RESIDENTIAL LAND USE RELATED TO LANDFILL SITES IN COLD REGION COMMUNITIES Ken Johnson, MASc, P.Eng. Land Use Planner ABSTRACT
INTRODUCTION
The 65 communities in the Northwest and Nunavut Territories of Canada each have a unique history of settlement and development. With settlement and development evolved waste disposal sites that were a product of convenience, rather than any appropriate waste management practices. As a result, many communities have waste disposal sites that are close to potential community residential expansion areas.
Landfill Practices and Types
The regulatory framework currently governing community residential development in the vicinity of either a remediated or unremediated waste disposal site in the Territories has a specific setback requirement of 450 metres. There is no specific setback distance for remediated solid waste sites pursuant to the NWT Public Health Act. In fact, the General Sanitation Regulations under the Act refers to the setback distance for all waste disposal grounds and as such, may be interpreted to include remediated waste sites. This approach to the setback for landfill sites is beginning to have impacts on communities as the communities continue to grow, and Land Use Plans are updated to identify areas for future growth. The impact on communities to “leap over” waste disposal sites in distances approaching 1,000 metres is significant from an infrastructure perspective (capital, operation, and maintenance costs) and a social perspective (distance to family, friends, and amenities). A rational approach to a potential relaxation of the setback distance is presented for the Territories based upon the criteria of: site activity, remediation undertaken, subsurface conditions, surface conditions and community perception. This rational is compared to the application of landfill setback distances and landfill management that have been developed in the State of Alaska.
Landfills in cold region communities are evolving from waste management of convenience to engineered landfill sites. The evolution of waste management sites from the so-called “dump” to the engineered landfill sites has occurred over many years, and is far from finished. Many landfills remain very unsatisfactory to regulatory officials from public health and environmental impact perspectives. The reasons behind the remaining poor waste management practices are many, and include insufficient resources for waste management to an incomplete understanding of what appropriate waste management should include. The landfills utilized in the cold regions may be generally categorized into four different types as shown in Figure 1. The depression and embankment types represent landfills developed from convenience rather than design. The mound and excavation types represent engineered landfills that cold region communities now strive to construct and maintain. Many local factors ultimately determine the ultimate configuration and location of the landfill in a community. The lining of community landfills in cold regions with an engineered material has never been undertaken and is unlikely to be undertaken in the foreseeable future given the added cost and the limited community capital budgets. Impact of Setbacks The impact of current setback requirements of the General Sanitation Regulations of the NWT and Nunavut Health Acts on residential development is twofold, as shown in Figure 2. The first impact is objective, and may be quantified in the capital cost of constructing a road and power supply which carries
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on to a new residential development; the cost of operating and maintaining the road; and the cost of operating water, sewer, fuel and waste management vehicles over this road.
Although the regulation conveys some discretionary authority by the Health Officer, in practice, the regulators have not exercised any discretion with regard to setbacks.
The second impact is subjective in the separation distance between neighbourhoods. This separation limits access to amenities, and the social structure of the community, both of which are very important to aboriginal communities.
As well, the Regulations also state that every waste disposal ground shall be:
BACKGROUND Leachate and Methane Gas The public health, public safety and environmental impact concerns with landfills arise primarily from the production of leachate and methane gas. The generation of leachate and methane gas is dependent upon a number of factors, including temperature, moisture and overall makeup of the landfill, including the chemical nature and the physical nature of the waste. These factors have been well studied, and well documented in a southern context, however, the variability of these factors in a cold region context is not well documented or well studied. Of the dependent factors, temperature and moisture may be considered to be limiting because without moisture leachate will not be generated, and without moisture or heat methane gas will not be generated. General Sanitation Regulations The General Sanitation Regulations to the Public Health Acts in the NWT and Nunavut are intended to address the public health and safety aspects. The Regulations state that no building used for human habitation shall be: nearer than 450 m to a waste disposal ground; or on any site, the soil of which has been made up of any refuse, unless the refuse has been removed from the site or has been consolidated or the site has been disinfected in every case and the site has been approved by a Health Officer.
located at least 90 m from any public road allowance, railway, right-of-way, cemetery, highway or thoroughfare; located at least 450 m from any building used for human occupancy or for the storage of food; and situated at such a distance from any source of water or ice for human consumption or ablution that no pollution shall take place. A Commissioner’s Exception to these regulations is possible, however, this is a long and potentially political process. A Commissioner’s Exception has only been granted in a few cases in the NWT. The Hamlet of Tuktoyaktuk The potential impact of these regulations varies from community to community, however, the community of Tuktoyaktuk in the Northwest Territories is a classic example of the potential influence of landfill setbacks on community residential development (See Figure 3). The community has three landfills at various stages of activity. Two of the landfills have been closed and remediated, however, under the General Health Regulations, these waste disposal grounds shall be located at least 450 metres from any building used for human occupancy. The impact to existing and future community development by the application of the setback is significant given the limited land base of the community. Obviously the application of the setback to the landfill near the community core would likely receive an exception based upon its proximity to a built up area and also the remediation completed. The other two sites present no opportunity under the current regulation for any change in the setback, and pose a significant impact on future residential development in a community which has extremely limited space for residential expansion.
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ANALYSIS Leachate and Methane Gas Production The generation of leachate is dependent upon factors including moisture, permeability of the landfill matrix, and absorption capacity of the landfill matrix. Of these conditions, moisture may be the primary limiting factor for the simple reason that without moisture leachate will not be generated. The moisture data presented in Table 1 compares the total precipitation for key cold region communities for comparison to several southern Canadian centres. In the cold region communities, with the exception of Iqaluit, the total average annual precipitation falls below or close to the expected precipitation in a desert. Deserts, by definition, receive less than 250 mm of precipitation. A unique consideration in cold regions is the availability of the moisture for infiltration into a landfill. Table 1 also presents the available moisture in the form of rainfall. The average annual rainfall reduces the available precipitation
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or moisture by /3 to ½. The rainfall moisture may reflect the true moisture available to leachate generation because frozen ground, including normally permeable ground, has a low permeability. This condition may be observed in communities such as Beaver Creek, Yukon and Fort Smith, NWT during the short melt periods in the spring where significant ponding occurs on normally permeable ground. TABLE 1 TEMPERATURE AND PRECIPITATION FOR SELECTED SOUTHERN AND NORTHERN COMMUNITIES Average Average Annual Average Yearly Temp. Precipitation Annual Rainfall (°C) (mm) (mm) Edmonton 3.6 461.3 349.3 Vancouver 9.9 1,167.2 1,117.2 Winnipeg 2.4 504 404.4 Toronto 8.9 818.9 689.3 Dawson City -5.1 306.1 182.7 Whitehorse -1.2 261.2 145.5 Yellowknife -5.4 266.7 150.2 Inuvik -9.8 266.1 114.6 Cambridge -15.1 136.3 68.1 Bay Rankin Inlet -11.6 258.9 145.5 Iqaluit -9.3 432.6 192.1 Resolute Bay -16.6 131.4 52.7
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A capital cost estimate of the road and power is presented in Table 2 and suggests a value of over $180,000 could be expected.
Trucked Water (500 L Tank & 4,500 L Truck) Trucked Sewage (750 L Tank & 4,500 L Truck) Solid Waste
3 times/week 9 houses/ truck 2 times/week 6 houses/ truck
866
1,559
31.2
$4,05 0
866
1,559
31.2
$4,05 0
1 time/week 25 houses/ truck 1 time/month 4 houses/ truck Weekly
104
187
3.7
$481
Fuel Oil (1,000 L Tank & 4,500 L Truck) Road Maintenance (Grader or Snow Plough) Total Cost/Year
150
270
5.4
$702
52
94
3.1 (30 km/hr)
$406
Cost at $130/hr
Time at 50 km/hr
the capital cost of a 450 metre access road beyond the existing landfill; the capital cost of 900 metres of power line; the operation and maintenance cost of operating of water, sewer, solid waste, and fuel vehicles along this additional 900 metres of road; and operation and maintenance costs of the road itself.
Extra km per Trip (1.8 km/trip)
The capital cost to bridge the region of no development, presented in Figure 2, has a number of elements including:
TABLE 3 ESTIMATED OPERATION AND MAINTENANCE COSTS FOR LANDFILL SETBACK ENVELOPE FOR A 50 LOT SUBDIVISION Trips per Year
Monetary Costs
The social costs associated with isolation from a community centre are difficult to measure. Informal community studies and consultation repeatedly identify the desire for residential development to occur close to the existing community centre. In the case of Tuktoyaktuk, a community survey suggested that the new residential area to the south is not considered to be part of the existing community.
Assumptions
Although biological activity is sustained at very low temperatures, the anaerobic biological activity necessary to produce methane gas would be significantly reduced in the cold region communities presented in Table 1. The average yearly temperature varies from -1.2°C in Whitehorse to -16.6°C in Resolute, compared to 3.6°C in Edmonton.
Social Costs
Activity
The generation of methane is dependent upon the factors of moisture, nutrients, and temperature. Since moisture is limited in cold regions, as previously discussed, methane generation is limited. A further, potentially more significant, limitation to methane generation is temperature, which is presented in Table 1 in the value of average annual temperature for key northern centres, for comparison to several southern centres.
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DISCUSSION Burden of Costs
TABLE 2 ESTIMATED CAPITAL COSTS FOR LANDFILL SETBACK ENVELOPE Assumptions m Total Road $300/m 450 $135,000 Power $5,000/pole 900 $45,000 100 m/pole TOTAL COST $180,000
The burden of the capital and operation and maintenance costs to a small community are significant. The estimated $180,000 road and power capital cost is equivalent to a 2 bay garage for the community. The estimated $10,000 annual operation and maintenance cost would be a significant percentage of a communities operation and maintenance budget, and these budgets are decreasing.
An operation and maintenance cost estimate for the operation and maintenance associated with the landfill setback is presented in Table 3 and suggests a potential annual cost of approximately $10,000.
Although the social costs are indeterminate, there is definitely a cost on an already overburdened social services system.
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Decision Rational A decision rational for a change in the existing setbacks may be developed based upon the following considerations:
site activity; remediation complete; subsurface conditions; surface conditions; and community perception.
These basic consideration, presented in Figure 4, suggest an opportunity for a change in the setback. The setback should ultimately include a consideration of the presence or absence of permafrost. Site activity should be the fundamental consideration for any landfill setback and, as such, an operating landfill should not be considered for any change in the setback. Remediation completed should be a minimal requirement for any action to change a setback distance, not only from a regulatory perspective,
but also from a modern waste management perspective. Subsurface conditions associated with the permeability of the in situ materials should be considered for their influence on the conveyance of any leachate or methane gas produced. This consideration may be independent of permafrost. Surface conditions for consideration would be associated with drainage and runoff which influence the availability of moisture within a landfill, and hence leachate or methane gas production even in a minimal amount. Community perception may ultimately determine the tolerable proximity of a remediated landfill, however, other factors such as residential development proximity to a community may be more important to the community. The final consideration would be permafrost conditions which could suggest a greater relaxation in the setback based upon the presence of permafrost.
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State of Alaska Regulation The State of Alaska does not have a prescriptive setback for landfills from residential areas, but they do however require owners of proposed landfills to evaluate the potential risk to the underlying aquifer from landfill leachate. Landfills are prohibited from violating water quality standards (include drinking water standards) at a “point of compliance” or “poc” for groundwater which is 45 m from the waste cell boundary on the landfill facility property. The landfill is also prohibited from adversely impacting adjacent properties or impacting use of adjacent property, therefore a “poc” may be established at a property line (located less than 150 m away) if the groundwater is or has the potential to be used as a drinking water supply. Based on the groundwater modelling, a landfill would have to be set back far enough away from a residential area not to impact groundwater quality, or a liner could be installed if necessary to protect water quality downstream. The minimum setback is a 15 m setback from the edge of waste placement (cell boundary) to the property line. Further to these setbacks, the State of Alaska does not require the installation of a liner, groundwater monitoring, or methane gas monitoring for a landfill located in regions of continuous or discontinuous permafrost if the landfill demonstrates that: site is developed and operated to prevent permafrost degradation; a thermal analysis must consider the site specific effects of local heat sinks and sources, and the disturbances or removal of natural or artificial insulating layers; areas of permafrost that are critical to the operation of the landfill will not be allowed to thaw; these areas must be monitored with a sufficient number of thermistors to detect any thawing; oils, liquids from spill cleanups, and waste that is incompatible with freezeback will not be placed in the landfill; the landfill is operated with a fluid management plan that minimizes any free liquid in the landfill; and after closure, the waste will remain frozen.
The landfill is excepted to be monitored for temperature and erosion during the active life and during post-closure of the landfill. CONCLUSIONS The State of Alaska approaches the regulation of landfill setbacks in a significantly different manner to the NWT and Nunavut. The fundamental difference is the use of analysis and monitoring in the determination of landfill development and maintenance criteria. Most significantly, this approach recognizes the inherent characteristics of “permafrost” to the installation of a liner, groundwater monitoring, and methane gas monitoring for a landfill located in regions of continuous or discontinuous permafrost. These conditions are subject to a thermal analysis, operation and long term maintenance to prevent the waste from thawing. The relaxation of restrictions that are more appropriate in a southern context has a precedent in the setback distance required for airports and landfills with regard to bird hazards to aircraft. The 8 kilometre setback guideline for Transport Canada was reviewed and revised in 1990 by the Department of Municipal and Community Affairs in consideration of factors unique to the north, and in reflection of setback guidelines utilized in the State of Alaska. Most importantly, the revised guideline identified the site specific factors that influence bird hazards to aircraft, and the spatial relation to landfills. The increasing financial responsibility being transferred upon cold region communities of the NWT and Nunavut along with decreasing funds for capital and operation and maintenance is a new challenge facing all communities. Any reasonable opportunity to reduce capital and operation and maintenance costs to communities should be considered by all levels of government. The decision rational presented does not suggest a specific relaxation limit to the current setback regulations. It does however suggest an opportunity for analysis in the reflection upon the rational used in another cold region jurisdiction.
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REFERENCES Environment Canada Climate Norms GNWT Health Act General Sanitation Regulations, 1990 Hamlet of Tuktoyaktuk General Plan and Zoning Bylaw, 2000 State of Alaska Landfill Regulations
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