NATURAL SOLUTIONS
Stormwater ponds enhance communities while managing runoff, improving quality
Community developers attempt to attract new home buyers with appealing amenities such as shimmering ponds full of ducks and frogs. Every new neighbourhood has at least one or two, but they’re more than mere selling features.
Every new community is required to have a stormwater pond, or several depending on the size of the area, as mandated in the late 1980s. They are large, engineered holes in the ground that serve as a big bathtub for rainwater and spring runoff, preventing sewer backups and the mass dumping of water into our rivers and streams.
Ponds also act as a natural filtration system for contaminated storm water. The idea of containing all this heaven-sent fluid is about environmental responsibility, but it also deals with the economics of the underground infrastructure that carries it away.
“If you didn’t have these ponds, then you would have to keep building massive draining trunk pipes and it’s completely untenable to do this,” says Cory Albers, a hydraulic systems engineer and co-owner of Source 2 Source Inc., a Calgary-based environmental design firm.
Storm sewer pipes in older communities drain directly into the nearest river or stream, and to carry the required volume, are about 1.5 metres in diameter. As you get farther away from the river, these pipes become narrower, limiting the capacity of storm water systems in outlying communities. Building a direct storm water pipe to a river is also difficult because of all the other communities in between.
The solution to urban drainage problems has been to build a pond, a temporary storage space connected to the end of those existing, but narrow, stormwater pipes.
Albers says the ponds take the huge rush of storm water and allow it to dissipate slowly so it won’t overwhelm the system.
This allows new communities to keep expanding.
In searching for the ultimate system to manage stormwater in the new Chestermere community of Dawson’s Landing, developer Qualico Communities partnered with Albers’ company and Magna Engineering Services to install the first residential Stormwater Kidney in Canada.
The self-contained system will pump water from the storage area of the pond and circulate it through a diverse ecosystem of plants and aquatic creatures, which will be nourished by the storm water, cleaning it to a much higher standard that anything seen before.
The Stormwater Kidney is more than ideal for a community that’s built on a lake and tied to the Western Irrigation District.
“There are definitely sensitivities in that region about how water is managed. It was important that we find new and better ways to make sure we’re discharging water that’s of the highest quality,” says Clark Piechotta, an associate director of development with Qualico.
Brendan Mccashin, a senior development manager with Brookfield Residential, says they’re also working with Magna to use this same technology in Livingston in north Calgary. The storm water cleansed from that kidney pond will be fed into the Nose Creek area, a protected watershed with stringent guidelines around the discharge of storm water.
“Whether it’s the Bow River or Nose Creek, the goal is to protect the water quality and quantity,” he says.
Another disrupter to the water cycle can be urban runoff from rooftops and pavement. This water is often warmer than natural runoff, which affects fish and vegetation downstream.
Francisco Alaniz Uribe, assistant professor in the Faculty of Urban Design at the University of Calgary, says storm water ponds act as a buffer, in addition to cleaning the sediment, heavy metals and oils from storm water.
They also help deal with the natural phenomena of prairie wetlands.
“This is land that doesn’t drain well. The ground is saturated, water is on the surface. Each community needs to manage that within the site,” he says. “Now we’re starting to create constructed wetlands to a higher standard, not just retaining the water, but filtering it while it’s sitting there.”
Science aside, ponds have also become a vital part of good urban design and developers feature them as an important community amenity that’s good for our soul.
“These areas are full of life and sounds from nature that enrich the community. Yes, there are mosquitoes, but all the birds and frogs help people connect with nature and we’re constantly searching for that. Ponds are a great amenity for communities — part of the open space to be enjoyed,” he says.