Containment systems in the Arctic
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MESSAGE FROM THE EDITOR KEN JOHNSON
This occasion of the 20th edition of the Journal provides an opportunity to reflect on what has been generated in this time – GADZOOKS! (An exclamation of surprise.)
Counting this issue and 19 previous issues at 10 articles per issue works out to be around 200 articles. I continue to find topics of potential interest to the NTWWA members and the 1,300 or so individuals on the mailing list – my thought is to just keep going for another 20.
The theme this year reflects a current concern across the panArctic of containment, which, as described by Anne Wilson in the first article, has a very broad context – well done, Anne. The balance of the articles are all on theme and all relevant to various
aspects of containment in the Arctic.
The current focus on the Arctic in the political realm is disconcerting, to say the least, but as my Danish colleague puts it, “Keeping an optimistic attitude, one could hope there could come something good of it.”
As usual, I have some tremendous editorial support – many thanks to Renata Klassen and Bianca Bocancea in this regard. The theme for the 21st edition of the Journal is microplastics in the Arctic, and anyone with a perspective to offer on the theme, or anyone with a comment on this current issue, is welcome to contact me at ken.johnson@exp.com, or cryofront@gmail.com or 780-984-9085 by voice or text. S
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To the editor, Ken Johnson
Once upon a time and long, long ago (30-plus years) in a place far, far away (Yellowknife), some 50 people gathered at a clandestine location (Explorer Hotel) to hear presentations and discuss issues about water and sanitation in the Northwest Territories (it was all the NWT then). Gathered were municipal officials, government officials, consultants. and community operators.
At the conclusion of the seminars, those assembled all agreed it was time the NWT had its own benevolent association to support those who took on this important work. There was a short discussion on the name, and it was agreed that it should be broad and sweeping (with Nunavut pending and an eye to others) so it would include all the northern territories and all of the issues. It was the birth (and an easy delivery, too) of the NTWWA – the Northern Territories Water and Waste Association.
The association was successful then and remains success-
ful today because of the people who join, attend, and teach. Thirty-plus years! And who are these people who enrich the knowledge base? Besides those from the NWT, we have seen attendees from Yukon, Nunavut, Alaska, Northern Quebec, all the western provinces, and even Greenland.
You are reading this because, like me, you are a proud member of the NTWWA and because of the Journal that continues communication and keeps us close and informed. The Journal is 20 years old! Wow. And what a piece of work it is! Clear and concise, the Journal defines the benevolence of this, our association.
Please stand with me and raise a glass of clean, life-giving water to congratulate the Journal and its editor, Ken Johnson, for 20 years of service to this, our NTWWA.
To the Journal!
Ron Kent, P. Eng., FEC, NTWWA Life Member S
2024 NTWWA Conference Report
By Rob Osborne, Executive Director, NTWWA
The 2024 NTWWA Conference, Trade Show, and Operator’s Workshop was held in Iqaluit, NU during the week of November 18-22. It was well attended by residents of Nunavut and southern Canada, and for the first time, representatives from the region of Nunavik (northern Quebec) were in attendance.
The conference started with a lunch at noon on November 18 followed by opening remarks and five technical presentations. A meet & greet was held on the first evening with entertainment provided by the Inuksuk Drum Dancers. On the second day, things got underway at 8:00 a.m. with presentations all day, followed by the AGM in the late afternoon. After the AGM was complete, the always popular Drinking Water Competition was held. All the water treatment plant operators brought water from their community to be judged on taste, clarity, and smell.
That evening was the annual banquet dinner. During and af-
ter the dinner, attendees were able to bid on items at the silent auction, with all the proceeds going to Water for People. Also after the dinner, the Drinking Water Competition winner was announced, with the honour going to the City of Iqaluit. Wednesday was the final day of the conference, with a full morning of presentations. After lunch, the NTWWA offered guided tours of the City of Iqaluit Water Treatment Plant and Solid Waste Transfer Station.
On Thursday and Friday, the NTWWA presented the Operator’s Workshop, which provides “hands-on” sessions for operators with great practical information that’s applicable in our northern communities.
The 2024 NTWWA Conference was a success, but we hope that next year will be even better as we are celebrating our 30th annual conference. It will be held in Yellowknife in November, and we hope to see you there! S
Peter Martel from the City of Iqaluit accepts the Drinking Water Competition trophy from Aaron Pooley and Megan Lusty.
Matthew Hough, ADM, Community Infrastructure, GN, presents to the conference.
NTWWA Annual General Meeting with Robert Osborne, Executive Director, taking minutes of the meeting.
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THE NEED FOR CONTAINMENT IN THE CANADIAN ARCTIC
By Anne Wilson, M.Sc., Environment Consultant
Containment is a common theme for a range of substances and activities in the Canadian Arctic. Containment can be to hold harmful substances so they don’t exit into the environment or to hold drinking water for winter supply when streams are frozen. Containment can apply to municipal wastewater treatment systems, solid waste disposal site leachate, bioremediation ponds, hazardous waste storage, fuel storage facilities, landfarms, and water reservoirs. The need for containment of various
substances and wastes is not something that is necessarily always front of mind – until there’s a failure of a containment system, and a resultant release brings on a case of hindsight and/or lessons learned! A look at the NWT and NU spill line database (https://www.gov.nt.ca/ ecc/en/spills) provides a snapshot of the magnitude and characterization of loss of containment across both territories. Hydrocarbons are by far the leading product spilled, with volumes released ranging from several litres to tens of thousands of litres. Municipal wastewa-
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ter spills have also occurred in significant quantities. Causes of spills can include dyke failure, leakage from pipes or tanks, breakage of lines, collisions or crashes, weather events, human error (aka “overflow event”) or deliberate discharge. Loss of containment can have consequences that range from inconvenient to devastating.
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Sewage treatment commonly uses lagoon systems, which provide containment to retain solids and to hold the effluent long enough for natural treatment processes to improve the quality. Release of under- or untreated sewage is harmful to fish and aquatic communities living in the receiving waters. The effluent may have high levels of ammonia, which can be toxic to fish and other organisms. Loadings of organic solids deplete the dissolved oxygen in the receiving waters as they decompose. Nutrient addition to lakes or streams can cause algal blooms and subsequent reductions in dissolved oxygen, which can also be harmful. Loss of containment and the subsequent sewage spills have been caused by factors such as equipment failure (e.g. pumps), power outages, breach of retention structures, or breakage of lines and fittings. Iqaluit has suffered examples of a range of wastewater spills going from a sewage spill in the airport terminal building crawl space to discharging hundreds of thousands of litres of sewage into the bay when lift station pumps failed. The latter case resulted in a substantial fine under the Fisheries Act.
Solid waste sites (landfills) can generate leachate as runoff from snow melt or
rain percolates through the wastes and exits the landfill area. Although it hasn’t typically been the case in the NWT or NU, landfills may have liners to contain leachate, which is then collected and potentially treated prior to disposal. Untreated leachate exiting solid waste disposal sites may have high levels of metals, high biological and chemical oxygen demand, and have other substances such as per- and polyfluoroalkyl substances or phenols. It is typically toxic to aquatic life. Leachate from unlined landfill sites may seep into the active layer and travel to surface waters in permafrost terrain. Monitoring with subsurface wells may can be useful to detect the presence and concentrations of chemicals downslope of landfills, such as at the Hay River Landfill.
Hazardous waste storage can be provided at solid waste sites which may have
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lined containment cells to hold contaminated liquids (e.g. Iqaluit landfill fire runoff) or solids (e.g. contaminated materials from spills, such as at the Hay River Treatment Facility). Dedicated hazardous waste storage areas at a landfill may need to be lined to prevent escape of any hazardous substances which are stored at the site resulting in a spill.
Fuel storage areas (tank farms) may rely on lined and bermed containment areas to provide secondary containment of fuels in the event of a spill. Discharges to the environment in the event of a spill can result when containment structures have lost integrity, such as liner failure, or when capacity of the structure has not been maintained. For example, when containment has been allowed to fill with snow or rainwater, there may be no longer sufficient room to hold the volume of the fuel tank. A recent example
of a large spill where fuel storage containment failed occurred at the Baker Lake tank farm, when 10,000 litres of gasoline was spilled in March 2021. The spill originated from two tanks and involved valve failure. This would not have been as difficult to clean up had the secondary containment functioned; however, liner integrity in the secondary containment had failed. As a result, about 1,700 cubic metres of contaminated ice and snow, plus soils, had to be cleaned up. Remediation required construction of two containment cells plus a wall to prevent movement of hydrocarbons downslope towards Baker Lake. Cleanup costs were estimated to be as high as $1 million.
Remediation of spill-impacted materials may use a landfarm, which is a lined and bermed containment area that holds contaminated soils and uses aeration and natural breakdown processes to reduce
hydrocarbon levels. The containment volume at the landfarm must be sufficient to hold the contaminated solid materials as well as meltwater and precipitation. Any discharges from the landfarm would need to be in accordance with standards and guidelines for acceptable residual hydrocarbon concentrations.
Drinking water is another municipal responsibility where containment is important. Engineered municipal water reservoirs may be above-ground (e.g. Inuvik, Norman Wells) or below-ground, where they may be lined (e.g. Pangnirtung, Arviat) or unlined (e.g. Igloolik, Chesterfield, Coral Harbour). These reservoirs must be able to contain the required water volume with minimal losses to seepage and outflows. Loss of the water supply could have disastrous consequences, particularly in winter when local streams are frozen and less accessible. An example
of this occurred in Arviat in January 2011, when a breach in the liner of the main water reservoir led to a water shortage.
In addition to the functional and practical aspects of control through containment, there are various other factors to consider including regulatory requirements, conditions affecting the operation, condition of containment structures, monitoring needs, and operational aspects.
Regulatory requirements can include the terms and conditions set out in each municipality’s water licence. For example, terms and conditions affecting municipal wastes can cover activities such as construction and operation of facilities (e.g. sewage lagoons, landfill cells), submission of operating plans, and planning for final closure of facilities and full remediation of the sites. Water licences are issued by the Nunavut Water Board in Nunavut,
and by one of the five land and water boards in the NWT. Inspections of municipal facilities are conducted periodically by either the federal department Crown-Indigenous and Northern Affairs Canada in Nunavut, or the Government of the Northwest Territories department of Environment and Climate Change inspectors in the NWT.
In addition to meeting the terms of the municipal water licence, municipalities must ensure they comply with the federal Fisheries Act subsection 36(3). This subsection prohibits the deposit of deleterious substances into water frequented by fish, or into any place where it may enter water frequented by fish. The severity of consequences laid out in this legislation make clear how important it is to prevent releases of substances which may be considered deleterious, such as raw or under-treated sewage or fuels and
other hazardous substances. When there is a discharge into waters that are known to contain fish, the violation of the legislation is based on the quality of the discharge, not on concentrations measured in the receiving waters, nor whether or not dead fish are seen. Fines can be up to $500,000 per day of discharge. Due diligence in preventing any harmful discharges can be a defence so it is important that municipalities have done all the right things to contain wastes and hazardous substances.
Site conditions will affect how well containment structures work. Factors such as depth of the subsurface water, bedrock qualities, and presence of permafrost must be considered when designing and constructing municipal sewage lagoons or landfill cells. The availability of construction materials such as till or sand to protect liners must
be considered. And of course, as weather conditions change and become more extreme and less predictable, there must be additional planning for more capacity to accommodate extreme weather events.
Understanding the potential for harm should containment structures fail is important and may include monitoring of seepage and runoff, regular measurement of water levels in lagoons and treatment cells, and characterization and quality of contained liquids or solids. Where subsurface seepage is an issue, it may be necessary to monitor groundwater quality. Regular geotechnical inspections can be done to detect potential problems before they become failures. Operation of any containment facility must respect the design capacity and follow appropriate operation and maintenance practices.
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Murphy’s Law seems to come into play all too often when working in the Arctic with the inherent remote locations, and difficult ground conditions – “if anything can go wrong, it will”! In the case of control through containment of municipal wastes and fuels, this can have serious adverse effects and devastating environmental consequences, let alone the practical and logistical difficulties associated with clean-up and remediation, and repair of facilities. When planning municipal facilities, the need for effective control through containment must be a front-of-mind consideration and incorporate a reasonable degree of redundancy in design and functionality. Additionally, robust contingency plans and spill plans should be in place to mitigate and manage any unplanned or uncontrolled discharges. S
GEOSYNTHETIC LINER MATERIALS AND SELECTION CONSIDERATIONS FOR AN ARCTIC SEWAGE LAGOON
By Ken Johnson, EXP Services Inc.
Introduction
Fully lined sewage lagoons are the generally accepted design approach to provide impervious containment for lagoons built with granular materials. Geosynthetic liners offer advantages for applications in Arctic regions where fine-grained soils are not available to construct a natural low-permeability liner for containment, such as compacted clay liner. Geosynthetic liners have low sensitivity to a warming climate and can be effective in both frozen and unfrozen conditions. Appropriately designed and constructed, these liners have good performance where the ground is stable and not subject to subsidence due to thawing of permafrost.
The name “geosynthetics” acknowledge that the materials are synthetic and are used in ground applications. Types of geosynthetics include geotextiles, geomembranes, geogrids, and geocomposites. Typically, single liners systems have been implemented for sewage lagoon systems constructed in the Canadian Arctic. Single liners provide an acceptable permeability rate that’s suitable for Arctic wastewater, as the wastewater retaining in the lagoon and ultimately discharged to the natural environ-
ment. If a more robust design is needed, a more costly doubleliner (or composite) system would be required. A double-liner system design incorporates a geomembrane liner to provide a primary containment, a drainage layer, and a secondary liner such as geosynthetic clay liner (GCL). Although the double-liner system provides an additional barrier of containment, the material costs to incorporate two liners and a drainage layer is substantial. Material costs for a double liner may be in the range of 150 to 200 per cent more than a single-liner system.
Geosynthetic liner materials
Historically, several geosynthetic materials have been used for sewage lagoon liners in permafrost regions. These liner configurations include geotextiles layered around a bentonite core known as geosynthetic clay liners (GCL), polyethylene (PE) liners, polypropylene (PP) liners, and polyvinylchloride (PVC) liners. GCLs, and PE liners applying high-density polyethylene (HDPE) have historically been the most common liner systems used for lagoons in Nunavut. PP and PVC lines are not commonly used in the Canadian Arctic because of performance issues in extremely cold weather.
Placing sand ballast on GCL liner.
Geosynthetic clay liners
GCLs combine a core of bentonite clay sandwiched between geotextile outer layers. Bentonite is a naturally occurring sealant, which is activated on contact with water, which is a process referred to as hydration. GCLs are installed in panels, which are sealed with an overlap in the panes and a bentonite powder placed in the overlap. In addition to the hydration requirements, GCLs must be anchored by a layer of ballast material, usually a fine-grained sand. The quality of the bentonite is an important consideration in the manufacturing of GCLs. Natural sodium bentonite clay, which is sourced from Wyoming, has superior performance compared to other types of bentonites. Lower quality bentonite may be susceptible to long term performance issues. The performance of a GCL may be improved upon by adding thin layer of polypropylene or polyethylene on the outside of the liner, which provide protection again wastewater that may be corrosive.
Polyethylene (PE)
Polyethylene materials have been extensively used for geomembrane liners in various containment and sewage lagoon projects because they are readily available, they have good chemical resistance, and they can withstand low temperatures of the Arctic. The most common PE materials are high-density polyethylene (HDPE), and reinforced polyethylene (RPE). HDPE is the most widely used as liner material because of its availability, however it must also be placed in panels, similar to GCL and these panels must be “welded” together with a thermal process, which has limitations in the Arctic. Additionally, HDPE cannot be fabricated into large panels because it becomes too stiff to fold and roll. Most HDPE today is made using a mixture of medium-density polyethylene and linear low-density polyethylene (LLDPE). Reinforced polyethylene (RPE) is a high-strength woven product with reinforcing characteristics. RPE liners are strong and lightweight but are typically used for short-term containments.
Rolling out Geosynthetic Clay Liner (GCL) liner with the appropriate overlap between panels.
Selection considerations
The consideration in selecting geosynthetic liners in the Canadian Arctic, in addition to long-term cold weather performance, is the cold weather installation. Ideally, geosynthetic liners should be installed in “warm” Arctic weather; however, the nature of Arctic weather creates an environment that may be cold at any time of the year.
The structure of HDPE makes it stiff and rigid in cold weather. The loss of flexibility makes handling, unrolling, welding and anchoring the liner difficult, and as such, highly trained resources are needed during the installation. Choosing an HDPE geomembrane material with a slightly lower density may reduce the handling issues and optimize other physical properties. One of the biggest advantages of this lower-density material is the potential to use a thinner liner, which can cover larger areas and be manufactured in prefabricated panels. Larger prefabricated panels significantly reduce the effort and number of welded seams required onsite. Prefabricated panels would be welded at the manufacturing facility, which would provide a greater integrity of the seams in a controlled environment. However, there is a trade-off as the thinner material may increase the risk of punctures that can result during the installation.
The characteristics of a GCL liner allow the material to remain flexible at cold temperatures and thus larger installation areas
may be achieved compared to an HDPE liner. However, the hydration and confinement layer requirements essential to GCL liner performance may be difficult to achieve and monitor onsite.
Geotechnical investigations and analyses
The nature of the soil materials is important to any civil engineering construction; however, in the Arctic, the soil materials are influenced by seasonally frozen ground and perpetually frozen ground or permafrost. The dynamic nature of frozen ground with the movement of heaving and settling and differential movement over in small areas provides stresses that may not be tolerated by even the most flexible of geosynthetic material. Therefore, the design of soil profile supporting geosynthetic materials must control the freeze and thaw soil dynamics.
Detailed site information is the key to controlling the freeze and thaw soil dynamics, and therefore, detailed site-specific geotechnical investigations and geotechnical analyses are a necessity. This includes the appropriate permafrost engineering analyses. The geotechnical profile associated with the lagoon base is vital to the long-term performance of a liner system, and this profile may include long-term monitoring of the soil conditions at the site. S
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LAGOON AND RESERVOIR LINER STUDY FOR THE NUNAVUT TERRITORY
Edited from Technical Report by Dillon Consulting, April 2024
Approximately a dozen communities in Nunavut currently use geosynthetic liner systems for wastewater retention. More than half of these lagoons are experiencing active or recurring liner leaks and issues associated with the berms supporting the liner. To advance the present and future performance of geosynthetic liner systems in Canadian high Arctic, the Government of Nunavut retained Dillon Consulting Ltd. to complete a liner study to investigate, consult, and report on potential improvements that could be made to liner systems. A workshop and a review of existing liner installations in Nunavut were part of the study.
Best practices
The report lists “best practices” for the design and construction of geosynthetic liner systems in Arctic climates which include: a simple design; a construction schedule with contingencies to account for project delays; shipment and storage of materials that provides a secure and dry environment; an installation that minimizes the potential for liner damage from environmental or equipment factors; appropriate quality assurance and quality control for the installation; appropriate subgrade that provides long-term stability and support for the liner; granular material and construction methodologies that do not damage the liner; and compatibility of the geosyn-
thetic material with Arctic conditions. The potential project delays are related to weather, contractor mobilization, shipment of materials, quality of construction, and worker productivity.
The best practices recommend an indepth geotechnical investigation at the planning stage of the project, and the necessary analyses to obtain good understanding of the soil dynamics, particularly the risk of differential settlement due to permafrost thaw. In addition, if a geosynthetic clay liner (GCL) is planned, the chemical composition of the soil should be determined to make sure there are no potential chemical interactions that could degrade the GCL.
The report recommends that a com-
Placement of bentonite powder between panels of Geosynthetic Clay Liner (GCL)
posite (dual) liner system with a GCL secondary liner to be the ideal liner design for Nunavut. The primary liner would consist of low-density polyethylene material, and the secondary GCL liner slows the leakage rate through small punctures and tears in the primary (top) liner while also protecting the primary liner from potential damage due to uneven subgrade. The construction of a composite liner system must consider the weight and movement of the equipment travelling on the GCL while installation of the primary liner is occurring.
A liner manufacturer survey completed during the study identified several single-liner systems using either highdensity polyethylene (HDPE) or GCL that may be appropriate for a lagoon system. However, these single-liner systems are not recommended for Nunavut applications.
Geotechnical risks
The report discusses the potential risk to the liner system associated with the uneven settlement of the lagoon base material due to melting of ice in the per-
mafrost caused by heat transfer from the wastewater deposited in the lagoon. If this “differential” settlement exceeds the elasticity limits of the liners, the liner could fail over time.
Two solutions to the differential settlement risk were proposed in the report. The first solution would be to use a geosynthetic liner with improved performance due to increased elasticity, such as a low-density polyethylene (LLDPE) liner. The second solution would be constructing the lagoon above the existing grade with the additional layer of soil providing an underlying insulation layer. Either of these solutions would add a considerable cost to the construction and prevent the use of a balanced cut/ fill excavation approach for berm construction.
Another solution that was not considered in the report is the use of a stiffening geotextile layer in the base of the lagoon, below the impermeable membrane. A geogrid stiffening layer was used for the lagoon constructed in Taloyoak.
Risk management
The report presents a risk management analysis with associated mitigations. Risks were identified and sorted based on five categories that mirrored the phases that are normally associated with design and construction. The five categories are: geotechnical information; site selection and preparation; liner installation; operational environment; and other miscellaneous risks.
The primary geotechnical risk is associated with construction of lined lagoons and reservoirs on top of permafrost related features. Mitigating action involves the screening of frost related features throughout the project and implementing actions to prevent differential soil settling and associated risk of liner tears from occurring. Site selection and preparation risks are the typical Nunavut civil project challenges that include short construction seasons and availability of granular materials for an engineered subbase. Liner installation risks focused on the liner seaming process including inadequate QA/QC procedures. Operational environment risks focused on the period following commissioning and include impacts from mechanical ice damage, flooding of the underdrain piping system, erosion at the truck discharge area, and heavy equipment damaging a liner. Other risks are site-specific, including wildlife punctures and vandalism damage.
Conclusion
The report provides the following key mitigation practices to implement on future liner projects in Nunavut:
• Use of a dual-liner system, with an LLDPE geosynthetic liner as a primary liner and a GCL as a secondary liner under the LLDPE liner.
• Covering liners for protection from external damage and ballasting to prevent liners from floating.
• Carrying out comprehensive geotechnical investigations to delineate ice at permafrost sites to support site screening during planning studies.
The report concluded that the current geotechnical investigations are generally insufficient during the project planning phase to identify the presence and extent of permafrost. Enhanced geotechnical investigations should be conducted earlier in the project cycle for meaningful site screening.
To mitigate multiple risks associated with liner damage or poor installation practices during construction, a full-time qualified QA/QC staff should be present during liner installation, as well as a full-time construction observer from the Government of Nunavut. S
GCL liner applied with a geogrid layer to stiffen the base for long term stability.
A DRONE’S EYE VIEW OF LAGOON CONSTRUCTION IN THE ARCTIC
By Rob Osborne, EXP Services Inc.
Drones are far superior to hand-held cameras (or worse--cellphones) for documenting and showcasing project site work. Using a drone, this photo shows workers placing rip-rap while also providing context with an overview of the entire overflow discharge system.
By flying higher still, the entire project area can be shown. This photo clearly shows three main work fronts -- subgrade preparation, geogrid placement and cover, and GCL placement and cover.
Drones allow for close-up photos like this one in places that are otherwise inaccessible on foot or by vehicle due to a lack of access and/or construction hazards.
Above: In addition to capturing photos, drones are an effective tool for monitoring construction - -in this case, ensuring that each seam has the proper amount of bentonite.
Drones are perfect for milestone moments. This photo shows the final commissioning of the lagoon. Such an iconic photo could never have been possible from the ground.
Left: Photos like this are a great tool to show compliance (or non-compliance) to the specifications. Some examples include the staggering of joints in the geogrid, length of overlap, proper equipment on sand, and proper turn radius followed.
THE POTENTIAL FOR COMMUNITY CONTAMINATION AS A RESULT OF THAWING PERMAFROST
Edited from an article by Kelley Christensen in Environmental Health Perspectives , March 2024
An estimated five million people live on the circumpolar permafrost of the world’s eight northernmost countries of Canada, Finland, Greenland, Iceland, Norway, Russia, Sweden, and the United States. These pan-Arctic lands have witnessed a variety of industrial and military operations over the past 125 years of significant Arctic activity, beginning in North America with the industrial activity that followed the Klondike Gold Rush and including legacies of nuclear waste deposits and the biological weapons waste storage that were associated with the Cold War activities of the United States and the Union of Soviet Socialist Republics
Engineering for the North
(USSR). Academic researchers, nongovernmental organizations, local Indigenous activists, and other groups around the world are turning their attention to the issue of thawing permafrost and the release of contaminants associated with these activities.
The gold rush in the Yukon, the nearly simultaneous iron rush in Europe, and related developments in Russia fostered the growth of infrastructure that opened the Arctic to industrialization, including mining, fossil fuel development, military operations, and scientific research. A legacy of this resource extraction is the wide variety of waste materials that were left behind.
A study has been conducted to document the extent of con-
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From concept to completion, we design for the unique Arctic environment within Northern Canada.
taminated sites in permafrost zones. The analysis of global and regional datasets extrapolated that across the Arctic region 13,000 to 20,000 contaminated sites are associated with various industrial locations. Of these sites, approximately 70 per cent are in Russia, 20 per cent are in the North American Arctic, and the remainder in Greenland and Norway’s Svalbard archipelago.
The major problem encountered by the study was the lack of data and detailed information on what contamination is where, in what quantity, and in what condition. There is a pressing need for international policy collaboration because Arctic countries have very different environmental legislation and data policies. There’s no single database, and in some cases the data is not publicly available.
Documentation is needed to measure industrial substances (types, quantity, and toxicity), their potential to leach and contaminate water, their proximity to waterbodies and their storage or disposal conditions. With the development of documentation, early warning systems could alert communities to sites in danger of becoming compromised by permafrost degradation and the potential release of contamination.
Traditional knowledge and the latest scientific findings will both be necessary in the new reality that Arctic communities are learning to navigate. Empowerment to face changes related to thawing permafrost is enormously important to Indigenous peoples’ well-being and satisfaction with life, as is continuing to
practice traditional ways of life, such as observing ceremonies and, to the extent possible, eating traditional foods.
The most important step is for communities and governments to discuss, listen, and talk about the possible future situation in environment, wildlife, water, and food security. Research gaps also must be addressed – for example, a 2020 scoping review of research at the intersection of climate, water, and health found no studies (up to 2018) that projected future climate change impacts on drinking water in the Arctic.
In Alaska, an organization is working closely with a group of Indigenous people to help community members study sources of contamination, engage in environmental activism, and influence state and national policy changes rather than waiting for help to arrive from elsewhere. Indeed, the continued existence of communities and their traditional ways of life may depend on their empowerment. This community-based research focuses on measuring contaminant levels and health indicators in children through a project called Protecting the Health of Future Generations.
There is no current means to measure releases of contaminants from permafrost, but it is known that it’s a large problem that must be addressed through urgent action. Chemicals, plastics, and climate must be recognized and urgently addressed as
TEMPERATURE INSTRUMENTATION AND DATA COLLECTION FOR EARTH CONTAINMENT STRUCTURES IN THE ARCTIC
By Renta Klassen, EXP Services Inc.
The construction of large containment structures in the Canadian Arctic relies almost exclusively on earth berms for structural support and geomembranes to create the low permeability for retention. The use of concrete may be applied to smaller structures, but the design must keep in mind the available quality of concrete prepared in the Arctic. Earth containment structures in the Arctic may factor in permafrost in pro-
viding the containment. If permafrost is expected to be preserved once the structure is built, the containment berms may be constructed of saturated compacted silty gravel to become part of the permafrost regime upon freeze-back. This is not the case in sewage lagoons where permafrost is expected to degrade because of the heat from the wastewater in the lagoon. The containment berms in sewage lagoons are usually not designed as freeze-back structures; however, some
freezing in berms takes place over time. This formation of permafrost would enhance the containment by the presence of the perennially frozen ground and suggests low flow condition due to frozen subsurface water. Including ground temperatures in long-term monitoring programs may be a useful tool in the performance assessments of sewage lagoons.
Ground temperatures are usually measured with thermistor probes on a cable inserted into drilled boreholes. The
cables are called ground temperature cables (GTC) because they are intended to measure temperatures in the ground. To assure that GTCs will reach the desired depth, the boreholes are equipped with pipe casings inserted into the boreholes after drilling. GTCs are then inserted into the casings and either backfilled with sand or left loose in the casings allowing for future replacements. As GTCs alone do not record data, they need to be connected to a reading device to acquire temperatures. A manual method of getting temperatures from a GTC includes a resistance meter connected to the GTC through a switch box which allows switching between thermistor probe channels. A more sophisticated method includes a datalogger, which when connected to the GTC provides continuous temperature readings according to a programmed frequency.
A ground temperature monitoring system was installed at a new sewage lagoon in Nunavut completed in 2024 to monitor the long-term thermal regime temperature pattern existing in the ground. The lagoon was constructed on permafrost and the impermeable containment for the structure was achieved by lining the earth containment berms with a geosynthetic clay liner (GCL). The lagoon will operate as a facultative lagoon system, with a seasonal discharge into a wetland system before ultimately discharging into the ocean. The monitoring locations were determined at the end of the construction and installed by drilling four boreholes on three berms and equipping them with 50-millimetre-diameter casings. The casings were installed near the top of the berms along the outside crest and reaching below the base of the berms into the berm foundations about 3.5 to six metres. GTCs were inserted into the casings to reach their bot tom. The casings with GTCs were enclosed inside
Ground temperature cables (GTC) are installed in pipe casings, which are connected to data loggers – the data loggers are positioned premanufactured plywood enclosures sized to fit and protect the dataloggers.
Data reading in mid-November when ground temperatures were below or slightly below 0°C.
remote data housings with locking caps for protection.
A site visit was completed after the facility was commissioned for the purpose of beginning the collection of temperature data from the four monitoring locations. Dataloggers were connected to GTCs for continuous data recording. The configuration of casings inside the remote data housings did not allow for housings to fit properly, resulting in the connected dataloggers remaining unprotected. Additional housing space was required to safely initiate the monitoring systems. The additional space was provided by pre-manufactured plywood enclosures sized to fit and protect the dataloggers. The enclosures were then fastened on top of remote data housings and secured with a steel cable wire.
The initial manual data collection was completed using a multimeter and a switch box to collect temperatures at
the four monitoring locations. Although intended to be redundant, the manual readings help confirm the operation of the GTCs prior to the connection of dataloggers.
One of the first sets of datalogger data collected from the ground temperature monitoring system was completed during a site visit. Data downloaded from the dataloggers provided insight into the ground thermal regime of the initial stage of berm construction and the berm foundations at the beginning of the project construction, confirming that the monitoring system set up was working. Despite the expectation that permafrost will not be preserved in the lagoon structure, ground temperatures in the lagoon containment berms and the berm foundations are of interest for future assessments of the lagoon performance. It has been stated that an impervious berm structure, such as a dam, is influenced
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not only by the water temperature on the upstream face, but also by the effects of the climate over the remainder of the dam surface and freezing devices, if any, and that thawing will penetrate mainly downward only under the reservoir and the upstream slope, and laterally into the structure and foundation. All the data recorded in mid-November were below 0°C or slightly below 0°C. The warmest temperatures were about two to three metres below the existing ground surface irrespective of the berm height. The temperatures of the bottom thermistor beads located about eight to 8.5 metres below the top of the berms varied between -5.6 and -4.0°C.
As the lagoon continues to operate, the collection of ground temperature data will provide insight into the operation of the current site as well as for the design of future lagoon systems. S
THE GIANT MINE REMEDIATION PROJECT
Update to article entitled “Giant Mine Water
Management System”,
NTWWA Journal 2010, by Ken Johnson
The history of Yellowknife is intrinsically linked to its start as a mining town. When gold was discovered on the shores of Great Slave Lake and the claims were staked, Yellowknife was born as a gold mining boomtown. Giant Mine, which was one of two longstanding and productive mines in the immediate Yellowknife area, was a result of the original exploration. Giant Mine closed underground operations in 2005 after 60 plus years of production.
The rock mined at Giant Mine is rich in gold associated with arsenopyrite, a mineral that has a high arsenic content. The gold extraction used at Giant Mine required a “roasting” process to extract the gold from arsenopyrite rock. Arsenic trioxide dust was created during the pro-
duction of more than 7 million ounces of gold between 1948 and 1999. When the arsenopyrite ore was roasted at extremely high temperatures to release the gold, arsenic was also released as arsenic rich gas, and as it cooled, it became solid arsenic trioxide dust.
In the early days, much of the arsenic was released into the air. Pollution-control hardware installed in the late 1950s prevented most of it from going up the stack, but that created a new problem, for which the solution was to store the arsenic trioxide dust in mined-out chambers underground.
Over a 50-year period, 237,000 tonnes of toxic arsenic trioxide dust were produced, which is still being stored to depths of nearly 250 metres (800 feet) below ground in various shafts and chambers.
Arsenic trioxide is water-soluble, containing approximately 60 per cent arsenic; therefore, it is critical to maintain the stored material “high and dry” to ensure that arsenic is not released into the environment. This effort requires that the groundwater be maintained below the storage areas with a dewatering system.
Almost all the arsenic trioxide dust at Giant Mine is stored in 15 underground chambers and stopes (irregular, minedout cavities) cut into solid rock. The “doorways” to the chambers and stopes were sealed with concrete bulkheads, which act as plugs, anchored into the rock. The material used for the plugs and related stabilizing was a paste made of cement and crushed rock. In all, 198,000 cubic metres of the paste was pumped into the mine – the equivalent of almost
Above: Sketch showing simple configuration of thermosiphon where heat is drawn out of ground during the winter through the vertical thermal siphon tubes.
When this underground storage method was originally designed, it relied in principle on the area’s natural permafrost working as a frozen barrier.
20,000 dump truck loads. The arsenic trioxide dust is surrounded by solid rock.
However, due to the extensive mining, the permafrost around Giant Mine thawed and water began seeping into the storage chambers and becoming contaminated, with the potential of entering the groundwater systems. In response to this issue, the water was pumped from the mine to a treatment facility on the surface. The contaminants in the water are removed through a treatment process before the water is released into the environment.
When this underground storage method was originally designed, it relied in principle on the area’s natural permafrost working as a frozen barrier. It was believed that when the time came to close Giant Mine, permafrost would reform around the storage chambers and stopes, and seal in the arsenic trioxide dust.
When the mine permanently closed some stakeholders wanted the arsenic trioxide dust removed from the mine and shipped elsewhere, away from Yellowknife’s 20,000 residents. Citing risks to workers and the environment, Crown Indigenous Relations and Northern Affairs Canada (CIRNAC) settled on the solution of reestablishing the permafrost around the underground chambers and stopes, locking the arsenic trioxide dust into a
big deep freeze (Frozen Block Alternative). CIRNAC has been working closely with the Giant Mine Oversight Board, which is an independent body that monitors the remediation project, which has grown to a budget of $4.4 billion.
The Frozen Block Alternative (FBA) intends to stabilize the arsenic trioxide dust by completely freezing the ground and the rock around each chamber and stope to permanently freeze the arsenic trioxide dust storage chambers and keep groundwater seepage out. Integral to the FBA is the automated dewatering pumping system to maintain the groundwater below the underground chambers.
In 2024, the project team completed all work needed to stabilize the underground and monitor it from the surface. Until 2024, workers on the project had been descending into the mine to monitor the stability of the rock and the chemistry of water entering the mine.
In addition to the monitoring systems, another change that eliminated the need to go underground is a new pumping system used to lift water that’s seeped into the mine to the surface for treatment through a new water treatment plant. With the previous system, workers had
to go underground to monitor and service the pumps.
All power and heat have been shut off, as has the main ventilation fans. All openings have been sealed shut. Closing the underground will reduce the annual care and maintenance costs by $6 million.
The clean-up plan will require for the ground around all the chambers to be frozen using a series of thermosiphons –devices that use gas to freeze the rock. This process has been started, with the installation technology already proven with a pilot project. The construction of the complete thermosiphon system is expected to be completed by 2035.
The freeze back process will take several years to complete after the system construction is finished. An estimated 860 thermosyphons will be installed to achieve the main objective of keeping the underground rock at -5°C year-round.
The remediation plan also calls to keep open the option of removing the arsenic dust stored underground if, at some point in the future, processes and technology are developed that allow it to be done safely. S
Thermosiphon installation at the Giant Mine surrounding one of the storage chambers below the surface.
A GEOCOMPOSITE BARRIER FOR HYDROCARBON CONTAINMENT IN THE ARCTIC
Edited from a technical paper with the same title by the GeoEngineering Centre at Queen’s University and the Royal Military College of Canada, August 2006
The Distant Early Warning Line (DEW Line) was a system of 33 radar stations stretching 6,000 kilometres across the Arctic from Alaska through Canada. It was constructed in the 1950s in response to a potential “over the top” nuclear attack from the USSR. The DEW Line was taken out of service in the late 1980s and replaced with the modernized North Warning system of radars. The DEW line was constructed with very little regard for environmental impacts and hence the sites were considered to have local but significant environmental impact legacies. In the early 1990s, the Government of Canada established a remediation program for the remediation decommissioning of 21 of the sites.
Remediation of the Brevoort Island DEW line site, 200 kilometres east of Iqaluit, was initiated in 1998 with a site assessment. The collection and analyses of limited soil samples revealed the presence of Arctic diesel (jet fuel) around the site. Further sampling was completed in 2000, and it was determined that fuel spilled or leaked at the tank source had migrated down-slope toward the ocean.
Based on the results of the assessments, Environment Canada and the stakeholders agreed that a short-term containment solution was immediately needed to contain the fuel spill migration. The solution had to be capable of being implemented at a remote site
Site configuration at Brevoort Island DEW line site before remedial work was undertaken.
within a short construction season. The cleanup of the contaminated ground would then be executed later.
The design criteria for a barrier system were developed with limited geotechnical data and therefore needed to be flexible to adjust to unforeseen site conditions and account for difficult site access. The volume of materials that could be shipped to the site was limited to a sea-lift staging out of Montreal and construction equipment was restricted to equipment currently on-site. Containment technologies such as compacted clay liners (CCLs) and slurry cut off walls could not be considered because of the material and equipment mobilization requirements.
The barrier system designed was a subsurface geosynthetic composite liner system consisting of a primary geomembrane barrier and an underlying geosynthetic clay liner (GCL). A high-density polyethylene (HDPE) geomembrane was
Site configuration after remedial work was completed.
selected for the primary barrier and the barrier was chemically treated so it would be more resistant to hydrocarbon diffusion. In selecting the HDPE geomembrane, it was recognized that welding of HDPE geomembrane panels could be problematic due to the cold and wet weather at the site. In addition, it was not known if a suitable granular bedding matter would be available at the site. A combination of the HDPE geomembrane and a GCL was thought to be the best option for containment of the spill because of their complimentary properties. In the event of leakage through the HDPE geomembrane, the GCL would perform as a backup containment layer.
The construction at the site involved the excavation of a continuous 70-metre trench for liner placement and then anchoring the liner into the existing permafrost immediately down-slope of the spill. The completed barrier would intercept the flow of groundwater in the
down-slope direction, thereby reduce the migration of the fuel contamination. The upstream side of the barrier was protected from the granular backfill by a needle-punched nonwoven geotextile cushion. The installation was covered with gravel, and the trench was backfilled with the excavated materials and covered with another polyethylene liner to reduce infiltration from surface runoff.
Instrumentation of the liner system was installed along the barrier to moni tor the ground temperatures and sam ples were taken to monitor the hydro carbon levels. The ground temperature profiles and the sampling for petroleum hydrocarbon (TPH) values provided evi dence that the geocomposite liner was performing as designed to stop the hy drocarbon migration. Further evidence on the successful performance of the system was collected through a program of laboratory studies combined with pe riodic retrieval and examination of sam ples of the liner materials from the field. Lab tests on the GCL sampled from the site concluded that the freeze-thaw cy cles experience at the site did not reduce the hydraulic conductivity of the GCL.
In addition, based on all the obser vations, it was concluded that the me chanical and chemical properties of the buried HDPE geomembrane had not changed significantly from the installa tion three years earlier.
The techniques and lessons learned from the project have provided a basis for the design and construction of a bar rier system that can be used to minimize subsurface hydrocarbon contaminant migration in the Arctic considering a very short lead time, a lack of geotechnical data, and difficult site conditions. S
In Memory
Nelson Pisco
We honour the remarkable life and legacy of Mr. Nelson Pisco, who recently passed away in Iqaluit. Nelson was more than a leader and colleague; he was a man of exceptional character, unwavering dedication, and extraordinary vision. As the Director of the Technical Services Division (TSD), Department of Community and Government Services, Government of Nunavut, Nelson exemplified integrity, resilience, and humility. Under Nelson’s stewardship, TSD became a cornerstone of the Government of Nunavut’s mission to build a sustainable future. While we mourn his loss, we are reminded of the profound legacy he leaves behind.
Richard Feilden
Richard Feilden was born in Calgary and raised in Vancouver, where he earned a Civil Engineering degree from UBC in 1967. After earning his degree, he moved to Yellowknife and worked with the GNWT until 1974, when he joined Associated Engineering in Edmonton. He got a Master of Engineering from the University of Alberta in 1983 and settled in to Reid Crowther/Earthtech and ultimately AECOM, from which he retired in 2012. Richard was known as Mr. Inuvik because of his extensive knowledge of the town’s above-ground water and sewer system. He was a strategic resource for the town, conveying his experience, wisdom, and enthusiasm over several decades. Sadly, Richard passed away in February 2023.
