| There are more than 300 outfalls in Calgary. These outfalls are exit points from which runoff flows from streets, parking lots, lawns, rooftops and other parts of the urban landscape into storm sewers. Most of this water enters directly into the Elbow and Bow Rivers untreated. Its contents endanger the aquatic ecosystem and reduce water quality for Calgarians and those living downstream from us.
According to Mark Bennett, Executive Director of the Bow River Basin Council, urban runoff is the most significant non-point source (meaning the sources of the various contaminants cannot be traced) of pollution to the Bow River. Over 11 million kilograms of waste is washed into the river from our city’s storm sewers every year.
The problem is, as rainwater travels over urban landscapes it picks up debris and dangerous substances. Litter, salt, road sand, gravel, pesticides, fertilizers, animal feces, automobile fluids like oil and antifreeze, soap, household chemicals and other toxic matter enter the storm drain system and end up in our rivers.
Before the concrete jungles of today’s metropolitan centres, natural landscapes absorbed the rain, replenishing groundwater and streams. When Calgary’s stormwater management system was designed, explains Paul Fesko, the City of Calgary’s Manager of Strategic Services for Water Resources, rain was viewed as a nuisance. The storm system was thus designed to get rid of rain as fast as possible. Unfortunately, this kind of design has a major impact on the river because of the amount of sediment picked up along the way.
There are a number of ways to mitigate this problem though. The City of Kelowna has installed stormceptors, devices that fit into storm sewers removing oil and other sediments in locations identified as high-collision zones. As a result, the effluent from automobile collisions doesn’t end up in local waterways.
In Portland, Oregon, city planners have tried to mimic natural conditions to deal with stormwater more efficiently. By using ecoroofs (also known as greenroofs) in some of their designs, they are able to reduce erosion and runoff while saving energy, filtering air pollutants and increasing habitat for birds and insects. These roofs have a layer of foliage over a growing medium on top of a waterproof membrane and are superior to conventional roofs because they are a living, breathing vegetated system.
Vancouver is also working towards a more natural drainage system using what it calls "sustainable streets" and "sustainable lanes." Both designs reduce the amount of impermeable paved area using swales, plantings of native grasses, shrubs and trees alongside roads, to absorb the water.
A similar project in northwest Seattle, called Street Edge Alternatives "SEA Streets," retrofitted a residential block. The project improved the area esthetically and reduced runoff from this block by 98 per cent. It also helped to protect and restore salmon habitat in the area’s Piper Creek watershed.
Locally, some organizations are recognizing their impact on Calgary’s waterways. The Calgary Exhibition and Stampede participates in the Yellow Fish Road Program through Trout Unlimited. Yellow fish have been painted and clearly marked beside many drains within Stampede Park. The purpose of this program is to increase understanding so that the public is aware what enters the storm sewers goes directly into the river and affects aquatic life. Stormceptors have also been installed within the Park’s parking lots. Additionally, no chemicals or detergents are used for cleaning vehicles or equipment where the runoff can reach a storm drain.
The City is also working to address runoff, committing to keeping the total suspended solids (TSS) entering the river from increasing over the next ten years. Fesko points to a number of ways to accomplish this.
"We are working to create areas where rainwater can be used as a resource, increase public awareness, redesign infrastructure and change policies."
Danielle Droitsch, Bow Riverkeeper, believes the City needs to be more ambitious, however. She would like to see upgraded, strict development standards. With the city’s boom, Droitsch worries "development is being taken more seriously than the impacts of development."
SIDEBAR:
How you can improve water quality
· Paint fish! Volunteer with the Yellow Fish Road Program by calling 221-8360.
· View water as a resource — use rain barrels and natural landscaping to reduce runoff from your property.
· Pick up after your dog.
· Use the carwash, not your driveway or the street.
· Use natural alternatives to pesticides and chemical fertilizers.
· Make sure your car is not leaking fluids.
· Support environmental groups like the Bow Riverkeepers, Bow River Basin Council, Trout Unlimited and Ducks Unlimited.
· Contact elected officials and ask them to support stricter standards for stormwater management.
Sources:
Interviews:
Jon Halford, City of Calgary Contracts Engineer, Transportation Infrastructure: 268-5870
Paul Fesko, City of Calgary Manager Strategic Services, Water Resources: 268-3588
Danielle Droitsch, Bow Riverkeeper: 678-7964
Anna Lee Carswell, Yellow Fish Program Head, Trout Unlimited Canada: 221-8360;
Mark Bennett, Executive Director, Bow River Basin Council: 254-3353
Robin Barnes, City of Kelowna Transportation Department: 250-469-8500
Websites:
Bow River Basin Council: www.brbc.ab.ca
Portland Oregon Sustainable Stormwater Program: http://www.portlandonline.com/bes/index.cfm?c=defji
Vancouver Sustainable Streets Program: http://city.vancouver.bc.ca/engsvcs/streets/design/enviro.htm
Trout Unlimited Yellow Fish Road Program: http://content.calgary.ca/CCA/City+Living/The+Environment/Water+and+Wastewater/Wastewater+and+Drainage/Yellow+Fish+Road+Program.htm
Calgary Exhibition & Stampede Environmental Stewardship: http://corporate.calgarystampede.com/community/environment.html
Bow Riverkeeper: http://www.bowriverkeeper.org/about-the-river/water-quality2.shtml
Seattle Natural Drainage Systems: http://www.cityofseattle.net/util/About_SPU/Drainage_&_Sewer_System/Natural_Drainage_Systems/Natural_Drainage_Overview/index.asp
Urban Storm Water Management: www.urbanswm.ab.ca |
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