Community planning for satisfactory sewage disposal in permafrost regions

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Planning for Satisfactory Sewage Disposal in Permafrost Regions

Abwasserplanung Sur It problime

J. W. GRAINGE,

in Dauerfrost-Gebieten deseaux d’hgout dans ler kgions de permafrost

J. W. SHAW, Edmonton, Alberta*

Abstract: Communities in permafrost regions should be planned so as to facilitate surface drainaga and the eventual installation of sewers. Sewage haulage is costly. Sewage is gathered only from the buildings which have holding tanks Toikt sewage from other residences is hauled away, but washwater and some sewa@ is spilled on the ground outside which pollutes the soil where children play. In most arctic communitks this waste-water cannot percolate away through the soil. Growth of the communttkr makes the public health problems more critical. The tort of hauling all waste-water is too high to be acceptable. Proposed rolutmns in&de the consolktation of communities and their location on hillsldes with the streets arranged so as to run down the hill at suffkient grade to provide good drainage in the road ditches (1 % minimum) but not so steeply that needed elevation is wasted. In Dauerfrostgebieten sollten Siedlungen so geplant werden, da6 oberflgchlicher Abflu6 und evenZuummenfassung: tuell Kanaliution m6glich sind. Abwassertransport wgre LU kostspielig;er w&de zudem Sammeltanks bei alkn GeMuden voraussetzen. Und wenn such Fgkalien von den Wohnhrusem abgeholt we&n, so fllegen doch andere AbwSsser ins Freie und verunreinigen den B&en, wo evrntuell Kinder spkien. In den meiste-n lrtttkchen Skdlungen kann das Abwasser nicht versickem. Das Anwachrn der Skdlunpn erschwert die hygknlschen Bedingungen. LLungsvorschlgge zkkn auf eine Zusammenfassung und Anlage der Siedlungen auf leicht geneigten HXngen (minksrns 1 %), urn den nattirlichen Ablauf zu gewlihrleisten.

Introduction Unsatisfactory and frequently hazardous disposal of sewage in the Canadian north results largely from a lack of planning of the northern communities in the early stages of their development. Such planning as does occur rarely takes into account the distinct environmental conditions of the north, namely, the severe cold climate and associated phenomena, and the remoteness from major cities and centers of supply. These factors seriously affect the cost of sanitary servicing. It is therefore most important to take a longterm view of every northern community, to predict its probable growth and to plan the sewerage -especially the collection sys*

J. W. GRAINGE, 6. SC., M. S., P. Eng., Department of Environment, and J. W. SHAW, 8. SC., P. Eng., Department of National Health and Welfare, both Public Health Engineerlng Dlvkkn, 257 Federal Public Building, Edmonton 2, Albetta, Canada. The opinkms expressed in this paper are those of the authors and they do not represent the policks of the Departments of Environment and National Health and Welfare of Canada.

tern, but also the type of sewage treatment system that will ultimately be required. Poorly planned areas should be rectifEd as soon as possible because the cost of sanitary servicing tends to increase at a faster rate than that at which the community grows. Of course poor planning, or lack of planning, may continue to a point at which the required changes will become more costly than is acceptable. Then the community will be saddled with a public health problem that will continue and increase as the community grows. In some cases it has become necessary to build a new community in another location to alleviate the problems in the old settlement. This paper briefly describes some of the problems which must be considered and a few proposak for improving planning in northern communities.

Sanitation Problems in Northern Communities It is very difficult to provide adequate sewage disposal. A northern community usually fronts on a lake or stream which serves as the source of water for both it and others

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downstream. These communities often do not have effective water treatment and distribution facilities, and the people take water themselvesfrom the nearestwater course without regard to the position of a wastewaterdischarge. Subsurfacedisposalof sewageis rarely practicable because the soils are usually either frozen or saturated with water and organic material, and have very poor assimilative characteristics for wastes. The health of the residentsof northern communities must be protected, and this requires potable water and a suitable meansfor sanitary waste disposal. Piped systemsare to be preferred. Piping water into each home is more effective in reducing the incidence of water-borne diseases than any other method of supply [l]. Sometimes a truck haulagesystem has a lower initial cost, but it is significantly more expensive to operate than a piped system. The planned layout of a community to encouragea compact development can make piped systemscompetitive for even a short to moderate design life. In larger towns truck haulage systemsbecome even lesseconomical when one considers the Costof encapsulating water and sewagesystems in each house [2]. The incidence of both gastric and skin diseasesis usually high where either truck servicesor ice are used. This is not only becauseof the methods of handling, but also becauseof the inadequate supply of water which results in a low standard of personal hygiene. Unfortunately, becauseof poor planning, there is a tendency in the Canadian north to abandon all hope of installing piped water supply and sewagesystemsin many communities. In typical communities water and sewage are hauled respectively to and from government employees’ residenceswhich have complete internal-plumbing systemsand holding tanks. The indigenous people have water delivered to storagebarrels and the plastic bagscontaining toilet sewageare hauled away. Washwateris spilled outside of those residenceswithout plumbing and sewageholding tanks; and becausethe ground surface is frozen for most of the year, the liquid does not seep away. A diverse spectrum of individuai household waste disposal systemsalso exists including pit privies and various attempts at subsurfacedisposal of septic tank effluent. In the spring the melted waste washwater and runoff in a settlement form pools around the houses and bigger pools in the upper road ditches which are dammed by ice-filled culverts. Open ditches and road culverts are critical problems in many areas[3,4]. An unfrozen source of water in early winter causesthe ditch or culvert to completely fill with ice. In spring children often play in the puddles of melted waste washwater and surface runoff. &cause of this and the fact that these pools also provide mosquito breeding grounds, they are an obvious public health hazard.

Piped water in large quantities and a flush toilet are the status symbols of the arctic. They should be available to all resident3 [S].

Clhmte and Perndrort

in Nor&em Canada

The extended periods of extreme sub-freezing weather, plus associatedthermal dependent phenomena, namely permafrost, extensive ice and snow gild-up and frost heaving, and also the lack of sunlight in mid-winter, have a very significant influence on engineering in the arctic. Permafrost or perennially frozen ground is defined as ground, such as soil and rock, in which the temperature remains below 0 ‘C (32 o F) continuously for a number of years. Permafrost is not “permanently” frozen. Changes in climate and terrain can causepermafrost to thaw and disappearand aiso to develop. Vegetation shields the permafrost from the thawing effects of summer air temperatures and sunlight. Removal or even disturbance of the surface 'cover results in ~~~~~ of the un~rlying permafrost (Fig 1). The combination of permafrost and frost-heaving soils results in the formation of ice crystals and their agglomeration into ice lenses,often of massivesize severalmetres in thickness. Ice lens’ growth occurs most readily in soil when the air temperature is only slightly below 0 ‘C. The moisture contents of such soils can easily approach sixty to seventy-five per cent. Thawing of these materials produces an unstable viscous mud.

Engineering and Construction Diffiiulties The environmental factors of the north influence almost all construction techniques and increasethe cost of an urban development project throughout its life. The low temperatures causebrittleness and considerable thermal contraction in construction materials and consequently a higher rate of failure and breakage. Outdoor operations carried on by men and machinesdecreasein efficiency to twenty-five or forty per cent of normal in low temperatures [5]. Furthermore the decomposition processesin both sewageand garbageare very slow. Major problems of differential settling occur with highice-content and frost-heaving type soils. If heat is allowed to escapefrom pipelines and buildings, then the permafrost recedes,and the ice crystals and lensesin the ground will melt. Therefore, the underlying soil condition or the presenceor absenceof bedrock are of extreme importance with regard to foundation conditions for buildings and underground services[6]. The location and size of any community permanent or temporary, in the high-icecontent soil areas,is dictated by the availability of “dry” gravel [S].

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Fig. 1 0 Selected Arctic physical-geographical boundaries 0 Einige ausgewghlte physischgeographische Grenzlinien in der Arktis l Quelques d&imitations

physicogCographiques dans ler rt?gions arctiques

In many cases, it is necessary to run pipelines in insulated and usually also heated boxing above the ground surface. The decision to place the system above or below ground is influenced by site topography, soil condition, economy, and the functional requirements of the community. These utilidors, as the aboveground systems are known,

lower expenditures for thermal protection and maintenance. Consolidation provides other advantages such as reducing the cost of road building, maintenance and snow clearance as well as reducing the discomfort of moving about in an open windy community, especially during a winter bliuard.

cost from ten to thirty times as much as for laying standard sub-surface piped systems in the temperate regions. More-

Consolidation may be accomplished in a variety of ways. Northern towns are usually small, therefore parks and

over, the utilidors are costly to maintain because they are unprotected from the weather and vandalism, and because heat losses are very high.

school playgrounds may be developed on the edge of the town rather than in the center. The center of the town should be a multi-functional complex including recrea-

The remoteness of Canadian arctic communities from major cities and centers of supply and the gl?neral tack of locally available material and skilled labor require the expensive importation of both.

Community Planning Concepts Community planning must take careful consideration of the environmental and engineering probiems outlined above and, therefore, the planning of utility systems must be an integral component of the overall community plan.

Consolidation and Layout Concentration gives exceptional advantages in the north. A compact arrangement of serviced structures within the town will minimize the cost of utilities by reducing the total length of piping required, which in turn results in

tional facilities, shopping center, offices, residences and restaurants. Combining business facilities with residences and other types of activity would avoid desertion of any part of the town on Sundays and holidays. An example of well integrated facilities is the multistorey city hall in Kemi, Finland which contains an elevated water storage tank for the city, and also has a restaurant and observation platform on top of the building. Certain street patterns should be avoided, for example, cul-de-sacs, loop streets and P-loops. Such patterns have resulted in many critical problems in water distribution and sewer systems in northern communities. It is difficult to accommodate a recirculating water distribution system to these street patterns and consequently water main dead ends occur which are prone to freezing. The circles at the end of GUI-de-sacsrequire very long service connections which are particularly vulnerable to freezing. Such streets also block drainage paths, require more culverts than would otherwise be necessary, and create prob lems of snow clearance and removal.

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Planned communities should provide a need for some exposure to the elements if only for short periods of time throughout the week. Living without exposure to the elements for extended periods lowers both morale and efficiency. Variety in recreation, sports and entertainment

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good land, and (4) the need for more sewage lift stations than an necessary. Sewage lift stations are costly to construct, operate and maintain.

lism may take over [5].

There is little experience with insulated pipelines in shallow burial where frost-heaving soils and permafrost occur. However, one installation at Hay River, N. W. T. has proven to be successful. It has not frost-heaved out of align-

Micro-Climate and Topography

ment; it has not blocked the roads at crossings, and the winter heat losses have been half those for similar installa-

is essential, othenvi4e boredom may creep in and alcoho-

For micro-climatic masons, the town, where possible,

tions aboveground.

should be built on a southern slope where the radiation from the low arctic sun is more intensive than on the flat

Aboveground pipelines should be as short as possible, extending from one building to the next, and not existing

country and where protection from the cold northerly winds is greater. Shadowed northern slopes should be avoi-

as a stem with service connections branching from it. Un-

ded for residential development, but they may be used for industrial development such as warehousing The tops of the hills should be crested by the tallest buildings to give additional protection from the wind to the main part of the residential area on the slopes below.

laid out, the result is a very unesthetic maze of pipe systems with many unsightly pipe bridges required at every road crossing. The initial costs of an aboveground utilidor system are usually so high that they are feasible only if a

Under a relatively still air condition, which may occur in late spring or early fall, there is a tendency for cool air to flow into flat areas or depressions which in turn are losing heat to the atmosphere. This condition will result in the creation of frost pockets, while air movements on the slopes will keep these areas frost free for a long period. At the same time, low areas or depressions which are periodically flooded are also particularly subject to insect infestation, while upper slopes may be relatively free. All factors being considered, flat poorly-drained ground, where possible, should be avoided for residential purpo ses. Parks, school grounds and industrial developments, which do not require sanitary servicing, may be located on this land. A settlement should be located on a hillside with the streets so arranged that they run diagonally down the hill slope, at sufficient grade to provide good drainage in the road ditches (1 % minimum} and not so steeply that there is a waste of needed elevation. This arrangement will facilitate gravity sewerage if the sewers must be laid aboveground or in shallow burial. An added advantage obtained by this planning is that the roads will be laid out for adequate drainage with a minimum number of road culverts. As previously noted, road culverts freeze solid in winter and remain plugged in the spring long after the snow on the ground has melted. Large pools of melt water form behind the culvert often deep enough to drown children and in a few cases even adults. Frost-heaving Soils and Se&a

Pipes

Where frostheaving type soils occur, communities and ultimately sewer lines must be very carefully planned to avoid (1) excessive length of utility pipes, (2) wastage of elevation. (3) the rendering unserviceable of otherwise

less aboveground pipelines are very carefully planned and

compact, efficient arrangement can be imposed on the community.

Implementation Provision of piped utilities to all residences must be considered at the outset as the ultimate target. It is not usually financially possible to service completely and at one time a whole community which has grown up without sewerage and a water distribution system. Also, many of the residences may not be suitable for or have space available for modem conveniences. In an unserviced community servicing should begin with the major buildings which should be located or relocated, as necessary, so as to allow an efficient system of sewerage, to facilitate expansion of the utility system to other areas of the community, and to begin a rational organization of the layout of the community. All new housing, whether or not it can be connected to sanitary services immediately, should contain bathrooms. The possibility of future expansion must be considered and provision for such growth must be one of the essentials of planning. Because of their high cost, utility systems for arctic and sub-arctic communities become one of the dominant factors in community planning. Therefore, the direction of new growth in the community be influenced by providing utilities in certain areas and by strict zoning to control development elsewhere (21. There should be no obstacle to the implementation of the above planning concepts. They are becoming recognized by a few of the planners and engineers engaged in working on northern communities. However, the legitimate desires of the local residents and deficiencies in government and the training of those responsible for community development continue to constrain good planning.

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Human and Social Constraints on Community Planning Northern people are conscious of living on the perimeter of civilization. They maintain the emotional threads of contact by imitation of the styles of the southern cities even if the styles serve no other useful purpose [7]. The local people often oppose good planning, as is common elsewhere, and planning authorities are reluctant to impose a plan against their wishes, even when they are only short-term residents. The indigenous people wish their houses to front a river or lake with space for their dogs, boats, fishing equipment, etc., which might be subject to vandalism if not under continuous surveillance. This tends to elongate the settlement along the river or lake shore and to vastly complicate the sewicing of the houses.

The wide-spread communities lead to limited or nomxistent piped water distribution systems. In turn, the lack of water distribution system and hence the lack of fin hydrants has resulted in fire protection regulations which require the wide separation of the buildings because in northern communities they are mainly of wood construction and in the arctic the winds are commonly high. Most of these probkms could be overcome except for the fact that the majority of architects, engineers, sunreyors, community planners and administrators have only a superficial understanding of the special problems of the north. Nearly all were born, raised, educated and trained in the temperate regions. Northern development also uses the planning concepts developed by mortgage corporations for the maintenance of property values in southern residential subdivisions. For example, such concepts include large lots with single

Other factors contribute to haphazard development. Squatters have built their shacks indiscriminately. Govemment surveyors have subdivided land, in order to organize

family houses arranged in a&k-sacs,

ownership and title, without considering planning aspects.

a cold climate.

which are very diffi-

cult to service with piped water and sewenge systems in

Early missions and traders took title to large tracts of the best developable land which in many cases is now in the center of the settlement. Unfortunately,

town planners

do not usually suggest that, in the interests of community development, some of this choice land should be surrendered. The economic demands of urban areas tend to promote high density development. However, many northern communities are heavily subsidized by the senior governments, and as a result, development and operating expenses are not sufficiently appreciated by the local peopk. Since these expenses are not an immediate problem to them, they are happy to see a wide-spread community. Eventually, however, the cost of operation will be transferred to the community which of necessity will impose a very

Conclusions Some concepts of community

planning for permafrost

regions have been described in this paper which would greatly reduce the technical and economic problems of sanitary servicing, in particular the colkction of waterborne sewage. If these concepts are applied, no doubt other concepts will also be developed that will further enhance northern communities. With imaginative architecture, high density communities may be built that will ‘be as attractive as the closely clustered villages and towns of medieval and renaissance Europe.

heavy tax burden on the residents. A factor which has particularly mitigated against higher density living in the north is poor quality apartment construction. Poor sound-proofing of apartments and the consequent loss of privacy have reinforced the desire for single family dwellings. The land around most northern settle-

Engineers, planners, those others responsibk for northern development and the people who live in northern communities must take into account the environment and the economies of sanitary servicing if these communities are to be healthy and pleasant places to live.

ments is not used for farming or other productive purpo ses and is therefore, freely availabk for housing The settlements are small. In the forested areas building material is readily available and people may build their own cabins as close to or as far away from the community as they choose. Government subsidized housing, for aboriginal people in Canada, is mainly single family dwellings. By contrast, in Greenland, the Danish government has provided mainly apartment houses, of good masonry construction, for the indigenous people.

Admowledgcment Apprcchtion is expressed to the World Health Organization for two Travel Fellowships to study sanitary angimerlng and community planning In northern Scandinavia, Greenland and Iceland, which studks stimulated this paper. The authors ako wish to expree their appreciation to Mr. R. E. Tait, Chief, Public Heakh Engineering Division, Department of Envimnmcnt, Ottawa, Canada for his support and for mvbwinp this paper.

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References [l]

RYAN, N. L., LAUSTER, K. C. (1966): Design and Operadon of a Water System for the Eskimo Vil@a of Unalakket, Alaska;jour. A, I+‘. W./l., 55, No. 8,pp. 1045-1051.

(21

REED, 5. C. (1967) : Planning UtiMy Systws for Ant/c &Sub-Antic CommunJtkk USA CRREL internal Re-

[3]

~~R~E,W.(l963~: Wu~rSu~~~~~i~~A~~ Au, i~rna~~al Confennca on Permafrost.

[4]

SANGER, F. J. (3 964) : WuterSupply, Sewage Dkposal and Oralin Cold Re#ikwts, UnpubHshed Manuscript, USA CRREL.

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LAWRENCE, N. A. (1970): On ahe Humon Ayrrctof Cold Climate Opemtions, pmsented at 99th Annual Meetinp of the American institute of Mining, Metallurgical and Petroleum Engineers, Inc. Denwr, Colorado. Paper No. SPE 2827, Febrwy, 1970. GORDON, C. E. (1965) : An Applkxtiw! of EnvhvnmenMI Prlncples to Conwmigy Mnnhg In the Subdntic, pmsented at the Annual Technical Conference, Underwood, McLelfan and Associates, Winnipeg, Man,, March, 1%5. ERSKINE, R (1967) : 3u~d~ in the North, pmsen&d at the Worid Scknce Design Deqade Conference, Montmal,

August, 1967.