All 3
branches are clearly visible as the 3 main green corridors in the
satellite view. (63K JPEG) The Don Watershed covers an area of 360 sq. km. It has 3 major branches. The west branch rises in the hills of the Oak Ridges Moraine in Maple and descends 48 kilometres to the lake. The east branch, also called the Little Don, has several tributaries which originate in the area north-east of Maple to North of Richmond Hill. The main tributary is German Mills Creek which flows through Richmond Hill. It joins the west branch at the Forks of the Don where Don Mills meets the Don Valley Parkway. The third branch is Massey Creek which originates in Scarborough and changes its name to Taylor Creek as it crosses into East York. Its original sources are buried under the 401 highway at Victoria Park. It flows 15 kilometres until it joins the east branch just north of the Forks.
All 3
branches are clearly visible as the 3 main green corridors in the
satellite view. (63K JPEG)
When the ice fronts of the last Ice Age retreated 11,000 to 13,000 years ago, the Don River flowed out of the long glacial deposit north of Toronto, the Oak Ridges Moraine. At first the river's 2 main branches flowed as separate rivers south into a large lake which we call Lake Iroquois. The escarpment of that lake is still very visible from Davenport Road which follows ancient trails along its base.
As the thawing continued, the St Lawrence, which was blocked with ice, opened up and about 9,000 years ago Lake Iroquois shrank to become Lake Ontario. The 2 rivers flowed south and were joined by Taylor / Massey Creek at what is today the Forks of the Don.
A detailed history of the glaciation of Southern Ontario is
contained in the book "Legacy : the natural history of
Ontario" published by McLelland & Stewart in 1989.
Archaeologists are confident that the Don Watershed has been continuously inhabited since the glaciers retreated from 9,000 to 11,000 years ago.
The first large quantities of physical evidence were left by the "Archaic Indians" of about 7,000 to 1,000 B.C. whose stone tools have been found in virtually all parts of the Don. These were followed by the ceramic-making peoples of the "Initial Woodland" period from about 1,000 B.C. to 500 A.D. The Iroquoian people of the "Late Woodland" from 900 to 1550 A.D. were the first settled agriculturists. At least a dozen villages have been identified - some with thousands of artefacts and a population of 300 to 400 people. About 1550, these people moved north to Huronia and the archaeological record becomes confused as the wars commence among the Europeans for control of a continent, supported by their various native allies.
The French first arrived in the Toronto area in 1615 when Etienne Brűlé; was sent by Samuel Champlain down the Humber. The Don first appears unnamed in a 1688 map of the Great Lakes and the Toronto portages drawn by Jesuit Father Raffeix. The French had a series of settlements and forts in the area of the Humber which was the entry to the Toronto Carrying Place for the fur trade.
In August 1788, the British bought the "Toronto Purchase" including the Don Watershed from the Mississauga Indians who had several encampments in the area. The river was then known as Necheng Qua Kekong.
In 1793 Col.
John Graves Simcoe, Lieutenant Governor of Upper Canada, moved
the capital from Niagara to Toronto (which he promptly renamed
York) in order to distance it from the danger of American
invasion. The settlement was laid out in a 10 block pattern on
the edge of Taddle Creek near the Don as shown in the 1793 survey
by Alexander Aitkin.
The river was named after the Don River in Yorkshire which flows East from the Pennine moors through the town of Sheffield.
By 1834 York
was incorporated as Toronto with a population of 9,252. With the
barrier of the river valley and marshes, Toronto spread out to
the west of the Don, slowly burying Russell Creek, Taddle Creek
and in the 20th century Garrison Creek.
By 1852 almost 40 flour, grist, textile and lumber mill lined the Don and its tributaries from Todmorden south of the Forks to the headwaters in Vaughan and Richmond Hill and the agricultural settlement of the Don was complete. The original ecosystem that had existed only 60 years before had been forever altered.
At the turn of the century, Toronto's 181,000 residents had urbanised most of the Don south of the Forks. As the City grew, various projects were undertaken for industrial purposes. In the late 1880's - the Don was channelised and widened from Gerrard south to Queen in the hope of allowing shipping to come up the Channel.
The enormous
Ashbridge's Marsh remained as shown in this 1873 painting by
Lucius O'Brien. However it was under assault from many sources. 
To remedy the
pollution problems and create new industrial land, the largest
lake filling project in North America was undertaken between 1912
and 1918. All the buildings in Toronto south of Front Street sit
on this landfill.
The agricultural character of the Don north of the Forks was relatively unaltered for about 100 years from the mid-1800's until the mid-1900's. In the post-war development years, the suburbs exploded in growth in Toronto as they did elsewhere in North America. A new urban form and lifestyle centred around the automobile drove the population of Toronto to over 2 million and the population of North York, which encompasses much of the Lower East and Lower West Don, to over 500,000 people by 1971. Don Mills, designed in 1954 by Macklin Hancock established a new model for Canada for suburban development.
In the early 1960's the Don Valley Parkway was completed, destroying much of what remained of the historical valley in the City.
In the 70's and 80's this growth continued as the region of York which includes the municipalities of Vaughan, Richmond Hill and Markham in the Don watershed, grew from 175,000 to 475,000 people.
Today about 80% of the Watershed
is developed with this wave of suburbanisation and we can expect
that 90% plus will be developed by the year 2000.
A lot less polluted than it was!
The paint factories, paper mills and 30 of the 31 sewage treatment plants are gone. The water for many decades has not routinely run in multi-coloured hues. There are still occasional problems from spills or illegal connections to the storm sewer system.
The Don today is certainly not hazardous to the touch, but it is certainly not drinkable, often unswimmable and although there are fish, they are radically diminished in the number and distribution of species.
The "Muddy Don" that we all are familiar with is often normal sediment in water. Today the excesses come mostly from poorly managed construction sites. You can see major spikes in the records when the Don Valley Parkway was built!
We are left with 2 big problems:
and
When sewers were constructed in the 19th century, and more or less up until W.W.II, one pipe carried both sanitary sewage from our bathrooms and kitchens, and water that ran off our roofs and roads. With increased urbanisation, the capacity of these sewers is greatly exceeded in a heavy rain causing Combined Sewer Overflow (CSO) into the river.
In Toronto, East York and Scarborough there are 30 combined sewers that as many as 50 to 60 storms per year cause to overflow. When this happens, parks can acquire a distasteful smell and curious tree ornaments, and the fecal coliform level goes up in the harbour and on Lake Ontario beaches. CSO is the root cause of beach closings in Toronto.
Since 1974 the City of Toronto has separated 70% of its original combined sewers, primarily to reduce flooding. There is a major debate underway as to what the next steps should be to eliminate CSO as the costs could be in the hundreds of millions of dollars.
Stormwater is the primary source of pollution in the Don River. It enters the Don and its tributaries through 1,185 outfalls and makes up 71% of the river's total flow. Stormwater carries everything that washes off the streets, expressways, shopping plazas, driveways, front yards, golf courses, and farm fields, directly and untreated into the river.
When we cut down the forests for Agriculture and hardened the surfaces of our Cities, we dramatically changed the natural water cycle. Instead of percolating through the ground over a number of days, and entering the river slow, cool and clear, water rushes down in a few hours and comes in fast, warm and turbid. On the way it picks up and dissolves whatever we have deposited and takes it to the river and on to the Lake.
The most recent, major study of the Don's water quality was undertaken by the Ontario Ministry of the Environment in the 1980's. The figures below are taken from the summary report dated September 1989. It is unlikely that much has changed.
| Water Quality Parameter (Target Value) |
Percentage Excedance |
Location |
|---|---|---|
| Total Phosphorus (0.03 mg/L) | 99-100% 89-90 99- 100 |
Lower Don East Don West Don |
| Fecal coliform (100 counts / 100 ml) | 75-96 89-96 60- 80 |
Lower Don East Don West Don |
| Copper(0.005 mg/L) | 80-90 30-40 60-70 |
Lower Don East Don West Don |
| Lead (0.025 mg/L) | 11-28 9-17 3-10 |
Lower Don East Don West Don |
There is no silver bullet - especially for stormwater. CSOs can be fixed with the application of enough money, but it is not yet clear that the very large projects which are being proposed are the best environmental approach.
The Don Watershed Task Force report - 40 Steps to a New Don -
lists 12 steps with 34 individual actions that need to be taken
to improve water quality.
More than you might think. But there is much to be done.
Although the last spawning salmon was speared near Pottery Road in 1874, and long gone are the dense and trackless forests that Mrs. Simcoe saw in 1793, the immense coveys of wildfowl, the many bear and enormous overflights of pigeons, the Don still functions as a habitat and migratory route.
Foxes are regularly seen south of Bloor Street in the heart of the city, coyotes have migrated down the Don and breed on the Leslie Street Spit, white-tailed deer have been seen in recent years in North York back yards and in the Cahrles Sauriol nature reserve.
Black-crowned Night Heron are nesting in Riverdale Park in the middle of the City, muskrat, pileated woodpeckers, great blue herons can be found throughout the watershed. 176 species of birds have been recorded in 8 ravine surveys by the Toronto Field Naturalists with a total of over 60 nesting species.
Fish have been probably the hardest hit by urbanisation and the virtual elimination of cold water habitat. 18 species have been counted with the most common being creek chub, blacknose dace, long nose dace (all minnows to you and me) and white sucker. With the conversion of the 2 weirs north and south of Pottery Road, and the weir north of Lawrence to rocky fish ladders, trout, salmon and white sucker are again able to migrate freely up the East Don from the Lake.
25 species of amphibians have been identified although only 5 of 14 potential species are common in the Watershed.
Based on recent reviews of air photographs of the watershed, stands of natural vegetation are mainly restricted to narrow bands of forest on the slopes and floodplains adjacent to watercourses. All of these areas are threatened by the invasion of foreign species such as the Norway Maple. The areas of the watershed in the Lower Don are particularly vulnerable as they are the northernmost limits of Carolinian species such as Shagbark Hickory.
If we stop destroying and start regenerating and extending the habitat, the biological reserves exist in the Greater Toronto Area (the Oak Ridges Bioregion) to re-establish many species in the Don. That is our challenge.
The Don Watershed Task Force report - 40 Steps to a New Don - lists 11 steps with 56 individual actions that need to be taken to regenerate the Don's habitat.
Personal responsibility is how it starts. An understanding of how the place you live connects with, affects, and supports the local ecosystem.
or email the Task Force to Bring back the Don or the Don Watershed Regeneration Council
Much of the information in this document originates in one of 3 books:
I have taken the liberty of quoting extensively without specific attribution. Since I chaired both of the task forces who produced 2 of the documents and the third was produced as background for the MTRCA's task force, I trust I will be indulged.
Other good histories of the Don include those written by the late Charles Sauriol.
The Metropolitan Toronto Municipal Reference Library at Metro Hall has been building a Don collection over the years. There is an extensive overview on their Web Site
If you're specifically interested in water quality, start with "Clean Waters, Clear Choices" available from the Toronto Remedial Action Plan (RAP) .
The Royal Commission on the Future of the Toronto Waterfront,
led by David Crombie, published its landmark document
Regeneration in 1992. It includes a special section on the Don.
The Commission as been re-incarnated as the Waterfront
Regeneration Trust and is actively developing plans for the
Lower Don Lands.
© mark wilson 1998
