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ONTARIO DEPARTMENT OF MINES

HON. Allan F. Lawrence, Minister of Mines D. P. DOUGLASS, Deputy Minister J. E. THOMSON, Director, Geological Branch

Pleistocene Geology and Ground Water Resources Township of Etobicoke

York County

By A. K. WATT

Geological Report 59

TORONTO 1968

Crown copyrights reserved. This book may not be reproduced, in whole or in part, without the permission of the Ontario Department of Mines.

Publications of the Ontario Department of Mines

and price lists

are obtainable through the

Publications Office, Ontario Department of Mines Parliament Buildings, Toronto, Ontario, Canada.

Orders for publications should be accompanied by cheque, or money order, payable to Treasurer of Ontario. Stamps are not acceptable.

2,000—E23—1968 iti CONTENTS

PAGE Introduction. Introductory Remarks...... l Scope of Report...... 2 Ground Water Survey...... 2 Pleistocene Geology...... 3 Acknowledgments...... 3 Literature...... 3 History of the Development and Utilization of Ground Water for Municipal Purposes.. 4 Township of Etobicoke...... 4 Police Village of Thistletown...... 4 Geography...... 6 Topography and Drainage...... 6 Climate...... 6 Population...... 6 General Geology...... 7 Bedrock...... 7 Overburden...... 7 Pleistocene Deposits...... 8 Glacial...... 8 Interglacial...... 8 Illinoian Stage...... 8 Sangamon Interglacial Stage...... 9 Wisconsin Glacial Stage...... 9 Till Deposits...... 9 Ground Moraine...... 9 Mechanical Analyses of Tills...... 14 Glacio-fluvial Deposits...... 14 Stratified Clay and Silt...... 14 Stratified Sand and Gravel...... 16 Glacio-lacustrine Deposits...... 16 Stratified Silt, Sand and Gravel...... 16 Glacial Lakes...... 16 Recent...... 17 Vertical Sections...... 17 Section A - A©...... 17 Section B - B*...... 18 Section C - C©...... 18 Ground Water...... 19 Source, Storage, and Movement...... 19 Water Well Data...... 19 Occurrence of Ground Water in the Bedrock...... 19 Occurrence of Ground Water in the Overburden...... 21 Observation Well...... 21 Quality...... 25 Chemical Analyses of Well Waters...... 25 Residue on Evaporation...... 25 Calcium (Ca) and Magnesium (Mg)...... 25 Sodium (Na)...... 26 Sulphate (SO4)...... 26 Chloride (CI)...... 26 Silica (SiOz)...... 26 Iron (FeiOit) and Aluminium (AljOi)...... 27 Alkalinity as CaCOs...... 27 Hardness...... 27 iv PAGE Utilization...... 28 Domestic and Stock...... 28 Commercial and Industrial...... 28 Irrigation...... 28 Public Supply...... 28 Summary of Ground Water Conditions...... 29 Appendix A Water data for drilled wells...... 31 Appendix B Summary of dug well data...... 44 Selected References (see Literature, p. 3) Index...... 49, 50 Tables 1 Mechanical analyses of selected samples of till...... 12 2 Summary of drilled well data contained in Appendix A...... 20 3 Chemical analyses of well waters...... 24 Photographs 1 Pleistocene section on the West Branch of the Humber River...... 2 2 Dundas shale and limestone, West Branch of the Humber River...... 7 3 Illinoian till, Lake Ontario shore bluff, Long Branch...... 9 4 Weathered granite boulder in Wisconsin till, Long Branch...... 10 5 Glacio-fluvial sand and gravel, Ellins Construction Company Ltd., Scarlet Road, near Weston...... 15 6 Glacio-lacustrine sand and silt, Martin Grove Road, near Township of Etobicoke Water works plant...... 15 7 Observation well shelter near Township of Etobicoke Waterworks plant...... 22 8 Automatic instrument for recording ground water levels...... 22 9 Pump-house over one of municipal wells, Town of Weston...... 29 Figures 1 Key map showing location of map-area...... vi 2 Graphs of temperature and precipitation data for Toronto...... 5 3 Trilinear chart showing results of mechanical analyses of tills...... 11 Geological Map and Charts (back pocket) Map 2111 (coloured) Pleistocene geology of Etobicoke township, southern Ontario. Scale, l inch to J^ mile. Chart A Location of water wells, and bedrock contours. Scale, l inch to J^ mile. Chart B Vertical sections showing Pleistocene stratigraphy. Horizontal scale, l inch to J^ mile; vertical scale l inch to 100 feet. Chart C Hydrographs of water levels in observation well No. 304. Figure!—Key map showing location of map area PLEISTOCENE GEOLOGY AND GROUND WATER RESOURCES

TOWNSHIP OF ETOBICOKE York County Ontario

BY A. K. WATT1

INTRODUCTION INTRODUCTORY REMARKS

This is the second in a series of reports dealing with the ground water resources of townships where special ground water problems exist. The Township of Etobicoke has an area of approximately 50 square miles and is situated in the southwest corner of York County. It is bordered on the east by the Humber River, and on the west by the Etobicoke Creek and Toronto township; it extends from Lake Ontario in the south to Vaughan township in the north. The built-up areas along the lakeshore and adjacent to the Humber River have used lake-water from the New Toronto waterworks system for many years. Prior to 1923 all the residents of the township areas were dependent on individual wells for their water supply. Since then, a gradual extension of areas serviced by lake-water, and the establishment of a waterworks system supplied by deep wells north of Islington, have been used to supply water to the residents of the township. The water supply was generally adequate until the period immediately following World War II when the rapid increase in residential and industrial growth caused an acute water shortage to develop. A test-drilling program designed to locate additional ground water supplies was unsuccessful, and by the winter of 1953-54, Metropolitan Toronto Corporation took over the manage ment of the township waterworks system with lake-water completely replac ing the well water in off-peak periods. A more detailed description of the waterworks plant and well system is given briefly in historical notes in this report. Ground water data on 1,160 wells assembled in this report are intended to be of help to the great many home-owners and others in the township to Pleistocene Geologist, Ontario Department of Mines, Toronto. Manuscript received by Chief Geologist, April 1956. Etobicoke township

ODM7608 Photo l—Pleistocene section on the West Branch of the Number River in which three, and possibly four, tills are exposed. The occasional large boulder, found near the base of the section, marks the line of separation between Illinoian and Wisconsin drifts.

whom the municipal water supplies are not available. The majority of these home-owners have to use ground water. The locations and particulars of wells listed in this report will give some idea of ground water conditions in various parts of the township. The most likely areas of large yields of ground water are indicated on the bedrock contour map. Although surface water is being used more extensively for municipal purposes, the availability of ground water in the more remote parts of the township, and as an alternate source of water supply to lake-water in cases of emergency, is of considerable importance.

SCOPE OF REPORT Ground Water Survey A detailed survey of the ground water resources of the Township of Etobi coke was carried out during June and July in 1948. Investigations made inter mittently in the township from then until 1955 have yielded considerable additional hydrological information. The water-well data were obtained partly by a house-to-house survey, which provided a rather general ground water picture, and partly from water- well records filed with the Ontario Department of Mines by drillers. The information gained by drilling proved to be more reliable and formed the basis for much of the control data needed in contouring the bedrock surface. The surface elevations of wells ending in the bedrock were obtained mostly by telescopic alidade or transit. A few were obtained with a surveying aneroid. Pleistocene Geology

All excavations for large buildings, road cuts, river sections, and lake cliffs were studied to obtain as much information as possible on the Pleistocene geology of the area. A pick and shovel were the regular tools used. A hand auger was also employed to determine depths of certain surficial deposits in areas where good exposures were lacking.

ACKNOWLEDGMENTS

The author is indebted to members of the township engineering staff, especially W. Swann, Township Engineer, S. W. Evans, formerly superinten dent of the waterworks plant, and S. Parker, the present waterworks super intendent. These men provided maps, well data and regular supervision and assistance in measuring water levels in the observation wells near the pump- house. The co-operation of the township residents, water-well drillers, and drilling firms who supplied well data is gratefully acknowledged. Field assistance was ably provided in 1948 by S. A. Forman, F. T. Clifton, H. A. Gorrell, and J. G. MacDonald; in 1952 by J. Cody and D. G. Colclough; in 1954 by J. B. Mcclellan; and in 1955 by L. Fraser and W. Schoonhoven. The chemical analyses of well waters and the mechanical analyses of soil samples were done by members of the Provincial Assay Office, Department of Mines, Parliament Buildings, Toronto. Acknowledgment of appreciation is extended to A. D. Margison and Associates Limited and James F. MacLaren Associates for copies of test boring data near the mouth of the Humber River.

LITERATURE

A selected list of literature dealing with the geology of the general area and ground water information in adjoining townships is given below: Caley, J. F. Palaeozoic geology of the Toronto-Hamilton area, Ontario; Geol. Surv. Canada, Memoir 224. (Published 1940) Chapman, L. J., and Putnam, D. F. The physiography of Southern Ontario; Ont. Research Foundation, Toronto. (Published 1951) Coleman, A. P. The pleistocene of the Toronto region; Ont. Dept. Mines, Vol. 41, pt. 7. (Published 1932) Hainstock, H. N., Owen, E. B., and Caley, J. F. Ground water resources of Toronto Gore Township, Peel County, Ontario; Geol. Surv. Can., Water Supply Paper No. 289 (Published 1948) Hainstock, H. N., Owen, E. B., and Caley J. F. Ground water resources of Vaughan Township, York County, Ontario; Surv. Can., Water Supply Paper No. 287 (Published 1948) Etobicoke township

HISTORY OF DEVELOPMENT AND UTILIZATION OF GROUND WATER FOR MUNICIPAL PURPOSES

Township of Etobicoke The Township of Etobicoke was incorporated in 1850 and until 1923 the residents obtained their water from individual wells. From 1923 until 1932 water services were developed in the more populated parts of the township with most of the water purchased from New Toronto and minor amounts from Weston. After a serious water shortage developed in 1931, a water works plant was put into operation in November 1932, with a supply of water available from three drilled wells. The wells were located in the valley of Mimico Creek near the waterworks on Martin Grove Road north of the Village of Islington. The iron content of the water was about 1J^ parts per million; the hardness of the water was equivalent to 320 parts of calcium carbonate per million. In order to remove some of the iron and hardness from the water, a zeolite soften ing plant was installed. The hardness of the well-water was reduced by this process to about 80 parts per million, and the processing eliminated at the same time most of the undesirable content of iron from the water. Over a period of years the original hardness of the well-water rose gradually from 320 to 420 parts per million. In 1941, additional water treatment was introduced. A small amount of sodium hexametaphosphate was added to the water to fix the iron in a soluble state. This supplemental treatment has been continued to the present. A fourth well was added to the system in 1946 to meet the needs of the steadily increasing population. As the demand for water increased, and the capacities of some of the four wells decreased or deteriorated to an extent that they were abandoned, three additional wells were subsequently completed, one in 1947, 1949, and 1950. The wells were unable to supply all the water needed, however, and during the winter months bf 1953-1954 they were abandoned in favour of lake-water as the regular source of supply. The water was purchased from Metropolitan Toronto Corporation through the New Toronto waterworks system. Four wells were operated during the summer months of 1954 and 1955 in peak demand periods. At such times they supplied close to 3J^ million gallons of water during an 18-hour pumping day. The municipal wells are thus being used in case of emergency or water shortage.

Police Village of Thistletown In 1948 and 1949 ten test holes were drilled near Thistletown to obtain a water supply for the village. All but two of these were located near the Humber River. Only the last test hole drilled was recorded in Appendix A and shown on Chart A as number 300. It was developed as a well and used by the village until 1953 when the Township of Etobicoke took over its operation. The well was abandoned, except as a stand-by unit, in October 1954, when lake-water was supplied to the residents through the township system. The well was operated along with the other township wells during the summer months of 1955 to supply peak load demands. ^-^* ^~"~~-^,^ O.D.M. 1612 60 s "\ 50 S N. Yearly Mean 45.90 S \ 40

30 X \

irt ^ \ Average Monthly Temperature over 70 Year Period

JAN FEB MAR APR MAY JUN JUL AUG SEPT OCT NOV DEC

f f /3 year period Monthly Precipitation

Figure 2—Graphs for temperature and precipitation data for Toronto. Information obtained from the Meteorological Division, Department of Transport, Ottawa. Etobicoke township GEOGRAPHY

TOPOGRAPHY AND DRAINAGE The Township of Etobicoke varies in width from 4 to 5 miles near Lake Ontario to 3 miles at its north boundary and is a little more than 12 miles long. The southern quarter of the township is a lake plain, sloping from the glacial Lake Iroquois shoreline near Dundas Street to Lake Ontario. The elevation of the ancient shoreline is slightly over 400 feet while Lake Ontario is about 246 feet above sea level. A modest cliff is usually present above Lake Ontario standing 5 to 15 feet above a narrow beach composed mostly of limestone shingle. In a few places a sandy beach has formed, usually in the vicinity of the mouths of rivers. The lake plain is composed of a veneer of sand and clay over till. The over burden has a thickness in the range, generally, of 5 to 10 feet. In a few places, however, a much greater thickness of drift is present indicating that bedrock valleys of greater or lesser magnitude are present in the township or adjacent to its borders. Above the Iroquois shorecliff a flat to gently undulating till plain rises gradually to an elevation of 575 feet above sea level. The till plain is dissected by the following creeks and rivers and their tributaries: Etobicoke Creek, Mimico Creek, Humber River, and the West Branch of the Humber River. All the streams are youthful, with rapids and small waterfalls present where bedrock outcrops in their courses. The drainage is in a southerly to easterly direction. The summer flow is gentle but floods may build up quickly particu larly after the spring thaw because there are few sandy or wooded areas on the clay till plain to retard run-off.

CLIMATE Temperature and precipitation conditions in Toronto are described here. They should not be too different from those within the township. The mean annual temperature at Toronto based on a 70-year period was 45.9 degrees Fahrenheit.1 During 1955, the mean temperature was 49.20F. The average monthly precipitation at Toronto varies between 2 and 3 inches. During a period of 105 years, the annual precipitation averaged 32.05 inches. In 1955, the total precipitation was 32.14 inches. Figure 2 shows graphically average temperature and precipitation figures for Toronto along with the monthly greatest and least amounts of precipita tion over various periods.

POPULATION In 1923 when water services were supplied to some of the more heavily populated areas, the township had a population of 12,594. In 1940, it was 17,684. Between 1945 and 1950 the population increased from 22,686 to 44,137. There was an average annual increase of approximately 10,000 each year until 1955 when there were 93,997 people in the township. Annual Meteorological Summary, Toronto, Ontario, 1954, Dept. of Transport, Meteorological Division, Toronto. ODM7610 Photo 2—Interbedded shale and limestone of the Dundas formation, West Branch of the Humber River.

GENERAL GEOLOGY

BEDROCK Interbedded shale and limestone of the Dundas Formation outcrop in the valleys of all rivers in the township. The bedrock is exposed in many places along the shore of Lake Ontario between the mouths of the Etobicoke and Humber Rivers where it has been eroded into vertical bluffs up to 7 feet high. In the southern part of the township the shale is usually close to the surface and is often reached in road and building excavations. North of the Dundas highway the overburden is thicker and bedrock outcrops are usually confined to the river valleys. The Dundas Formation has a maximum thickness of several hundred feet. There is a regional dip to the southwest of about 25 feet to the mile. This formation and other bedrock formations of the region have been described by Caley1 . OVERBURDEN Most of the overburden is composed of Pleistocene deposits which were mostly laid down under great thicknesses of ice or in the glacial rivers and lakes associated with them. The ice masses were continental glaciers that flowed from centres in northern Ontario, Quebec, or Labrador. 1J. F. Caley, "Palaeozoic Geology of the Toronto-Hamilton Area, Ontario", Geol. Surv. Can., Mem. 224. Etobicoke township

The area has been covered by continental glaciers during at least two separate periods in the past million years. Although three or four tills are some times recognized, only meagre evidence of an interglacial period other than the present has been found in the township.

Pleistocene Deposits GLACIAL The deposits formed by a continental glacier may be classified into two groups: 1. those deposited by the ice itself forming a till which is mainly un sorted by water action; 2. those formed by melt waters associated with the glacier resulting in various types of stratified deposit. Till is usually a mixture of clay, silt, sand, gravel, and stones of all sizes. It may be composed, however, mostly of any one of these materials. It is identified by an absence of horizontal layering or stratification, which character izes materials deposited by water. At least three till sheets were recognized in the township. The lowest one was Illinoian or older in age and the others probably all Wisconsin. They are subsequently described here in more detail. The stratified materials, clay, silt, sand, and gravel, of glacial origin, were deposited above, in front of, or beneath the ice masses when they were melting. Outwash sands and gravels deposited in meltwater streams flowing off the glacier are referred to as glacio-fluvial deposits. Stratified clays, silts, and sands, which were formed in glacial lakes ponded between the glacier and higher land, are called glaciolacustrine deposits. These deposits often show varving, which means that there is a repetition of pairs of layers within the deposit. The sediment in a pair of layers may be composed of fine and coarse clay, or clay and silt, or clay and sand. The separa tion into the fine and coarser part in a varve is generally considered to be the result of alternating cool and warm temperature conditions affecting the rate of melting of the glacier. Varved deposits are sometimes limited in extent. Because extensive glaciolacustrine deposits would be likely to precede and follow any major ice invasion of the area, their presence is helpful in deter mining boundaries between till sheets.

INTERGLACIAL Evidence of a previous interglacial period was scanty. In foundation exca vations for the new market buildings in the Humber Bay area, fragments of small shells and pieces of reeds and stems occurred in sands and silts that were rather contorted in places and could have been glacio-fluvial in origin rather than interglacial. The Pleistocene deposits of the township are shown on Map 2111.

ILLINOIAN STAGE Overlying the shale bedrock in many parts of the township area is a tough blue-gray clay till with numerous stones of igneous and sedimentary origin. 8 ODM7611 Photo 3—Fragments of limestone and shale in Illinoian till. Lake Ontario shore bluff. Long Branch.

The sedimentary stones are principally pieces of the hard sandy limestone layers of the underlying bedrock. Shale fragments are also plentiful. The till is sometimes lacking entirely but is usually present in thicknesses of one to four feet. The upper foot or two is occasionally weathered to a greenish-grey colour. This till is considered to be Illinoian by the author. It may be seen readily above the bedrock in many places along the shore of Lake Ontario or above the shale in river exposures.

SANGAMON INTERGLACIAL STAGE

No conclusive evidence of an interglacial period was found in the sections observed in the river valleys or along the lakeshore. However, small amounts of peaty material were seen in stratified sands above a brown, silty till in foundation trenches of the Ontario Food Terminal at the Queensway near the Queen Elizabeth Way. It is possible that this material was reworked from the original interglacial deposit situated elsewhere in the Toronto region during an interstage of the Wisconsin glaciation.

WISCONSIN GLACIAL STAGE Till Deposits

Ground Moraine. Most of the township lying north of Highway 5 is a flat or gently rolling plain where it is not affected by river dissection. This type of plain is called ground moraine. The uppermost material is chiefly a stony clay Etobicoke township

Photo 4—Granite Boulder in Wisconsin till, lake bluff at Long Branch. Weathered annular ring is approximately 4 inches wide. or till. In some parts of the area, however, this till is overlain by, or interbedded with, a variable thickness of varved clays that were deposited during the final ablation of the ice. Where the stratified clays occur, they seldom exceed two or three feet in thickness but they usually contain pebbles which give the deposit a till-like appearance. In the accompanying Pleistocene Map 2111 (back pocket) the veneer of stratified clays has not been shown as a separate map unit, partly because of the irregular occurrence of the clays, and partly because it is often interbedded with the till and cannot be readily separated from it for mapping purposes. Three till sheets of the last, Wisconsin, glaciation are found in the town ship. They are rarely all in one section, but, through the correlation of nearby exposures, the separation of tills into three divisions can be made with some degree of confidence. The most complete sections are found along the West Branch of the Humber River east of Highway 27. The lowest Wisconsin till is sometimes lacking here but it can be recognized most readily where it is asso ciated with the underlying older Illinoian till in the sections along the shore of Lake Ontario. The till sheets are usually separated from one another by a bed of stratified clay, silt, or sand of variable thickness. Sometimes the one till lies directly on the older one. Occasionally, a concentration of boulders, a boulder pavement, is present. In general, the lowest Wisconsin till appears as a buff-weathering silty till with or without pebbles. Occasionally, it is a pink or mauvish colour. In the northern part of the township it is greyer in colour and appears to be sandier. Its maximum observed thickness was 12 feet. The middle Wisconsin 10 -90 A Uppermost Wisconsin

B Middle Wisconsin

9 Lowest Wisconsin -80 tt Illinoian

-GO

%Clay

o'o

Figure 3—Trilineor chart showing results of mechanical analyses of tills. The position of each sample on the chart is dependant on the percentages of clay, silt, and sand in it.

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13 Etobicoke township

till is a grey to brown, dense to friable, sandy till. It had a variable thickness up to 20 feet. The upper till is a dark-grey to brown stony clay till with occa sional sand lenses and partially "modified" till till interlayered with varved clays. The thickness of the upper till sometimes exceeds 30 feet. Most of the southern part of the township below Highway 5 is a lake plain largely moulded by waters of Lake Iroquois and subsequent glacial lakes. Much of it is covered by a relatively thin layer of lake sands, but most of the southern part of the lake plain has a till surface. The lowest and middle Wisconsin tills and the Illinoian till are all recognized in this area, especially the last two, because the bedrock is generally only 5 or 10 feet below the surface.

Mechanical Analyses of Tills. Mechanical analyses were made of a number of till samples to determine whether or not the till sheets could be separated readily on the basis of their constituent particles. Table l lists the results of 12 of these analyses. No sample was taken of the middle sandy Wisconsin till but, for the sake of comparison, the results of one middle Wisconsin till from the adjoining Township of North York was included along with an Illinoian till from the Don Valley Brick Yards, Toronto. With the exception of these two tills all the samples were collected in the township. A trilinear chart in Figure 3 shows the groupings of the tills on a basis of the percentage of sand silt and clay com position. The oldest identified till, the Illinoian, shows a remarkable consistency in analysis. It is very sandy, and low in silt. It could be described as a clayey sand-till. The lowest Wisconsin till samples were all collected in the southeast part of the township above variable thicknesses of stratified silts and clays. This till is, consequently, very high in silt and clay and may be termed a clayey silt-till. The middle Wisconsin till was readily observed in many sections throughout the township as a sandy sil t-till. It often exhibited a schistose fabric that seemed to be characteristic of the till sheet. Sample No. 4 in Table l was collected in an adjoining part of the Township of North York. The upper till is a sandy, or silty, clay-till. It has less silt and sand but a higher clay percentage than the same till in North York Township to the east. This is probably due to the fact that the final advance of the Wisconsin glacier took place over more silt and clay beds in the Etobicoke township area than it did in North York township where it overrode extensive interstage sands at higher elevations.

Glacio-fluvial Deposits

Stratified Clay and Silt. Stratified clay and silt are found in several parts of the township interbedded with the till. They are most extensive in the Humber Bay area where they are overlain with fine sand. The complete section has not been exposed here, but it probably has a maximum thickness of 15 feet. Elsewhere, throughout the township, the stratified clay and silt layers seldom exceed 5 feet in thickness. The Humber Bay silts and clays are part of a deltaic deposit formed in ponded glacial waters when the glacier had melted back from the area. After fine sand and a little gravel were added to the delta, the whole deposit was over- 14 ODM7613 Photo 5—Glacio-fluviol sand and gravel, Ellins Construction Company Limited. One of several pits that have been operated more or less continuously by different companies in the Number Valley area, south of Weston.

ODM7614 Photo 6—Glacio-lacustrine sand and silt overlain by 20 feet of till, Martin Grove Road near Township of Etobicoke Waterworks Plant.

15 Etobicoke township ridden by the ice, leaving a cap of sandy till. This till has been removed in most places by subsequent lake, stream, and human agencies.

Stratified Sand and Gravel. Sand and gravel layers of variable thicknesses occur between the different till sheets. The thickest deposits are adjacent to the Humber River between Lambton Mills and Weston suggesting that their origin was likely associated with a river or bay during intervals between sub- stages of the Wisconsin glaciation. Dissection by present and earlier streams has revealed the underlying sands and gravels that have been, and in a few places still are being, worked as sand and gravel pits. The deposits are usually fine to medium sand with small amounts of gravel. One section on the west bank of the Humber River at Thistletown revealed 36 feet of sand and gravel overlying 14 feet of fine sand and silt and capped with 15 feet of clay till and sand. Following the final retreat of the last glacier, river and lake sands were built up in the estuary of what has now become the Humber River. In places, between Lambton Mills and Weston, these sands lie directly on top of interstage sands.

Glacio-lacustrine Deposits

Stratified Silt, Sand, and Gravel. Some of the stratified materials interbedded with the tills may have been associated with lake rather than river action. The most obvious deposits formed in glacial lake waters are found near the ancient Iroquois shore line or at lower elevations. They are chiefly sand with minor amounts of gravel and silt which form a thin veneer over much of the lake plain south of Highway 5. The lake sands occasionally exceed 10 feet in thickness but are usually less than 5 feet thick. The sand has been removed almost entirely in places by stream and lake action but even in these areas some sand may be present as rolls or isolated patches above the till. Above the Iroquois shoreline sandy patches and veneer are found in several places suggesting the presence of glacial lakes occupying a level higher than that of Lake Iroquois.

Glacial Lakes

The presence of faint to well-pronounced shore cliffs and lake deposits found on what is now dry land high above the Lake Ontario water level, point to the succession of glacial lakes that existed throughout the township area following the melting of the Wisconsin glacier. The most pronounced abandoned shoreline had an elevation of 417 feet above sea level on Kipling Avenue, just south of the Dundas Highway. This level corresponds to the Lake Iroquois shoreline de scribed by Coleman. 1 Less pronounced waterlines were observed at higher levels. A few of these were associated with minor unmapped veneers of sand. Some of these may have been cut by river action, but several are believed to be the result of higher lake ©A.P. Coleman, "Lake Iroquois"; Ont. Dept. Mines, Vol. XLV, pt. 7, 1936. 16 levels than Lake Iroquois. Unusual concentrations of erratics were observed near La Rose and Islington avenues at an elevation of approximately 475 feet above sea level. A series of waterlines and sand ridges are seen below the Iroquois shoreline to within 20 feet of the present level of Lake Ontario. Some of these are faint and of doubtful continuity. Othersare well-pronounced, and they probably indicate significant pauses in glacial lake conditions following Lake Iroquois. Some of the waterlines below the main Iroquois shoreline indicate earlier levels of Lake Iroquois established prior to the uplift of the land that followed the melting of the glacier. The uplift was greatest in the eastern part of the Lake Iroquois basin, and it caused a deepening of lake waters and consequent raising of beaches in the southwestern part of the lake, including the map-area.

Recent The flat valley-floors of all rivers and streams in the township are covered with clay, silt, sand, and coarse rubble intermixed with plant and animal re mains. These recent deposits are built up periodically by the flooding of the rivers and the thickness seldom exceeds 10 feet.

VERTICAL SECTIONS Three vertical sections are shown on Chart B to indicate the Pleistocene stratigraphy and variations in the bedrock surface.The position of the bedrock is known or assumed from well data and field observation. The nature and thickness of the overburden formations are based entirely on field studies. The vertical sections are drawn from exposures along, or close to, the line of section. Sand layers that separate tills of different substages are shown, although they may be only one foot thick. Lenses of sand within a till sheet have not been shown. The surface profiles have been taken from topographic sheets issued by the Department of National Defence.

Section A—A' This section runs from the Indian Line at the west boundary of the town ship to the Humber River, passing through the north part of Thistletown. The exact position of the bedrock on the west part of this section is unknown except near Highway 27 where it outcrops in the valley of the West Branch of the Humber. It drops away rapidly a few hundred feet north of this point where a buried bedrock valley crosses under the highway, but the exact course of the remainder of this valley is unknown. The thickest Pleistocene sections available for observation occur along this tributary of the Humber River, which has cut into the shale bedrock along much of its valley. In the vicinity of Thistletown, near Islington Avenue, the bedrock has been eroded away to form another buried channel which trends off to the southeast. In this buried valley, high capacity wells have been developed for the municipalities of Weston and Thistletown. The Thistletown well is presently being maintained as a stand-by unit only. 17 Etobicoke township

Section B—B'

This section commences at the Etobicoke Creek where it enters Etobicoke township and extends easterly to the Humber River near South Drive. Till comprises most of the overburden west of Highway 27 and has not been differentiated because of the lack of suitable exposures. The till is, probably, mostly upper Wisconsin till. The line of section crosses the bedrock valley at Mimico Creek. In this buried valley close to the line of section, the Township of Etobicoke has developed its wells. Relatively shallow exposures are found to the east of the section, which is characterized in places by the removal of the upper till due to the action of glac ial streams and lakes. The underlying interstage sands have, therefore, been exposed at the surface, facilitating the development of sand and gravel pits in several places.

Section C—C'

This section commences a little west of the mouth of the Etobicoke Creek and extends northeasterly close to Lake Ontario to the mouth of the Humber River. Bedrock is exposed on the lakeshore a half-mile east of the mouth of Etobicoke Creek and appears to be close to the surface until east of Mimico Creek. It is frequently encountered in the bottom of sewer or water-main trenches and occasionally in house foundations. The overburden in this Section is as complex as, and in some cases is more complex than, the overburden in the northern part of the township where it is thicker. Good exposures are found along the lakeshore in the Long Branch and Humber Bay area. The formations are usually only a few feet thick and reveal many of the characteristics of glacier movement. Boulder pavements exhibit striae, and contortion of sediments and tills exhibit the effects of ice shove. The lower till is ordinarily only two or three feet thick and is generally fresh, but occasionally it has a foot or two of upper weathered zone. This till is desig nated Illinoian, and the upper weathered zone may have been the remains of a thicker profile that was weathered during the Sangamon interglacial period. The thin layer of stratified silts and clays with some sands is shown as inter glacial, not because of any fossil evidence, but because of its position. It could be glacial in origin and still underlie the first Wisconsin till. In the Humber River area some peaty material and a few small shells were found in stratified silts and sands that were probably of this age. The till above the shale from Kipling Avenue to east of Church Street has not been differentiated. It is shown as Illinoian, but could be partly, or even entirely in places, Wisconsin till. Near the Humber River a separation is made between the sands and the silts and clays that make up the sediments under the middle Wisconsin till. The lower silts and clays contain considerable thicknesses of fine sand in places. The middle Wisconsin till is present in a few localities at higher elevations in the Humber Bay area, thus establishing the age of the bulk of the sands and silts in this area as interstage. 18 GROUND WATER SOURCE, STORAGE, AND MOVEMENT

Fresh water in wells and springs comes from precipitation. Some of the rain and snow is lost to evaporation at the land surface while much of its runs off into the streams and rivers without actually entering the ground. A considerable portion of the water that soaks into the ground is retained by the soil in the upper few feet of the land surface, particularly during the summer months when the water needs of vegetation are heavy. In Etobicoke township the land north of the Iroquois shoreline has very little sand at the surface. The material is mostly clay till, which contributes to surface run-off and is not conducive to infiltration after each rain. The till, however, is interlayered with sand at depth in many places or has sandy lenses in which ground water may be stored. At varying depths below the land surface the ground is saturated with water. When this depth is reached, a well is possible, provided there is sufficiently coarse sand or gravel to allow the water to flow into the well. If only clay, silt, or fine sand is present in the zone of water saturation, a well will not be satis factory because either the clay will retain most of the water or the silt and fine sand will flow in with it. This water in the saturated zone moves slowly through the sands and gravels or through the rock crevices and feeds the springs and streams that continue to flow during periods of no rainfall.

WATER WELL DATA

At the time of the field survey in 1948 information was collected on 1,028 dug and drilled wells. Records of 69 wells drilled in the township between 1948 and 1955 have been added to these along with logs and well data on 64 test- holes and wells. The water data for the drilled wells have been assembled in Appendix A and summarized in Table 2. Information on the dug wells has not been tabulated individually but has been summarized in Appendix B. Chart A shows the locations of the drilled wells and contours on top of the bedrock. The 53 test-holes seldom show well data other than the log. Water was encountered in most of them but geological conditions were not favourable enough to indicate a large-capacity well could be developed. In order to obtain the available information on ground water conditions on any lot in the township, the following procedure should be observed: for drilled well data, refer to Chart A and Appendix A; for dug well data, refer to Appendix B.

OCCURRENCE OF GROUND WATER IN THE BEDROCK

Two out of every three wells drilled in the township are bedrock wells. Whenever the overburden is too scanty or composed of too much clay to have a water-bearing sand or gravel, the well must be drilled into the shale bedrock for a distance that varies from a few feet to over 40 or 50 feet before encoun- 19 s ^

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^ g g U ^ggggggg 3 (S g g II i " i * i f O fi BC 20 tering water. The shale is a poor aquifer, seldom yielding more than three gallons a minute. The shale must be ruled out as a possible water-bearing formation if a large capacity well is required. Drilling to deeper depths in the shale increases the risk of obtaining salty water. If the five wells reporting mineral water in Table 2 are included with the 27 containing salty water, 12 percent of all the drilled wells encountered salty water. In the southern parts of the township where the overburden is thin, wells are often first dug to rock. A hole is then blasted or chiselled out of the shale and limestone to create a reservoir. The water is usually found on top of the shale or a few feet in it.

OCCURRENCE OF GROUND WATER IN THE OVERBURDEN

Most of the dug wells in use at the time of the survey were obtaining water from the overburden. Sixty of the drilled wells had sand and gravel aquifers. The high-capacity wells that yielded water up to, or in excess of, 1,000 gallons a minute were overburden wells. Whereas most of the dug wells were relatively shallow, tapping water-bearing sands in the upper part of the overburden, the high-capacity well invariably ended in sand and gravel near the bottom of valleys eroded in the shale. These buried valleys were formed in interglacial or preglacial time and their courses, if known, would reveal a different drainage pattern than exists in the township to-day. A search for a high-capacity well in the township is, therefore, a search for the buried valley, which is more likely to contain well-sorted sands and gravels. Water contained in these deeper channels would be recharged from sources not only in the upstream areas within the township but very likely in the sandy moraine areas much farther north. The dug well, particularly the shallow dug well, is the first to be affected by drought. The water-level in such instances will gradually fall until it drops be low the bottom of the well. If it is not a perched saturated zone, the water may be reached again by deepening the well. If it is a perched zone, the water-bearing formation may completely dry up and will not yield water again until recharged through sufficient precipitation. Forty-two dug wells, which had proven in adequate, had to be deepened by drilling. Although it is true that the drilled well is seldom affected by drought and is, therefore, a more dependable source for water, it is noteworthy that there were at least 3 times as many dug wells in use in the township as drilled wells and many of the dug wells were reported to have never gone dry. It is probable that many of the dug and drilled wells in use in 1948 are now abandoned due to the extension of water service lines in the township.

OBSERVATION WELL

One of the abandoned municipal test wells in the Mimico Creek valley was used as an observation well. Measurements of the water levels were taken with an automatic recorder, which was set up originally over test well "B", number 304 in Appendix A. Measurements were discontinued on this well in March 21 Etobicoke township

ODM7615 Photo 7—Observation well shelter in the valley of Mimico Creek, north of Etobicoke Township Waterworks Plant. Flood waters rose above this shelter during Hurricane Hazel.

ODM7616 Photo 8—Weekly automatic recorder marks variations in ground-water level on chart. The chart surrounds a drum rotated by a float in the well. A pen traverses the chart at constant speed controlled by an 8-day clock. 22 1955 in favour of the abandoned township well No. 5, number 323 in Appendix A. Ground water levels at the new location responded similarly to the first observation well. The move to the No. 5 well was made primarily to provide protection for the recording instrument, which is now located in a pumphouse. Flood waters at the time of Hurricane Hazel completely covered the automatic recorder at the site of test well "B". The previous and present observation wells are both located close to the Etobicoke township municipal wells. Any lowering of the water level in the area as a result of pumpages from these wells was quickly recorded on the charts in the recording instrument. Water levels for the four-year period, 1951 to 1954, are shown in Chart C (back pocket). The daily pumpage of wells in 1952 and most of the water level hydrographs were drawn directly from a chart prepared by W. M. Swann, engineer for the Township of Etobicoke. The important factors that influence the ground water levels, such as pre cipitation, amount of stream flow in Mimico Creek, and well-field pumpages, are included in Chart C. The levels were highest during the months of April and May. Except in 1951, the water levels commenced to rise during the fall months. In all instances the rate of rise was the greatest immediately following thaw conditions in the late winter or early spring. A notable exception to this occurred in October 1954 following the heavy rains that accompanied Hurricane Hazel. It is interesting to note that during the weeks and months that followed this disastrous flood, the ground water levels continued to rise, indicating that the water-bearing formations had been far from saturated at the time of the flood. The rate of infiltration of the surface waters into the drift was not sufficiently high to handle the large quantities of water available from precipitation. A pumping rate slightly over 1,000,000 gallons a day in the well field seemed to result in a steady water level during the late spring and summer months of 1952. Pumpage above or below this rate caused a lowering or raising of ground water levels. This would appear to have been the natural recharge rate during the summer months of that year. A much higher rate of pumping could be sus tained with only a temporary lowering of water levels if a yearly observation period were considered. Ground water supplies are usually recharged more quickly during winter and spring months when loss of soil water through evaporation and transpiration processes is at a minimum. Although the precipitation figures were those of Toronto, they probably indicated fairly well the conditions existing in the Mimico Creek watershed. In most instances a slight rise in water level or a break in a trend to a lower level is observed immediately following precipitation figures of any magnitude. A substantial rise in ground water level was apparent during the winter months of 1953-1954 when the municipal wells became idle. A pumpage of 3,500,000 gallons of water daily was maintained at times of peak demand in the 1954 summer season. The reduction in overall annual pumpage from the well field coupled with unusually heavy rainfall at the time of Hurricane Hazel resulted in considerably higher ground water levels at the close of 1954. The variations in water level at the site of the municipal wells shown in Chart C could not be considefed comparable to water level conditions prevailing in other parts of the township. Seasonal variations are present in all the wells but from year to year the levels remain remarkably constant. 23 piSur S ^2

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24 QUALITY Salty water was reported in 14 percent of the drilled wells. The highly mineralized water was encountered in most parts of the township, and was likely to be encountered anywhere if the well was drilled deeply enough into the shale bedrock. Generally, wells were drilled at least 10 or 20 feet into the shale before salty water was encountered. In some of the wells listed in Appendix A, where the data was collected from the home-owner, the thickness of drift was not known. In these cases, there would be no way of knowing where the salt water horizon existed within the shale. Chemical Analyses of Well Waters Chemical analyses were made of water samples taken from eleven wells in the northern half of the township. The analyses were made by the Department of Mines Assay Office and are shown in Table 3. Seven of the wells were dug. Their depths ranged from 20 feet to 55 feet. The water m these wells did not necessarily come from aquifers at the bottom of the wells at the depths indicated, but could have entered the wells from one or more horizons above. It is likely, though, that the water-bearing formation is at, or close to, the bottom of each well. The depths of the four drilled wells varied from 80 to 260 feet. Three of these were drilled into the shale bedrock. The most noticeable difference in quality between the dug wells and the drilled bedrock wells was in the hardness and the sodium chloride content. The drift wells had harder water and the bedrock wells were higher in sodium chlo ride. The following discussion of the chemical constituents has been adapted from publications of the United States Geological Survey and the Geological Survey of Canada, particularly that by Thomas. 1

Residue on Evaporation Ground water dissolves soil and rock particles with which it comes in contact. The residue on evaporation will include both dissolved solids and suspended matter unless the water is free from turbidity. Water containing less than 500 parts per million of dissolved solids is preferred for most domestic uses. Calcium (Ga) and Magnesium (Mg) Calcium and magnesium are usually found in appreciable amounts in well waters. Their presence is due to the action of carbon dioxide in water on lime stone and dolomitic rocks and on clays and other soil materials containing cal cium and magnesium. They are usually present as calcium and magnesium bicarbonates, sulphates, or chlorides, which are the main constituents causing hardness in well waters. ©J. F. J. Thomas, "Scope, Procedure, and Interpretation of Survey Studies," Dept. Mines and Tech. Surv., Canada, Water Survey Report No. l, 1953.

25 Etobicoke township

Sodium (Na)

Sodium is derived from a number of the rock-forming minerals and is common in most ground waters in the form of sodium bicarbonate, sodium sulphate, and sodium chloride. Its presence in large quantities in the underlying shale bedrock suggests its origin in a brine solution that has been associated with these rocks since their deposition in brackish seas millions of years ago. Water high in sodium salts may be undesirable because of the taste, reaction with other compounds, or corrosion. Samples 2 and 7 were high enough in sodium to indicate the wells from which these samples were taken would have at least a slight salty taste in the water.

Sulphate (SO4)

Sulphate is formed in well waters chiefly from the oxidation of iron sulphides, such as pyrite, which are present in small quantities in the overburden and in the bedrock. It is also associated with trade-wastes and bacterial action of other sulphur compounds. It is important to determine the amount of sulphate in water, because its combination with calcium and magnesium causes non-carbonate or "permanent* hardness in water, resulting in scaling in piping, boilers, and condensers. In sufficient quantities, and as sodium or magnesium sulphate, it gives water a bitter taste and a laxative effect. The U.S.A. Public Health Service recommends 250 parts per million as the upper limit for sulphate content in drinking water. None of the wells sampled in Etobicoke township had sulphate in an amount that would be objectionable for drinking purposes.

Chloride (CI)

The chlorides occur in well waters chiefly through the dissolving of chloride- containing rocks or minerals, from brines associated with the deposition of the bedrock shales, as indicated under sodium above, and from pollution. Chlorides markedly increase the corrosiveness of water and cause "permanent" hardness. In excess of 300 parts per million, they give a salty taste to the water and when present to the extent of 400 parts per million, they render the water unfit for domestic purposes. Two samples were relatively high in chloride content. Sample No. 7 was taken from a well drilled into bedrock, and indicates the higher amounts of chloride that are usually found in the shales. Sample No. 10 was from a rela tively shallow dug well and the high chloride content could indicate pollution.

Silica (SiO2)

Silica may be dissolved by ground and surface waters from most rocks. Its state in water is not known definitely, but it is generally considered to be present in a colloidal form. Silica, in well waters, has a detrimental effect because it forms boiler scale and may act as a cementing agent for the softer carbonate scale. All of the samples examined were within the normal range of silica content. 26 Iron (Fe2O:!) and Aluminium (A12O3)

The iron and aluminium constituents are reported together in Table 3. Aluminium in small amounts has little known effect on the use of water. Iron on the other hand is often a very troublesome constituent of well water; it contributes to the hardness of the water. When in excess of one part per million, the iron dissolved in well water will normally oxidize to a ferrie oxide, which precipitates as a brown sediment that stains fabric and porcelain. Iron can be almost completely removed by aeration and filtration of the water. Three samples, numbers 7, 10, and 11, were objectionably high in iron and aluminium.

Alkalinity as CaCO3

Table 3 shows total alkalinity as CaCO3. It is likely, however, that the carbonates in solution will be present in most cases entirely as bicarbonates. Ground-water contains carbon dioxide in solution, and this dissolves limestone and rock-forming minerals. This weathering process results in large amounts of carbonates being taken into solution as bicarbonates of calcium and magne sium. When the water is boiled the process is reversed and the insoluble carbon ates are precipitated out of solution and may form a scale on the sides of cooking utensils. The carbonate content of waters is discussed further under the heading Hardness.

Hardness

Hardness is caused chiefly by calcium and magnesium compounds that are dissolved in the water. Most of the bicarbonates of these minerals can be removed by boiling and they are, therefore, spoken of as causing temporary or carbonate hardness. The hardness due to other compounds, such as chlorides and sulphates of calcium and magnesium, cannot be removed by boiling and it is called permanent or non-carbonate hardness. Thomas1 gives the following classification of hardness of water: Hardness of l to 60 p.p.m. as CaCO3 soft water Hardness of 61 to 120 p.p.m. as CaCO3 med. hard water Hardness of 121 to 180 p.p.m. as CaCO3 hard water Hardness greater than 180 p.p.m. as CaCO3 very hard water All the samples of well waters were medium to very hard. Individual softening units are desirable for domestic use when the hardness exceeds 120 parts per million. Certain commercial operations or industries which require a minimum amount of boiler scale would probably wish to soften the water in the medium-hard range. Table 3 does not indicate the amount of carbonate or non-carbonate hardness, but shows the total hardness expressed as parts per million CaCO3 in terms of calcium and magnesium present. 1J. F. J. Thomas, "Scope, Procedure, and Interpretation of Survey Studies," Dept. of Mines and Tech. Surv., Can., Water Survey Report No. l, 1953, p. 50. 27 Etobicoke township

UTILIZATION Domestic and Stock

Out of a total of 1,161 dug and drilled wells on which data were collected in the township, 827, or 71 percent, were being used for domestic or stock purposes. It is very likely that many of these wells have now been abandoned because of increased municipal water services. Since the survey was conducted in 1948, no information is available on the number of new dug wells that would have been put down chiefly for domestic purposes. All wells drilled from the time of the survey until the spring of 1955 are reported in Appendix A. The dug well has a definite place in the water-supply picture for the average household where geological conditions are unsuited to the drilled well. When the overburden is thin, and salty water is known to exist near the top of the shale bedrock, a dug well will often provide the required amount of water. It usually exists at the top of the shale or a few feet in it. By blasting or chiselling a hole in the shale below the water horizon, a reservoir is created to help store even the small available supply until it is needed. A dug well should be considered at other locations in the township where the overburden is deeper but drilling tests reveal predominantly clay materials in it and salty water present in the shale. Generally a drilled well is preferable, however, because it usually yields more water, is not seriously affected by drought conditions, and is less likely to be contaminated from surface sources.

Commercial and Industrial

Four service stations were using well water at the time of the survey and these are classified as commercial use in Table 2 and Appendix B. Seven wells were being used for industrial purposes in sand, gravel, and cement block operations, meat packing establishments, and the dairy industry.

Irrigation

Nine drilled wells and eleven dug wells were used partly or entirely for irrigation purposes. This is less than 2 percent of the wells included in this report. It is likely that the number has increased to some extent with the increasing interest in irrigation methods.

Public Supply

Three schools were using ground water from individual wells in 1948. The remaining public supply wells were municipal wells one supplying Thistletown, four supplying Etobicoke township, and two supplying the Town of Weston. The first five municipal wells are presently being used intermittently as standby units during peak demand periods. 28 ODM7617 Photo 9—Pumphouse, seen left of centre, in the valley of the Number River is the site of one of the municipal wells of the town of Weston.

SUMMARY OF GROUND WATER CONDITIONS

Ground water is derived chiefly from rain and snow, which infiltrates buried sand and gravel layers and openings in the bedrock. Almost 50,000,000 gallons of water are available from this source on each square mile of land sur face in the township. Because the overburden materials contain so much clay, a large proportion of this available water flows off into streams and does not recharge ground-water reservoirs. Geological and water data for 323 drilled wells are listed in Appendix A. The locations of these wells are shown on Chart A. A summary of data on 838 dug wells is given in Appendix B. There are almost three times as many dug wells as there are drilled wells being used in the township. The majority of these provide an adequate supply of water. In the southern parts of the township where the overburden is under 15 or 20 feet thick, the dug well often provides the only satisfactory source of water. Twenty-four percent of the wells are drilled and these are located almost entirely north of the Dundas Highway where the overburden gradually in creases in thickness towards the north. The interbedded shale and limestone bedrock is a poor water-bearing formation. Sufficient water for household needs is usually obtained in most places but if a large-capacity well is needed the bedrock must be ruled out as a possible aquifer. Deep penetrations of the shale will likely encounter salty water. 29 Etobicoke township

About one-half of the drilled wells obtain water in sand and gravel forma tions above the bedrock. These aquifers are not uniform throughout the town ship area, but are much more favourable in certain areas than in others. A study of the locations of wells on Chart A and the logs and water conditions encountered in these wells set out in Appendix A will indicate the localities of the more favourable water-bearing formations in the drift. The high-capacity well suitable for municipal, industrial, or irrigation use will be found in the buried valleys in the shale. The positions of all these buried valleys are not known completely, but some of them are indicated by the bed rock contours on Chart A. The extensions to these valleys and their tributaries should be sought in any further search for high-capacity wells. Three to four million gallons a day are available in one of these valley locations at the site of Etobicoke township©s municipal wells north of Islington. The quality of the ground water is generally hard and contains noticeable amounts of iron. Water obtained at the top of the bedrock in one or two localities and at depth in any part of the area is likely to be highly mineralized. The residents of the township used ground water entirely until 1923. From that year to 1932 a water system was developed in the more populated parts of the township using water purchased from New Toronto and Weston. In 1932, a waterworks system was installed using water from wells developed near the present waterworks plant. This source of supply was finally abandoned, except for auxiliary purposes in the winter of 1953-1954 when lake-water was supplied through the New Toronto system. The township population has increased from 12,600 in 1923 to 94,000 in 1955. Many areas are still not supplied with water services. Some of these will be dependent on wells for many years. The individual well records and the indicated areas favourable for the development of high-capacity wells set out in this report should prove helpful to these domestic users and others interested in ground water for commercial, industrial, or irrigation purposes.

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48 INDEX

PAGE PAGE oandoned shoreline...... 16 Geology, general...... 7 Dondoned wells: Glacial lakes...... 16 Municipal test-wells...... 21 Glaciers, continental...... 7 :knowledgments...... 3 Glacio-fluvial deposits...... 14 juifer...... 30 Glacio-lacustrine deposits...... 16 Sand and gravel...... 21 Gorrell, H. A...... 3 Shale...... 21 Ground moraine...... 7 Ground water: ;aches...... 17 History, development...... 4 :drock...... 2, 7, 8,14, 30 Levels...... 23 Contours...... 19 Occurrence Contour map...... 2 in bedrock...... 19-21 Shale and limestone...... 29 in overburden...... 21 Valleys...... 6 summary...... 29 Wells...... 19 Source, movement...... 19 mlder pavement...... 10 Summaries...... 31-41,44-48 iried valleys...... 21 Survey, notes on...... 2 Utilization...... 28 larts: Hydrographs, water levels, Hardness, well water...... 4, 25 observation wells...... back pocket Humber Bay...... 8,14 Location of wells and bedrock Humber River...... l, 3,4,6,16 contours...... back pocket Hurricane Hazel...... 23 Vertical sections and Pleistocene Hydrographs stratigraphy...... back pocket Water levels in observation well.. .. .back pocket lemical analyses...... 3 Well waters...... 24, 25-27 jys, varved...... 14 Illinoian State...... 8 ifton, F. T...... 3 Illinoian till...... 8,14 ^mate...... 6 Industrial water use...... 28, 30 dy, J...... 3 Interglacial period...... 8 lclough, D. G...... 3 Interstage sands...... 16 mmercial, use of water...... 28, 30 Iroquois shore line...... 16, 17,19 ntinental glacier...... 7,8 Iron, in well water...... 4, 27 ntours, bedrock...... 19 Irrigation water use...... 28, 30

iry industry...... 28 Lake Iroquois: ta, water well...... 2,19, 31-47 Glacio-lacustrine deposits...... 16 Itaic deposit...... 14 Level...... 16 'inestic water use...... 28 Waters of...... 14 •n Valley Brick Yards...... 14 Shoreline...... 6,16 ainage...... 6 Lake Ontario, till on shoreline...... 9 ought conditions...... 28 Lake plain...... 6,14,16 g wells...... 19, 21 Lowest Wisconsin till, description of...... 10,14 5ata summary...... 44-48 ndas formation...... 7 MacDonald, J. G...... 3 MacLaren Associates, James F...... 3 :vations, well surface...... 2 Map, Pleistocene geology...... back pocket •atics...... 17 Margison, A. D. and Associates Limited...... 3 jbicoke Creek...... 1,6 Mcclellan, J. B...... 3 ans,S. W...... 3 Mechanical analyses: Soil samples...... 3 •man, S. A...... 3 Tills...... 14 iser, L...... 3 summary of data...... 12-13 49 PAGE PAG Trilinear chart...... 11 Test wells, abandoned municipal...... 2 Metropolitan Toronto Corporation Thistletown Water from...... 1,4 Sand and gravel deposits...... l Middle Wisconsin till, description of...... 14 Test holes Mimico Creek...... 4,6, 21 Well supply...... 2 Modified till...... 14 Till: Municipal wells...... 4, 23, 28 Description of...... 8,9, l Illinoian New Toronto Mechanical analyses of...... 12-1 Water from...... 4, 30 Wisconsin...... 8-1 Water works...... 1,4 Till plain Topography Toronto, climate. Observation wells...... 3, 21 Toronto township. Water level variations in...... 21, 23 Township of North York...... l See also Hydrographs Ontario Food Terminal...... 9 Upper Wisconsin till, description of...... l Utilization of water...... 28, 2 Parker, S...... 3 Peaty material...... 9 Pleistocene deposits...... 7, 8 Varved clays...... l Pleistocene geology Vaughan township Method of surveying...... 3 Vertical sections, notes on...... 17-1 Population...... 6, 30 Precipitation...... ,...... 6, 19, 21, 23 Water quality, in well water Public water use...... 28 Description of...... 25-i Pumpages, well field...... 23 Water supply: Islington Quality of well water Treatment. Description of chemical constituents...... 25-27 Water wells Data.... drilled wells...... 31-^ Recent deposits...... 17 dug wells...... 44-^ Records Salty water...... 21, 25, 28, 29 Waterworks, Sand ridges...... 17 Installation of...... Sangamon Interglacial Stage...... 9 Well, high capacity Schoonhoven,W...... 3 Wells, municipal Shalebedrock...... 25 Weston, Town of Stratified clays...... 10 Water purchased from...... 4, Swann, W. M...... 3, 23 Wells supplying West Branch of Humber River. Test-boring data...... 3 Wisconsin Test-drilling program...... l Glacial stage...... 9-10,14- Test holes...... 19 Till deposits...... 9-

50

Etobicoke Area Report Chart C Hydrographs

Automatic recorder put out of commission by flood for three days.

"V Hurricane Hazel

s .,

V

1954 1 : \f x \• J

v -

S \f\J

, ~./ v ~y—' !\ V ' V./v X

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s •S 2

I rt

Daily pumpage from Etobicoke Township municipal wells in 1952.

Ice conditions December 14, 1951 to March 7, 1952.

Daily discharge of Etobicoke Creek at Summerville in 1952. (Discharge of less than 50 cubic feet per second not shown)

iL January February March April May June July August September October November December

ODM23 Daily precipitation at Toronto in 1952.

Chart C-Hydrographs of water levels in observation well No. 304 Etobicoke Area Report Chart A Water Wells and Bedrock Contours

VAUGHAN

Chart A LOCATION OF WATER WELLS AND BEDROCK CONTOURS

Accompanying Map 2111

Scale l Inch to y2 Mile

SYMBOLS

Controlled access highway. Abandoned or unused well.

Road. ® Municipal well.

Concession line, approximate. Abandoned municipal well.

-250 Contour on bedrock surface in feet above Municipal boundary. sea level.

,49B Bedrock exposure. Number refers to elevation of highest part of outcrop. W&ll drilled to or into bedrock. The upper 186 1 364 number refers to well number in Appendix A. The lower number is the elevation of the top of the bedrock. When the lower number is missing, the depth to rock is uncertain, although the well is reported as a rock well.

NOTE

In addition to information from drilled wells and bedrock exposures, depths to bedrock were obtained from test borings at the mouth of the Humber River, from dug wells not shown on this map, and from numerous excavations in which bedrock occurred.

SOURCES OF INFORMATION

Base map from Engineering Branch, Borough of Etobicoke, with additional information by A. K. Watt. Water well information derived from field survey and records of water well drillers to 1948. Bedrock contours by A. K. Watt 1948. Cartography by R. G. Curtis, and J. M. McDougall 1967.

TORONTO

MAP A

inn T" \ "T l fm LAKE

ONTARIO

1 Etobicoke Area Report Chart B Vertical Pleistocene Sections

Chart B VERTICAL SECTIONS

SHOWING PLEISTOCENE STRATIGRAPHY

Accompanying Map 2111

Horizontal Scale l Inch to Vfc Mile

Vertical Scale l Inch to 100 Feet Vertical Section along line A—A'

LEaEND

CENOZOIC RECENT FLOOD PLAIN 7 Clay, silt, sand, gravel; wood, shells. Deposited on the flood plains of the present streams and rivers.

PLEISTOCENE WISCONSIN (GLACIAL) LAKE AND RIVER DEPOSITS 6b Sand, gravel, minor amounts of clay and silt. Deposited in Lake Iroquois and in the rivers emptying into Lake Iroquois and older glacial lakes. 6a Varved clay and stratified silt; minor.. amounts of sand and gravel. Depos ited in Lake Iroquois and in the rivers emptying into Lake Iroquois and the older glacial lakes. 5b Sand and gravel with minor amounts of clay and silt. Deposited in glacial lakes and rivers in the intervals be tween substages of the Wisconsin glaciation. The deposits occur under one or more till sheets except where the till has been removed by lake or stream action. Varved clay, stratified silt. Deposited in the glacial lakes and rivers in the Vertical Section along line B—B' intervals between substages of the Wisconsin glaciation,

GROUND MORAINE 4ae Uppermost till. Dark grey to brown,, stony, clay till; contains some sandy lenses and stratified clay and silt.

4ad Middle till. Grey to brown, dense to friable sandy till.

4ac Lowest till. Buff to mauve silty till, with or without pebbles.

Boulder pavement.

SANGAMON (INTERGLACIAL) ALLUVIAL DEPOSITS 3 Clay, silt, sand; some shells and peaty remains.

ILLINOIAN (GLACIAL) 2 Till. Tough, blue-grey, day till; con tains many igneous and sedimen tary pebbles and stones. PALEOZOIC ORDOVICIAN DUNDAS FORMATION BEDROCK Vertical Section along line C—C' Interbedded shale and limestone. Etobicoke Area Report Chart A Water Wells and Bedrock Contours

fcS sie^

Chart A LOCATION OF WATER WELLS AND BEDROCK CONTOURS

Accompanying Map 2111

Scale l Inch to V2 Mile

SYMBOLS

Controlled access highway. Abandoned or unused well.

Road. ® Municipal well.

Concession line, approximate. Abandoned municipal welt.

—— - —— Municipal boundary. -Z50 Contour on bedrock surface in feet above sea level.

.498 Bedrock exposure. Number refers to elevation of highest part of outcrop. Well drilled to or into bedrock. The upper 186 '364 number refers to well number in Appendix A, The lower number is the elevation of the top of the bedrock. When the lower number is missing, the depth to rock is uncertain, although the well is reported as a rock well.

NOTE

In addition to in formation from drilled we/Is and bedrock exposures, depths to bedrock were obtained from test borings at the mouth of the Humber River, from dug wells not shown on this map, and from numerous excavations in which bedrock occurred. TORONTO

SOURCES OF INFORMATION

Base map from Engineering Branch, Borough of 385 Etobicoke, with additional information by A. K. Watt. Water well information derived from field survey and records of water well drillers to 1948. Bedrock contours by A. K. Watt 1948. Cartography by ft. G. Curtis, and J. M, McDougall 1967.

r*3ilMV.©rVrJi©"P-W:©}

MARA

LAKE 306 ~"l"~ \ T — lr /jfi; A.

ONTARIO Etobicoke Area Report Charts Vertical Pleistocene Sections

©:: Chart B VERTICAL SECTIONS

SHOWING PLEISTOCENE STRATIGRAPHY

Accompanying Map 2111

Horizontal Scale l Inch to Vfc Mile

Vertical Scale l Inch to 100 Feet Vertical Section along line A—A'

LEGEND

CENOZOIC RECENT FLOOD PLAIN 7 Clay, silt, sand, gravel; wood, shells. Deposited on the flood plains of the present streams and rivers.

PLEISTOCENE WISCONSIN (GLACIAL) LAKE AND RIVER DEPOSITS 6b Sand, gravel, minor amounts of clay and silt. Deposited in Lake Iroquois and in the rivers emptying into Lake Iroquois and older glacial lakes. Varved clay and stratified silt; minor amounts of sand and gravel. Depos ited in Lake Iroquois and in the rivers emptying into Lake Iroquois and the older glacial lakes. 5b Sand and gravel with minor amounts of clay and silt. Deposited in glacial lakes and rivers in the intervals be tween substages of the Wisconsin glaciation. The deposits occur under one or more till sheets except where the till has been removed by lake or stream action. 5a Varved clay, stratified silt. Deposited in the glacial lakes and rivers in the Vertical Section along line B—B' intervals between substages of the Wisconsin glaciation.

GROUND MORAINE 4ae Uppermost till. Dark grey to brown,, stony, clay till; contains some sandy lenses and stratified clay and silt.

4ad Middle till. Grey to brown, dense to friable sandy till.

4ac Lowest till. Buff to mauve silty till, with or without pebbles.

Boulder pavement,

SANGAMON (INTERGLACIAL) ALLUVIAL DEPOSITS 3 Clay, silt, sand; some shells and peaty remains,

ILLINOIAN (GLACIAL) 2 Till. Tough, blue-grey, clay till; con tains many igneous and sedimen tary pebbles and stones.

PALEOZOIC ORDOVICIAN DUNDAS FORMATION BEDROCK Vertical Section along line C—C' 1 Interbedded shale and limestone. Map 2111 Etobicoke Township Pleistocene Geology

Scale l inch to 50 mrles

CENOZOIC RECENT FLOOD PLAIN 7 C/ay, s/'/t, sand, gravel; wood, shells. Deposited on the flood plains of the present streams and rivers.

PLEISTOCENE WISCONSIN (GLACIAL) LAKE AND RIVER DEPOSITS LAKE IROQUOIS SHORELINE. Beach cobble, sand, and gravel. In some places only the bluff or cliff cut in shale or till marks the position of the shoreline. 6b Sand, gravel, minor amounts of clay and silt. Deposited in Lake Iro quois and in the rivers emptying into Lake Iroquois and older glacial lakes. 5b Sand and gravel with minor amounts of clay and silt. Deposited in glacial lakes and rivers in the intervals be tween substages of the Wisconsin glaciation. The deposits occur under one or more till sheets except where the til! has been removed by lake or stream action. 5a Varved clay, stratified silt. Deposited in the glacial lakes and rivers in the intervals between substages of the Wisconsin glaciation.

GROUND MORAINE 4 Till, mostly uppermost Wisconsin till. The uppermost till is overlain in places by a thin layer of modified till consisting chiefly of varved clay containing pebbles, stones, and irreg ular layers of till. Older till, including Illinoian, has not been differentiated on this map from the uppermost Wisconsin til! sheet.

Township boundary.

County boundary.

Topographic contours.

Geological boundary, approximate.

For other conventional signs refer to 1:25,000 National Topographic Map Series.

SOURCES OF INFORMATION

Geology oy A. K. Watt and assistants, 1948.

Cartography by R. G. Curtis and R. T. Marcroft, Ontario Department of Mines, 1966.

Topography directly from maps 30M!11a, 30Mj11e, 30MI12a, 30MI12h, 30MI12g, 30Mi13a and 30MI13b of the National Topographic Series.

Magnetic declination approximately 7"10'W, 1966.

ONTARIO DEPARTMENT OF MINES HON. RENE BRUNELLE, Minister of D. P. Douglass, Deputy Minister J. E. Thomson. Director, Geological Branch

Map 2111 Pleistocene Geology of ETOBICOKE TOWNSHIP SOUTHERN ONTARIO

Scale 1:31,680 or l Inch to V2 Mile o i