas.html



Northside Interceptor Tunnel
Design is underway on the Northside Interceptor Tunnel, which will convey and store combined sewer flows from the North Hill neighborhood in Akron, Ohio. The mainline tunnel inside diameter is 16.5 ft and length is 6,660 ft. An ancillary tunnel will also be constructed that will be 8 ft internal diameter for a length of 2,400 ft. The project will include major baffle drop shafts, drill drop shafts, and related structures. RFQ for construction is expected in January 2023 with RFP in April 2023.

Web: akronwaterwaysrenewed.com


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 major upcoming tunnel projects include:
Southerly Storage Tunnel – 18,340 lf of 23-ft diameter CSO tunnel.
Big Creek Storage Tunnel – 22,400 lf of 18-ft diameter CSO tunnel. Design is anticipated to begin in 2024/25.
Web: neorsd.org


Delaware and Chester Counties

DELCORA Tunnel Alignment

DELCORA Wastewater Tunnel Project
The Delaware County Regional Water Quality Control Authority (DELCORA) is planning upgrades to its system to allow it to treat its own effluent vs. contracting treatment through the Philadelphia Water Department. In addition to upgrading the Western Regional Treatment Plant in Chester, DELCORA will also build a new deep tunnel underground to convey wastewater from the communities it serves to the updated plant. The DELCORA Wastewater Tunnel is 8.5 miles long, running approximately 100 ft underground from Darby Township to the treatment plant in Chester. Construction duration is about 5 years.

Web: delcora.org


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. Procurement for a design-bid-build contract for the Ohio River Tunnel is expected in 2024.

CDM Smith is the Clean Water Program Director, Jacobs is the Tunnel Program Manager Consultant, and Mott MacDonald is the Ohio River Tunnel Final Design Consultant.

Web: alcosan.org



Project Connect
On Nov. 5, 2020, voters in Austin, Texas, approved the $7.1 billion Project Connect transportation proposal. This proposal, which includes a 1.6-mile tunnel in the city’s downtown area, includes using property tax revenue to fund the project, with 45% coming from federal sources.

Project Connect is to include:

  • A new rail system would serve North and South Austin, the airport, downtown and Colony Park.
  • A transit tunnel downtown would separate rail from traffic to improve on-time performance.
  • Expanded bus service with an all-electric bus fleet, new routes and on-demand circulators within certain neighborhoods.
  • Nine new Park & Rides throughout the region with improved connections and new amenities.

The Downtown Transit Tunnel will separate proposed light rail service from street traffic, enabling faster, safer and more reliable travel through downtown. The new rail system will connect at underground stations at Republic Square and other downtown locations. These stations are planned to include such amenities as retail, restaurants, a transit store and service center.

The tunnel’s stations will provide connections to the new rail system and expanded bus service. In addition to a transitway, the stations will provide a new public space for transit customers and the larger community. The stations will be climate-controlled and are planned to include features such as public art installations, a performance venue for live music, shops, coffee shops, restaurants, free Wi-Fi access, comfortable seating, public restrooms and security cameras. Agents at the CapMetro Transit Store will serve customers with transit information and sell tickets for all services.

The City of Austin is one of multiple taxing entities to which property owners pay property taxes annually. With the approval of Proposition A, 8.75 cents of the City’s property tax rate revenue will be dedicated to the Austin Transit Partnership to fund implementation of Project Connect. Now approved by voters, the Project Connect portion of the City’s property tax rate will become part of the City’s property tax rate each year.

The initial investment includes 27 miles of rail service and 31 stations, including the downtown tunnel and stations. According to recent report in CommunityImpact.com, the construction estimate for the tunnel portion of Project Connect at the 30 percent design phase was approximately $4 billion. Planners are currently looking into ways to reduce cost, which could involve replacing the underground alignment with street level transit.

Web: projectconnect.com


D2 Subway
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 project team led by DART, the City of Dallas, the North Central Texas Council of Governments (NCTCOG), and the Texas Department of Transportation, recently completed its East End Evaluation to review potential changes to the eastern alignment. The review led to a new recommended alignment that was approved by Dallas City Council and the DART board.

The project budget is $1.7 billion and initial plans included 1.3 miles of alignment below grade (2 miles total) and three underground stations (four total).

Web: dart.org/D2


Flood Control Tunnels
The Harris County Flood Control District is entering the second phase of a study to explore the feasibility of building deep tunnels to divert storm water to prevent flooding. The district signed a $2.5 million contract with Black & Veatch to study the size and effectiveness of tunnels at various locations in the county, as well as funding sources.

According to the communityimpact.com, early estimates indicate that it would cost about $1.5 billion to build 10 miles of 40- to 50-ft tunnel. The next phase would include preliminary engineering, which would take approximately 12-18 months.

Web: hcfcd.org



West Seattle and Ballard Link Extensions
Sound Transit is planning for new extensions to its Link Light Rail system including:
West Seattle to Downtown: includes 4.7 miles of light rail services and four stations with a potential tunnel and underground station, and Ballard to Downtown: includes 7.1 miles of new LRT service including a new downtown Seattle rail-only tunnel.

On July 28, the Sound Transit Board identified preferred light rail route and station locations for the West Seattle Link Extension and directed staff to conduct further studies and community engagement, primarily on the Ballard Link Extension.

In the West Seattle extension, the Board identified the Preferred Alternative for the West Seattle Link Extension as the Medium Tunnel 41st Avenue Station alternative in the West Seattle Junction segment, the Andover Street Station Lower Height alternative in the Delridge segment, the South Crossing alternative in the Duwamish Segment, and the At-Grade Alternative Staggered Station Configuration in the SODO segment.

In the Final EIS, expected to be published in late 2023, Sound Transit will respond to comments received during the Draft EIS comment period. Following the publication of the Final EIS, the Board will select the project to be built. Construction is expected to begin in 2026, according to the Sound Transit website.
Web: soundtransit.org

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