1/24/10

A green roof for your house?

Since roofs represent 40-50% of impermeable surfaces in urban areas, green roofs have a big role to play in reducing urban runoff.  They have other benefits as well--read on....

 The following is condensed from a blog by Amy Norquist.
Too much weight is currently put on the need for more "infrastructure," meaning more pipes, more engineering, more disruption, more trying to control the flow, especially when it combines with rain. (It is as futile a solution as holding back the waters of Lake Ponchartrain during a major hurricane.) These "end of pipe solutions" represent the traditional approach to solving a problem caused by too many people paving over too many acres.
So what can better solve the problem with our sewers? The most obvious -- and most affordable--solution is bringing vegetation back into the cities that paved over green space to get there.

Green roofs can dramatically reduce runoff and sewage overflows. Green roofs--roofs covered with living plants, which are, by the way, beautiful -- as opposed to ones made of tar or other impervious materials, absorb water and are a less expensive way to capture water than trying to control it through end-of-pipe ideas. Nature becomes a bigger player, acting as the engineer. Building owners benefit and so do municipalities who have to spend much less on controlling their storm water.
Diagram from Greensulate
Green roofs also can indirectly effect the entry of heavy metals, nitrate, diesel soot, volatile organic compounds (VOCs), hydrocarbons and pesticides into local waters....

Green roofs last 20 to 75 years longer than conventional ones. And, for good measure, they improve air quality and provide habitat to endangered butterflies and bees, and arguably improve humans' experience of the world by providing more visually accessible green space.

Green roofs are not only the economically superior strategy but their additional benefits are huge: reducing Co2 and particulate matter, and flooding cities with beauty instead of contaminated storm water.

Looking even further -- and more globally -- down the road, scientists at Columbia University (NASA's Goddard Institute) have concluded that the combination of planting more street trees along with Green roofs looks like the best single mitigation strategy for the effects of climate change in urban areas.

Green roofs in Madison
  • City Engineering's Emil Street office has a small green roof
  • The new Microbial Sciences Building on Linden Dr.
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More about Amy Norquist.
Read Amy Norquist's blog on the Huffington post.

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