Trees Please Hamilton

Green Solutions to Air Pollution

Rain Gardens and Storm Water Management Forum

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The Restoring Resilient Spaces workshop series kicked off last Tuesday evening at the Perkins Centre with a Rain Gardens and Storm Water Management Forum.  Our guest speakers hailed from Credit Valley Conservation, the City of Hamilton, and Green Venture, the Bay Area Restoration Council, and the Hamilton Conservation Authority all attended the event to share their knowledge and ongoing projects.

With the expectation of more extreme weather events into the future and an aging infrastructure system, the time is now to restore resilient green spaces in our cities.  More intense “100 year” storms will lead to greater flooding and more rapid erosion in systems that were not designed for these major and frequent events.  The results can be costly, both municipally and personally.

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Flooding on the Red Hill in 2009. Photo: Lynda Lukasik

Melanie Kramer introduced the topic of Green Infrastructure (or rainscaping, bluescaping, Low Impact Developments, etc.) with a simple goal for rain water: slow it down, soak it up, and keep it clean.  By changing the traditional storm water management techniques, we can treat rain where it falls, along the path, and before it reaches the waterway.  This begins with spreading the knowledge that storm drains go directly to the lake, untreated, picking up contaminants along the way.  During a major rain event in Hamilton, this issue is compounded with the old combined sewer overflow system, meaning raw sewage is occasionally spilling out into the harbour.

Slowing down the water reduces the opportunity for flash floods. Water collects and flows quickly on the impermeable surfaces that cover the city, picking up contaminants along the way.  By reducing the amount of impermeable surfaces and replacing pavement with permeable material, rain gardens, and other green infrastructure, more water will be absorbed by the system before it pools and floods.  Constructing green roofs or disconnecting your downspout and redirecting it into a rain barrel, or to flow into a rain garden removes it from directly flowing into the storm drain.

Rain is processed and filtered naturally by soaking it up in a rain garden.  Low Impact Developments like these filter, store, and return rainwater to the ground, mimicking nature in a cost effective way, and reducing the stress on traditional storm water infrastructures.  Throughout the city, boulevard plantings could be vastly improved through smart design: curb cuts to allow water to flow in from the street, permeable sandy soils, water-loving plants and trees, all cleverly arranged to capture, hold, and filter rainwater before it can flood.  These projects can also add beauty, interest, amenity space, and education opportunities in the community.  Soak away projects used trenches of gravel lined with fabric to help collect water in an attractive garden feature, or can be designed with topsoil and grass for a hidden feature that will deal with ponding in a low maintenance way.

Winston Wang enlightened us about what Low Impact Development practices have already been constructed in the City of Hamilton, and what is underway.  See the full list here, and a fantastic website by the Toronto and Region Conservation Authority here that tracks projects around the province.  These projects include infiltration trenches to reduce ponding in alleyways, infiltration trails in parks with flooding issues, soak away pits with curb cutaways along the roads, rain harvesting barrels at Limeridge Mall, green roof at City Hall, depave projects and garden planting to improve permeability, and beautification of traffic calming bump outs by creating bioswales to capture and drain rainwater.  In new developments in the City, downspouts are no longer allowed to be attached directly to the storm drain, and the City promotes Proactive Plumbing, through downspout disconnection and storm water management.  The lesson learned here: talk to your councillor to let them know that these projects are important to you and worth the investment for the future.

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Adele Pierre wrapped up the evening by combining the two former presentations into a vision for the future in Hamilton: the use of green infrastructure to beautify and better the beloved Ottawa Street.  While the community adores this street, it is notably lacking in green space.  There is so much impermeable surface and nowhere for water to go. Projects have already successfully reimagined the streets of Brooklyn and Portland as beautiful and functional storm water management systems.  The sidewalks on Ottawa Street are large – wide enough to accommodate bioswales and allow generous space for pedestrians, while adding amenities like benches under a richer tree canopy.  Adele invisions permeable pavement, with soak away systems underneath.  Curb cut outs and grates bring water from the street to bioswales, in which native plants and sandy soil soak up rain water.  Traffic calming curb bump outs would be filled with these bioswale gardens and healthy trees that have ample soil to grow.  The similar road installations in Portland and Brooklyn have been shown to manage almost all of the runoff from a 25 mm storm event.  The existing parking lots in the area produce over 1,000 m3 of runoff in a 25 mm storm that carries oil, grease, and other contaminants right to the harbour.  By using permeable pavement in the parking spots and adding bioswales down the centre, 95% of runoff is absorbed into the ground, and 99% of the oil, grease, heavy metals and other pollutants are held in the soil.  Her incredible and visual Master’s thesis is online here.

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From Adele Pierre’s Master’s thesis

Presently, the Hamilton Conservation Authority has grants available to help create rain gardens in Ward 1 and Waterdown.  Learn more about the need for a fair storm water fee  in Hamilton and let your councillor know that this is important for our city.

Be sure to attend our “How to Build a Rain Garden 101” workshop on Tuesday, April 10 from 7pm-9pm at the Perkins Centre (register at treespleasehamilton@gmail.com) to learn how to transform your own yard!

UPDATED Restoring Resilient In Urban Green Spaces

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Author: treespleasehamilton

A project of the Hamilton Naturalists' Club and Environment Hamilton. Funding by Ontario Trillium Foundation.

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