The official magazine of WCW professionals across Western Canada Winter 2009
Volume 61
Issue No. 4
PM 40065075 PM 40065075 Return undeliverable Canadian addresses to: kelly@kelman.ca
Northern Systems
Northern Systems Water Reuse & Recycling
Municipal engineering
“North of 60”
By Ken Johnson, AECOM
A unique view Living “North of 60” presents a unique view of our Nation too few Canadians have the opportunity to see. However, a lot of Canadians would rather not experience -45°C with winds at 20 to 30 km-per-hour. As an engineer working “North of 60” the experience is memorable, from a personal point of view and a professional point of view. Travels “North of 60” in Canada may take one to Beaver Creek in the west, and Iqaluit (Frobisher Bay) in the east. On a national perspective this is all the way across Canada, considering Beaver Creek lies well west of Vancouver Island, and Iqaluit lies almost as far east as New Brunswick. Municipal engineering “North of 60” provides some very unique working conditions,
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as well as engineering conditions. The working conditions include extended periods of daylight and darkness, extended periods of travel, and extremely cold temperatures. The engineers working on municipal projects in the north are a fairly small group, so we are often running into each other in our travels. Any engineer with more than a couple of continuous years working “North of 60” may be considered “well-seasoned,” and those with 10 to 15 years of working experience may be considered “old-timers.” The engineering conditions of municipal engineering “North of 60” are unique in comparison to those in the south because these conditions are often pushed to the extreme. Frost penetration, where there is not permafrost, may extend 3.5 to 4.0 metres into the ground.
Material supply and delivery is very often controlled by a limited opportunity for accessing either an ice road or sealift, depending upon the location of the project. Construction is also controlled by the very short summer season (June through September). Project scheduling The scheduling of a project is an important aspect of municipal engineering “North of 60.” A realistic timeframe for many projects may be a four-to-five year period. The first year of a project schedule is utilized for project planning. This is a necessary, but often time consuming and expensive step to establish the necessary lines of communication between the various groups involved in the project, and to refine the project needs and project resources.
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Northern Systems
The theme and expenses are due to the isolation of the project site and the cultural differences of the project users. A simple visit to a project site may take several days of travel each way and may cost thousands of dollars. The second year of a project schedule is utilized for preliminary engineering and detailed design. These technical stages of the project may be characterized by the various technical activities with typical “southern” engineering. However, the design criteria include careful consideration of cold temperatures, ice and snow, and how these are influenced by wind, darkness, and isolation. The third and potentially fourth year of a project is utilized for project construction. Construction of roads, pipelines, reservoirs, and lagoons is limited to a window between June and October. Construction before or after this period is certainly possible, but the cold temperatures often create problems that may jeopardize the integrity of the project. Projects in the coastal communities “North of 60” are faced with the problem that material and equipment supply cannot occur until late July, at the earliest. This is due to the fact that arctic waters are not free of ice until the mid-summer to allow the annual sealift to occur. Airlifting of materials and equipment is a last resort because it is extremely expensive. Other projects, particularly in the western arctic, may have access to all-weather roads or winter roads for material and equipment delivery. This allows for delivery during the winter months and for construction to begin as soon as temperatures permit. The final year of the project schedule is post construction and warranty. This period of a project is not without its own particular problems, which may result from the necessity for the contractor to complete deficiencies once his forces are demobilized, and the general “bugs” that may have to be worked out of a newly completed project.
pal projects “North of 60” strays away from strict number crunching. Many of the technical issues may be approximated by calculation, but intuition and experience play some part in determining whether the calculated solution will actually work. A basic design principle used over and over again “North of 60” is that water will freeze. The design criteria for water and sewer systems may include preventing the pipes from freezing, and also allowing access to thaw the pipes when they do freeze using systems such as the access vaults. A reasonably safe assumption is that at some point in the future the pipes will freeze. Consideration of pipe insulation, water temperature, and minimum flow to prevent freezing are standard in any northern water or sewer system. Development projects involving road construction or other jobs where there is a need for granular material present another potential problem for the supply of suitable material. If material is available, it may or may not fit the desired specification, even if the characteristics of the material are known. A lack of complete information is another hurdle for municipal engineering “North of 60.” The isolation of projects and short construction season present a constant challenge to the
northern contractors who undertake the work and the engineers who monitor the work. Mobilization and demobilization become significant portions of the project cost, if a contractor is not based in a community. Cost estimating in the north may at times also be considered more of an art than a science. Even the project cost estimate founded upon the best possible historical information may end up being significantly lower than the price tendered by the contractor. Factors such as competitiveness, contractor experience and confidence, and transportation which play a major role in northern construction may at times only be judged with a crystal ball, which most engineers do not have at their disposal. The specifics of costs for municipal engineering “North of 60” are often mind-boggling. A good example is the construction of a municipal sewer system in the Town of Iqaluit. Insulated small diameter sanitary sewer mains in Iqaluit are approximately $1200 per metre. This cost does not include the supply and installation of simple Access Vaults, which are approximately $70,000 each. The variety of the projects and the unique nature of each project one encounters in municipal engineering “North of 60” provide a continuing challenge for the northern municipal engineer.
The art and science of engineering “North of 60” To associate engineering with art, as well as science, may turn the heads of some engineers. However, the finesse required for some municiClick here to return to Table of Contents
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Northern Systems Water Reuse & Recycling
Northern infrastructure -
a pictorial overview By Ken Johnson, Cryofront The North boasts some unique examples of water and wastewater infrastructure. Here are just some examples.
Truckfill station - Sachs Harbour, Northwest Territories Trucked water delivery from a truckfill station remains the primary means of water distribution in the North, and is the only means of water distribution in Sachs Harbour. Water use in Sachs Harbour (71° 59’ N, 125° 14’ W) is approximately 100 litres per person per day.
Sewage eduction – Tuktoyaktuk, Northwest Territories Trucked sewage collection or ‘eduction’ is used in most communities in the North. Sewage haulers in Tuktoyaktuk (69° 27’ N, 133° 02’ W) use 4,500 L vacuum trucks to haul 7 km to the sewage lagoon.
Sewage lagoon – Kugluktuk, Nunavut One of a very few lined sewage lagoons was completed in Kugluktuk (67° 50’ N, 115° 06’ W) in 2008. The $6M lagoon stores the sewage for a seasonal discharge into a natural wetland.
Landfill – Pelly Crossing, Yukon The Yukon is working toward a ban on all landfill burning by 2012. However burning vaults like the one in Pelly Crossing (62° 50’ N, 136° 35’ W) may have continued merit for solid waste management in small northern communities.
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Access vaults – Iqaluit, Nunavut The access vault commonly used in Iqaluit (63° 45’ N, 68° 31’ W) is an insulated, doublewalled steel container providing essential access for maintenance of shallow buried sewer and water systems.
Insulated water and sewer – Rankin Inlet, Nunavut Shallow buried and insulated water and sewer was first installed in Rankin Inlet (62° 49’ N, 92° 6’ W) in the 1970s. Even at an air temperature of -40°C the ground temperature will be a relatively ‘balmy’ -10°C.
Insulated water supply – Alert, Nunavut Water supply at Alert (82° 28’ N, 62° 30’ W), the world’s most northerly inhabited place, has to endure extreme cold weather and freezing temperatures for all but 28 days a year on average.
Utilidor – Inuvik, Northwest Territories The utilidor system in Inuvik (68° 22’ N, 133° 44’ W) was originally constructed over 50 years ago. The original utilidor box is slowly being replaced with separate insulated above-ground water and sewer mains.
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