Why is the grass left long?
We get a lot of questions about the ponds in Keswick and why the grass does not get cut on a regular basis. It’s not laziness. Not negligence. We promise. It’s about respecting nature and Keswick’s sustainability mandate.
The ponds in Keswick are constructed wetlands and they were designed so that they would complement and cohabitate comfortably within the pristine North Saskatchewan River setting. Traditionally, storm water ponds are designed to be manicured right to the water’s edge, but that would not benefit our beautiful ravine setting.
Our approach is more ecologically focused. It prioritizes naturalized spaces with native vegetation and this benefits both the environment and Keswick residents over the long term.
Filtration and Water Safety
The ponds act as a digestive system before storm water enters the North Saskatchewan River. Because of Keswick’s location approximately 5km upriver of the E.L. Smith Water Treatment Plant, the ponds serve to purify water before it flows into the river. That water then becomes our drinking water.
No wonder it’s important that what goes into the ponds leaves as pure as possible! If the ponds are mowed on a regular basis, that would lessen the quality of our drinking water.
Jeff Fenske, a Landscape Specialist at Stantec, explains how the system works:
“Water enters the ponds at one end. The long grasses and emergent vegetation (anything below water level) take out hydrocarbons, silt, and sediment. These vegetative blockers knock out the sediment and as the water makes its way through it becomes much more clear.”
He says that this process of naturalization of the vegetation around the ponds takes a few years and with the last two years of drought the grasses have struggled. But it will come along.
“The ponds emulate a wetland and use different grass species that are natural to the area,” explains Jeff. “When sod goes in it looks great right away, it’s true. Naturalized areas take some years to establish. It’s part of the process and we’re in the cusp period now. The ponds will start to look really good, but it takes time.”
Frogs, amphibians, and birds utilize the cattails and longer grasses to live in and thrive. Red winged blackbirds, geese, and ducks are just some of the incredible species that use this fringe area for nesting and protection.
Plus, there are 31 fish species, three types of frogs and toads, mammals, and waterfowl that call the North Saskatchewan River home. We felt that we had a responsibility to keep the river environment in as natural state as possible. Fostering a diverse ecological habitat for native species translates into a landscape that residents can enjoy as a genuine ravine setting for years to come.
Have you noticed the yellow fish on the pavement near storm water drains.? These are to remind residents that water that goes down those drains directly affects the river water. Soap, waste—whatever is put down them enters our drinking water.
On June 23rd, 2015 the City of Edmonton banned the use of herbicide on city land. Without pesticides, dandelions can be an unsightly, expensive problem. But with naturalized areas like the ones designed for Keswick, dandelions won’t actually be as much of a nuisance. Once the grasses are long and established and have good density, says Jeff, they choke out weeds. That’s great news for all Keswick residents over the long term. Especially when it comes to maintenance down the line.
Because the depth of storm ponds varies drastically with rainfall and they aren’t safe to be in, longer grasses keep residents and their small children at a safe distance. The ponds are meant to be enjoyed visually or from the lookout points built around them.
“Patience is important,” says Jeff. “The native vegetation is coming in. A healthier turf stand IS coming.”