Periodically, Trenchless Technology Canada likes to check the pulse of the industry across the country in the form of a roundtable discussion. This year, we wanted to check on the status of the industry from the system owner’s standpoint.
Weighing in on the discussion are:
- Dustin Abt, manager, Public Works, White Rock, British Columbia
- Kate Polkovsky, director of utilities and environment, St. Albert, Alberta
- Henry Polvi, P.Eng., senior engineer, water treatment and supply, Toronto Water
- Charles Pullan, P.Eng., senior project engineer, infrastructure delivery, water resources, Calgary
- Ashley M. Rammeloo, MMSc., P.Eng., division manager of sewer engineering, London, Ontario
- Velimir Stetin, P.Eng., project manager, engineering department, Maple Ridge, British Columbia
Briefly describe your water/sewer system and its condition. What is unique about your system and/or the way it operates?
POLKOVSKY: Our water system has three reservoirs and a pressurized system. We get our water from the neighboring community, so it is typical. Our wastewater system is a little different in the sense that the community is split by a river and we have two large interceptors that serve each side of the river. Our interceptor that serves the north side of the river is not designed as a conveyance system; it is designed more as a storage system with a series of orifices that allows the wastewater to slow its velocity. Flows are generally at full capacity and 10 to 14 m in depth. It slowly releases to a regional lift station at the end. This system reduces the influx of I&I during our wet weather flow, so it mitigates the impact on the pumping system downstream. We have a lot of old clay tile and brick and mortar sewers, as well as the new pipe using modern standards. We have about 9,000 km of pipe underground.
PULLAN: We have a large system, about 5,300 km of water, 4,700 km sanitary and 4,500 km of storm. The condition of our systems is good. A unique aspect for us is that on our sanitary services we do not have any clean outs so that provides some challenges for certain technologies to try and rehabilitate sanitary services. On the water side we have been installing pretty much all of our distribution pipe as PVC since the early 1980s. So there has been a large amount of growth in our network meaning that we have a large percentage of our system that is made of plastic pipe. There used to be two separate departments, one focused on water the other on wastewater. The water department was running into issues in the 1970s with main breaks and had lots of replacement of pipe, so there was a lot more drive into the research on the water side.
ABT: We are a small community on the bluff and the hillside on the southwestern corner of the province and on border with America and right on the bay. Our system is older; however, it is well functioning because we invest in our systems. Our drainage system is mainly ditch infills, so we have shallow storm mains and all of them drain into the Semiahmoo Bay. This makes us extremely cognizant of what enters the bay. As we share our neighbor’s – the Semiahmoo First Nation – concerns regarding water quality entering Semiahmoo Bay. There are two sanitary pump stations and three storm drainage pump stations. All our sanitary sewers go to a Metro Vancouver pump station and on to a treatment plant. In the last five years we acquired our water utility from Epcor and built a water treatment plant.
STETIN: The City of Maple Ridge has a water system that is in good shape, not very old, and mostly constructed of cast iron, ductile iron, and some asbestos cement (AC) pipes. The system consists of reservoirs (fed from Metro Vancouver watermains), pump stations, pressure reducing valves and the pipe network. The City’s sewer systems are in good shape too and there are no combined sewers. The sanitary sewer system consists of two major interceptors (reinforced concrete), that are discharged into Metro Vancouver’s sanitary system and treatment, lift stations and the pipe network, mostly PVC pipes. And the City’s stormwater system is a gravity pipe network, mostly concrete pipes.
POLVI: Toronto Water’s transmission watermains are welded steel, cement mortar lined and concrete encased. They appear to be in excellent condition even at 80 years old. We have approximately 500,000 water meters and wholesale water to York region where about 1 million people live.
RAMMELOO: Our sewer system dates to 1852 and we still have a few of those egg-shaped brick pipes in the ground, but they have been lined at this point. Older areas of the city were built with combined sewers and some of those remain today. One of our challenges is to continue to separate those sewers. We have 2,800 km of sanitary and 1,450 km of storm. We draw water from Lake Huron and Lake Erie and most of the city is fed via gravity sewer from two large reservoirs. The City of London has more than 1,600 km of watermains, five reservoirs and nine pumping stations.
What specific trenchless technologies do you use? Which ones work best? How has your use of trenchless technologies changed over the last few years?
POLVI: We have ROV and submersible and wheeled internal inspections. Toronto Water made the decision to go with trenchless and tunneling works in the downtown core area or where there is major traffic to keep the open cut work to a minimum. We have used tunnel boring machines, hand tunnels and microtunneling for new watermains. For rehabilitation, there is quite a lot of lining work being done on the distribution side, but on the transmission side, we have only done three pipes, two 750 mm and the 900 mm.
POLKOVSKY: We have a crew of two who handle CCTV work in-house with a vehicle that we use, and then we have a CCTV program that we contract out for larger diameter pipes. We do most of our flushing in-house and those crews are going full-time. We have added a robotic camera for our reservoirs and the lateral launch system. Our biggest challenge is getting data for our water system non-destructively. We have used a fair bit of CIPP, and we are looking at CIPP for our water system. Two years ago, we put in about 3,000 m large-diameter sanitary using microtunnelling. We are also using auguring to fix sanitary lines and we use HDD as well.
STETIN: During the last 15 years we have used most of the trenchless technologies, for new installations and restoration. Each trenchless technology is suitable for a particular situation, HDD mostly for pressure pipes installation (watermain and forcemain), pipe bursting for replacement/upsize of the older pipes, pipe jacking where a steel casing is required (mostly under highways, railways), CIPP and sliplining for culvert restoration if the host pipe is still in decent shape.
What have you learned from your experience with trenchless technologies?
ABT: Trenchless technology is more about planning than implementing. I can ask my crews to go to a location, do a job hazard assessment and then dig it and everyone knows what to do. You dig it, you shore it, put base rock in, lay the pipe, haunch the pipe and backfill. With trenchless technology, no matter the method, you must put the time and effort into the planning before you execute.
PULLAN: On the rehabilitation side, it is the quantity of infrastructure that can be rehabilitated for the same dollar value. It is incredible even if you get a shorter service life, it still makes the most sense financially. On the new installation side, it is based on our triple bottom line analysis that we use on all our large projects. We equally weight social, environmental and financial costs and it always manages to help on the environmental and social aspects when there is less disruption from having trenchless installations. One of the largest takeaways from our use of trenchless is the importance of being knowledgeable of the technologies being used. It can be challenging because there are all of these different aspects and benefits of the technologies and you need to understand what everything is, how it works and what the limitations are to ensure you are using the right tool for the right job. It is important to have that knowledge in house because as the owner of the system, you need to know what you are getting out of the work that you are putting in and the public dollars you are spending.
What are the limits to the amount of work you can perform each year?
POLVI: In Toronto, we have healthy competition that keeps the costs lower. When we open bids, we see that the contractors are all close in their numbers. And for different projects, there always seems to be new parties getting into the game. The challenge is that we are in three operating groups: water treatment and supply, water distribution and collection and wastewater. Each of these groups competes for limited capital funding. It is not just divided one-third, one-third and one-third. It is up to the groups and the organization to determine where the money goes.
ABT: Funding is always an issue and roadblock. We are lucky because White Rock was forward thinking in the 1970s and added a sanitary fee, so we have a surplus, but not on the storm drainage side. In talking to other system managers in the province’s municipal operations management group, we all have the same issue with the storm drainage infrastructure. Back in the day, the drains were not made to last like the sanitary is. A lot of municipalities do not want to camera their storm drains because it is so bad. We must do what we can, with the money we have. When I look at a section of the sewer, I look at it in terms of five years. My engineers give me the status in green, yellow and red. Red is not going to last five years, yellow yes it will last five years, and green means do not touch it. So, with the yearly budget, I will do all the reds and knock off as much yellows as possible. It is about planning and managing and knowing what you have.
What are some of the unique approaches your organization has taken to solving its infrastructure problems? Alternative contracting? Innovative technologies?
PULLAN: We have focused on qualification-based selection where it is not exclusively low bid. Specifically, this is done when it comes to trenchless technologies where having the proven technologies, workforce with experience, etc. is very important. On the larger microtunnel projects we are investigating design-build because in those projects it often depends on which contractor wins the bid as to what equipment they will use, how they construct their shafts, et.c All this plays into the design, so we do not want to constrain the contractor with the design. That is pushing it more towards design-build. We always like to push the envelope and see what new technologies are upcoming and where we can be cutting edge and help stretch every dollar, we have by using trenchless technologies to achieve our asset goals.
RAMMELOO: For our trunk watermains, we have invested heavily in inspection and monitoring for the condition of the pipe. In strategic locations this can include periodic inspection, leak monitoring and acoustic/fiber optic condition monitoring. That has really helped with our water assets. On the sewer side we are very proactive with our CCTV inspections and we have a robust lining program every year. For our trunk sewer lining, we instituted a request for proposals system rather than just a simple tender. That allowed us to utilize the contractor’s expertise to tell us the best way to do it. We got exceptionally good results from that. We also have projects where there was considerable risk involved and we partnered with the contractors with a shared risk model to get the work done.
How has the pandemic impacted your operations?
STETIN: We are pleased to see that the contractors did not slow down during pandemic, I recently closed a tender that had six bidders, and two more tenders had about seven interested bidders on each. It is good that we all can continue our work as before these abnormal times.
PULLAN: Thankfully, Alberta allowed construction, so we could continue our construction work with some changes regarding mask wearing and social distancing. I know revenues are affected somewhat but that is mainly focused on future projects that are in the design phase. Now that people are at home, people can see a lot of what we are doing and what is happening with the systems, so there is more connection with the customer. There has been a little more back and forth questions explaining what we are doing and trying to accomplish because people are seeing the visibility of the work.
POLKOVSKY: We have a reduced staff, and this will extend our summer operations into the fall. In terms of projects, they have continued as status quo. We have delayed the start on some to see how the pandemic will go, but I have a supportive council who understand the importance of our program and the need to be proactive, so no one wanted to cancel projects.
POLVI: The Province of Ontario declared potable water as an essential service, so all the work continued. The work in the field has progressed without any stoppage and carry on with a lot less traffic. I know a lot of contractors had to manage their staffs into small groups because of social distancing, but we have not received any notice of work being delayed. All the contractors were able to get a lot of work done in the last three months. The projections are that we will do very good on capital delivery this year. I think for next year, some of the budget might be reduced a bit and that will affect our capital program. Everyone realizes, the whole city, country and the entire world is under different circumstances. We are all working to get the necessary work done.
ABT: With the pandemic, the projects are moving slower, but we are still on track and on budget. The health and safety of the workers is paramount. Probably the biggest silver lining is the increased personal hygiene awareness and more planning. A lot of the time, sewer guys just want to jump in and fix things and figure it out as we go. That works, but you can probably be 50 per cent more efficient with good planning.
RAMMELOO: Most projects went ahead, but we did have a couple open-cut projects that were delayed due to already tight scheduling. We did have some sewer lining work delayed due to travel restrictions but those will still be completed this year. We have a project slated to be tendered in the fall. Our watermain contract is running well ahead of schedule partially due to a lack of traffic and homeowners were around to easily coordinate the required bypass. The pandemic allowed us to focus on what our priorities need to be. I think it will also result in companies allowing increased flexibility for employees. For utilities it really drove home the fact that what we do in water and sewer is an essential service. Our work is critical to people’s health and safety.