Trenchless Technology Preserves A North American United Nations World Heritage Site
A municipal water main may not last forever, but a rich history and heritage can.
Québec City, located on the shores of the St. Lawrence River, is Canada’s second oldest city and one of the country’s top cultural centers and tourist destinations. It is the only North American city that has fully preserved its historical character, protecting the fortifications and military barracks that date back to the 1600s. Original cobblestone streets line narrow alleyways, winding through historic stone buildings, while below the surface, the aging water main infrastructure is in need of repair before a break occurs. With this section of the City recognized as a United Nations World Heritage site, the challenges were plenty especially, how to repair without disturbing surrounding structures.
The 121-ft (37-m) section of underground water main that required attention dates back to the 1890s and runs beneath the famous ‘’Breakneck Steps.’’ This centuries-old outdoor staircase, the oldest in Québec City, dates from the beginning of the French colony and its steep 59 steps connect Upper and Lower Town. Many tourists take photographs at this location, as it offers a wonderful view of one of Canada’s most picturesque streets.
Traditional open-cut pipe replacement would have been highly disruptive not only for tourism in the area, but more importantly, it would require damaging this historical site. The City turned to SANEXEN to implement its ALTRA proven water technology cured-in-place pipe (CIPP) solution that would both reduce the amount of disruption to this beautiful area and that would ensure a structurally strong and resilient water main for decades to come.
Project Challenges
The project was challenging, but with SANEXEN’s extensive experience renewing water main infrastructure in historically significant cities across North America, including its recent “Taraval Street” project in San Francisco, the team was able to deliver a trenchless solution that exceeded all requirements, including safety when dealing with a crowded tourist area, keeping surrounding businesses open, the tight space in which to operate, the tricky elevation linking Upper and Lower Town, and preserving the heritage sites.
The water main renewal project began in late June at the peak of tourist season in Québec City. The cafés, restaurants, shops, hotels, museums and residents surrounding “Breakneck Steps” were filled with visitors day and night. After more than a year living through the global pandemic, ensuring that businesses remained open for visitors was key, especially in a city like Québec City that relies on tourism dollars.
As opposed to traditional dig-and-replace methods, which would have caused major disruption to the area’s tourism and businesses for an extended period of time, the installation of ALTRA’s trenchless solution was quick and efficient and required minimal digging. Only two small access pits were required, one at the top of the stairs in Upper Town and one at the bottom in Lower Town. ALTRA’s proven water technology was installed within the existing pipe, creating a brand new solid and resilient pipe without affecting the comings and goings on the stairs and in the surrounding restaurants. Not only could tourists keep enjoying the area with little noise and dust due to our trenchless technology, but the heritage buildings and structures also remained intact. Plus, for this type of renewal, the speed with which the project can be completed far exceeds the old way. ALTRA solution is a technology to deal with these challenges: in less than three weeks, the water main was renewed and normal activity was able to continue throughout. The open-cut method would have taken months to replace the water main and rebuild the stairs and the terraces around. It would have jeopardized the whole summer and would have stretched into July and August, important months for the tourist season.
Another specific challenge with this project was the elevation, angle and trajectory of the pipe. There was a drop of more than 40 ft (close to 12 m) between the access pit at the top in Upper Town and the pit in Lower Town under steps and neighboring restaurants, not in a straight line. Also, the work areas around the pits were tight and limited by buildings, challenging for our trucks to park and impossible to accommodate traditional dig-and-replace equipment like excavators or cranes and materials to rebuild the road.
As an important added bonus, ALTRA’s solution reach beyond minimal disruption for communities and speed of execution. It is also a climate smart technology involving minimal demolition, less reconstruction, fewer trucks going to and from the site and reduced GHG emissions. We estimate ALTRA’s GHG reduction at 443 kilotons so far.
Renewing a water main infrastructure in an historic city center is a complex undertaking. The success story of this water main renewal “Breakneck Steps” perfectly illustrates that ALTRA trenchless technology is the proven solution for water infrastructure that offers a quality service in a record time with low disruption for the community while preserving the important heritage sites. A solution that eliminates water loss, that is climate smart and that adds resiliency for 50-plus years so that people can continue to visit and enjoy beautiful Québec City for years to come.
Watch this video and see the SANEXEN team at work renewing this underground water main from 1890 without impacting the tourists returning to the city: https://www.youtube.com/watch?v=fFwV7qBRlhM&t=8s .
Martin Bureau is vice-president-innovation for SANEXEN Environmental Services Inc.
