Umbrella Stormwater Bulletin 41
17 February 2016
Published by Green Communities Canada
Capturing rainâ€”finding the right words
Photo credit: Seattle Public Utilities
Rain falls on a city - but instead of running off into a storm drain, it flows into a curbside rain garden, off a roof into a cistern, or is absorbed into vegetation planted on roofs.
What is this called?
Storm drains and pipes are known as grey infrastructure - thereâ€™s no debate about that. But techniques for managing rain where it falls, including rain gardens, bioswales, infiltration galleries, green roofs and cisterns are known by many names.
In the Umbrella bulletin, we tend to use the terms green infrastructure or green stormwater infrastructure- terms that emphasize the economic value of the ecosystem services they provide. But other terms are also popular in Ontario. These include Low Impact Development (LID), stormwater innovations, or source controls (these terms, along with green infrastructure, can all be found in government policies and reports). In the rest of Canada and the world other terms are popular - sustainable rainwater management practices, sustainable urban drainage systems and water-sensitive urban design are just a few others.
The multitude of terms can lead to confusion when discussing stormwater with different stakeholders. Some people may be familiar with one of these terms and be unaware that others refer to the same thing. Those new to the issue do not find the terminology very descriptive. Low impact development, for example, is very popular among the engineering and consulting sector, but it would be quite hard to make an educated guess at its meaning if you werenâ€™t familiar with the term. Shortening it to LID makes it even harder to guess at.
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Is rain garden soil toxic? Rain gardens are designed to capture stormwater and to slowly absorb rain into the ground. Stormwater commonly contains nitrogen, phosphorus, heavy metals, petroleum, fecal matter, and a variety of other pollutants that are filtered through the soil in a rain garden. Studies show that rain gardens provide a variety of services that help to capture and reduce soil contamination, and keep pollutants out of our lakes and streams.
The pros and the cons of stormwater credit trading.Cities can realize the infiltration potential of private land by requiring on-site stormwater retention as a condition of construction permitting. To help property owners meet these conditions, credit trading programs enable people to meet a portion of their retention requirements by buying stormwater â€˜creditsâ€™ from other property owners who are able to exceed the requirements. While these programs can be costly to administer they encourage many smaller retention sites across a watershed which provides better water quality outcomes than a few larger green stormwater infrastructure sites.
Snowy neckdownsâ€”a free resource for city planners.Neckdowns are a form of traffic calming that narrows the roadway so pedestrians have a shorter distance to cross at intersections, and also causes cars to slow down when making turns. When it snows, car tracks reveal just how little of the road they use and where neckdowns are possibleâ€”also indicating spaces that can be used for rain gardens and bioswales to absorb road runoff. British town avoids winter floods by mimicking local moors. While many British cities experienced extreme flooding this winter- one town in Yorkshire has remained â€œdryâ€. Pickering has a history of extreme flooding but by building leaky dams with logs and branches, planting 72 acres of woodlands, and building smaller dams from bales of heather they reduced peak flows and avoided the flooding that impacted neighbouring communities.
Parks that turn into ponds. Copenhagen is retrofitting in order to weather the impacts of climate change. The city is building parks that will turn into small ponds during heavy rains, allowing them to capture and retain water on site. Landscape architect Rafn Thomsen says, â€œWater is used as a resource to improve urban life. We look at Copenhagen as a hybrid city where you can fuse nature, urban biology, and human beings in a more appropriate balance.â€
Helping communities soak up rain. Green Communities Canada has created the Soak It Up! toolkit, a document that showcases a variety of tools for integrating green stormwater infrastructure across the urban landscape. Each section contains an overview the tool, examples from real-world experience (many from within Canada), and insights from practitioners about what works bestâ€”and what doesnâ€™t.
Public response to incentive programs for rain gardens.This study reviews household responses to a rebate program to incentivize rain garden adoption in the Baltimore-Washington corridor. The study concludes that a cost-share rebate approach is likely to significantly affect household adoption decision, and the partial contributions paid by a household can assist with lowering the costs for local governments to manage stormwater.
Tools, strategies, and lessons learned from green infrastructure projects. Created by the US Environmental Protection Agency, this document summarizes green infrastructure solutions for municipal challenges for managing stormwater.
Want to see more events? Check out the RAIN Events Calendar for other upcoming green infrastructure workshops, training, webinars and conferences.
The Umbrella Stormwater Bulletin is a free, biweekly newsletter on green stormwater infrastructure published by the RAIN Community Solutions program of Green Communities Canada. Our audience is made up of municipal stormwater professionals, policymakers, academics, engineers, conservation authorities, nonprofits, and interested community members. We encourage submissions from our readers. Please contact the editor to submit a news item, blog idea, or event. RAIN Community Solutions builds support for and participation in stormwater innovations that reduce runoff by managing rain where it falls.