View source for Don River (Ontario)

{{Short description|River in Canada}}
{{Not to be confused with|Don (river)}}
{{Infobox river
| name = Don River
| name_native = 
| name_native_lang = 
| name_other = 
| name_etymology = <!---------------------- IMAGE & MAP -->
| image = New Mouth of the Don River 2024.jpg
| image_caption = The new mouth of the Don River
| map = 
| map_size = 
| map_caption = 
| subdivision_type1 = Country
| subdivision_name1 = [[Canada]]
| subdivision_type2 = [[Provinces and territories of Canada|Province]]
| subdivision_name2 = [[Ontario]]
| subdivision_type3 = 
| subdivision_name3 = 
| subdivision_type4 = 
| subdivision_name4 = 
| subdivision_type5 = Cities
| subdivision_name5 = {{hlist|[[Toronto]]|[[Markham, Ontario|Markham]]|[[Vaughan]]|[[Richmond Hill, Ontario|Richmond Hill]]}}
<!---------------------- PHYSICAL CHARACTERISTICS -->| length = {{convert|38|km|mi|abbr=on}}
| width_min = 
| width_avg = 
| width_max = 
| depth_min = 
| depth_avg = 
| depth_max = 
| discharge1_location = [[Keating Channel]] and the [[Toronto Harbour]]
| discharge1_min = 
| discharge1_avg = 
| discharge1_max = <!---------------------- BASIN FEATURES -->
| source1 = [[Oak Ridges Moraine]]
| source1_location = [[Ontario]], [[Canada]]
| source1_coordinates = {{coord|43|59|20|N|79|23|57|W|display=inline}}
| source1_elevation = 
| mouth = [[Keating Channel]]{{!}} and the
[[Toronto Harbour]]
| mouth_location = [[Ontario]], [[Canada]]
| mouth_elevation = {{convert|75|m|abbr=on}}
| progression = {{RLake Ontario}}
| river_system = [[Lake Ontario]] [[drainage basin]]
| basin_size = {{convert|360|km2|abbr=on}}
| tributaries_left = [[Taylor-Massey Creek]]
| tributaries_right = [[German Mills Creek]], [[Burke Brook]], [[Mud Creek (Toronto)|Mud Creek]], [[Yellow Creek (Toronto)|Yellow Creek]], [[Castle Frank Brook]]
| custom_label = 
| custom_data = 
| extra = 
| mapframe = yes
}}
The '''Don River''' is a [[watercourse]] in southern [[Ontario]] that empties into [[Lake Ontario]], at [[Toronto Harbour]]. Its mouth was just east of the street grid of the town of [[York, Upper Canada]], the [[municipality]] that evolved into [[Toronto]], Ontario. The Don is one of the major watercourses draining Toronto (along with the [[Humber River, Ontario|Humber]], and [[Rouge River, Ontario|Rouge]] Rivers) that have headwaters in the [[Oak Ridges Moraine]].

The Don is formed from two rivers, the East and West Branches, that meet about {{convert|7|km|mi|0}} north of [[Lake Ontario]] while flowing southward into the lake. The area below the confluence is known as the "lower Don", and the areas above as the "upper Don". The Don is also joined at the confluence by a third major branch, [[Taylor-Massey Creek]]. The [[Toronto and Region Conservation Authority]] (TRCA) is responsible for managing the river and its surrounding watershed.

==Toponymy==
In 1788, [[Alexander Aitkin]], an English surveyor who worked in southern Ontario, referred to the Don River as ''Ne cheng qua kekonk''.<ref>City of Toronto [http://www.toronto.ca/parks/golf/history.htm Toronto Golf History]. Accessed March 24, 2007</ref> [[Elizabeth Simcoe]], wife of Lieutenant Governor [[John Graves Simcoe]], reported in her diary that another name used was ''Wonscotanach''.<ref>Robertson, J.R. 2001. ''The Diary of Mrs. John Graves Simcoe''. Toronto, Ont. Prospero Books.</ref>  This is an [[Anishinaabe language|Anishnaabe]] phrase meaning ''the river coming from the back burnt grounds'', which could refer to an earlier forest fire in the poplar plains to the north.{{sfn|Scadding|1873|p=233}} The name Don River was given by Lieutenant Governor Simcoe because the wide valley reminded him of the [[River Don, South Yorkshire|River Don]] in [[Yorkshire]], England.{{sfn|ODPD|1950|p=Part IV, 1}}
[[Image:CurlingonDonRiver.jpg|thumb|left|An 1836 watercolour depicting people [[curling]] on the Don River]]

==History==
Humans are believed to have first arrived in the Don River area approximately 12,500 years [[Before Present|BP]], most likely as nomadic hunters.<ref name="bbtdbook">{{citation |author=Task Force to Bring Back the Don |date=August 1991 |title=Bringing Back the Don |publisher=City of Toronto}}</ref> While there is little archaeological evidence in the Don valley itself, regional finds in the Great Lakes St. Lawrence area have revealed that permanent settlements started to occur about 6000 BP.<ref>{{cite web|url=http://www.civilisations.ca/archeo/hnpc/npvol06e.html|title=Civilization.ca. Early Great Lakes-St. Lawrence Culture|website=civilisations.ca|access-date=8 April 2018}}</ref> The most significant recorded find is known as the "Withrow Site". It was discovered in 1886 during road building just east of [[Riverdale Park (Toronto)|Riverdale Park]]. It contained human remains and other artifacts dating back to about 5000 years BP.<ref name="bbtdbook" />  

[[Wyandot people|Wendat]] longhouse villages were developed along the river starting in the 1300s when corn became a staple food.{{citation needed |date=September 2023}} In the 1700s, the [[Mississaugas]] moved into the region, seeing the [[Haudenosaunee]] withdraw south of Lake Ontario. The French were the first Europeans to visit the region, trading at posts in the area. In the 1760s, the French were displaced by the British after the fall of Quebec.

The British and the Mississaugas concluded the problematic ''[[Toronto Purchase]]'' treaty in 1787. Believing the purchase to be a rental of the area, and not the release of their rights to the land, the Mississaugas surrendered most of the land that would become [[York, Upper Canada|York]], and then Toronto, and York County to the British.<ref>{{cite news |url=https://donrivervalleypark.ca/about-the-park/history/#:~:text=The%20Don%20River%20and%20the,far%20as%207%2C000%20years%20ago. |title=About the Park |publisher=Evergreen in partnership with the City of Toronto and the Toronto and Region Conservation Authority}}</ref> After a land claims process, the surrender of aboriginal title to the Toronto Purchase lands was eventually concluded in 2010 for financial considerations.<ref>{{cite news |newspaper=Toronto Star |url=https://www.thestar.com/news/gta/2010/06/08/shrugs_greet_historic_145m_toronto_land_claim_settlement.html |title=Shrugs greet historic $145M Toronto land claim settlement |date=June 8, 2010 |last=Edwards |first=Peter |access-date=April 29, 2013}}</ref>

After the founding of York in 1793, several mills were constructed along the lower Don. One of the first was at [[Todmorden Mills]]. These mills initially turned out lumber, flour and paper products. By the 1850s, there were more than 50 mills along the Don and its tributaries.<ref name=cottage>"When the Don Valley was cottage country".''Toronto Star'', September 4, 2016, page IN4.</ref> The Lower Don was becoming an industrial setting. Petroleum storage facilities, poultry and [[William Davies Company|pork]] processing plants were constructed along the banks of the Don. In 1879, the [[Don Valley Brick Works]] opened.<ref name="donstory">{{cite web|publisher=City of Toronto |url=http://www.toronto.ca/don/watershed.htm |title=Story of the Don |year=1998 |author=Task Force to Bring Back the Don |url-status=dead |archive-url=https://web.archive.org/web/20110607062913/http://www.toronto.ca/don/watershed.htm |archive-date=2011-06-07 }}</ref> Polluted effluent from these factories and the growing city nearby was turning the Don and its marshy mouth into a polluted hazard.

There were two prominent hills that were north of Bloor. "Sugar Loaf Hill" at Bloor Street was a [[conical hill]] removed during the construction of the [[Prince Edward Viaduct]] (commonly referred to as the Bloor Viaduct).<ref>{{Cite web|url=https://www.blogto.com/city/2013/08/that_time_toronto_opened_the_don_valley_parkway/|title=That time Toronto opened the Don Valley Parkway}}</ref> "Tumper's Hill", near Don Mills Road, was flattened in the 1960s during the construction of the [[Don Valley Parkway]].{{citation needed|date=September 2023}}

In the 1880s, the lower part of the Don south of the former Winchester Street bridge was straightened (east of the original mouth) and placed in a channel to create additional harbour space and industrial dock space for boats. Known as "The Don Improvement Project", the straightened river was also supposed to divert the polluted waters into the [[The Beaches, Toronto#Ashbridge's Bay|Ashbridges Bay marsh]]. This proved unsuccessful so the mouth was turned 90 degrees west where it empties into the inner harbour. This short extension of the harbour is known as the [[Keating Channel]]. The channel north of [[Lake Shore Boulevard|Lake Shore Blvd. East]] ceased being navigable when the [[Gardiner Expressway]] was constructed in the 1950s.{{citation needed|date=September 2023}} Large boats can no longer enter the Keating Channel due to the removal of the [[Cherry Street lift bridge]] and it's replacement by the [[Villiers Island#Bridges|Cherry Street North bridges]].
[[File:Don River looking south to Prince Edward Viaduct, Toronto, Canada.jpg|thumb|Construction of the [[Prince Edward Viaduct]] over the Don River in January 1917]]
During the early part of the 20th century the river and the valley continued to be neglected. 31 separate sewage treatment facilities were constructed along the river.<ref>{{cite web |title=How polluted is the Don. Don Watershed Regeneration. Note: only one treatment plant remains |url=http://www.mwilson.on.ca/Don/DonFAQ.html |url-status=dead |archive-url=https://web.archive.org/web/20071231084516/http://www.mwilson.on.ca/Don/DonFAQ.html |archive-date=2007-12-31 }}</ref> Over 20 sites in the valley and adjacent ravines were used as landfills for garbage and industrial refuse.<ref>{{cite journal |first1=K.W.F. |last1=Howard |first2=N. |last2=Eyles |first3=S. |last3=Livingstone |year=1996 |title=Municipal Landfilling Practice And Its Impact On Groundwater Resources In And Around Urban Toronto, Canada |journal=Hydrogeology Journal |volume=4 |issue=1 |pages=64–79|doi=10.1007/s100400050092 |bibcode=1996HydJ....4...64H |s2cid=129112142 }}</ref> In 1917, the Don Destructor was built beside the river, just north of Dundas Street East. The [[incinerator]] operated for 52 years, burning about 50,000 tonnes of rubbish annually.<ref>{{cite web |url=http://www.lostrivers.ca/points/dondestructor.htm |title=The Don Destructor |publisher=Lost Rivers}}</ref>

In the 1910s through to the early 1930s, the Don Valley was used as a camping site by the homeless. These sites were commonly referred to as the "hobo jungle" of the valley.<ref>{{Cite book |last=Bonnell |first=Jennifer L. |title=Reclaiming the Don : an environmental history of Toronto's Don River Valley |publisher=University of Toronto Press |year=2014 |isbn=9781442643840 |pages=97–103}}</ref> Campers at the hobo jungle were often harassed, arrested, and raided by police.<ref>{{Cite web |last=Joesph |first=Mobólúwajídìde |date=2023 |title=A Brief History of Toronto Encampments: Don Valley |url=https://exhibits.library.utoronto.ca/exhibits/show/torontoencampments/islandstoronto |access-date=2023-05-11 |website=University of Toronto Exhibits}}</ref>

In 1946, a plan by the [[Shirriff]] company to demolish pioneer dwellings in the area of Todmorden Mills led outraged citizens to form the Don Valley Conservation Association volunteer organization. The Association's opposition was successful in causing Shirriff to abandon the project in 1947.{{citation needed|date=September 2023}} The Association continued its activities, planting tree seedlings, halting the picking of wild flowers, particularly [[trillium]]s and preventing vandalism. The Association held educational events to educate the public about the Don Valley, including special trains through the valley, and a recreation of Lt. Governor Simcoe's journey up the Don by canoe. The Association also advocated for the building of trunk sewers to stop the run-off of pollution into the Don.{{sfn|Sauriol|1992|pp=268–281}}

After World War II, rapid urban expansion occurred in the northern reaches of the watershed. At the same time, interest in conservation led to the formation of conservation authorities across Ontario for watershed management. Authorities were established to manage watersheds, and the Don Valley Conservation Authority was established in 1947.{{citation needed|date=September 2023}} The authority had limited powers, and was funded by local municipalities which had to pay for specific land purchases. For example, a 1950 plan to build a large conservation area on the East Don River at Milne Hollow at Lawrence Avenue never came to fruition over the high cost of development.{{citation needed|date=September 2023}}

In 1954, [[Hurricane Hazel]] struck the Toronto area. Most of the damage occurred in the [[Humber River (Ontario)|Humber River]] area. While there was some flooding, substantially less rain fell over the Don Watershed and there was no loss of life.<ref name="donec">{{cite web |author=Peter Bowyer |year=2004 |access-date=2009-06-17 |publisher=Canadian Hurricane Centre |url=http://www.ec.gc.ca/ouragans-hurricanes/default.asp?lang=en&n=6A9B162F-1 |title=Impacts&nbsp;— Don River}}</ref> However, the impact of the hurricane led to changes for the conservation authorities in the Toronto region. In 1957, the DVCA, along with other Toronto-area conservation authorities, was reformed into the Metro Toronto and Region Conservation Authority and given a mandate to construct flood control features as well as acquire property in the Don and other valleys to prevent a future re-occurrence of the disaster. Large tracts of industrial land adjacent to the river were added to the regulatory floodplain. This meant that the MTRCA had a veto on any developments that were not flood-proofed. The MTRCA became the TRCA in 1998.

[[File:Don Roadway looking north.jpg|thumb|left|Construction of the Don Roadway along the eastern portion of Don Valley in 1910. Most of the Roadway was later incorporated into the [[Don Valley Parkway]] in the 1960s.]]

In the 1950s and early 1960s, the [[Don Valley Parkway]] (DVP) was constructed through the Lower Don to serve growing commuter traffic. The project was a large civil engineering project. Homes, farms, and cottages in the valley were expropriated.<ref name=cottage /> Two hills within the valley were leveled and the soil used for grading the highway. The railways and the river were re-routed, Don Mills Road was improved and the [[Eglinton Avenue]] and [[Lawrence Avenue]] [[concession road]]s were extended across the valley. At the intersection of Lawrence and the Parkway, the remains of the old village of [[History of neighbourhoods in Toronto|Milneford Mills]] were removed.{{sfn|Brown|1997|p=167}} [[Bayview Avenue]] was extended south into the valley along the west bank of the valley.

Increasing development reduced the natural areas of the watershed. This impacted the Don with increased pollution, heavy flooding, and turbid sediment laden waters. The combined result meant that by the 1960s the river had become a neglected, polluted mess. In 1969, Pollution Probe held a much celebrated "Funeral for the Don" to highlight the plight of the river.<ref name="donstory" />

Efforts to restore the Don gathered steam in 1989 with a public forum at the Ontario Science Centre which was attended by about 500 people.<ref>{{cite web |title=Frequently Asked Questions: How did the Task Force to Bring Back the Don get started? |first=Mark J. |last=Wilson |website=Bring Back the Don |year=2001 |url=http://www.toronto.ca/don/faq.htm |url-status=dead |archive-url=https://web.archive.org/web/20070927194439/http://www.toronto.ca/don/faq.htm |archive-date=2007-09-27 }}</ref> The result was the formation of the [[Task Force to Bring Back the Don]], a citizen's advisory body to Toronto City Council. Their mandate and vision was to make the Don "clean, green, and accessible". Since then they have hosted garbage cleanups, tree plantings, and help to create or restore eight wetlands in the lower reaches of the valley, including Chester Springs Marsh, a {{convert|3 |ha}} site south of the Bloor Viaduct.<ref>{{cite web|url=http://www.lostrivers.ca/points/CSMarsh.htm|title=Chester Springs Marsh|website=www.lostrivers.ca|access-date=8 April 2018}}</ref> Other groups also became active including [[Friends of the Don East]]. In 1995, the MTRCA created the Don Watershed Regeneration Council to coordinate restoration efforts throughout the watershed.<ref>{{cite web |publisher=TRCA |url=https://trca.ca/conservation/watershed-management/don-river/community/ |title=Community: Don Watershed Regeneration Council |access-date=October 21, 2016}}</ref>

In 1991 Bring Back the Don released a document called "Bringing Back the Don" which laid out plans for restoration, including a renaturalized mouth of the Don. In 1998 a plan to revive Toronto's waterfront was initiated. One of the four projects mentioned was a natural mouth for the Don River. In 2001 an environmental assessment was started to look into a natural mouth of the Don. The project was also coupled with a plan to handle a major flood modeled on the expected output from a Hurricane Hazel size storm. In 2007, the Toronto Waterfront Development Corporation (now WaterfrontToronto) held a design competition that looked at four different configurations for the mouth of the Don. The winning bid was made by [[Michael Van Valkenburgh|Michael Van Valkenburgh Associates]].<ref>{{cite web |url=http://waterfrontoronto.ca/dynamic.php?first=43fa75b221b08&second=4637868526923&third=45abd9e029036&fourth=461fa1c548c13 |title=Portlands Estuary |year=2007 |publisher=Waterfront Toronto}}</ref> The environmental assessment was completed in 2014 and construction began in 2016.<ref>{{cite web |title=Don Mouth Environmental Assessment, Terms of Reference |year=2006 |author=Toronto Region Conservation Authority |url=http://www.trca.on.ca/Website/TRCA/Website.nsf/Webpage/water_protection_don_mouth_whats_new_terms_of_reference?OpenDocument&Language=EN |url-status=dead |archive-url=https://web.archive.org/web/20071122051702/http://www.trca.on.ca/Website/TRCA/Website.nsf/Webpage/water_protection_don_mouth_whats_new_terms_of_reference?OpenDocument&Language=EN |archive-date=2007-11-22 }}</ref>  In 2024, Waterfront Toronto announced that it had connected the Don River to the new mouth of the river channel and completed the creation of a new island, [[Ookwemin Minising]]. For the first time since the 1880s the Keating Channel was no longer the primary outlet for the river into Toronto Harbour.<ref>{{Cite web |last=Weingarten |first=Naama |date=November 8, 2024 |title=Toronto's 'waterfront city' project reaches new milestone |url=https://www.cbc.ca/news/canada/toronto/port-lands-north-plug-1.7378533 |access-date=November 14, 2024 |website=CBC News}}</ref>
{{Don Valley}}
Since the cessation of industrial pollution and the cleanup efforts by various groups, the river has regenerated to the point where a number of species of fish have returned to the river, and there is a limited sports fishery.<ref name="star">{{cite news |last=Hunter |first=Paul |date=August 28, 2016 |title=Urban fishing enthusiasts feel the lure of the Don River |url=https://www.thestar.com/news/insight/2016/08/28/urban-fishing-enthusiasts-feel-the-lure-of-the-don.html |work=Toronto Star}}</ref>

===Wonscotonach Parklands (Don River Valley Park)===
In October 2016, the city of Toronto announced the creation of a {{convert|200|acre|ha}} Don River Valley Park that will stretch for {{convert|7|km|mi}} from the West Don Lands up to approximately Todmorden Village in the north.<ref name="donrivervalleypark.ca">{{cite web|url=http://donrivervalleypark.ca/|title=The Don River Valley Park|website=donrivervalleypark.ca|access-date=8 April 2018}}</ref> The park will have three zones, an urban zone from West Don Lands to Riverdale Park, a park zone from Riverdale north to Bloor and finally a natural zone for the remaining section to Todmorden Village. Trails for biking and pedestrian use will be connected from existing ones for recreational and transportation needs.<ref name="donrivervalleypark.ca"/> Another aim for the park is restoration of land and the upper sections of the Don River.<ref name="donrivervalleypark.ca"/> The project aims to revitalize the ravine space through a series of projects that will advance the priorities set out in the city of Toronto's Lower Don Trail Master Plan, prepared by DTAH.<ref name='eg'>{{cite web|url=https://www.evergreen.ca/downloads/pdfs/Lower_Don_Master_Plan_Final_2013-09-09.pdf|title=Lower Don Trail : Access, Environment + Art Master Plan|website=Evergreen.ca|access-date=27 May 2018}}</ref><ref>{{cite web|url=http://dtah.com/|title=Welcome to DTAH|website=Dtah|access-date=8 April 2018}}</ref> Together with a series of accessible new entry points, the Master Plan calls for the reclamation of former green spaces throughout the valley, including the former snow dump site north of the Bloor Viaduct.<ref name='eg'/> Naturalized ecological conditions throughout the valley would offer improved flood protection. A "nature-inspired" public art program is set to launch in 2017, aiming to strengthen the cultural presence of the Don Valley, which—according to the Master Plan—already serves as a de facto backyard to some 250,000 Torontonians.<ref name='eg'/> This new park will be under the management of the [[Toronto Parks, Forestry and Recreation Division]]. In 2018 City Council directed staff to consult community about naming the network of parks in the Lower Don "Wonscotonach Parklands", with ''Wonscotonach'' meaning "black burnt grounds" or "area previously swept by fire", deriving as an Anglicized form of the name "Waasayishkodenayosh" meaning "burning bright point" or "peninsula" in [[Anishinaabemowin]].<ref>{{Cite web|url=https://donrivervalleypark.ca/news/wonscotonach-parklands-what-were-hearing/|title = Wonscotonach Parklands: What we're hearing &#124; the Don River Valley Park}}</ref><ref>{{Cite web|url=https://www.evergreen.ca/about/|title = About Evergreen &#124; Evergreen}}</ref>

==Geography==
===Geology===
[[File:CPR East Don Trestle Bridge.jpg|thumb|The Don Valley, which surrounds the lower portion of the Don River, is a {{convert|400|m|yard|adj=mid|-wide}} valley in spite of the river being only {{convert|15|m|yards}} wide. The Valley's formation was a result of the [[last glacial period]].]]  
The Don Valley is notable because of its deep wide valley in the lower reaches. At the Bloor Street Viaduct, the valley is about 400 m wide while the river is only about 15 m wide.<ref>{{cite web|url=http://maps.google.ca/maps?hl=fr&ie=UTF8&ll=43.675065,-79.36385&spn=0.003313,0.007231&t=h&z=17&om=0|title=Google Maps|website=Google Maps|access-date=8 April 2018}}</ref> This is due to its glacial origins. The Don River and its deep valley were formed about 12,000 years ago at the end of the [[Last glacial period|Wisconsinan Glaciation]]. During that glaciation which lasted for 35,000 years, all of Ontario was covered in ice. As the climate warmed the glaciers began to melt. As the ice front retreated in southern Ontario, several rivers were formed that drained into [[Glacial Lake Iroquois|Lake Iroquois]], a glacier lake which was the precursor to Lake Ontario.{{dubious|Questionable assertions about Lake Iroquois|date=October 2014}} The Don River is now small in comparison to the deep and wide valley that resulted from its glacial origin. The Don River is now classified as an [[Misfit stream|underfit river]].

The landscape at that time was loose glacial till so the large amounts of glacier melt water eroded deep valleys over thousands of years. As time progressed, isostatic uplift caused the earth's plate to rise and tilt. This caused Lake Iroquois to drain towards the south.{{dubious|Questionable assertions about Lake Iroquois|date=October 2014}} A remnant of its shoreline can be seen on the north side of [[Davenport Road]] in Toronto. In the Don Valley, the old shoreline is evident just north of [[Eglinton Avenue]].<ref>Chapman, L.J., Putnam, D.F. 1972. Map 2226:Physiography of the South Central Portion of Southern Ontario. Ontario Department of Mines and Northern Affairs. Ontario Research Foundation.</ref> Today the source of the Don River is the [[Oak Ridges Moraine]], another legacy of the Wisconsin glaciation.

The location of the old shoreline delineates a change in the soils in the Don watershed. Soils north of the old shoreline are mostly luvisolic ''Halton Till'' while south of the shoreline they are sandy glaciolacustrine deposits.

The Don Valley provides an appropriate location for studying the regional geological history. The Don Valley Brick Works was an old brick making factory with a quarry where they extracted shale. At the rear wall, local geologists discovered a record of the past three glaciations. There are nine distinct layers visible dating back 120,000 years.<ref>Nick Eyles. 1997. Toronto Rocks. Fitzhenry and Whiteside.</ref>

===Hydrology===
[[File:Don flood, south from Bloor Viaduct.jpg|thumb|View of the Don River flooding the Don Valley south in February 1918. Water levels on the Don River can rise quickly following moderate to heavy rainfall.]]
Due to the urbanized nature of the watershed, the Don River experiences low base flows interspersed with high volume floods. The water level can rise very quickly following a moderate to heavy rainfall, up to 1–2 metres inside of three hours. The average base flow for the Don River is about 4 m<sup>3</sup>/s.<ref>{{cite web |title=Archived Hydrometric Data for Station 02HC024 (Todmorden Mills). 1962-2005. |publisher=Environment Canada |url=http://www.wsc.ec.gc.ca/hydat/H2O/index_e.cfm |url-status=dead |archive-url=https://web.archive.org/web/20071231224943/http://www.wsc.ec.gc.ca/hydat/H2O/index_e.cfm |archive-date=2007-12-31 }}</ref> Peak flows occur in late February and late September which corresponds to seasonal variation in the Toronto region. Maximum flows, based on a Hurricane Hazel level flood have been estimated at nearly 1700 m<sup>3</sup>/s.<ref>{{cite web|title=Lower Don River West Remedial Flood Protection Project, Class Environmental Assessment Environmental Study Report Section 4.1. |year=2006 |publisher=Toronto and Region Conservation Authority. |url=http://www.trca.on.ca/Website/TRCA/Website.nsf/Webpage/water_protection_lower_don_ea_whatsnew_classEA?OpenDocument&Language=EN |url-status=dead |archive-url=https://web.archive.org/web/20071030140701/http://www.trca.on.ca/Website/TRCA/Website.nsf/Webpage/water_protection_lower_don_ea_whatsnew_classEA?OpenDocument&Language=EN |archive-date=2007-10-30 }}</ref> On August 19, 2005, an [[Southern Ontario tornado outbreak of 2005|unusually strong summer storm]] caused short term flooding in the Don Valley. Peak flow rates for that event were measured at 55.3 m<sup>3</sup>/s. Since high flow rates occur during storm events, the resulting floods tend to scour the bottom of the river which reduces fish habitat. In addition, the flood waters carry a large amount of sediment washed into the river from surrounding tablelands. The sediment collects in the Keating Channel just past the mouth of the river. The TRCA which is responsible for the dredging estimates that the amount of sediment dredged is 35,000 m<sup>3</sup>/year weighing nearly {{convert|60000 |tonnes}}.<ref>{{cite book |title=Terms of Reference – Don Mouth Naturalization and PortLands Flood Protection Project, Section 8.1 |year=2006 |author=Toronto and Region Conservation Authority }}</ref>

===Course and tributaries===
[[File:Don River near Riverdale 2023.JPG|thumb|Don River near [[South Riverdale]]]]
The east branch of the Don, also called the Little Don River,<ref>{{cite web |url=http://ceaa.gc.ca/052/details-eng.cfm?pid=37563 |title=Archived - Stormwater Control Facility Rehabilitation, Little Don River, Town of Richmond Hill |date=24 March 2009 |publisher=Canadian Environmental Assessment Agency |access-date=October 21, 2016 }}</ref> rises at the south edge of the Oak Ridges Moraine just to the west of [[Yonge Street]], flowing south-eastward through ravine forests in [[Richmond Hill, Ontario|Richmond Hill]], [[Thornhill, Ontario|Thornhill]], east of [[Willowdale, Toronto|Willowdale]] and [[Don Mills]].

A second branch of the eastern Don, known as [[German Mills Creek (Don)|German Mills Creek]], parallels the main eastern branch and joins it at Steeles Avenue, the northern boundary of Toronto. South of Lawrence Avenue the river passes through the Charles Sauriol Conservation Reserve. This area is mostly undeveloped parkland. The reserve occupies the valley south to the forks of the Don. It was at one time home of a [[Maple sugar]] [[Sugar shack|shack]] and [https://www.sciencephoto.com/media/491124/view/maple-sap-tapline tapline], which was visited yearly by students from across [[East York]]. [[Charles Sauriol]] was a historic protector of the Don.

The western branch starts [[Vaughan, Ontario|Vaughan]], in the [[Maple, Ontario|Maple]] district; flowing south-east through the suburban industrial area of [[Concord, Ontario|Concord]], and the G. Ross Lord [[reservoir (water)|Reservoir]]. It crosses Yonge Street as it flows through [[Hoggs Hollow]], past [[York University]]'s [[Glendon College|Glendon]] ("valley of the Don") campus, and then flows on to [[Leaside]], [[Flemingdon Park]], and [[Thorncliffe Park]] before joining the eastern half.

The western section of Taylor-Massey Creek and the southern portion of the western branch are surrounded by parkland (see also: ''[[Toronto ravine system]]''). In more recent years the retreat of the industrial plants and rail infrastructure has freed up room which is now being turned into [[bicycling]] trails, which now extend from the shore of Lake Ontario northward in several directions to provide some 30&nbsp;km of off-road paved trails. While Toronto is fairly flat in general, local cyclists have developed a number of technically challenging [[singletrack]] trails throughout the area, following the main trails.
[[File:View North from Commissioners Street 2019 vs 2024.jpg|alt=The image on the left shows the view in October 2019. The view is of a fence and a vacant lot with a shrubland. In 2024, there is a broad river valley and the Don River can be seen in the distance where it flows into the Keating Channel and new river valley.  |thumb|View looking north from Commissioners Street in 2019, before the new river valley was excavated, and in 2024, after the Don River was connected to the river valley. Ookwemin Minising is to the left of the river in the 2024 image, and Don Roadway is to the right. ]]
Downstream from the forks, the river flows through a wooded area known as [[Crothers' Woods]] which is designated as an Environmentally Sensitive Area due to the high quality [[beech-maple forest]] that grows on the ravine slopes. South of Pottery Road it enters a more degraded section and ends up in a straightened section that includes cement and steel dock wall, a remnant from an earlier industrial era. The river flows from there into the [[Keating Channel]] at [[Lake Shore Boulevard]] East which is at the north east corner of the [[Toronto Harbour]].

To control flooding from the Don River, [[Waterfront Toronto]]'s [[Villiers Island#Flood control|Port Lands Flood Protection Project]] extended the river south past the Keating Channel (roughly parallel to the west side of the Don Roadway), and then west (roughly parallel to the south side of Commissioners Street) to a new mouth at [[Toronto Harbour]]. The man-made extension naturalized the river valley and provided new parkland. Since 2024, water now flows into the Keating Channel from the Don River and the new mouth of the river. A byproduct of the river extension is the creation of [[Ookwemin Minising|Ookewmin Minising]], at the north-west corner of Toronto's [[Port Lands]].<ref name="WFT-Map">{{cite web |url=https://portlandsto.ca/project-map/ |title=Breaking Down the Port Lands Flood Protection Project |publisher=Waterfront Toronto |access-date=October 27, 2020 }}</ref>

==Cleanup==
[[File:Don River and Bayview Ave Flooding in 20240716.jpg|thumb|On July 16, 2024, the flooding of the Don River and the nearby Bayview Avenue]]
In the 1880s, sewers were laid through ravines in the Don Valley to carry sewage, offal and industrial effluents. Pollution and foul odours continued until the late 1950s. Since then, small improvements have been made. The city installed waste water storage tanks, required homeowners to disconnect downspouts, and swept streets for contaminants that flowed into waterways. Since 1979, the Lower Don has shown improvements in dissolved oxygen, phosphates and suspended solids; however by 2021, the tributary Taylor-Massey Creek had shown little improvement.<ref name="G&M-2021-04-23" />

{{as of|2021}}, the Don River still suffers from sewage pollution during heavy rainfalls, when storm sewers carrying both rain water and sewage overflow into the Don River and its tributaries. To remedy this problem, the city is spending $3{{Nbsp}}billion to build three tunnels totaling {{convert|22|km}} in length to divert sewage away from the river and redirect it to the Ashbridges Bay Treatment Plant. The project began in 2018 with an expected completion in 2038 of all three tunnels plus five storm water storage shafts. {{As of|2021}}, a tunnel boring machine has completed roughly half of the {{convert|10.4|km|adj=on}} Coxwell Bypass tunnel located {{convert|50|m}} underground alongside the Lower Don south of the [[Leaside Bridge]].<ref name="G&M-2021-04-23">{{cite news |url=https://www.theglobeandmail.com/canada/article-torontos-natural-drainage-systems-its-ravines-get-a-makeover/ |title=Toronto's natural drainage systems, its ravines, get a makeover |newspaper=[[The Globe and Mail]] |first=Matthew |last=McClearn |date=April 23, 2021 |access-date=April 25, 2021}}</ref>

In October 2025, a peer-reviewed study found that the river carried the equivalent of 18-cars worth of [[microplastics]] into Lake Ontario every year.<ref>{{Cite news |last=Omstead |first=Jordan |date=October 23, 2025 |title=This river sends 500 billion microplastics into Lake Ontario each year: study |url=https://kitchener.citynews.ca/2025/10/23/this-river-sends-500-billion-microplastics-into-lake-ontario-each-year-study/ |access-date=October 23, 2025 |work=[[CityNews]] |agency=[[The Canadian Press]]}}</ref>

==See also==
* [[List of Ontario rivers]]
* [[List of bridges in Toronto]]
* [[Corktown Common]]

==References==
===Notes===
{{Reflist}}

===Bibliography===
* {{cite book |last=Bonnell |first=Jennifer L. |date=2014 |title=Reclaiming the Don: An Environmental History of Toronto's Don River Valley |publisher=University of Toronto Press}}
* {{cite book |last=Bonnell |first=Jennifer |publisher=thesis, University of Toronto |year=2010 |title=Imagined Futures and Unintended Consequences: An Environmental History of Toronto's Don River Valley }}
* {{cite book |last=Brown |first=Ron |title=Toronto's Lost Villages |year=1997 |publisher=Polar Bear Press |isbn=1896757022 }}
*{{cite book |author=Ontario Department of Planning and Development |title=Don Valley Conservation Report |location=Toronto, Ontario |year=1950 |ref={{harvid|ODPD|1950}}
}}
*Sauriol, Charles (1981) ''Remembering the Don: A Rare Record of Earlier Times Within the Don River Valley''. Consolidated Amethyst Communications. {{ISBN|0-920474-22-5}}
*Sauriol, Charles (1984) ''Tales of the Don''. Natural Heritage/Natural History. {{ISBN|0-920474-30-6}}
* {{cite book | last = Sauriol | first = Charles | title = Trails of the Don | year = 1992 | publisher = [[Hemlock Press]] | isbn = 0-929066-10-3 }}
* {{cite book | last = Scadding | first = Henry | author-link = Henry Scadding | year = 1873 | title = Toronto of Old | url = https://archive.org/details/ytorontoofoldcol00scad | publisher = [[Adam, Stevenson & Co.]] }}

==Further reading==

* {{cite book |last=Bonnell |first=Jennifer L. |date=2014 |title=Reclaiming the Don: An Environmental History of Toronto's Don River Valley |publisher=University of Toronto Press}}

==External links==
{{Commons category|Don River, Ontario}}
*[http://trca.on.ca/protect/watersheds/don-river/ Don River Watershed] at the [[Toronto and Region Conservation Authority]]
*[https://web.archive.org/web/20061003075454/http://www.on.ec.gc.ca/laws/coa/don-river-e.html Environment Canada (Toronto Remedial Action Plan) Great Lakes Portrait: Bringing back the Don River]
*[https://web.archive.org/web/20040614213836/http://www.toronto.ca/don/ Task Force to Bring back the Don]
*[https://web.archive.org/web/20040602211922/http://www.mwilson.on.ca/don.html Don Watershed Regeneration]
*[http://www.lostrivers.ca/LowerDon.htm Lower Don River] at Lost River Walks
*[http://www.fode.ca Friends of the Don East]
*[http://www.hopscotch.ca/tmwp/preserve/index.html Todmorden Mills Wildflower Preserve] in the Don River Valley

{{Toronto Waterways|state=expand}}
{{Toronto}}
{{greatlakes}}
{{Authority control}}

[[Category:Don River (Ontario)| ]]
[[Category:Rivers of Toronto]]
[[Category:Dredged rivers and waterways]]