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The Don River is a watercourse in southern Ontario, that empties into Lake Ontario, at Toronto Bay. Its mouth was just east of the street grid of the town of York, Upper Canada, the municipality that evolved into Toronto, Ontario. Of the various watercourses that drained Toronto, the Don, the Humber River, and the Rouge River have headwaters in the Oak Ridges Moraine. The Don is formed from two rivers, the East and West Branches, that meet about 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. ==History== Humans first arrived in the Don approximately 12,500 years BP, most likely as nomadic hunters.〔Task Force to Bring Back the Don. August 1991. Bringing Back the Don. City of Toronto.〕 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.〔(Civilization.ca. Early Great Lakes-St. Lawrence Culture )〕 The most significant recorded find is known as the ''Withrow Site''. It was discovered in 1886 during road building just east of Riverdale Park. It contained human remains and other artifacts dating back to about 5000 years BP.〔 It is unclear whether the Don River had a native Canadian name. In 1788, Alexander Aitkin, an English surveyor who worked in southern Ontario, referred to the Don River as ''Ne cheng qua kekonk''.〔City of Toronto (Toronto Golf History ). Accessed March 24, 2007〕 Elizabeth Simcoe, wife of Lieutenant Governor John Graves Simcoe, reported in her diary that another name used was ''Wonscotanach''.〔Robertson, J.R. 2001. ''The Diary of Mrs. John Graves Simcoe''. Toronto, Ont. Prospero Books.〕 This is an 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. The name Don River was given by Lt. Gov. Simcoe because the wide valley reminded him of the River Don in Yorkshire, England. 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, the Lower Don was becoming an industrial setting. Petroleum storage facilities, poultry and pork processing plants were constructed along the banks of the Don. In 1879, the Don Valley Brick Works opened.〔(Story of the Don. 1998. Task Force to Bring Back the Don )〕 Polluted effluent from these factories and the growing city nearby was turning the Don and its marshy mouth into a polluted hazard. In the 1880s, the lower part of the Don south of the former Winchester St. 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 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 Blvd. East ceased being navigable when the Gardiner Expressway was constructed in the 1950s. Boats may still enter the Keating Channel by going underneath a lift bridge at Cherry St. During the early part of the 20th century the river and the valley continued to be neglected. 31 separate sewage treatment facilities were built along the river.〔How polluted is the Don. Don Watershed Regeneration. Note: only one treatment plant remains.()〕 Over 20 places in the valley and adjacent ravines were used as landfills for garbage and industrial refuse.〔K.W.F. Howard, N. Eyles, S. Livingstone. 1996. Municipal Landfilling Practice And Its Impact On Groundwater Resources In And Around Urban Toronto, Canada. Hydrogeology Journal. Vol 4, No. 1, 64-79.〕 In 1917, the Don Destructor was built beside the Don just north of Dundas Ave. East. It was used as a garbage incinerator for 52 years burning about 50,000 tonnes per year.〔(The Don Destructor. Lost Rivers )〕 After World War II, rapid urban expansion occurred in the northern reaches of the watershed. At the same time, interest in conservation of watersheds across Ontario led to the formation of conservation authorities for watershed management. Conservation authorities were established across Ontario to manage river valleys, and the Don Valley Conservation Authority was established in 1947. The authority had limited authority, funded by local municipalities. Land purchases had to be specifically paid for by local municipalities. For example, a 1950 plan to build a large conservation area on the East Don River at Lawrence Avenue never came to pass over the cost of developing it. 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. The Association continued its activities, planting tree seedlings, stopped the picking of wild flowers, particularly trilliums and preventing the vandalism of trees. The Association held educational events to educate the public about the Don Valley, including special trains through the valley, and a recreation of 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. In 1954, Hurricane Hazel struck the Toronto area. Most of the damage occurred in the Humber River area. While there was some flooding, substantially less rain fell over the Don Watershed resulting in no loss of life. 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. In the 1950s and early 1960s, the Don Valley Parkway (DVP) was constructed through the Lower Don to serve the growing commuter traffic. The project was a large civil engineering project. Two hills within the valley were levelled and the soil used for grading the highway. The railways and the river were re-routed, Don Mills Road was expanded and the Eglinton Avenue and Lawrence Avenue arterial roads were built across the valley. At the intersection of Lawrence and the Parkway, the remains of the old village of Milneford Mills were removed. 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 was a neglected, polluted mess. In 1969, Pollution Probe held a much celebrated “Funeral for the Don” to highlight the plight of the river.〔 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.〔How did the Task Force to Bring Back the Don get started? Mark J. Wilson. Frequently Asked Questions. BBTD. 2001. ()〕 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 3 ha site south of the Bloor Viaduct.〔(Chester Springs Marsh. Lost Rivers )〕 Other groups also became active including Friends of the Don East. The TRCA created the Don Watershed Regeneration Council to coordinate restoration efforts throughout the watershed. 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 modelled 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 Associates.〔(Portlands Estuary. 2007. Waterfront Toronto )〕 The environmental assessment is expected to be complete in 2008 and construction is scheduled to begin in 2010.〔Don Mouth Environmental Assessment, Terms of Reference. 2006. Toronto Region Conservation Authority. ()〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Don River (Ontario)」の詳細全文を読む スポンサード リンク
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