Proceedings of the Ninth Canadian Soil Mechanics Conference

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The Associate Committee on Soil and Snow Mechanics is

one of about thirty special committees which assist the

National Research Council in its work. Formed in 1945

to deal with an urgent wartime problem involving soil and

snow, the Comnittee is now performing. its intended task of

co-ordinating Canadian research studies concerned with the

physical and mechanical properties of the terrain of the

Dominion. It does this through subcommittees on Snow and

Ice, Soil Mechanics, Muskeg, and Permafrost. The

Com-mittee, which consists of about fifteen Canadians

ap-pointed as individuals and not as representatives, each

for a 3-year term, has funds available to it for making

research grants for work in its fields of interest.

In-quiries will be welcomed and should be addressed to: The

Secretary, Associate Committee on Soil and Snow Mechanics,

c/o The Division of Building Research, National Research

Council, ottawa, Canada.

This publication is one of· a series being produced by the Associate

Committee on Soil and Snow Mechanics of the National Research Council. It may

therefore be reproduced, without amendment, provided that the Division is told in advance and that full and due acknowledgement of this publication is always

made. No abridgment of this report may be published without the written

authori-ty of the Secretary of the A.C.S.S.M. Extracts may be published for purposes

NATIONAL RESEARCH COUNCIL CANADA

ASSOCIATE COMIvIITTEE ON SOIL AND SNOW MECHANICS

PROCEEDINGS OF THE

NINTH CANADIAN SOIL MECHANICS CONFERENCE

-DECEMBER 15 AND 16, 1955

Technical Memorandum No.41

ottawa October 1956

( i )

FORWaRD

This is a record of the Ninth Canadian Soil Mechanics

Conference held at the University of British ｃｯｬｵｭ｢ｩ｡ｾ Vancouver,

December 15th and 16th, 1955. The conference was sponsored by

the Associate Committee on Soil and Snow Mechanics of the

National Research Council. It was arranged by a local comnlittee

with the co-operation of the University of British Columbiae

Meetings on both days were conducted in the Engineering Building

of the University of British Columbia. The emphasis of the

conference was placed on the inter-relationship of pedology, geology, and engineering in dealing with the complex soils of British Columbia.

On the evening of December 15th, following a reception

and dinner at the ｕｮｩｶ･ｲｳｩｴｾ of British Columbia Faculty Club,

the conference joined with the Vancouver Branch of the Engineering Institute of Canada and the British Columbia Professional Engineers

to hear papers by F. L. Peckover and D. J. Bazett on soil mechanics

aspects of the st. Lawrence Seaway Development. On Saturday,

December 17th, there was a field trip to the site of the Cleveland Dam in the Capilano Canyon.

The Associate Committee wishes to acknowledge the assistance in the preparations of the conference made by the

local committee under the chairmanship of Mr. Cu Fo Ripley. The

efforts of Dr. N.A.M.MacKenzie, President of the University of British Columbia, Dean H.C. Gunning, Faculty of Applied Science, and Dean Bo Eagles, Faculty of Agriculture, are greatly

appreciated and contributed to the success of the conferenceo The field trip was arranged through the co-operation of Mro T.V. Berry, Commissioner of the Greater Vancouver Water District o Finally, the stenographic assistance in the preparation of this record given by Mrs. A. Peebles and Mrs. R. Taylor is appreciated o

(ii) TABLE OF CONTENTS Session of December 15 Section 1 Section 2 Section

3

Section

4

Section

5

Section 6 Secti0!l

7

Introductory ｲ･ｭｾｫｳ by ｈｾｃｯｇｵｮｮｩｮｧ and R.F.Legget 1

Climate and physiography of British

Columbia by W.H.Mathews 2

Soils of British Columbia by Lo Farstad 10

Applica.tion of geology to soil problems in the lower mainland of British Columbia

by J.E.Armstrong 11

Agricultural soils of the Fraser Valley

by E. Hughes ' 20

Foundati09 conditions and problems

-Vancouver, B.C. by PoM.Cook and Lo Brandon 26

Joint evening meeting with EoI.Co and BoC.

Association of Professional ｅｮｧｩｮ･･ｾｳ

-Soil Mechanics aspects of the StoLawrence

Seaway by F.L.Peckover and DoJ.Bazett

31

Session of December 16

Section 8.

Section 9

Section 10

Section 11

Problems of foundation settlements in

British Columbia by E.JoKlohn

48

The Park Bridge slide by RoCoThurber 66

Measurements of lateral movements in soils

by W.LoShannon

75

Consolidation characteristics of organic

Section 12 Section

13

Section

14

Section

15

Section 16 Appendix A Appendix B (iii)

Research at Garibaldi Lake, BoCo by W.H.Mathews

Report of the National Soil Survey Committee, Saskatoon, Saskatchewan by Lo Farstad

Soils in relation to forestry by FoGoHaddock

Reports of research work at the Division of Building Research, National Research Council

General business

Trial of one-point liquid limit method by WoJ.Eden

List of those present at the Ninth Annual Canadian Soil Mechanics Conference

88

90

93

98

SESSION OF DECEMBER

1$, 1955

SECTION I

Introductory Remarks by

Dean H.C. Gunning and R.F. Legget

Dean H. C. Gunning welcomed the delegates on behalf of

the University of British Columbia and introduced Mr. R.

Peterson who acted as Chairman for the morning session. Mr.

Peterson then called on Mr. R. F. Legget, the Chairman of the

Associate Committee on Soil and Snow Mechanics.

Mr. Legget outlined the history of the past eight

conferences and the work of the Associate Committee on Soil

and Snow Mechanics. The Ninth Conference,

Mr.

Legget stated,

would be devoted to the problems arising from the use of soils

in British Columbia. Mr. Legget stressed that the word soil

was being used in its broadest sense at the Conference and

embraced three fields, that of pedology, geology and engineering. He hoped the members of each discipline would have much to learn from the others represented.

2 -Section 2

Climate and Physiography of British Columbia by

Dro WoH. Mathews

The next speaker, Mr. F.rstad, and I, have been asked to

introduce to you the soils of British Columbia and something of

the conditions under which they have developedo My assignment

relates to the environments and Mr. Farstad's to the soils

them-selveso I will feel my duty accomplished if I can but leave

with you some idea of the enormous range of soil-forming condi-tions that exist within this Province, and of the problems

accompanying this diversity.

Of the five soil-forming factors listed by Jenny, three have played a dominant role in the evolution of the soils of the Province - topography, climate, and parent material; hence

the title of this paper. Of these factors, topography plays a

double part inasmuch as it has, itself, exerted ｡ｾ｡ｲｫ･､

influence on local climate.

The major topographic units of the Province consist of northwesterly trending mountain ranges and intervening lowland and

plateau beltso These have been defined recently by Bostock (1948),

and by Brink and Farstad (1947)p from west to east as follows:

West

East

Insular mountains (of Vancouver and Queen Cnarlotte Islands)

Coastal Trench (including Georgia and Hecate Straits)

Coast and Cascade Mountains

Interior Plateau, Skeena and Hazelton Mountains and Stikine Plateau

Columbia, Omineca, and Cassiar Mountains Rocky Moununn Trench

Rocky Mountains Great Plains

3

-Throughout the Province, except in its northeastern

corner, the local relief is greato Vanderhoof in the Interior

P'Lat e au , has been reputed to be the only town in B<, Co, in which it is not possible to see a mountain and this reputation, I

suspecty originates from the ｦ｡ｾｴ that the town is nestled in

a valley whose walls restrict the distant viewso Extreme

relief within limited areas is not uncommon9 local relief

of 5y

ooo

feet is generalo In the mountain belts and in

several localities, differences in elevation of as much as

10,000 feet occur within a horizontal distance of 15 mileso

Rough terrain is widespreado Mulholland (1937)9 has estimated

that 66 per cent of the area of the Province is unsuited for

either forestry or agriculture; most of this is mountainous

terrain, much of it near or above timberlineo About 70 per cent

of British Columbia lies more than 39 0 0 0 feet ｡｢ｯｶｾ sea level,

and this area 1s mountainous terraino A high proportion of the

steeply-sloping ground consists of bare rock or rock thinly

covered by slide debris or by taluso

British Columbia" lying in the belt of prevailing

westerly winds9 is swept by maritime air masses moving in from

the Pacific Oceano These discharge much of their moisture on

the windward r-ange s , and most of the pr-e cLp Ltat Loe- on anyone

range falls near its western limite Thusv in the southern part

of the Province the highest precipitation is found on the western side of Vancouver Island" where at Henderson Lakey a 13-year

average of 263 inches per year has been recordedo Only 35 miles

away on the eastern side. of Vancouver Island" as little as 30

inches a year falls at Parksvilleo Mean annual rainfall averages

about 35 inches in most of the southern Coastal Trencho In the

Coast Mountains precipitation is at a maximum of 100 to 150 inches on its western slope£) and declines gradually to lows of

about

8

to

15

inches at its eastern baseo Farther east" the

extremes of precipitation are much ｾｳｳ ｰｲｯｮｯｵｮ｣･､ｾ but lows of

from 8 to 18 inches per year are experienced in many of the valleysv and highs of more than 50 inches experienced in the

mountainso From the scanty data for the northern interior of the

Province9 rainfall ranges generally between 12 to

24

incheso

Marked local precipitation gradients occur of which one

of the most striking 1s in the vicinity of Vancouvero Vancouver

airport receives roughly 40 inches Of rain a ｹ･｡ｲｾ the City

itself£) 57 inches; west Vancouvery 64 inches9 Capilano Intake,

126 inches_f and Seymour Fallsy only 12 miles northeast of the

City" and within 20 miles of the airport" 147 incheso Vertical

gradients may also be notableo Britannia Beachy at sea level

receives 76 inches a year whereas Tunnel Camp, 2,9200 feet higher

4

-town of Hedley in the interior receives an average of 1105 inches per year, whereas the Nickel Plate Mine, 4,000 feet

higher and only 2i miles to the northeast, receives 23 08 incheso Throughout the coastal area and in the mountains of the western and southern part of the Province, the greatest

pre-cipitation occurs in the months of October to Januaryo On the

other hand, in the Interior ｐｬ｡ｴ･｡ｵｾ the southern Rocky Mountain

trench, and in the Plains area, the wettest month occurs in the

summer and is generally June. High winter precipitation in the

mountains leads to heavy snowfall, particularly at higher levels. In the mountains of Vancouver Island and in the Coast Mountains, the snow pack commonly attains depths of more than 10 feet by March (BoCo Snow Survey Bulletins) and in some years in the mountains overlooking Vancouver, 20-foot snow poles become

com-pletely buriedo At the higher, and cooler, levels within these

same mountains, snow may linger throughout the summer, and over a period of years contribute to permanent snowfields and glaciers.

The firn line, ｴｨｾｴ critical level above which these permanent

snowfields persist, varies in altitude in the north from about 3,500 feet near Juneau, Alaska to 6,500 feet on the east edge of

the Coast Mountains and lies at about 89000 feet in the Rockieso

Near latitude 50 it rises easterly from 5,000 feet on Vancouver

Island to 995 00 feet at the east edge of the Coast Mountains and

lies between 8,000 and 10,000 feet in the Selkirk and Rocky

Mountains. The easterly rise of firn line at both latitudes can

be correlated with an easterly decline in snowfall; the higher

elevations in the south are determined by higher temperatureso

Temperatures are closely related to altitude, latitude,

and distance from the Coast. Mean annual temperature is chiefly

determined by the first two. It decreases upward at a rate

of about 3°Fo per 1000 feet. The mean annual temperatures

such as would occur at sea level; ioeo after the effect of

altitude is eliminated, are close to 50 oFo across the southern

part of the Province, and close to 40oFo in the northwestern

and 35Opo in the northeastern cornerso The daily and seasonal

ranges show the marked influence of nearby bodies of water and

on the open coast the variations are particularly slight, Mean

annual rangei that is the difference between the monthly means of

the warmest and coldest months, is less than 20 oFo on the west coast, about 3SoFo on the east side of the Coast Mountains, 40°F. to 50Opo through much of the interior and more than SOoFe in the

northeastern part of the Provinceo The frost-free period is

correspondingly shorter away from the coastal areao Freezing

cycles, here regarded as a fall in air temperature below 28°F o and a rise above 33°F. as recorded in daily maxima and minima, occur less than 30 times per year throughout much of the coast,

5

-from 50 to 80 times per year in many of the interior valleys and exceed 100 per year in some of the mountain valleys.

Permafrost, a product of low prevailing temperatures

and light snowfall is probably rare in the Provinceg being for

the most part restricted to high levels and sheltered locations

in the dry interior. One notable exception to this general

rule is the permafrost exposed by the recent recession of Helm

Glacier (Mathews,

1955)

in Garibaldi Park,

45

miles north of

Vancouver, in a region of high snowfall.

A striking illustration of the extreme diversity of climatic conditions existing within the Province is provided by Chapman (1952)9 who finds places in Europe with comparable

climates to those of stations in British Columbia, considering temperature, precipitation, and their seasonal distribution, these are:

Istanbul, the analogue of Victoria;

Moscow, the analogue of Prince George$ and

Bergen (Norway), the analogue of Prince Rupert. Thus, the climatic conditions of the Continent of Europe are here telescoped into an area one-tenth its size.

Geology is no less varied in the Province than is climate, and the typical geologic map, regional or local, is a crazy-quilt

of patterns. Rocks of all ages from Proterozoic to recent are

present, and of all types, plutonic, volcanic9 sedimentary, and

metamorphic. The distribution is so complex that only a few

generalizations are possible, namely that granitic and volcanic

rocks predominate in the western and southern part of the Province9

and sedimentary rocks prevail in the Rocky Mountains and in the northeastern part of the Province.

The most important single geological event in so far as the soils of the Province are concerned, has been the Pleistocene

glaciation which affected the entire area9 save perhaps a few of

the mountain tops. A "provincial" Cordilleran ice sheet has been

responsible tor most of the glaciation, the Keewatin ice sheet, moving west from the r.anadian Shield, reached only to the eastern

edge of the Rocky Mountains. Material picked up by one or other

ice sheet has been comminuted, mixed, and re-sorted by various processes associated with glaciation to give rise to a variety of

unconsolidated deposits. Some of these, particularly at higher

elevations, reflect the composition of the underlying or nearby

bed-rock, others consist of material brought from a large area

and thus include many different rock types. The granitic rocks

and the metamorphosed volcanics, being blocky, jointed, and resistant to glacial abrasion, tend to be concentrated in the

6

-coarser fractions of the resulting deposits; the sedimentary

source rocks contribute largely to the finer fractionso Source

rock and distance of transport have a marked bearing on the mineral composition and particle-size distribution of glacial till but conditions of deposition have an even more marked bearing on composition and size distribution of the other

glacial deposits. Fluvioglacial deposits contain the coarser

and more resistant material carried by meltwater streams.

Glaciolacustrine beds, laid down in quiet water 9 contain the

finer fractions. Glaciomarine deposits may contain all sizes

but have a structure, and fossil cDntent that distinguish them from till on the one hand and glaciolacustrine beds on the

other. Fortunately for the mapping of the different types of

glacial deposits, they are concentrated in particular environ-ments and associated with more or less characteristic land

forms. Thus, air photographs, aided by ground control, make

it possible to ascertain the character and extent of at least

the near surface deposits. A knowledge of glacial processes

makes it possible, with a somewhat lower degree of assurance, to extrapolate information on buried deposits from limited surface exposures and drill logs.

Notwithstanding very large amounts of information on

topography, climate, and geology already collected, the variations within the Province in these factors are so great that much

additional information is vital to a full understanding of conditions.

Topographic maps, on a scale of

4

miles to the inch and

with 500-foot contour intervals are now available for most of the

Province, but detailed maps, on a scale of ＱＺＵＰｾＰＰＰ and with

contour intervals ranging from 25 to 100 feet, are available for

only about 9 per cent of the area. For many problems even these

detailed maps are inadequate, and use must be made of aerial

photo-graphs of which, fortunately, there is almost ｣ｯｭｰｾｴ･ coverage of

the Province on a scale of about 2 inches to the mile.

Climatic data, though adequate to provide broad general-izations, fail singularly in all but the populated southwestern corner .of British Columbia to provide a picture of local

vari-ations which so often have significant magnitudeo This problem

stems, in part, from the fact that until recently, meteDrological stations have been established very largely for the benefit of

farmers and mariners who operate at low altitudes. The effects

on climate of altitude, slope, and exposure are still to be

evaluated. The recently published Climatological Atlas of Canada

(1953) which has been based on data from these low-level stations,

can be particularly misleading in B.C· if the ･ｸｾｳｴ｡ｮ｣･ of

7

-the practice of equating 10 inches of snowfall, regardless of

its density, to 1 inch of precipitation as raino For this

reason, it is likely that in coastal areas where freshly fallen snow has a relatIvely high density, winter precipitation is

underestimated. Increased use of data from snow surveys, from

the elevation of firn line, and from stream flow measurements is desirable.

Geologic maps on a scale of

4

miles to the inch are

now available for somewhat less than

50

per cent of the Province,

and detailed maps are available for not more than a few per cent

of the area. Few of these maps, reconnaissance or detailed, show

the distribution of the different unconsolidated deposits, which are, as a rule, grouped together as "glacial drift and alluvium".

Of late" however, some geologists are undertaking the subdivision

of glacial deposits in the course of mapping. Nevertheless, for

most areas the only information currently available on the unconsolidated deposits comes from the maps and reports of the Dominion-Provincial Soil Survey.

The limitations of existing data are pointed out to emphasize the difficulties of applying present information to specific localities rather than to embarraSR the responsible

organizations. These organizations have, indeed, performed a

creditable job with limited resources and in a complex area in accumulating and disseminating information on our environmental

conditionso Nevertheless, when a new project is undertaken,

whether this be a power line or a highway through the mountains,

the establishment of a new pulp mill or a townsite, the construc-tion of a dam or the development of a new agricultural area, much additional research is imryerative in such items as snow depths, distribution, bearing strength and permeabilities of various glacial deposits, landslide and snowslide hazards, and

frost-free periods. Past experience elsewhere will continue to be a

valuable guideo Topographic and geologic maps and air

photo-graphs will still be useful tools, but new studies in the field

remain essentialo

REFERENCES

Atlas of British Columbia Resources: Map

3

(Geology);

Map

4

(Glacial geology); Map

7

(Precipitation);

Map

9

(Temperature). B.C.Natural Resources Conference

(In Pre ss ) •

Bostock, HoS·

(1948)

Physiography of the Canadian Cordillera

with Special Reference to the Area North of the

Fifty-Fifth Parallel. Geological Survey of Canada, Memoir

8

-Brink, V.C. and L.Farstad (1949) The Physiography of the

Agricultural Areas of British Columbia. Scientific

Agriculture, Vol.29, p.273-30l.

British Columbia Snow Survey Bulletins. B.C.Department of Lands

and Forests.

Chapman, J.D. (1952) The Climate of British Columbia. Fifth

B.C.Natural Resources Conference, p. 8-54.

Climate of British Columbia, Tables of Temperature, Precipitation,

and Sunshine -- Report for 1954. B.e.Department of

Agriculture.

Mathews, W.R. (1955) Permafrost and its Occurrence in the

Southern Coast Mountains of B.C. Canadian Alpine

Journal, Vol. 137, p.94-98.

Mulholland, F.D. (1937) The Forest Resources of British

Columbia. King's Printer, Victoria, B.Co

Thomas, MoKo (1953) Climatological Atlas of Canada.

Meteorological Division, Department of Transport and Division of Building Research, National Research

Council. N.R.C. No. 3151.

DISCUSSION

In reply to a question, Dr. Mathews stated that most B.G.glaciers are found in the coastal belt, the Rockies and

Selkirks and in the northern interior. These areas could be

referred to as high precipitation or high altitude areas.

ｉｾＮ Crawford asked if, in view of the large number of

freeze-thaw cycles in the Province, B.C. usually had a severe

spring break-up of roads? Mr. Crawford referred to studies

relating climate to frost action at Calgary where severe

break-up occurred with only about 15 freeze-thaw cycles. Dr. Mathews

defined a freeze-thaw cycle as daily changes based on temperature;

a change which would probably not affect roads. On this basis

Calgary would have about 90 freeze-thaw cycles each winter.

Mr. Chapman asked if Dr. Mathews would care to venture

an opinion as to whether the climatp. was warming up or cooling

down. Dr. Mathews replied that the long-term average temperatures

since 1910 have shown an increase, but since 1930$ if there is any

trend, there has been a slight drop in temperatures. Practically

9

-Dr. Mullineaux commented that measurements on Mount Rainier and the Olympic Mountains in Washington have indicated

that glaciers are advancing in recent years. This is contrary

to the trend being experienced in Europe. Dr. Mathews reported

that B.C. glaciers under observation have shown a definite slacking in the rate of retreat but no advances have been observed.

In reply to a question from Mr. Legget, Dr. Mathews

stated that he knew of no large areas of residual soils. There

could well be small deposits particularly in the higher areas. Dean Gunning reported some instances of soil showing

pre-Pleistocene weathering which was now buried by fresher deposits.

In reply to a question from Dr. Wiloon, Dr. Mathews

stated that a large post-glacial lake existed in the Peace River

country. Other lakes or groups of lakes occurred in the Prince

George and Fort, St. James area and in the Okanagan and Kamloops

districts. There are evidences of many small lakes in local

drainage areas.

Professor Baracos asked if the residual soils show

high pre-consolidation loads. Dr. Mathews replied that he knew

of no quantitive measures because, until the present, no

equipment was available by which very large pre-consolidation

pressures could be determined. He added further that at the

site of the Cleveland Dam, there was an estimated 4000 to 5000

foot thickness of ice.

Mr. Crawford asked if there was any information available

on the ground temperatures beneath a glacier. Dr. Mathews

knew of no observations in BoC. He thought the temperature

of the ground should be near the pressure melting point of ice.

For this reasong the occurrence of permafrost at the Helm Glacier

was very puzzling. ｾｨ･ depth of this occurrence was not

determined. It could have been due to pre-glacial climate or

ｾ 10

-Section 3

Soils of British Columbia by

Lo Farstad

Manuscript of this paper was not available at the time of publication.

DISCUSSION

In opening the discussion, Mro Farstad mentioned the

variation in clay content in the soil horizonso For sandy soils,

the clay content of the B horizon is higher than the A and the

Co For loam soils, the clay content is again higher in the B

horizon than the A or C with the clay content of C horizon

approaching that of the Be In clay soils, the clay content

usually increased with depth through the A, Band C horizons o

Mro Peterson questioned the author about the use of

Atterberg limits in soil survey worko Mro Farstad did not know

how extensively they were used but he had used them on soil

survey work in central BoCo Dr o Rowles added that Atterberg

limits were not used on a routine ｢｡ｳｾ but only for special

work Qr soils which presented peculiar problemso

Mro Sinclair asked about the use of Atterberg limits

in SOlL survey work; ｩｦｾ for instance, Atterberg limits are

conducted9 will the information be included on survey maps and

can the Atterberg limits be related to workability of the soil? Mro Farstad was aware of no definite relationship between

Atterberg limits and workabilityo Generally soils ｣ｯｭｰｾ｣ｴ

easily near the plastic limit and work most easily near the plastic limite

Mro Marantz asked if it was necessary to use

sulphate-resisting concrete in BoCo Mro Ripley replied that soil with

ｳｾｬｰｨ｡ｴ･ｳ was found in some of the interior valleys and in the

Fort StoJohn area o

Mro Bozozuk, referring to the figures quoted for extraction

of moisture by plant root systems, asked if this was also true

for trees o Mro Farstad replied that the figures quoted were for

grasseso Dro Haddock aaded that if trees had access to ground

waterj they would obtain the bulk of their water from ground

water supplyo

Following ｾｾｯ Farstad's paper the conference adjourned

for luncheon .at which Dr , MacKenzie, President of the University

11

-Section

4

Application of Geology to Soil Problems in the Lower Mainland

of British Columbia by

J c Eo Ar-mst.r-ong«

INTRODUCTION

The geological study and mapping of the Lower Mainland of British Columbia was undertaken because such a study can

greatly aid in the future development of the area o The proper

realization of the influence of geological conditions on

industrial and agricultural development is essential in

intelligent planning and may result in saving considerable sums

of moneyo Application of geological information in the planning

stage may indeed prevent floods, slides and other disasterso All

too often in the past such information has been ignoredo

From 1949 up to, and including, the summer of 1955 the

writer and his co-workers have been engaged in the geological investigation of the Lower Mainland of British Columbia and the adjoining Coast Mountmns for the Geological Survey of Canadao The study includes both bed-rock geology and the geology of the

unconsolidated sediments lying above bed-rock, that ｩｳｾ the

soil in the engineer1s terminologyo Geological maps and reports

are in the process of compilation and will be published by the Geological Survey of Canada, Department of Mines and Technical

Surveysy Ottawa o

PHYSICAL FEATURES

The Lower Mainland is the lowland area bordering the

Fraser River and extending from the Gulf of Georgia

80

miles

eastward o It is bounded on the north by the Coast Mountains,

on the east by the Cascade Mountmns and on the south by the

International Boundaryo The Coast Mountains rise abruptly

several thousand feet from deep U-shaped valleys9 which are

occupied by rivers, lakes, and arms of the seao The Cascade

Mountains do not concern us in this discussiono

The dominant topographic feature of the Lower Mainland is the Fraser River which occupies a post-glacial valley up to

*

Published by permission of the Acting Deputy Ministerg

ｾ 12

-3 miles wide and 50 feet deep in a much larger lowlando It

terminates in a growing delta 19 miles long and 15 miles wideo North and south of the Fraser River and comprising most of the Lower Mainland are wide, relatively flat-topped uplands

separated by wide flat-bottomed valleyse Most of these uplands

consist largely of unconsolidated materials and do not exceed 500 feet in elevation, although three bed-rock uplands exceed

1000 feeto The uplands range in size from 1 to 150 square miles o

GENERAL GEOLOGY

The geological history and stratigraphy of the Lower Mainland of British Columbia are synopsized in Table 10

Before discussing Table 1, the writer believes a few

general remarks on the terminology and types of deposits are in

ordera

The terms clay, silt and sand, as used in this ｲ･ｰｯｲｴｾ

are based on the diameter of the constituent particles and are

used as follows: clay, less than 00002 rom o, silt, 00002 to 0005

mrn o; and sand 0.05 to 2 rom o The clays and silts are composed

chiefly of rock flour produced through mechanical abrasion by glaciers, and only to a very minor extent of clay minerals formed by chemical decomposition of rock.

Of special interest are the stony, clayey ｳｩｬｴｾ and

related till-like mixtures, which are in a large part glacio-marine and to a lesser extent normal glacio-marine deposits that were laid down in the sea during, and following, the advance and

retreat of an ｩ｣･ｾｳｨ･･ｴ and during the subsequent uplift of the

lando The glacio-marine deposits are marine drifts that is,

the stones and part of the fine material were transported by floating ice and the remainder of the fine material carried by

meltwater and sea water. The somewhat similar deposits of normal

marine origin are mainly re-worked till and marine drift resulting

from submarine erosion as the land rose above the seao Mechanical

analyses of stony, clayey silts show that, exclusive of the stones,

they comprise about 50 per cent silt, 40 ppr cent ｳ｡ｮ､ｾ and 10

per cent clayo Many of these deposits are very similar in

appear-ance to true tillo

Mechanical analyses of the fine fraction of representative sample s of tills from lowland are as yielded the following average

ｲ･ｳｵｬｴｳｾ Surrey till

S7

per cent sand, 41 per cent silt, and 2

per cent clay, Semiamu till,

47

per cent ｳ｡ｮ､ｾ 45 per cent silt,

and 8 per cent clay; and SeYmour till,

44

per cent ｳ｡ｮ､ｾ 46

TABLE 1

Geological History and Stratigraphy of the Lower Mainland of British Columbia

- 13 ｾ

lNo. Group Origin Deposits

12 Salish post-glacial Beach (25 feet)

Richmond delta (700 feet plus) Marine delta (50 feet plus)

Fraser floodplain (50 feet plus) Alluvial (50 feet plus)

Swamp (35 feet)

11 Sumas post-Vashon Sumas till (25 feet)

glacial Abbotsford outwash (125 feet)

Whatcom stony clay (500 feet plus)

10 Capilano post-Vashon Cloverdale sedtments (700 feet)

marine and Bose gravel (25 feet)

non-marine Sunnyside sand (25 feet)

Huntingdon gravel (100 feet plus) Capilano gravel (50 feet)

9 Vashon last glaciation Surrey till (7'5 feet)

Newton stony clay (100 feet plus)

8 Erosion

Interval.

7 Semiamu glacial Semiamu till (60 feet)

Semiamu sediments

coarse (25 feet plus) fine (150 feet plus)

6 Erosion

Interval

5 Quadra inter-glacial Sapperton sediments (40 feet)

Colebrook gravel (85 feet)

Estuarineg floodplaing etc. (250 feet)

Point grey beds (60 feet)

4 Seymour glacial SeYmour till ｾＶＰ feet)

LInn outwash 25 feet glus}

S ster's varved clay (00 eet plus)

Glacio-marine (-)

3 Pre-Seymour sediments p:'Qbebly ｧｬ｡｣ｩ｡ｾ interglacial and Jre-glac1al origin

2 Tertiary sedimentary formations (10,000 feet plus)

14

-The unconsolidated materials vary in thickness from a few feet to 3600 feet in the Boundary Bay area.

Study of Table 1 indicates that the area was subject

to at least three major glaciations, namely: ｓ･ｾｾｯｵｲ (4),

Semiamu (7), and Vashon (9). The Seymour and Vashon glaciations

reached ice-sheet proportions during their maxima at which time they were probably 7,500 feet or more thick over the valleys. At these times the ice moved in a general southerly direction;

that is, off the Coast Mountains. Also the Semiamu ice was

possibly of ice-sheet proportions but due to later erosion, deposits of this group a'l'e so poorly preserved that a reliable

history of this ice advance cannot be pieced together.

Poat-Vashon Sumas valley ｩ｣ｾ (11) advanced westward across the Lower

Fraser Valley lowland to wi thin about

25

mile s of the Vancouver

area. This took place about 10,000 years ago.

During each major glaciation the land was depressed

relative to the sea, possibly a tnousand feet or more. During

the retreat of the Vashon ice (9), and probably during the

advance of Sumas ice (11) the ice floated and the glacio-marine Newton stony clay and Whatcom stony clay (11) deposits laid down.

ENGINEERING GEOLOGY

Adequate data on the kind and distribution of geological materials aid in solving many problems pertaining to foundation materials, sewage disposal, flood control, slides and washouts, and construction materials.

Foundation Materials

Although in the past it has often been disregarded, it is now apparent that a knowledge of the properties of foundation materials is particularly desirable wherever the stability and durability of structure may be affected by the nature of

under-lying materials. The more important properties are permeability

and drainage, stability and shearing ｳｴｲ･ｮｧｴｨｾ and workability.

Information on these properties is valuable in the design and location of buildings, roadways, airport runwaysj bridges, dams,

and playing fields. Some of this information can be supplied by

the geologist, other information must be supplied by the engineer. In areas of clay, silty clay, stony silty clay, glacio-marine till-lik'" 'mixtures, till and bed-rock, most of the drainage

is by surface or near surface ｲｾｾｦｴＬ as these materials are

nearly impervious and permit very little downward percolation

of water. Areas of sand and gravel are, however, rather pervious

and allqw much downward drainage, except where the water-table

15

-River delta. Although the tills contain relatively little

clay and a high percentage of sand, their cqmpact nature

tends to make them nearly impervious. The compaction is due

to the angularity of the fine materials and to the weight of

glacial ice beneath which the till was deposited. Even when

excavated, broken up, and used for fill or other purposes, the till soon becomes impervious due to the fines washing into and sealing the channels or cracks; if loaded it readily

becomes quite compact once more. There are many examples in

the Greater Vancouver area of drainage problems involving tills, one of the more recent being at Empire Stadium.

Of particular interest is the fact that the Surrey till and older deposits have been pre-loaded by at least

7,500

feet of ice, whereas, the post-Surrey deposits have only been pre-loaded by the weight of the sediments above

them. Consequently the Surrey till and Newton stony clay,

although very similar in appearance, behave very differently

to load; the former is, except possibly for bed-rocks the

best foundation support available and the latter9 because it

undergoes considerable comnaction under load, is one of the

poorer foundations. The very different reaction of similar

appearing materials to load is readily explainable when the origin

of the two is considered. The till was deposited under a ｧｲ･ｾｴ

weight of ice whereas the till-like stony clay was dropped

from floating ice. Fortunately for builders in the Greater

Vancouver area, in most places the glacio=marine sediments

are less than

25

feet thick and rest directly on till. East

of the Vancouver area, however, the glacio-marine and related

marine deposits are up to 500 feet or more thick.

The peat bogs of the Fraser River delta, which range

from a few feet to more than

30

feet thick, and to a lesser

extent in the uplands present probably the most obvious

found-ation problems of any of the deposits mapped. They undergo

extreme compaction when loaded and are very difficult to

drain. Hard-surfaced roads laid across these bogs tend to

develop alternating swells and depressions and deteriorate very rapidly unless the peat is excavated and where necessary replaced by fill before building the road.

With the exception of the tills and to a much Ie s

ser-extent the glacio-marine sediments all the unconsolidated

deposits found in the area are easy to excavate. In the tills

cohesion is so high in places that they have to be blasted

before being excavated. Occasionally large stones in both the

tills and glacio-marine sediments may have to be broken to be removed.

ｾ

16

-Sewage Disposal

Wherever sewage disposal is dependent on septic tanks a

knowledge of drainage and subsoil conditions is necessaryo Most

of the uplands are covered by nearly impervious to impervious

Surrey till and Newton stony clay glacio-marine deposits atJ or

within a few feet of, the surface. For all practical purposes

these materials permit no downward drainage. Where these are not

at the surface they are overlain by thin deposits of Bose gravel and Sunnyside sand, deposits that permit downward drainage

to the impervious materials underlying them. These sands and

gravels are, however, so thin that in the rainy season» the

water-table is close to or at the surface even in these permeable

depositso It is therefore evident that much of the overflow

from septic tank absorption fields in the uplands must eventually drain down the slopes by surface or near surface run-offo

Septic tank sewage ､ｩｳｰｯｾ｡ｬ systems will not onerate

satisfactorily Hhere the ground-water level is up tOg or nearly up to the absorption tile, or in areas that are periodicdlly

flooded. These conditions exist in much of the lowlands

especially the Fraser River delta. Flood Control

To combat flooding effectively along rivers by means

of diking and dredging the nature of the ｲｩｶ･ｲｾ｢｡ｮｫ and bottom

deposits must be known. Most of the diking troubles along the

Fraser River are becau6e the dikes have had to be built on

permeable sand. Consoquently, when the River is in flood and the

water-level is higher than the land behind the dike9 the

hydrostatic head developed forceB some of the water through the sand beneath the dike and dike failures have resulted from such seepage.

The streams that flow off the Coast Mountains occasionally

reach flood stages and bring destruction9 and continued erosion

in the mountains and continued floods into the valleys are to be

expectedo Except for raised delta deposits along some of the

streams most of the slopes have impervious till or bed-rock at

the surface, which allows an extremely fast surface run-off9

especially where the vegetative cover has been removed o Serious

flooding occurred in north and west Vancouver in November

1955

following excessive rainfall. Protection by vegetative cover and

topsoils check dams, and other expedients are designed to minimize

the destructive effect of these natural forceso The ｭ｡ｩｮｴ･ｮ｡ｮ｣ｾ

of the Greater Vancouver watershed north of Vancouver with regulations preventing removal of forest growth has certainly helped to prevent more serious flooding on Seymour and Capilano Creekso

17

-Landslides and Washouts

Over the years large slides and washouts have occurred in

the Lower Mainlapd area. These slides and washouts always occur

on steep slopes where the soil conditions are rendered unstable by heavy rainfall and generally excessive clearing of the land. One of the best examples of a large washout took place near the

University in

1935.

Here the sea-cliffs reveal about

150

feet

of Quadra sands and related deposits overlain by about

10

feet

of Surrey till. Following an exceptionally heavy rainfal19 a

small stream, whose banks had been cleared of most vegetation,

cut through the till into the underlying sands. Great quantities

of these sands were eroded and carried away, and by undercutting, much of the overlying impervious till also.

In other places the disturbance of the angle of repose of the sediments combined with geological conditions somewhat

similar to the above have caused slides. A knowledge of the

geology cannot prevent all such slides and washouts, but it enables many to be foreseen and if necessary precautions are taken most of these can be prevented.

AGRICULTURAL APPLICATIONS

The geological information obtained by the writer should

｡ｩｾ in the study and mapping of agricultural soils, in problems

concerning drainage and irrigation, and in outlining a source of agricultural peat.

Agricultural Soil

Modern soil classification is based upon the nature of the soil profile, which reflects the influence of the various factors of soil development including parent material, climate,

topography, organisms, time and geological environment. The

last factor is not normally considered in discussions on agricultural soils, but some writers believe that the factor

has not been emphasized sufficiently, especially the stratigraphy

and geological structure in and around a particular soil. Each

of the factors in soil development mentioned above is in itself dependent on geological history.

The geologist is most able to help the soil scientist in

his interpretation of soils by indicating the role played by

parent material and geological environment. The soil profiles

in the Lower Mainland area are poorly developed and the texture

18

-author believes that when the agricultural soils of the area are re-mapped the broad divisions of the completed soil map will show a very marked similarity to the divisions on the surficial

geological mapse

Undoubtedly very significant soil differences are to be found in soils developed from similar parent materials but in

different geological environmentso A very important factor in

these differences is changes in the deposits underlying the

parent material o For exampleg in the Fraser River delta the top

15

feet may consist of anyone of the following: all peati all

silty clay and clay; all sandg silt above peat above silty clay

and clay, peat above silty clay and clay; peat above silty clay

and clay above sand, silty clay and clay above sand, and silt

above sando The claYg silty clay and silt are impermeable; the

sand is permeable, and the peat has a very high absorptive

valueg that iSg it will store as much as twenty-six times its

own weight of water o Obviously the drainage pattern encountered

will vary greatly depending on which of the combinations described above is found and therefore the moisture and other soil=climate

conditions in the soil may show very significant differenceso

Differences in materials underlying the upland soils

also play an important role in their developmento FurthermoreD

variation in surface drainage c)nditions may result in differences

in the kind of upland soil developed from a single p2rent materialo

The geological history of the Vancouver area has greatly

｡ｦｦ･ｾｴ･､ the nature of many of the upland soils particularly

those developed on tillg and glacio-marine stony silty clays and

till-like mixtureso Following the retreat of the Vashon ice

the land rose above the sea and during. the up Ltf' t , that part of

the uplands now below 600 feetg underwent marine erosiono As a

result much of the fine material was washed out leaving a mantle of

19 -DISCUSSION

In reply to ｹｾｯ Legget,

geolGgica1 information on soils

st r e t l gr-aphy and s e dLmerrta td or, ,

not been used in the geological

Dr. Armstrong stated that

T,,TE'..S gathe r-ed t.hr-o ugh methods of

As yet engineering tests have correlations.

Dr. Armstrong, in response to ｹｾＮ McLean, stated that

many mountain valleys had artesian water conditions o Dr.

liullineaux asked to what extent local engineers and government

agencies used geological information. Dr. Armstrong said he was

encouraGed by its wide use and had had numerous requests to

report on speciel aspects of ｧ･ｯｬｯｾｹｯ

Dro Radforth asked if anyone knew of engineering

approaches to roae building over organic terrain other than its

removal. IT'o Thurber reported on a road built over peat near

Coqui.tLam , 30'_1 svrveys s howe d peat extending to a depth of 30

to

40

feet. An attempt was made to float the road across the

bogo Unfortunqtely culverts were placed on pilesg which meant

the road wculd not settle uniformly.

Professor Morrison stated that information on the density

of s oi.Ls _:culd be extreme ly valuable and sugge sted that engine ers

.:\0 not; pEy sufficient attention to the density of soil formations.

Mr. Ripley co®nented that in many instances in BoCo no

genera-lization cou:d be made on the density of a soil formation. He

cited ar Ｒｸ｡ｾｮｬ･ of the variation in depth of penetration in a

single piJ.":' groupo In such cases one could not rely on densi ty

rne82urements made frCJ:TI a sinQ"le bering or outcropo

Hr .. Hortie asked l..Jhether or not the r-eck flour referred

to posse3sed any predominant mineralo Dr .. AIT!strong replied

=

20

=

Section

.2

Agricultural Soils of the Fraser Vallez by

E. Hugnes

Soils classified by survey (1) in the Fraser Valley comprise

2f approximate total of

545,000

acres. Under this classification

there are ten series and types. While all the land in these classes

is not suitable for agricultural purposes, the descriptions of these

main groupings are as ｦｯｬｬｯｷｳＺｾ

31,454

acres (non-arable) acres

"

"

"

"

acres if

6,232

3,800

- 10,508

4,664

=

95,292

116,106

acres

(10

per cent

arable or

11

9 2 5 0 acres)

56,254

59,852

15,639

8,643

4,734

19,620

7,100

12,130

55,406

6,300

1$,502

11,267

Langley clay loam Custer loam

Kilner clay loam Haney clay

Ladner clay Monroe clay

Monroe clay loam Konroe loamy sand ronroe loam

Sub-total Whatcom silt loam Alderwood silt loam Alderwood sandy loam

Sub-total Lynden silt loam Lynden gravelly

silt loam Lynden gravelly loam

Sub=total

ｅｾ･ｲ･ｴｴ sandy loam Everett gravelly

sandy loam Everett loamy sand

Sub-total

10

20

100

In addition to t he foregoing, areas ma ppe d as complexes account for

33,116

acres, of which approximately two=thirds are arableo In

addition there are

50,890

acres of organic soils ranging from peat to

muck and from a few inches in depth to a maximum of over

25

feeta

The main division of soils correlate to a large degree with

the parent materials outlined by Dr. J. Armstrong in his geological

reporto The Monroe and Ladner series are situated on a combination

of alluvial and deltaic deposits. Intermixed with these series are

the major areas of non-marine swamp deposits or peatso These types

= 21

-The ｌ｡ｮｧｬ･ｹｾ Milner and Haney series are developed over normal

marine silty clays and siltso Bordering the edge of these soils are

a few areas of Custer series, developed over a combination of littoral

and alluvial sandso These series occur generally in the 25 to 150

feet above sea level area o

What is conmonly referred to as the "Upland area" includes the

Wha teem, Alderwood, Lynden and Everett serie so The Whatcom serie s is

developed on glacial marine silty depositso The Alderwood series9 as

classified by soil survey differs most from the geological mappingo It appears for the most part to have been developed over a glacial

till and glacial marine till-like mixtureso The Everett and Lynden

series is developed mainly over outwash sands and gravelso All the

agricultural soils occur below the 400=foot elevationo

In this paper an attempt is made to describe the soils only in general ter-ms , bringing out their agricultural potentialitieso I think there are few areas of comparable size in Canada that have

a greater variety of soils than the Fraser Valley soilso They range

from fine to coarse texture₉ very rapidly to very poorly dralned9

from acid to neutral and from marginal to highly productive o Each

have their management proble ms0

The "Upland area" can be readily broken into two ｣｡ｴ･ｧｯｲｩ･ｳｾ

excessively or rapidly dr-at.ned , and restricted or very slowly dr-aLned ,

The excessively drained soils include both the Everett and Lynden

serleso These soils consist of a shallow foregt litter (2 inches)

covering a loose sandy loam to silt loamo The subsoil is a sand or

gravelly sand, of some considerable depthv yellowish=brown horizon

8

to 20 inches thick which is freely permeable and of low moisture= holding capacityo

The restricted drainage uplands include the Alderwood and

ｖｾ｡ｴ｣ｯｾ series o The Alderwood has the greatest relief and includes

the rolling and hilly areaso Approximately 10 per cent of its area

of 1169000 acres is classed as arableo Two broad textural classes

have been ｭ｡ｰｰ･､ｾ sandy loam and silt loam underlain ｾｾｴｨ a compacted

cemented till of sands and gravelso The Whatcom topography is a

mixture of gently undulating round hills and depressionso Surface

texture is silt loam to a depth of 12 inches grading to a clay loam from 12 to 20 inches!! underlain by a cemented clay in which are

imbedded occasional stoneso Both soils are characterized by

impervious subsoils 9 a perched and moveable water=table9 and a pro=

gression of profiles related to the varying moisture condition9o The normal marine soils generally have moderately well=

developed profileso The Cuater series differs largely from the others

in textureo It has a sandy loam profile to a depth of 2 to 3 feet

= 22 ""

a forest meadow 80i19 has approximately a foot of black clay loam

topsoil of well aggregated structure grading to a ｧｲ･ｹｾ｢ｲｯｷｮ clay

overlying a dense clay similar to that underlying the Custer

ser-Les , The Haney and Milner series differ from the Langley and

Custer largely on the basis of drainage and position o They occupy

gently undulating and sloping positions as compared to relatively flat and depressional site characteristics of Langley and Custaro

Consequently they are better drainedo Milner soils range from

silty clay loam to clay loam in the surface textureo The Haney

series are generally somewhat finerIt.ex tur-e d , particularly on the

sure-face horizonso Both have subsoils similar to that of the Custer and

Langley series o

Ladner and Monroe series are developed on relatively recent

alluvial or deltaic depositso Both have flat topography and are

of insufficient age for the formation of well devoloped so11

horlzonso Many of the layers occurring in the profile tirB due to

stratification of the material as it was laid downo ThE Ladner

series mainly consists of approximately Ｖｾｩｮ｣ｨ bla ck silty clay loam

overlying varying depths of siliceous grey silty clay loam9 which9

in turnn is underlain with sands o The Monroe series differs from

the Ladtier largely by its COarser textureo The surface (0 to 6

inches) textures may be similar but the subsoila grade to 8 silty

alluvium, which in turn is abruptly underlain with sand at a depth

of approximately 20 incheso

Agriculturally the Fraser Valley soils have many

interesting features 0 Generally they are acid in r-ee ct i.on , low

in exchangeable bases and readily available nutrientso All pH

values below 300 have been recorded in Valley peat30 Tn ｧ･ｮｾｲ｡ｬ

the pH values in mineral soil ranges from about 600 to a low of

4000 This latter condition is associated wi:h poor" dr-a rnage ,

The solls as a group respond readily to liming" manurial and fertilizer application and when properly mana ge d , have a high

productiv» capac i ty0 Soil type of c ourseｾ determine s in. scme

instances the crops that Can be grown" but there is ample avidence to show that fertility response is dictated more by crop than by soil

type 0 However" within each ｴｹｰ･ｾ several phases or d13tinctions

based on practical considerations are apparento These phase5

bring out the complexi ty of the types and furnish tnror-ma

s

ion

relative to their na t.ur-e , suf t.aotLf.ty , limitations and management

. r-e quLr-emerrt s0

The Everett and Lynden series being open and porous have a

very low moisture=holding capaciJ:;yo With the exception of the

Lynden silt loam and without irrigation these 30ils are marginal

for agr-Lcu'l,t ur-e0 Even so9 Lynden silt loam is limited to t he

production of early rna tur-Lng crops such as atr'awberrie s or early

potatoes and require ::lupplemental water for other crop'=lo These

soils require addi tiona 1 moisture to carry C1:"OPS through to maturi tyo

=

23 ...

heavy aopLi.ce tdcna being conduc i ve to exce ssi ve leaching of pla nt

nutrients and erosiono Manager practices, which accelerate organic

matter ､･ｰｬ･ｴｩｯｮｾ further enhance this problemo

Alderwood series soils are also of limited agricultural

value 0 The porous top soils show a favourable non=capillary porosity

(which is

15

to 20 per cent by volume) but the Lmper-vI oua substratum

of cemented sands and gravels is, for practical purpcsesy impervious

to ｾ｡ｴ･ｲ and rootso Concentrated roots have been seen to depths

of 1 1/2 to 2 inches on this hardpan layer 0 The net ef'f'e ct,

agriculturallYD is that these surface soils permit rapid percolation

of moisture to the hardpan depthv from which point further movement

occurs only laterallyo Tap-rooted plants such as strawberries

and clovers will not tolerate this ｣ｯｮ､ｬｴｩｯｮｾ especially where

the impervious substratum is close to the surfaceo Grass species

and shallow-rooted crops could thrive except for the fact that

our summer ｲ｡ｩｮｦ｡ｬｬｾ which averages between 1 and 2 inches per

month9 is inadequate to maintain a constant supply of soil moistureo

The ｷ｡ｴ･ＡＢｾｨｯｬ､ｩｮｧ capacity of the soil to hardpan depth is Lnsuf'f'd«

ci.ent to carry general crops through a season when Bummer dr-ought

occurso These two ｦ｡｣ｴｯｲｳｾ summer drought and the impervious sub=

st.r-a t.um, are definite limiting factors militatir.g against the

complete utilization for arable agricultureo They assume more

importance in the utilization of Alderwood series when it ｩｾ

recalled that only 1 per cent of the total acreage 1s topographi=

cally suitable for agricultureo

The other upland member with restricted ､ｲ｡ｩｮ｡ｧｾＹ ｾｾ｡ｴ｣ｯｭ

s11t Lcam ; is of greater agricultural value than the Alderwood o It

has e. higher ｭｏｬｳｴｵｲ･ｾＬｨｯｬ､ｩｮｧ capacity in the top soil and Ls thus

able to wi &h5tar_d summer dr-ought. to a much gl"'eater degr-ee0 It toe11

however.' has ar... impervious subsoil (gener'slly oc cur-ring at greater

depth) making the necessity of adequate ､ｲ｡ｩｮ｡ｧｾ 1mperatlv8o I

he"'6 SN='!1 Bog r-ush . (Junella effusus) growing on a h:1.1l side of the

Wh.atc.om aerre s , Th15 illustrates the need for ｡｣ｾｱｵ｡ＧｴＲｩ drainage

even on s1.cpn.g Larid , There is also much of the Wha1,;·GOYn occupying

｢ＸＸｩｮｾｬｩｫ･ de pr-easLons and these depressions de nc; z-eadILy lend

themselves to dralnageo

The foregoing remarks may be applied in part to the Langley9

Haney and Custer aeries", and, to a somewhat Les ser- ex rent , to

Milner soils0 In gene r-aL, these soils all r-equi re a de quat e

drainage> for maximum pr-oduc td on , Growth in poorly dr-a Ine d fields

i8 often retarded weeks in the early springo Excessive ｭＰＱｳｾｵｲ･

produces a cold poorly aerated soil with properties unfavourable

to gr-owLng of crops common to the area0 Then." r-at.he r ironicallY!J

5ummer drought ｮ･｣ｾｳｳｩｴ｡ｴ･ｳ irrigation during late 5ummer'1I espe0ially

in pa s tur-e s C!' msadows where the maintenance of growth is e sserrt Le.I

f'or: high pr-oducti;vi tyo If fields of these soil type03> are adequately

drained a::ld properly managed they compare favourably inr:.rop

The Monroe and Ladner classes, can, I believe, be classed

as the most productive soil serieso Th9 Monroe, due to its

generally coarser texture, lends itself to a greater variety

of crops; climatically it is characterized by a slightly higher

summer rainfall and higher summer temperatures than Ladner, thus

permitting a greater variety of crops to be grown, eogo corn and

hopso .

Natural drainage in Ladner series is generally much

slower than in MonroeQ This is due largely to particle size

distributiono Generally, the Ladner soils contains

50

to

60

per

cent silt, and when distributed compacts readily with the formation

to a plough sole or tillage pano In its natural state weakly

developed structures are lacking and the A, (0 to 6 inches)

containing some organic matter, has a natural non-capillary

porosity varying from

6-15

per cente The C horizon is massive

and mottled and has a non-capillary porosity of ＳｾＶ per cent

by volume (2) Ladner soils generally have a high moisture holding capacity, but due to location the extreme portion around Ladner

Village suffers from summer droughto Rainfall distribution

during the summer in this area is the lowest for any section of

the Valleyo Since dairying is the major enterprise» late summer

pastures are definitely moisture deficientQ

These remarks, of course, do not apply to the Ladner

series of the more easterly Pitt Meadows ｲｾｧｩｯｮｯ Continuous

high water-table accented by poor general drainage of this area,

lowers the productivity of this fertile solI typeo At present,

unless more main ditches and pumps are installed in the larger

section of this region9 farm drains cannot function properly and

c.rops will suffero With adequate drainage9 however9 these soils

have as high a productivity potential as any other part of the

La dner- ser-aes , .,

Associated with the Ladner and to some extent the Monroe

ser-Les , are large areas of organic depo st t s , They are generally

all sphagnum moss type and form t he basis for CanadaI is large st

commercial peat harvesting operationso The peat originally is

very strongly acid and ｲ･ｱｵｩｾ considerable drainage and liming

before they can be croppeda Once these factors are overcome they

have proved to be our largest vegetable producing acreagsg

especially in the ｃｬｯｶ･ｲ､｡ｾ Mud Bay regiono A characteristic

of these acid peats ia a high moisture holding capacity and the

need for heavy fertilization of phosphates and potasho

Further-more9 once they have dried out, they take up water slowly and

I have tried to point out in very general terms the

agricultural soils of the Fraser Valley and t he problems related

to these 80i18 0 I believe you will agree that a major portion

requires a combination of adequate area drainage, and farm drainage, to remove excess water occurring naturally or in the

form of precipitation. Summer irrigation to compensate for

the lack of rainfall during the dry period, along with good management practices are necessary for maximum productivityo REFERENCES

(1) Soils Survey of the Lower Fraser Valley. CoCo Kelly and

R.Ho Spillsbury.

(2) Thesis Data. Soils Department, Faculty of Agriculture.

University of British Columbia. DISCUSSION

In answer to Mr. Chapman, Mr. Hughes reported that most

effective drainage was through tile drains. Some of the older

farms used cedar box drains for drainage.

In reply to Mr. Thrussell, Mr. Hughes thought that about

150,000 acres out of 545.000 acres in the lower mainland were not potentially arable.

Mro Trow asked if there had been any difficulties with

the ､･ｴ･ｲｩｾ｡ｴｩｯｮ of concrete drain pipes and foundations due

to the presence of peat. Mr. Hughes answered that although no

serious trouble was reported, concrete pipe was not recommendedo

No foundation difficulties were known because most farm bUildings

were built on higher ground and hence not in peat areaso

Dr. Mathews inquired about the amount of settlement that

results from the drainage of a peat bog. Mr. Hughes had no direct

figures but he thought that the figure of

4

feet over a period of

25

years would not be far wrong.

Mro Hortie asked if daily tidal variations caused

fluctuations in the ground water table in low lying areas. Mro,

Hughes reported that water levels in the ditches certainly were

affected. Mro Armstrong reported that the ground water table in

26

-Section

6

Foundation Conditions and Problems - Vancouver» BoCo by

P"Mo Cook and Lo Brandon

The first part of this paper will deal with geological conditions and the effect they havp upon building foundations

and other problems associated with buildingo The second part

of the paper will consist of a few examples to show that soil conditions themselves do not entirely govern the problems to be

met9 10eo that artificial conditions such as building regulations

and othersp have a great effect in creating problemse So far

as foundation conditions are concerned9 probably the best method

of getting a ｱｵｾ｣ｫ general appreciation of the Vancouver area is

to recall the paper by Dre Armstrong given earlier in this sessiono

To summarize this paper-, br-Le f'Ly , the Vancouver area can

be broken down into three zoneso On the north shore we have the

granites of tbe coast range, which in places come down to

tide-water-, Second we have the glacial till., overlying other materials,

but rendering them densec This till covers parts of north and

west Vancouver, and extends virtually over the entire area of

Vaneouver- and underlies the alluvials of the Fra ser Hiver and

comes up again at Point Robertso The third element in the

Vancouver area are the alluvials of the Fraser,·: Coqui tlam and

Pitt Hi ver-S0

Each of these areas has its own particular problemso Ir the Case of the rook this enters into such a small percentage of' the potential industrial land as to not be of much consequence" One problem in connection with this is that in regions where this comes down to tidewater it presents a severe problem in the

construction of docks in that it is difficult to get enough grip

for piles to hang on to the steep slopes o The ｮ･ｸｾ ｡ｲ･｡ｾ that

is the area chiefly occupied by glacial til19 presents a few

pr-ob Lems , The till of course is an excellent foundation mat er-La L,

It has a density varying between 125 to 145 on a wet basis with

moisture content ranging from

9

to 15 per cent depending on clay

contento The clay in this till is very low ｩｮ､･･､ｾ on the order

of 2 to

8

per cento This permits very high bearing loadso There

are buildings in Vancouver which use loads as high as

7

tons per

square ｦｯｯｴｾ although normal practice is somewhat lesso

Another characteristic of the till is that it is rather

expensive to excavateg This can be appreciated in the foregoing

remarks0 ｈｯｷ･ｶ･ｲｾ it stands well in vertical cuts and there