trenchless work in Regina, Saskatchewan

2023 Trenchless Technology Canada Municipal Roundtable: Water, Sewer System Owners Discuss the Status of the Trenchless Market

Taking part in our 2023 Trenchless Technology Canada roundtable discussion are:

  • Kyle Winters, C.E.T., manager of design and construction, Brandon, Manitoba
  • Neil Thomas, P.Eng., water and sewer, Fredericton, New Brunswick
  • Regina Sewer and Water Engineering Staff, Regina, Saskatchewan

It’s safe to say that the last three years have been a rollercoaster for sewer and water system owners. Many took advantage of the early days of the COVID-19 pandemic to get some much-needed work done. But, as things drew on, they became hamstrung by contractor labour shortages, supply chain issues and price hikes in the subsequent years. All of this has had a direct impact on the amount of work they can get done.

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According to data released by Statistics Canada in March as part of its Canada’s Core Public Infrastructure Survey, the replacement value of core public infrastructure in Canada is $2.1 trillion. Of that, water infrastructure is $771.8 billion. The cost to replace all assets rated in poor or very poor condition was estimated at $264.7 billion. Wastewater infrastructure is 13.9 per cent and potable water infrastructure is 11.1 per cent of that total.

When it comes to this replacement and/or repair work, trenchless technologies present a minimally invasive alternative to traditional open-cut methods. While trenchless technologies are by no means new technologies, there are still pockets where traditional open-cut methods remain the norm.

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To get an idea of what sewer and water system owners are doing when it comes to trenchless works across Canada, we present our annual system owners roundtable.

trenchless work in Regina, Saskatchewan

Describe your water/sewer system and its condition. Is there anything unique about your system and/or the way it operates?

Brandon: The City of Brandon maintains just over 300 km of underground piping for water distribution, including five booster stations, a reservoir and water treatment plant. The Assiniboine River is Brandon’s primary water source, which can be a challenge seasonally and particularly during drought conditions as low river levels can create issues with the gravity-fed intake.

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The wastewater collection system consists of 250 km of pipe, some of which is combined sewer, and an additional 24 km of forcemain for dedicated flow from our six lift stations ultimately ending up at the wastewater treatment plant. Efforts continue to remove storm sewer connections to the domestic sewer system.

Typical pipe materials are PVC, cast iron, ductile iron, asbestos cement, concrete and vitrified clay (VCP). Water and wastewater mains range in size from 150-mm diameter to 950/1,350-mm egg-shape pipes. The downtown area of Brandon has segments of infrastructure dating back to the early 1900s. Some homes in this area were serviced with lead pipes that remain in place today and impact water quality, which is a challenge that is not entirely unique to Brandon.

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Fredericton: The City of Fredericton water and sewer system operates as a utility financially separate from the general revenue (taxation) system. Our water source is groundwater extracted by 10 high-capacity wells serving a population of approximately 55,000. Our infrastructure comprises approximately 450 km of watermain, two water treatment plants (Mn removal) and 450 km of sewer main with a principle secondary aeration wastewater treatment plant. Our water system has been universally metered since the 1920s and we were probably the first Canadian municipality to chlorinate our water system, beginning in 1912.

Regina Water: The City has approximately 1,200 km of water pipes ranging from 150 mm to 1,200 mm. Around 200 km are trunk mains with pipe sizes larger than 450 mm, while the remaining 960 km are small diameter water mains less than 450 mm.

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Most of the trunk main is steel pipes with a total length of 166 km. The remaining pipe materials include concrete, cast iron, and PVC. The condition of the trunk mains is relatively good, except for approximately 10 km of cast iron pipes. These cast iron pipes have been in the system for over 100 years and experienced increasing leaks in recent years and need to be replaced or rehabilitated.

Among the small-diameter water mains, about 531 km are asbestos cement pipes, with the remaining going to PVC (412 km) and small quantities of other pipe materials. AC pipes have the highest total length and percentage in Canada. These pipes have accounted for most pipe breaks in the City since the 1980s and are the major focus of the City’s water main renewal plans.

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Regina Sewer: We have a separate sanitary system (not combined with storm system, for the most part) about 965 km in total length that is maintained by the City. Pipe materials include brick, concrete, clay, clay tile, various plastics, transite, no-corrode, AC, cast iron and steel.

All pipes older than 50 years have been inspected at least once in the past 12 years. Concrete pipes have been found to be deteriorating faster than expected; for example, some large diameter pipes installed in the 1980s are already showing surface degradation such that the reinforcement is visible. Conversely, there are segments of brick pipe installed over 100 years ago that appear in nearly perfect condition. A large proportion of our network was installed in the 1950s – generally the concrete pipe from that era needs rehabilitation due to surface deterioration up to and including missing wall, but the clay pipes of the same age are generally either structurally sound with some small joint offsets, or they are fractured and deformed, needing lining or replacement.

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trenchless work in Regina, Saskatchewan

What are the main problems/challenges you are facing with your system?

Regina Water: The City’s distribution main is slowly deteriorating, and as such, we experience several breaks in the year, especially during the cold season. Due to the age of the mains and the corrosive soils in Regina, cast-iron trunk mains are susceptible to leaks. As those trunk mains are located either in the downtown area or under critical artillery roads, any leaks may lead to significant disruption to traffic and damage to properties. Also, because of their locations, any renewal methods need to cause considerable inconvenience to traffic and businesses and to be completed in the shortest periods.

Asbestos cement pipes have unique issues in the City of Regina, not only because of their high total length but also the aggressive soil environments they are working on. The soil in Regina is highly expansive and changes volume significantly, leading to soil heave or settlement around pipes. AC pipes are susceptible to soil movement and tend to break when the movement reaches a certain degree. More than 90 per cent of watermain breaks occur to AC pipes in the City. To repair the water main breaks, the City has to allocate millions of dollars each year.

Regina Sewer: The sanitary system experiences significant I&I due to cross connections or the few remaining combined sewers. Another big source is likely leakage from laterals. Tree roots are prevalent especially in laterals and provide a pathway for infiltration.

Residential sewer back-ups are increasingly unacceptable. Growth of new areas, lack of slope/grade, create need for additional infrastructure. Climate change and the increase in storm intensity exacerbates problems caused by I&I. Expansive clay soils are susceptible to wet and dry climate cycles. Movement in the soils causes external stresses and movement, breakage, leading to exfiltration and loss of bedding material and support.

Brandon: Aging infrastructure and remaining capacity are top of mind. In recent years Brandon has made a lot of progress in increased maintenance/repair and replacement of our water distribution system. We have managed to reduce our water loss by 5 per cent since 2018. The City hopes to issue condition assessment bid opportunities soon to further understand the condition of our water distribution system.

The City began formal condition assessments of the wastewater network in 2020. It has been an informative process and we are only beginning to identify the problems associated with the aging collection system’s condition. The City also deals with a high water table in a number of areas. Inflow & infiltration is a known issue that needs to be managed in the coming years as it is impacting the available capacity for new development.

Fredericton: Approximately 20 years ago, the City had undertaken an asset management plan coinciding with the adoption of PSAB (Public Sector Account Board) compliance principles. Stemming from this, the Water & Sewer Division has been actively replacing cast-iron watermain and sanitary sewer main that were installed post-WWII and into the early 1970s. The new material – ductile iron for water and PVC for sanitary – is installed using newer methods, but primarily the City relies on traditional open-cut and fill construction methods. Cut-and-fill construction is well understood by City staff, consultants and contractors such that transitioning to a further adoption of trenchless methods will require a paradigm shift.

What specific trenchless technologies do you use?

Fredericton: For approximately 30 years, directional drilling techniques have been utilized for the installation of sewer mains and building services typically for one off projects. In 2011, we used cured-in-place pipe (CIPP) hot water cure to reline an inverted siphon sewer main located under a river. In 2019, we started to use ultraviolet (UV) CIPP to rehabilitate 1950- and 1960s-era sanitary sewer mains that were, for ease of construction in the day, installed in residential back yards. Over the intervening years, the residential neighbourhoods have changed with the construction of numerous encroaching fences, garages and the growth of many large matured trees and hedges. Due to limited access, options and our unwillingness to disrupt many residents’ private properties, the UV CIPP liner technology resolved the aging sanitary condition at an attractive price point. Prior to utilizing UV CIPP cure system technology, we contacted the Centre for Advancement of Trenchless Technologies (CATT) at the University of Waterloo in 2019 for advice.

Regina Water: The best trenchless technology depends on the current condition of existing water pipes and other factors, such as coordination with other utility/roadway work. No one method works best for all cases. For occasions where the roadways and other underground infrastructure are in good condition, rehabilitating the main using CIPP is cost-effective, provides minimal excavations and reduces disruption to citizens.

For pipe renewal work that needs to coordinate with service replacement, pipe bursting and/or horizontal directional drilling (HDD) may be the best method(s). Although excavation is required for repairing the services, pipe materials are relatively affordable.

The City is one of the pioneer municipalities in Canada that use CIPP to renew water pipes. The City started a pilot CIPP installation in 2010 and has installed more than 30 km of CIPP pipes since then. The City does recognize the limitation of the CIPP method and over the last few years has been exploring other methods that can supplement it. For example, the City tested HDD a few years ago and has an HDD program now.

Pipe bursting had been used by the City to install new pipes for particular situations, such as river/rail crossing, for some years, but had never been used to renew existing water pipes. The City started this method for renewing old pipes two years ago and is anticipating more applications in the coming years.

Regina Sewer: We have been using CIPP on our sanitary and storm systems for over 30 years. We use both trenchless spot repair and full segment CIPP. Approximately 140 km of the sanitary network (14.5 per cent) has been treated with full segment CIPP. We have used the guided auger boring method to install large diameter pipe under critical rail infrastructure.

We have found CIPP on our gravity systems (including siphons) is very cost-effective and performs extremely well. Use of CIPP has increased in the length relined each year and the increased size of pipe relined. Designs for future installations and replacements now consider trenchless methods to minimize surface and customer disruptions.

Brandon: Most trenchless installations have been completed through HDD or auger boring. An increasing number of projects are being tendered with the option of installation via HDD. Soil conditions in Brandon can be challenging for open cut installations. Giving the option of trenchless installation has provided flexibility for contractors and reduced project costs, benefiting all parties.

trenchless work in Brandon, Manitoba

What limits your use of trenchless technologies?

Brandon: The availability of qualified contractors is one of the biggest concerns. There are a few qualified HDD and CIPP contractors in our area and that’s really it. Tunnelling, microtunnelling and pipe bursting aren’t really an option as the cost of mobilization makes for an uncompetitive bid.

Fredericton: Limitation is most probably our own willingness to try different methods and develop a program, thereby attracting a larger talent pool of private contractors, as opposed to issuing several smaller scale projects.

Regina Water: The most significant challenge is the need for qualified contractors. Also, CIPP for water pipe renewal is a relatively new technology. Some procedures, such as pipe cleaning, are still in development and need to be standardized. Cost also limits its use, as these methods may not save or even cost more when compared to open cut. Thus, the City has to identify situations where these methods can fully achieve their benefits.

Regina Sewer: Lack of qualified contractors and materials, especially locally. CIPP is, by far, the easiest to access, even though materials are often sourced out-of-province. Other options require bringing in contractors from further away, which increases costs. There is also increasing political pressure to buy local.

What have you learned from your experience with trenchless technologies?

Regina Water: Trenchless methods are the best options for some situations but not all situations. When properly applied, these methods can reduce disruptions, shorten project duration, and save costs.

Fredericton: For our UV CIPP reline projects our design-build contractor, Eastern Trenchless Ltd., had recommended undertaking our projects with incremental steps. This has proven to be invaluable advice.
The first phase of our relining projects comprised notification of the residents, video inspection of the target section of sanitary, confirming location and condition of access manholes, flushing the mains and then a second video inspection was completed. This base information was packaged into a public tender call providing potential UV CIPP bidders with confidence of site conditions. This approach enabled the work to proceed smoothly and at attractive pricing, as the job had been substantially de-risked.

Do you see your use of trenchless technologies increasing in the next decade?

Regina Water: Yes, we believe that we will use trenchless technologies for most water pipe renewal in the next decade. We will probably use all the methods (CIPP, pipe bursting, HDD and other new technologies), and select one of the methods for locations that can fulfill the full benefits of the methods.

Regina Sewer: Increasing since our network need will increase as more assets will be reaching conditions appropriate for CIPP. Looking at more trenchless options to address a wider range of conditions (collapse, severe deformation, bypass requirements). Tunnelling for installation will be used to limit disruption under protected lands. Expanding use of lateral relining.

Brandon: With minimal trenchless installations to date, there is certainly room to expand on the use of trenchless technologies. The City has put a lot of resources into assessing the condition of our wastewater network. When looking at strategies to address the condition concerns, prioritization is key. We plan to grow our CIPP lining program to address a large number of the issues found.

trenchless work in Regina, Saskatchewan

What changes are occurring in the way the public utility systems are operating?

Brandon: Like most places, the City of Brandon is faced with limited funding and rising costs to replace, rehabilitate and maintain. With less funding available we must adapt and ensure the right projects and the right treatments are chosen. I would say that funding limitations did not initiate the change though. Asset management and formal condition assessments did. Knowing what we know now about the condition of some of our infrastructure then highlighted the need to invest more in preventative maintenance of our underground piping before they fail.

The benefit of changing the way we operate is that it drives us to try new technologies, products, procurement methods and installation methods. With a limited construction season in Manitoba, trenchless rehab methods are going to be more commonplace.

What unique approaches is your organization taking to solving its infrastructure problems?

Brandon: To increase interest in trenchless installation options the City has issued several bid opportunities where both conventional and trenchless installation options are accepted. In most cases bids have been awarded to contractors opting for a trenchless solution as they were able to reduce restoration costs. We continue to look for ways to adopt new technologies through small pilot projects as they allow us to better understand new products before fully adopting them.

Fredericton: Repair and installation of new infrastructure within difficult to access locations or under high traffic volume roadways has forced us to use “new to us” trenchless technologies. The success and cost effectiveness of these projects should lead us to embrace other technologies and to develop broader programs.

Mike Kezdi is the managing editor of Trenchless Technology.

Read our previous Trenchless Technology Municipal Roundtable Stories below.