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This is from today's Daily Construction News and gives a pretty good overview of the plans.
Waterfront Toronto harbours ambitious ideas for Lower Don Lands
PETER KENTER
correspondent
There’ll be plenty of civil construction centred around the mouth of Toronto’s Don River in years to come if Toronto city council approves a series of environmental assessments (EAs) for the area.
Waterfront Toronto has just released its Lower Don Lands Infrastructure Master Plan and Keating Channel Precinct Environmental Study Report.
The report sets out an ambitious new plan to alter stormwater flows through the Lower Don Lands, the Don River and the Keating Channel.
The Toronto and Region Conservation Authority is preparing an Individual EA concerning the naturalization of the mouth of the Don River—the Don Mouth Naturalization and Port Lands Flood Protection Project Environmental Assessment (DMNP EA)—which examines steps to remove flood risk from 230 hectares of land south and east of the existing Keating Channel.
The DMNP EA will also provide hydraulic conveyance requirements for each bridge crossing and provide recommendations for the design and location of infrastructure crossings.
The study area is similar to the Lower Don Lands Master Plan, but includes the Don Narrows up to Riverdale Park.
The preferred alternative in the master plan would centre the new mouth of the Don River in the middle of the Lower Don Lands study area, south of the Keating Channel.
“The mouth of the Don was engineered to its current state in 1914 with a 90 degree turn into the Keating Channel,” says John Campbell, president and CEO of Waterfront Toronto. “That part of the city should be the jewel of the waterfront, instead of a dredging pit. In its current form, if we had a Hurricane Hazel in the Don River watershed, the flood could reach Leslieville, blocks to the east.”
Campbell says construction work designed to engineer wetlands, improve stormwater and flood control, and modify bridges could tally around $600 million.
Waterfront Toronto has already overseen a $20-million river-widening program, which included extending the CN rail bridge crossing the Don River at Lakeshore Boulevard from two spans to three.
The master plan recommends establishment of a low-flow channel about 15 metres wide and 1.5 metres deep with an associated floodplain of 150 to 200 metres wide.
It also proposes construction of a large peninsula extending 150 metres into the Inner Harbour from Cousins Quay.
The proposed plan also includes recommendations to build large stormwater tanks, designed to treat stormwater using filtration and UV light before releasing it.
Under the preferred stormwater plan, the Keating Channel would be retained but would not be used to accept flow from the river mouth during normal conditions.
In case of a large flood, the flow would be diverted through three separate paths.
This first would be the new naturalized river valley that continues south along the Don Roadway.
The second would continue west through the Keating Channel as before, but only when flood waters top the new weirs that would be installed at the east end of the channel.
The third path allows water to pass through the Ship Channel Wetland or Greenway, a wetland habitat in the naturalized area of the mouth of the Don.
Stormwater in newly developed areas of the Lower Don Lands will be separated into streams. Road runoff containing salt and other pollutants won’t be of sufficient quality to feed the needs of the wetlands, so a discreet stream of water collected from building roofs will be used to feed the naturalized habitat.
Excess water from this stream will be used to irrigate Silva Cells, underground structures designed to prevent soil compaction and retain stormwater beneath roads and sidewalks. The units provide a framework to protect and encourage the growth of tree roots.
“The life of a tree in downtown Toronto is usually no more than about five years,” says Campbell. “With this system, each tree gets about 30 cubic metres of soil, which will allow us to grow legacy trees.”
The proposed plan will require Toronto city council approval before it can be funded.
“It’s a challenge,” says Campbell. “You can’t begin to secure funding until you know exactly what you’re asking for. To us, the environmental assessment before council defines for us the cheapest and most effective way to create the most value in that area of the city. If there’s another round of stimulus funding, these projects will be shovel-ready.”
Waterfront Toronto harbours ambitious ideas for Lower Don Lands
PETER KENTER
correspondent
There’ll be plenty of civil construction centred around the mouth of Toronto’s Don River in years to come if Toronto city council approves a series of environmental assessments (EAs) for the area.
Waterfront Toronto has just released its Lower Don Lands Infrastructure Master Plan and Keating Channel Precinct Environmental Study Report.
The report sets out an ambitious new plan to alter stormwater flows through the Lower Don Lands, the Don River and the Keating Channel.
The Toronto and Region Conservation Authority is preparing an Individual EA concerning the naturalization of the mouth of the Don River—the Don Mouth Naturalization and Port Lands Flood Protection Project Environmental Assessment (DMNP EA)—which examines steps to remove flood risk from 230 hectares of land south and east of the existing Keating Channel.
The DMNP EA will also provide hydraulic conveyance requirements for each bridge crossing and provide recommendations for the design and location of infrastructure crossings.
The study area is similar to the Lower Don Lands Master Plan, but includes the Don Narrows up to Riverdale Park.
The preferred alternative in the master plan would centre the new mouth of the Don River in the middle of the Lower Don Lands study area, south of the Keating Channel.
“The mouth of the Don was engineered to its current state in 1914 with a 90 degree turn into the Keating Channel,” says John Campbell, president and CEO of Waterfront Toronto. “That part of the city should be the jewel of the waterfront, instead of a dredging pit. In its current form, if we had a Hurricane Hazel in the Don River watershed, the flood could reach Leslieville, blocks to the east.”
Campbell says construction work designed to engineer wetlands, improve stormwater and flood control, and modify bridges could tally around $600 million.
Waterfront Toronto has already overseen a $20-million river-widening program, which included extending the CN rail bridge crossing the Don River at Lakeshore Boulevard from two spans to three.
The master plan recommends establishment of a low-flow channel about 15 metres wide and 1.5 metres deep with an associated floodplain of 150 to 200 metres wide.
It also proposes construction of a large peninsula extending 150 metres into the Inner Harbour from Cousins Quay.
The proposed plan also includes recommendations to build large stormwater tanks, designed to treat stormwater using filtration and UV light before releasing it.
Under the preferred stormwater plan, the Keating Channel would be retained but would not be used to accept flow from the river mouth during normal conditions.
In case of a large flood, the flow would be diverted through three separate paths.
This first would be the new naturalized river valley that continues south along the Don Roadway.
The second would continue west through the Keating Channel as before, but only when flood waters top the new weirs that would be installed at the east end of the channel.
The third path allows water to pass through the Ship Channel Wetland or Greenway, a wetland habitat in the naturalized area of the mouth of the Don.
Stormwater in newly developed areas of the Lower Don Lands will be separated into streams. Road runoff containing salt and other pollutants won’t be of sufficient quality to feed the needs of the wetlands, so a discreet stream of water collected from building roofs will be used to feed the naturalized habitat.
Excess water from this stream will be used to irrigate Silva Cells, underground structures designed to prevent soil compaction and retain stormwater beneath roads and sidewalks. The units provide a framework to protect and encourage the growth of tree roots.
“The life of a tree in downtown Toronto is usually no more than about five years,” says Campbell. “With this system, each tree gets about 30 cubic metres of soil, which will allow us to grow legacy trees.”
The proposed plan will require Toronto city council approval before it can be funded.
“It’s a challenge,” says Campbell. “You can’t begin to secure funding until you know exactly what you’re asking for. To us, the environmental assessment before council defines for us the cheapest and most effective way to create the most value in that area of the city. If there’s another round of stimulus funding, these projects will be shovel-ready.”
