As urban centers continue to grow and climate challenges reshape infrastructure demands, tunneling projects play a vital role in transit expansion, water management, and flood control. Across North America, major tunneling initiatives are in development, offering significant opportunities for civil engineers, construction contractors, and municipalities.
At Stiver Engineering, we closely track large-scale civil infrastructure projects and develop engineering solutions that deliver efficiency, safety, and structural integrity. Below is a look at some of the biggest tunneling projects of 2025 and active Request for Proposal (RFP) opportunities for contractors seeking to get involved.
Major Tunneling Projects in 2025
California
In California, transit and water infrastructure remain at the forefront of civil development. Los Angeles Metro’s Eastside Transit Corridor Phase 2 is a planned nine-mile rail extension, with three miles running underground. The project has completed environmental approvals and is expected to begin construction in 2029 and open in 2035.
Another major transit initiative is the Sepulveda Transit Corridor, which aims to improve connectivity between the San Fernando Valley and the Westside through a high-capacity rail system. The project remains in the environmental review phase, with a draft report expected in early 2025.
The Delta Conveyance Project is a $20.1 billion plan to construct a 45-mile tunnel through the Sacramento-San Joaquin Delta. This project is designed to modernize the state’s water infrastructure by protecting against climate change impacts, reducing reliance on aging facilities, and ensuring a more resilient and reliable water supply for millions of residents.
Texas
Texas is seeing major tunneling efforts in both flood control and transit infrastructure. The I-35 CapEx Drainage Tunnel in Austin, designed to mitigate stormwater issues along the corridor, will stretch 6.5 miles with a 22-foot internal diameter. The project is set to begin construction in 2025 and finish in 2028.
In Houston, the Harris County Flood Control District continues evaluating a multi-tunnel system to reduce flooding. The proposed project includes eight tunnel segments ranging from 8 to 25 miles in length, with diameters between 30 and 40 feet. With an estimated price tag of $30 billion, it is one of the most ambitious stormwater conveyance projects under consideration in the U.S.
East Coast
On the East Coast, several massive infrastructure projects are moving forward. The Hudson Tunnel Project will add a new 26,400-foot tunnel under the Hudson River as part of the $16 billion Gateway Program, improving transit access between New Jersey and Manhattan. Federal funding has been secured, and procurement is underway.
In New York City, the Kensico-Eastview Connection is a critical component of a $1.9 billion drinking water upgrade. The project involves a two-mile, 27-foot diameter tunnel linking the Kensico Reservoir to the Catskill-Delaware Ultraviolet Light Disinfection Facility. Construction is set to continue through 2035.
In Pittsburgh, the ALCOSAN CSO Tunnels are part of a multi-billion-dollar effort to manage combined sewer overflows. This system of three major tunnels, including the Ohio River Tunnel, the Allegheny River Tunnel, and the Monongahela River Tunnel, will be delivered by design-bid-build, with the Ohio River Tunnel expected to break ground in 2025.
The Cemetery Brook Drain Tunnel Project is a vital infrastructure initiative aimed at reducing combined sewer overflows and improving water quality in the Merrimack River. As part of Manchester’s Phase II CSO Program, this 11,700-ft-long tunnel will be constructed 30 to 80 feet beneath the city, addressing stormwater management challenges while enhancing urban resilience. By integrating advanced engineering techniques, this project will mitigate flooding and support long-term environmental sustainability and urban development in Manchester.
Midwest
The Midwest is also seeing significant tunneling activity. In Cleveland, the Project Clean Lake initiative includes the construction of multiple deep tunnels to manage stormwater and wastewater. This project is set to enhance water quality and improve the resilience of Northeast Ohio’s wastewater infrastructure for future generations.
Explore Active RFPs & Bidding Opportunities
With so many major tunneling projects in motion, civil contractors and engineering firms have a range of opportunities to get involved. Several key projects are currently in the bidding phase, with RFQs and RFPs available for submission. For contractors looking to participate in these large-scale initiatives, we have compiled a list of current RFPs. Visit our site to explore bid opportunities and project specifications: https://stiverengineering.com/bid/
How Stiver Engineering Supports Large-Scale Tunneling and Infrastructure Projects
At Stiver Engineering, we provide expert civil engineering solutions that enhance the efficiency, safety, and cost-effectiveness of tunneling projects. Our work includes tunneling design, dewatering systems, and structural engineering, ensuring that underground infrastructure is both functional and resilient. Our ability to support contractors and municipalities in developing custom solutions for excavation, stormwater management, and transit tunnel reinforcement makes us a trusted partner in major infrastructure development.
If you are looking for engineering support on any of these major projects, our team is here to assist. Contact us today to discuss your project needs and learn how our expertise can help bring your tunneling initiative to life: https://stiverengineering.com/contact-engineering-design-firm/
