Green infrastructure: Cost comparison

Wed, 2014-10-29 17:12 — ED
Below is a note to the heads of environmental services and development reviews at the City, copied to Councillor Chernushenko.

Re the reference to the new PPS, here is an excerpt from province of ontario/new provincial policy statement 2014/:

+ “Green infrastructure” is explicitly encouraged (new s. 1.6.2). It is defined as: “natural and human-made elements that provide ecological and hydrological functions and processes. Green infrastructure can include components such as natural heritage features and systems, parklands, stormwater management systems, street trees, urban forests, natural channels, permeable surfaces, and green roofs.”


From: Erwin Dreessen
Sent: Wednesday, October 29, 2014 4:44 PM
To: Dixon Weir; John Moser
Cc: Councillor David Chernushenko
Subject: Low Impact Development – cost comparison


I take the liberty to bring to your attention a March 2012 brief from the US Environmental Protection Agency showing some cost comparisons between conventional and low impact development (LID) practices for stormwater management and flood control.

“A U.S. Environmental Protection Agency study of 17 LID case studies around the country found that, in the majority of cases, total capital cost savings ranged from 15 to 80 percent when LID methods were used. (For details, see [no longer online].)” This is in addition to a range of benefits that are more difficult to quantify.

With the strengthened directive about green infrastructure in the new Provincial Policy Statement we expect to see increased application of its principles in City works and approved developments. Is any person or group among your respective staffs dedicated to ensuring that this happens?


Erwin Dreessen


Greenspace Alliance of Canada’s Capital

[Archivist’s note: The reference to “nps/lid/costs07” could no longer be found on the EPA web site, but here is an older reference on the subject: <>.]


No response was received from the addressees.  I forwarded the above to some staff members whom I knew to be sympathetic to new practices. One of them advised on November 4, 2014:

A few of us attended a workshop last Thursday about Low Impact Development and protection/resilience of systems.

Please see the attached links below.

As well, Credit Valley Conservation is a leader in Low Impact Development. We are endorsing this approach and so are the Conservation Authorities. If you have not seen these resources, please check out this link as well.

[Posted to the GA List, 5Nov2014]