Much of the work on underground infrastructure in mature economies calls for the investments to deal with age and change, although new projects are abundant too. This is perhaps particularly true for the US and Canada.
In this feature we look at a few such projects from the many, such as, in the US:
- the bypass tunnel to help resolve the problems with leaks in the Delaware Aqueduct;
- the drainage capacity improvements in Manchester, NH, to help handle problems with overflows and to improve water quality; and,
- in the Great Lakes area, for an initiative to improve energy availability and resilience a tunnel is proposed to be built to house pipelines carrying oil and natural gas liquids.
In Canada, like the US, a number of transport projects are underway in major cities. One such project is Toronto’s Eglinton Crosstown West Extension, which is at an advanced status.
These projects are briefly outlined below.
US: FIXING THE LEAKING DELAWARE AQUEDUCT
Water leaks from conduits, but ideally with minimal losses and insignificant impact upon the conveyance infrastructure. But deterioration of different kinds does happen, in different ways, by different means, and at different times.
There are leaks on sections of the 85 mile-long Delaware Aqueduct tunnel. They were discovered in the 1990s, deep under the Orange County Town of Newburgh, adjacent to the Hudson River. Fixing such a problem is no small task.
In 2010, New York City (NYC) announced a plan to repair the leaking sections of the aqueduct. The budget for large programme of improvements to fix leaks has been put at around US$2 billion.
A key feature of the repair and improvement programme is to build a 2.5 mile-long bypass tunnel around extensive zone of the leaks.
NYC’s Department of Environmental Protection (DEP) is undertaking a new procurement and contracting process for the bypass tunnel.
The change followed the project having had to be paused in late 2024, following the historic drought that Fall, ending the existing construction contract and forcing the final connection to the bypass to be completed under a new procurement process. Those challenges, plus plans to upgraded pumps, mean the final connection for the bypass is not due for completion until after 2027.
The final bypass connection requires an eight-month shutdown and draining of the aqueduct, starting in October of any given year as demand is lower in Winter.
US: NH SEWER TUNNEL JOB BY TBM
The City of Manchester, NH, aims to transform its drainage system in such ways as to reduce combined sewer overflows and also improve the water quality of the Merrimack River which is a critical natural resource, supplying drinking water for 600,000 residents.
Key infrastructure in the drainage improvement include the construction of a new, 2.25 mile-long sewer – the Cemetery Brook Drain Tunnel.
The overall project is budgeted at US$360 million and is being undertaken by the US Environmental Protection Agency and the NH’s Department of Environmental Services.
The contract to construct the Cemetery Brook Drain Tunnel was recently awarded to Methuen Obayashi Joint Venture and is to be completed in 2028.
Tunneling is to be performed by TBM boring with the sewer tunnel alignment running about 26 yds below the ground surface. The sewer is to be a 12ft-i.d. tunnel.
Construction is the start on the banks of the Merrimack River. Seven drop shafts and corresponding structures are to be built. The shafts will be excavated in in rock either by mechanized excavation or controlled blasting.
The shafts will provide construction access, and DS-7 shaft will be used to retrieve the TBM.
During its operational life the shafts will convey flows into the drainage tunnel.
US: ENERGY PIPELINE BOOST WITH TUNNEL
In January, the US declared a national energy emergency to help accelerate expansion of US energy production. One project is Enbridge’s proposed tunnel to carry for the Line 5 oil and gas pipeline, in the Great Lakes area.
The oil and gas pipeline tunnel is to be located in the Straits of Mackinac. Recently, the US Army Corps of Engineers (USACE) granted national energy emergency status for planned 3.6 mile-long tunnel to help fasttrack the environmental review process.
The project is among the first to receive such emergency designation.
In 2023, Michigan regulators approved Enbridge’s application to build the US$750 million tunnel but USACE assessment and permission were still needed. The project has been opposed by environmentalists and Native American tribes.
Enbridge has already appointed a JV of Barnard Construction and Civil and Building North America.
CANADA: EGLINTON CROSSTOWN WEST EXTENSION
Over the next decade Ontario is investing nearly Can$70 billion (US$51.3 billion) in public transit, which includes the largest subway expansion in Canadian history, covering the Ontario Line, the Scarborough Subway Extension, the Eglinton Crosstown West Extension, and the Yonge North Subway Extension.
Toronto’s 5.6 mile (9km)-long Eglinton Crosstown West Extension will connect seven new stations to the Eglinton Crosstown LRT, making travel faster and more convenient, while bringing more than 37,500 people within a 10-minute walk of transit facilities.
Works on Eglinton Crosstown West Extension have been underway for the last few years and are at advanced stages at different points.
Recently, Government of Ontario broke ground on the final tunnel segment of the project. This section involved construction of 547 yds (500m)-long twin tunnels on the line’s eastern section. The tunnels will run just east of Jane Street to Mount Dennis Station, where the extension will connect to the future Eglinton Crosstown LRT service.
Tunneling is to be performed using the sequential excavation method (SEM) and progress of 1m-2m per day is anticipated to be achieved.
Elsewhere on the project, WestEnd Connectors achieves substantial completion of the scope of its works, marking the successful completion of two 3.9 mile (6.3km)-long tunnels, nine cross-passages, 12 headwalls for four underground stations and two emergency exit buildings, construction of the launch shaft and Light Rail Transit portal.
WestEnd Connectors, consisting of Dragados Canada Inc, Aecon Infrastructure Management Inc, and Ghella Canada Ltd, says all the structures were completed with over 1.9 million hours worked without a lost time injury.
TBMs ‘Rexy’ and ‘Renny’ spent two years excavating the twin tunnels, completing their drives on the western section last year.
