Permafrost in Canada: Its Influence on Northern Development 9781442632615

Table of contents :
Preface
Acknowledgments
Contents
1. Nature of Permafrost
2. Engineering Considerations
3. Development of Permafrost Investigations and Northern Settlement
4. Buildings
5. Services
6. Transportation
7. Mining and Oil Production
8. Agriculture
9. Conclusion
References
Bibliography
Index

Citation preview

CANADIAN BUILDING SERIES Sponsored by the Division of Building Research National Research Council, Canada Editor: Robert F. Legget 1 Canada Builds, by T. Ritchie 2 Performance of Concrete, edited by E. G. Swenson 3 Muskeg Engineering Handbook, edited by Ivan C. MacFarlane 4 Permafrost in Canada, by Roger J. E. Brown

PERMAFROST I CANADA N Its Influence on Northern Development

Roger J. E. Brown

UNIVERSITY OF TORONTO PRESS

© University of Toronto Press 1970 Printed in Canada SBN 8020-1602-2

Preface

The author is a Research Officer in the Division of Building Research, National Research Council, Ottawa. He joined in 1953 as a member of the Division's Northern Research Group to study the distribution of permafrost in Canada and the physical factors affecting it. In the course of this work investigations have been carried out in many parts of northern Canada. In September, 1956, he was granted two years' leave of absence by the National Research Council to pursue graduate studies toward obtaining a PH.D. degree in geography at Clark University in Worcester, Massachusetts. The first year of these studies was spent at the Graduate School of Geography, Clark University, taking formal course work for the degree. The second year was spent in library research on the PH.D. thesis at the Scott Polar Research Institute, Cambridge. The degree was conferred in 1961. Because of the increasing interest in permafrost in Canada, Dr. Robert F. Legget, Director of the Division of Building Research, National Research Council until his retirement in 1969, suggested to the author the possibility of rewriting the thesis in book form. Through his efforts, the University of Toronto Press agreed to consider the manuscript for publication. This book, appearing eight years later in the Canadian Building Series, is the result of encouragement the author received from both Dr. Legget and the Press. Since permafrost underlies one-half of Canada's land surface it is an important area of study for this country. This work attempts to survey the major scientific and engineering aspects of permafrost: its definition, origin, and occurrence, the climate and terrain of permafrost areas, economic and historical considerations, problems of building and transportation on permafrost, and its effects on mining and agriculture. Examples are given in these different spheres of activity to illustrate the major problems and various techniques employed in northern Canada to counteract the adverse effects of permafrost. It is not possible to give the whole story because of space limitations and gaps in the records, but the historical background and some details of the current situation are presented. Before the Second World War there was little experience with permafrost in northern Canada as economic activities were underway at only a few widely

VI

PREFACE

scattered locations. The existence of permafrost suddenly became of major concern during the war in northern military operations; and interest increased steadily in the postwar period as the North opened up to new economic ventures, mostly in the Subarctic where permafrost is for the most part discontinuous but also in the Arctic where permafrost is continuous. These developments are progressing steadily and permafrost continues to be a vital factor on many fronts. At the time of the writing of this book, activities in the Arctic are reaching new levels of intensity as tremendous reserves of oil are discovered and exploration continues for more. As economic developments grow in number and scope, it is becoming increasingly difficult to keep track of all the experiences with permafrost. It is hoped that errors of omission and fact will be forgiven since the author's intention was chiefly to convey an impression of the nature of permafrost and its impact on economic developments. This book is, however, only an introduction to the exhaustive documentation that awaits preparation to present the total picture of the effects of permafrost on the development of northern Canada.

Acknowledgments

The author is particularly indebted to Dr. Legget, for his valuable support and continued interest throughout graduate studies, the writing of the thesis, and subsequently this book. The two years' leave of absence granted by the National Research Council for the degree work, the second year being supported financially by the Council, was obtained largely through his efforts. His permission to use permafrost research material of the Division of Building Research and the facilities of this Division for the reproduction of all maps, diagrams, and photographs in this book is gratefully acknowledged. His assistance and inspiration played a large role in the ultimate publication of the book. The author's association over the past sixteen years with his immediate professional colleagues, G. H. Johnston and the late J. A. Pihlainen, of the Northern Research Group, Division of Building Research, has also been of great value in the writing of this book. Much of the information was obtained by working with them both in the office and in the field. Mr. Pihlainen initiated and guided the permafrost investigations carried out by the Division in the early 1950s and was involved with permafrost until his death in 1964. The author profited greatly in working with him on various research projects. I am grateful to Mr. Johnston for reviewing the manuscript of this book and offering many constructive suggestions. Much of the current unreferenced information on the engineering aspects of permafrost in Northern Canada has been obtained in discussions and association with him. His knowledge and experience in this field is unequalled in Canada and this book could not have been written without his assistance. The staff of the Graduate School of Geography at Clark University was of continued assistance during graduate studies and writing the thesis. The author wishes to record his special appreciation to the late Dr. R. J. Lougee who was staff adviser until his death in May, 1960. Dr. Lougee assisted in the selection of the topic and gave much valuable guidance in the writing and revision of the first draft of the text. After his passing, Dr. R. E. Murphy very kindly agreed to assume the position of adviser. His guidance in the final stages of completing the thesis is gratefully acknowledged. Finally, the author wishes to record his gratitude to Dr. S. VanValkenburg, former Chairman of the Graduate School of Geography,

Vlll

ACKNOWLEDGMENTS

for his continued interest in the author's progress at Clark University and in the subsequent years. The author is grateful to the Scott Polar Research Institute, Cambridge, for placing its facilities at his disposal in obtaining research material for the thesis. The Librarian, H. G. R. King, and his staff made available much published and unpublished material. Without this valuable and untiring support, the writing of the thesis would have been much more difficult. The author wishes to record his appreciation for the time spent by Dr. T. E. Armstrong, Senior Research Fellow, in helping to obtain and evaluate the Russian permafrost literature at the Institute. In addition to the financial support granted by the National Research Council, the year of research at the Scott Polar Research Institute was supported also by predoctoral awards from the Royal Society of Canada and the Social Science Research Council of Canada. This generous assistance was indispensable to the successful completion of graduate studies. During the writing of the book, many valuable suggestions and comments were offered by two gentlemen who have many years of experience in the North, G. W. Rowley, Department of Indian Affairs and Northern Development, Ottawa, and Professor K. B. Woods, Goss Professor of Engineering, School of Civil Engineering, Purdue University, Lafayette, Indiana. Both spent considerable time reading the thesis manuscript and suggesting revisions for the book. Their assistance is gratefully acknowledged. The author appreciates the continued interest of Miss Francess G. Halpenny and the expert assistance of Miss Margaret Gillies and Mrs. Diana Swift Sewell of the University of Toronto Press. He is also grateful to Mr. F. Crupi, Division of Building Research, National Research Council for drafting the maps and diagrams. Finally, the author acknowledges the valuable assistance and support given by his wife through the entire period of studies leading to the degree, and later in the writing of the book. She provided continued encouragement as well as spending many hours in assisting with the revision, editing and proofreading of the manuscript.

Contents

Preface Acknowledgments

v vii

i

Nature of Permafrost

2

Engineering Considerations

31

3

Development of Permafrost Investigations and Northern Settlement

43

4

Buildings

55

5

Services

82

6

Transportation

105

7

Mining and Oil Production

139

8

Agriculture

180

9

Conclusion

204

References

208

Bibliography

221

Index

225

3

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PERMAFROST IN CANADA

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1

Nature of Permafrost

About one-half of Canada lies in the permafrost region. This area (whose most prominent natural features, political divisions, and settlements, are shown in Figures 1 A, B, c, D) comprises the Yukon and Northwest Territories and the northern parts of most of the provinces, with a sparse population scattered over vast distances. Economic development and other human activities have been hampered by a number of factors, chiefly severity of climate, remoteness from the populated south, inaccessibility, and permafrost. Since the end of the Second World War, and particularly during the past decade, Canada has become increasingly aware of her northern frontier. Despite more intensive activity, however, it is unlikely that this region will be developed to the same degree as southern Canada, although the wealth of natural resources, particularly minerals, will encourage such development. The existence of permafrost usually necessitates modifications in conducting various tasks described in the following chapters because of the need to counteract its adverse effects. Thus, costs are higher than in temperature regions where there is no permafrost. Increasing knowledge of permafrost properties and characteristics has raised the level of technology to the point where it is possible to build virtually any structure in the permafrost region. Even though new methods will probably bring the cost of many operations nearer to those in temperate regions, permafrost will continue to be an adverse factor in the development of northern Canada.

A

DEFINITION AND ORIGIN

The term "permafrost" was coined by S. W. Muller, who used it as a convenient short form of "permanently frozen ground" (Muller 1945). It is a term used to describe the thermal condition of earth materials, such as soil and rock, when their temperature remains below 32° F continuously for a number of years (Muller 1945; Pihlainen and Johnston 1963; Shvetsov 1959; Stearns 1966; Sumgin et al. 1940). Ice is an important component of permafrost but all water in the ground

4

FIGURE IA Eastern Canada.

FIGURE IB Prairie Provinces.

PERMAFROST IN CANADA

NATURE OF PERMAFROST

FIGURE Ic Yukon Territory and Mackenzie District.

FIGURE ID Arctic Archipelago.

5

6

PERMAFROST IN CANADA

does not freeze at 32° F if it contains impurities or is under pressure. Although freezing implies a change of state, the presence of unfrozen water in the soil at temperatures below 32° F causes semantic difficulties in the use of the term. Despite these problems, it is generally agreed that defining permafrost solely on the basis of temperature is the most workable arrangement. Permafrost includes ground that freezes in one winter, and remains frozen through the following summer and into the next winter. This is the minimum limit for the duration of permafrost; it may be only a few inches thick. At the other end of the scale, permafrost is thousands of years old and hundreds of feet thick. The mode of formation of such old and thick permafrost is identical to that of permafrost only one year old and a few inches thick. In the case of the former, even a small negative heat imbalance at the ground surface each year results in a thin layer being added annually to the permafrost. After several thousands of years have elapsed, this process repeated annually can produce a layer of permafrost hundreds of feet thick. However, the permafrost does not increase in thickness indefinitely. Rather a quasi-equilibrium is reached whereby the downward penetration of frozen ground is balanced by heat from the earth's interior. Above the permafrost is a surface layer of soil or rock, called the "active layer," shown in Figure 2, which thaws in summer and freezes in winter. Its thickness depends on the same climatic and terrain features that affect the permafrost. In recent years, it has been realized that permafrost is not necessarily permanent. Changes in climate and terrain can cause the permafrost to thaw and disappear. Thus the term "perennially frozen ground" is now used instead of "permanently frozen ground." This change in terminology is also evident in Russian literature where the term mnogoletnemerzlyy grunt meaning "perennially frozen ground" is replacing vechnaya merzlota meaning "eternal frost." The origin of permafrost is not well understood but it is suspected that it first appeared during the cold period at the beginning of the Pleistocene. During subsequent periods of climatic fluctuations, corresponding changes have occurred in its extent and thickness. In the north, where winters are long and severe and summers are short, the depth of winter frost penetration will be generally greater than the summer thawing of the ground. In this regime, a layer of frozen ground will persist through the summer and another layer will be added to it during the following winter. If the climate remains sufficiently cold over a period of years a considerable thickness of perennially frozen ground will accumulate. For example, it can be calculated, on the basis of simple conduction theory, that at Resolute, NWT, on Cornwallis Island, about 10,000 years was required for the ground to freeze to a depth of 1,300 feet, the present estimated thickness of the permafrost. A more precise estimate would have to take account of such factors as the latent heat of fusion of ice, proximity of the ocean, fluctuations in mean

NATURE OF PERMAFROST

7

annual air temperature since the initiation of permafrost accumulation, and changes in terrain conditions (Brown and Johnston 1964). If the climate becomes warmer, some or all of this permafrost may disappear, but if the climate becomes even colder, the permafrost may increase in thickness at a faster rate. At present it is known to be diminishing in some areas and increasing in others.

B

DISTRIBUTION AND OCCURRENCE

1 Geographic Extent and Thermal Regime Permafrost underlies 20 per cent of the world's land area, being widespread in North America, Eurasia, and Antarctica. In the northern hemisphere it occurs mostly in Canada and the Soviet Union, each country having about one-half of its total land area underlain by it (R. J. E. Brown 1961 b, Permafrost Map shown in Figure 3). It is found also in most of Alaska, Greenland, northern Scandinavia, and in Outer Mongolia and Manchuria. It occurs also at high elevation in mountainous regions in other parts of the world.

FIGURE 2 Typical profiles in permafrost region.

8

PERMAFROST IN CANADA

The permafrost region is divided into two zones - discontinuous in the south, and continuous in the north. Various criteria have been used in North America to delineate the division between these zones. The method employed in Canada by R. J. E. Brown 1967b, Permafrost Map (see Figure 3) is based on the arbitrary selection by Russian permafrost investigators of the minus 5 ° c ( 2 3 ° F ) isotherm of mean annual ground temperature measured just below the zone of annual variation (Bondarev 1959). This criterion appears to apply to the Canadian situation according to the presently known distribution of permafrost but more field observations are required to assess the validity of its uses in this country. American investigators have used the Russian and other criteria to delineate the permafrost zones in Alaska (Black 1954, Ferrians 1965). In the continuous zone, permafrost occurs everywhere beneath the ground surface except in newly deposited unconsolidated sediments where the climate has just begun to impose its influence on the ground thermal regime. The thickness of permafrost is about 200 feet at the southern limit of the continuous zone increasing steadily to more than 1 ,000 feet in the northern part of the zone as Figure 4 shows. The active layer generally varies in thickness from about 1M to 3 feet and usually extends to the permafrost table. The temperature of the permafrost in this zone, at the depth at which annual fluctuations become virtually imperceptible (i.e., less than about 0.1° F) known as the level of zero annual amplitude, ranges from about 23° F in the south to about 5° F in the extreme north. In the discontinuous zone, frozen and unfrozen layers occur together (see Figure 4). In the southern fringe of this zone, permafrost occurs in scattered

FIGURE 4 Typical vertical distribution and thickness of permafrost.

LEGEND PERMAFROST

[TT1 CONTINUOUS PERMAFROST ZONE i

|!S

'

[TTTI

SOUTHERN

LIMIT

OF CONTINUOUS

PERMAFROST ZONE

DISCONTINUOUS PERMAFROST ZONE WIDESPREAD

PERMAFROST

lO

SOUTHERN

FRINGE OF PERMAFROST

P