The Sleeping Lion subdivision development on Line 6 was originally promoted as Innisfil’s first Low-Impact Development (LID) community, incorporating new urban design features that included community retail fronting on an interior park in addition to raingardens.
Raingardens are engineered low areas or ‘soak pits’, designed to trap rainwater as it comes off roofs, walkways and driveways, and reduce the amount of runoff generated by the subdivision. Less runoff means less erosion, and fewer pollutants washed into stormwater ponds and the watershed.
The Sleeping Lion raingardens in Phase 1 were designed to span two front yards, sufficient to hold the runoff from a 15 mm rainfall event.
Filled with coarse ‘bioretention soil filter media,” the raingardens were planted with species capable of surviving both drought conditions and periodic inundation – grasses like Canadian Reed grass, Indian grass and Tufted hair grass; shrubs that included black chokecherry, Bayberry and Bush honeysuckle; and native perennials like purple cornflower, wild geranium and wild bergamot.
It was a unique project, and it was effective. Engineering studies have suggested that the 197 raingardens in place in Phase 1 of Sleeping Lion absorb over 29,000 cubic metres of rainwater per year.
But in 2018, the landscape changed, figuratively speaking.
The Lake Simcoe Region Conservation Authority introduced a Water Balance Off-setting Policy that would let developers offer a cash payment instead of following through on LID features, “if constraints make it difficult to maintain pre-development groundwater recharge rates on site.”
At its June 24 virtual meeting, Innisfil Town Council approved a Water Balance Offsetting Agreement with Cortel Group that would allow the developer to eliminate the planned raingardens from Phases 2 and 3 of Sleeping Lion.
The argument wasn’t that it was difficult to maintain pre-development recharge rates, but that residents dislike the raingardens, and the gardens could be a barrier to future sales.
Several members of Council said that they had received complaints from residents of Sleeping Lion regarding the raingardens, but Coun. Alex Waters championed the technology.
“I’m terribly disappointed” by Cortel Group’s decision, said Waters, who is a Senior Manager with the Toronto & Region Conservation Authority, in charge of The Living City Campus research facility, demonstrating renewable energy and green building.
Waters noted that on-site remediation is the best way to control downstream flooding.
“After a few complaints and one try, we’re going to scrap raingardens?” he asked, questioning how the Town will ensure Cortel Group will deliver on its promises for the visionary Mobility Orbit community if they back away from something as simple as raingardens.
Waters pointed out that eliminating raingardens from the plans puts additional pressure on the Town to develop Stormwater Management Ponds, which are costly to maintain and manage.
Scott MacKenzie, Innisfil Development Engineering Leader, told councillors that the raingardens in Phase 1 only trap runoff from the roofs, not from roads or driveways, and therefore provide only minimal pollution control.
Asked about bioswales as an option, MacKenzie suggested they get in the way of pools and sheds, and tend to be removed by homeowners.
“It’s very hard for staff to control what happens in a yard, let alone a backyard,” MacKenzie said, claiming that some residents of Sleeping Lion have already ripped out the raingarden plantings, and put in their own topsoil and flowers – making the features ineffective.
Coun. Bill Van Berkel agreed, noting the raingardens span two properties, raising issues of maintenance.
“It’s a deterrent for purchasers,” Van Berkel said, adding that he has had “at least 20 complaints” in the past two years. “They’re just not doing any good… Take the money in lieu, and figure something else out.”
But Waters suggested that it was the lack of promotion of the raingardens to homeowners, that was the problem.
“What is the alternative?” he asked. “A stormwater management pond (SWMP)? They are highly polluted.”
MacKenzie suggested the funding could be used not for a new SWMP, but to provide enhancements to existing stormwater ponds, such as infiltration areas.
“I share in Coun. Waters’ disappointment, but I’m also getting the calls (regarding the raingardens) – 'What is it, and when can I get rid of it?'” said Mayor Dollin.
She suggested it was up to environmentalists to teach people to want features like raingardens. “Make people understand and value them,” Dollin said. “When they want to purchase them, the developers will build them. It’s got to be what people want.”
She added, “Hopefully, people will start to value the LID, if it becomes more common.”
Deputy Mayor Dan Davidson asked about the maintenance of the existing raingardens in Phase 1, and how the town could ensure they continue to operate, if it signs the Offsetting Agreement.
Although the raingardens are registered on title, MacKenzie suggested that a bylaw is required to enforce the restrictions.
“Enforcement of a bylaw may be difficult and time-consuming, and could result in excess operation costs for by-law and operations staff,” noted a staff report, suggesting that it is easier to maintain “one centralized facility.”
Council voted in favour of the Offsetting Agreement, with only Coun. Waters voting against.
Just how effective raingardens actually are was shown by the amount of cash that Cortel Group will have to pay, to drop the 291 remaining planned features. An engineering study found that all 488 raingardens or “soak pits” would have trapped over 48,000 cubic metres of water per year.
To eliminate the raingardens in phases 2 and 3 of Sleeping Lion, Cortel Group will be asked to make an offsetting payment of $945,612.
Cortel Group also did not follow through with the original plans for community retail fronting on an interior park, instead placing the building on Line 6, citing lack of economic viability of the retail if it did not front on a major road. At present, the structure is being used as a presentation centre.
After the meeting, Coun. Waters explained the principle of the raingardens.
“Generally, the faster you can get rain water back into the ground, the better it is for preventing flooding downstream… Letting water run off the property allows volumes to accumulate which makes it harder to manage,” leading to erosion, and the washing of silt and pollutants into the water downstream, he said.
“Studies show that with peak rains you get higher levels of phosphorus entering the lake,” as well as increased erosion.
Stormwater management ponds tend to silt up over time, Waters noted, trapping pollutants – which means that dredged materials need to be treated as toxic waste, a huge expense to the Town.
“Rain gardens allow rain to get quickly absorbed back in to the ground, therefore preventing… increasing volumes of water downstream,” he explained. “By doing this, you reduce sediment, salt, chemicals and phosphorus levels” in creeks, and ultimately, Lake Simcoe.
The plants in a raingarden also absorb the rain, and many are native species, supporting native pollinators.
Waters blamed the failure of the pilot project on a lack of an education/communication plan, and worried that the precedent will set back efforts to find localized solutions.
“Now developers will be able to pay a water balance fee and not consider site-based solutions,” he said, noting that Conservation Authorities have plenty of information on the value of raingardens, but there is a bar to implementation:
“Municipalities don’t want to force developers to do the right thing.”
For more information on raingardens, click here.
