EARTHWATCH: GREEN ROOFS AND MORE
September 2004
Articles
By Paul Henderson
PLANTING GARDENS IN THE SKY
As concrete jungles go it’s hard to find a square kilometre in Canada that is any greyer, any louder, or any stinkier than the roof of the City of Toronto’s John Street Pumping Station.
Exhaust emanating from the traffic just metres to the south on the Gardiner Expressway permeates the air creating an asthmatic haze and a smoggy barrier, masking the view of the sliver of Lake Ontario visible between condominiums. Looming ominously above to the north is that concrete albatross, SkyDome. Then add to the relentless drone of nearby traffic the clanging and banging of cranes, trucks, and workers erecting two high-rise condominiums to the west.
What a perfect location for butterflies, birds, and 9,127 square feet of green space. No, it’s not a new park. It’s not even on the ground. Kaaren Pearce and her company Elevated Landscape Technologies have recently finished greening the roof of the John Street Pumping Station with sedum plants and wildflowers.
Green roofs, living roofs, rooftop gardens, are all becoming more common in Toronto and around the world because of their many environmental benefits. And, quite simply, according to Pearce: “There’s no real reason not to do it.”
A major benefit of green roofs is to combat what is known as the “urban heat island effect.” Urban areas are noticeably hotter because of the lack of green spaces that cool the air through a process known as “transpiration.” This occurs when plants secrete water through pores drawing heat as it evaporates. This cools the air and it is estimated a mature tree with a 30 foot crown can transpire up to 40 gallons of water in a day.
Greening as much as 50% of the roofs of Toronto — as some are suggesting the city should do — could have a major impact on temperature in the city.
Possibly the most important benefit of green roofs is storm water management. Think of the massive number of buildings in the city. When it rains, all that water collects all the chemicals and toxins on all the roofs and much of it is washed into the lake.
In a natural cycle 30% of the water is used by plants, 30% percolates to aquifers, and 40% is returned to the atmosphere through transpiration. There is no surface runoff. In the urban environment about 5% goes to aquifers, 15% is returned to the atmosphere, and 75% is surface runoff, according to Pearce.
During heavy rainfall excess runoff can overwhelm the city’s sewer system leading to water draining through the streets, picking up all kinds of crap, ending in the lake.
Green spaces, parks, private lawns and gardens, and green roofs hold on to that water, transpiring some of it and helping to keep the runoff in check.
“Everything in the city is non-permeable,” Pearce explains. “This type of roof slows heat down and means we aren’t washing various nasties into the lake. Parks in cities provide green links, and this is another way to further the green links.”
Green roofs also help to cool the building they are on, saving money on air conditioning and lessening the ecological footprint of the building using less electricity. More green spaces also help to provide more habitat in the concrete jungle for butterflies and birds.
There are two types of green roofs: intensive and extensive. Extensive green roofs, like the newly greened John Street Pumping Station, have a very shallow depth of soil and are planted with mosses and herbs. These roofs are primarily designed for their environmental benefits as opposed to a place for people to visit and hang out.
Intensive green roofs require much more soil, elaborate irrigation, and are planted with larger plants and trees. Vegetables can be grown on these types of roofs and indeed are a great way to help supplement the local food supply. The office building at 401 Richmond Street West has a rooftop garden where they grow herbs and vegetables, and the Royal York Hotel grows the herbs for their kitchen on a rooftop garden on that building.
The one downside to green roofs, which is more a factor with intensive green roofs, is the fact that they can be quite heavy. Indeed a building with a rooftop garden requires substantially more load-bearing capacity than a standard roof. This means more wood and steel, which means the building’s environmental footprint is bigger. Depending on the type of roof green roofs also require metal flashing, a rubber membrane, and other materials that may counteract the decreased environmental footprint the green roof is intended to create.
It is for this reason that Pearce is taking green roofs to the next level, to ensure they are only a benefit to users, and to the environment.
“I’ve done 18 of them and discovered they aren’t all environmentally friendly,” Pearce confesses. “That’s why now we want to make sure our materials are Canadian, recycled, environmentally friendly, post-industrial waste, and we use native plants and native soils.”
The green roof at the John Street Pumping Station is planted mostly with sedum in an aggregate made with waste slag from the steel industry. This makes for a relatively light green roof that will not require watering once the plants are established. While Pearce designed this roof it was not done with the patented system from her company Elevated Landscape Technologies. The Easy Green green roofing system is a pre-grown system on an interlocking water retention and drainage layer, and it is made with mostly recycled products. It is very lightweight meaning it works on most roofs regardless of load-bearing capacity. This green roofing system is so light and practical that it can easily be installed on inclines and even vertically.
“I did my front porch,” Pearce said, “and all my neighbours want it now. You can do gazeboes, pool houses, garages.”
Like many emerging and environmentally friendly technologies, this one requires a broad-based recognition of its societal and fiscal value, and therefore subsidies and/or tax incentives to accelerate development and usage.
As with wind power, Germany and much of Europe is miles ahead on green roofs. In certain jurisdictions governments tax water runoff so people have an incentive to green their roofs. In Germany, Sweden, and Austria governments have implemented tax incentives and density bonusing to encourage green roofing.
According to Pearce, Toronto was initially a North American leader in green roofing but things are happening slowly here. Portland, Oregon has a density bonus allowance meaning if you are building and you put up a green roof you can put up an extra floor. Calgary has said that all new civic buildings will have green roofs. New York has a program called Greening Gotham.
The City of Toronto government has greened the Eastview Community Centre, and city hall has a 3,200 square foot green roof, yet the city is still claiming they need to do more studies to find out the benefits.
Pearce and others know the benefits and with their enthusiasm more and more roofs all over the city will be turning up green. Check out www.eltgreenroofs.com for more information on Pearce's company. Also see www.greenroofs.com. Nigel Dunnett and Noël Kingsbury’s authoritative book, Planting Green Roofs and Living Walls (Timber Press, 2004) is work a look if you’re really keen to learn more.
ENWAVE COOLS THE CITY WITH DEEP LAKE WATER
While Vitality was getting a tour of the newly greened roof of the John Street Pumping Station, workers were busy refitting the inside of the station for part of what is being dubbed one of the largest alternative energy systems in the world.
Enwave announced in August the deep lake water cooling system that will be used to cool buildings in downtown Toronto including Royal Bank Plaza, the Metro Toronto Convention Centre, and the Steam Whistle Brewery.
The system works by drawing near-freezing water from 83 metres below the surface of Lake Ontario. Then, at the John Street Pumping Station heat exchangers transfer the energy from the cold water to be used in the downtown buildings.This water then continues through the station for normal distribution into the city’s potable water supply.
According to Enwave this system will reduce energy usage by 75%, freeing up more than 59 megawatts form Ontario’s electrical grid. This will remove 40,000 tonnes of carbon dioxide from the air, equivalent to taking 8,000 cars off the road.
WATER WARS ARE LOOMING
This sounds a little like a bleak futuristic Hollywood movie starring Kevin Costner, but “water wars” could be coming, according to scientists.
Scientists at the World Water Week conference in Stockholm last month said that ignorance and complacency about the growing problems related to water could lead to wars, particularly in “potential flashpoints” such as the Middle East.
“We’ve had oil wars,” Prof. William Mitsch of Ohio State University told Reuters. “Water wars are possible.”
The global population will grow to 8 billion by 2025 with almost all new growth in urban centres. That is, and will continue, causing real stress on water supplies to provide clean drinking water and food. The worldwide infrastructure investments in water systems of $80 billion has been half of what it should be, according to the scientists.
“I can’t ... see a way out over the next few years,” Dr. David Molden, co-author of the water institute’s report, said. “I think we will reach a real crisis.”
In North America where, for the time being, water is relatively abundant we are consuming water and draining aquifers at an astronomical rate. And when it comes to water use one of the most mind-bogglingly wasteful uses is factory farming meat production. Many have heard some variation of the calculation, originally from visionary Frances Moore Lappé in her 1971 classic, Diet for a Small Planet, that the grain it takes to feed one serving of meat could have fed 10 people with the grain itself. A compelling statistic to be sure. But when it comes to water usage for meat production the numbers are startling. It takes about 25 gallons of water to produce one pound of wheat, but about 2,500 gallons of water to produce one pound of beef, according to John Robbins, author of The Food Revolution (2001) and Diet for a New America (1987).
If you are thinking of installing a low-flow shower head in your house that’s a great idea. But for comparison, the water you save per year with that low-flow shower head might be about the same amount of water as it takes to produce a pound of beef. Cut out a few meat meals a month and you could be saving many thousands of litres of water. So here’s a thought: A vegetarian who takes long, hot showers twice daily is wasting considerably less water than a beef eater who never bathes.
ECOPALOOZA COMES TO NIAGARA REGION
Ecopalooza, Niagara's 1st Annual Expo Of Green Living, Alternative Architecture And Wicked Tunes, will be held in St. Catharines, Ont., on October 3 from 11a.m. to 6 p.m. Here you can learn about environmentally responsible, economical options open for nearly every choice you make. Sample vegetarian cuisine, pick out some fresh organic produce, try your hand at straw bale building, while listening to the area's best musicians. For more information call (905) 714-9912, or visit www.ecopalooza.com
PLANTING GARDENS IN THE SKY
As concrete jungles go it’s hard to find a square kilometre in Canada that is any greyer, any louder, or any stinkier than the roof of the City of Toronto’s John Street Pumping Station.
Exhaust emanating from the traffic just metres to the south on the Gardiner Expressway permeates the air creating an asthmatic haze and a smoggy barrier, masking the view of the sliver of Lake Ontario visible between condominiums. Looming ominously above to the north is that concrete albatross, SkyDome. Then add to the relentless drone of nearby traffic the clanging and banging of cranes, trucks, and workers erecting two high-rise condominiums to the west.
What a perfect location for butterflies, birds, and 9,127 square feet of green space. No, it’s not a new park. It’s not even on the ground. Kaaren Pearce and her company Elevated Landscape Technologies have recently finished greening the roof of the John Street Pumping Station with sedum plants and wildflowers.
Green roofs, living roofs, rooftop gardens, are all becoming more common in Toronto and around the world because of their many environmental benefits. And, quite simply, according to Pearce: “There’s no real reason not to do it.”
A major benefit of green roofs is to combat what is known as the “urban heat island effect.” Urban areas are noticeably hotter because of the lack of green spaces that cool the air through a process known as “transpiration.” This occurs when plants secrete water through pores drawing heat as it evaporates. This cools the air and it is estimated a mature tree with a 30 foot crown can transpire up to 40 gallons of water in a day.
Greening as much as 50% of the roofs of Toronto — as some are suggesting the city should do — could have a major impact on temperature in the city.
Possibly the most important benefit of green roofs is storm water management. Think of the massive number of buildings in the city. When it rains, all that water collects all the chemicals and toxins on all the roofs and much of it is washed into the lake.
In a natural cycle 30% of the water is used by plants, 30% percolates to aquifers, and 40% is returned to the atmosphere through transpiration. There is no surface runoff. In the urban environment about 5% goes to aquifers, 15% is returned to the atmosphere, and 75% is surface runoff, according to Pearce.
During heavy rainfall excess runoff can overwhelm the city’s sewer system leading to water draining through the streets, picking up all kinds of crap, ending in the lake.
Green spaces, parks, private lawns and gardens, and green roofs hold on to that water, transpiring some of it and helping to keep the runoff in check.
“Everything in the city is non-permeable,” Pearce explains. “This type of roof slows heat down and means we aren’t washing various nasties into the lake. Parks in cities provide green links, and this is another way to further the green links.”
Green roofs also help to cool the building they are on, saving money on air conditioning and lessening the ecological footprint of the building using less electricity. More green spaces also help to provide more habitat in the concrete jungle for butterflies and birds.
There are two types of green roofs: intensive and extensive. Extensive green roofs, like the newly greened John Street Pumping Station, have a very shallow depth of soil and are planted with mosses and herbs. These roofs are primarily designed for their environmental benefits as opposed to a place for people to visit and hang out.
Intensive green roofs require much more soil, elaborate irrigation, and are planted with larger plants and trees. Vegetables can be grown on these types of roofs and indeed are a great way to help supplement the local food supply. The office building at 401 Richmond Street West has a rooftop garden where they grow herbs and vegetables, and the Royal York Hotel grows the herbs for their kitchen on a rooftop garden on that building.
The one downside to green roofs, which is more a factor with intensive green roofs, is the fact that they can be quite heavy. Indeed a building with a rooftop garden requires substantially more load-bearing capacity than a standard roof. This means more wood and steel, which means the building’s environmental footprint is bigger. Depending on the type of roof green roofs also require metal flashing, a rubber membrane, and other materials that may counteract the decreased environmental footprint the green roof is intended to create.
It is for this reason that Pearce is taking green roofs to the next level, to ensure they are only a benefit to users, and to the environment.
“I’ve done 18 of them and discovered they aren’t all environmentally friendly,” Pearce confesses. “That’s why now we want to make sure our materials are Canadian, recycled, environmentally friendly, post-industrial waste, and we use native plants and native soils.”
The green roof at the John Street Pumping Station is planted mostly with sedum in an aggregate made with waste slag from the steel industry. This makes for a relatively light green roof that will not require watering once the plants are established. While Pearce designed this roof it was not done with the patented system from her company Elevated Landscape Technologies. The Easy Green green roofing system is a pre-grown system on an interlocking water retention and drainage layer, and it is made with mostly recycled products. It is very lightweight meaning it works on most roofs regardless of load-bearing capacity. This green roofing system is so light and practical that it can easily be installed on inclines and even vertically.
“I did my front porch,” Pearce said, “and all my neighbours want it now. You can do gazeboes, pool houses, garages.”
Like many emerging and environmentally friendly technologies, this one requires a broad-based recognition of its societal and fiscal value, and therefore subsidies and/or tax incentives to accelerate development and usage.
As with wind power, Germany and much of Europe is miles ahead on green roofs. In certain jurisdictions governments tax water runoff so people have an incentive to green their roofs. In Germany, Sweden, and Austria governments have implemented tax incentives and density bonusing to encourage green roofing.
According to Pearce, Toronto was initially a North American leader in green roofing but things are happening slowly here. Portland, Oregon has a density bonus allowance meaning if you are building and you put up a green roof you can put up an extra floor. Calgary has said that all new civic buildings will have green roofs. New York has a program called Greening Gotham.
The City of Toronto government has greened the Eastview Community Centre, and city hall has a 3,200 square foot green roof, yet the city is still claiming they need to do more studies to find out the benefits.
Pearce and others know the benefits and with their enthusiasm more and more roofs all over the city will be turning up green. Check out www.eltgreenroofs.com for more information on Pearce's company. Also see www.greenroofs.com. Nigel Dunnett and Noël Kingsbury’s authoritative book, Planting Green Roofs and Living Walls (Timber Press, 2004) is work a look if you’re really keen to learn more.
ENWAVE COOLS THE CITY WITH DEEP LAKE WATER
While Vitality was getting a tour of the newly greened roof of the John Street Pumping Station, workers were busy refitting the inside of the station for part of what is being dubbed one of the largest alternative energy systems in the world.
Enwave announced in August the deep lake water cooling system that will be used to cool buildings in downtown Toronto including Royal Bank Plaza, the Metro Toronto Convention Centre, and the Steam Whistle Brewery.
The system works by drawing near-freezing water from 83 metres below the surface of Lake Ontario. Then, at the John Street Pumping Station heat exchangers transfer the energy from the cold water to be used in the downtown buildings.This water then continues through the station for normal distribution into the city’s potable water supply.
According to Enwave this system will reduce energy usage by 75%, freeing up more than 59 megawatts form Ontario’s electrical grid. This will remove 40,000 tonnes of carbon dioxide from the air, equivalent to taking 8,000 cars off the road.
WATER WARS ARE LOOMING
This sounds a little like a bleak futuristic Hollywood movie starring Kevin Costner, but “water wars” could be coming, according to scientists.
Scientists at the World Water Week conference in Stockholm last month said that ignorance and complacency about the growing problems related to water could lead to wars, particularly in “potential flashpoints” such as the Middle East.
“We’ve had oil wars,” Prof. William Mitsch of Ohio State University told Reuters. “Water wars are possible.”
The global population will grow to 8 billion by 2025 with almost all new growth in urban centres. That is, and will continue, causing real stress on water supplies to provide clean drinking water and food. The worldwide infrastructure investments in water systems of $80 billion has been half of what it should be, according to the scientists.
“I can’t ... see a way out over the next few years,” Dr. David Molden, co-author of the water institute’s report, said. “I think we will reach a real crisis.”
In North America where, for the time being, water is relatively abundant we are consuming water and draining aquifers at an astronomical rate. And when it comes to water use one of the most mind-bogglingly wasteful uses is factory farming meat production. Many have heard some variation of the calculation, originally from visionary Frances Moore Lappé in her 1971 classic, Diet for a Small Planet, that the grain it takes to feed one serving of meat could have fed 10 people with the grain itself. A compelling statistic to be sure. But when it comes to water usage for meat production the numbers are startling. It takes about 25 gallons of water to produce one pound of wheat, but about 2,500 gallons of water to produce one pound of beef, according to John Robbins, author of The Food Revolution (2001) and Diet for a New America (1987).
If you are thinking of installing a low-flow shower head in your house that’s a great idea. But for comparison, the water you save per year with that low-flow shower head might be about the same amount of water as it takes to produce a pound of beef. Cut out a few meat meals a month and you could be saving many thousands of litres of water. So here’s a thought: A vegetarian who takes long, hot showers twice daily is wasting considerably less water than a beef eater who never bathes.
ECOPALOOZA COMES TO NIAGARA REGION
Ecopalooza, Niagara's 1st Annual Expo Of Green Living, Alternative Architecture And Wicked Tunes, will be held in St. Catharines, Ont., on October 3 from 11a.m. to 6 p.m. Here you can learn about environmentally responsible, economical options open for nearly every choice you make. Sample vegetarian cuisine, pick out some fresh organic produce, try your hand at straw bale building, while listening to the area's best musicians. For more information call (905) 714-9912, or visit www.ecopalooza.com