Sponging up the rain, taxing impervious surfaces — what other communities are doing
This is the sixth in a series of articles about how urban stormwater runoff has negatively impacted Comox Valley waterways, what local governments are doing to address the issues and what other communities have done.
Urban development in the Comox Valley has fundamentally altered the natural water balance. As impervious surfaces like roads, parking lots and buildings replaced vegetated land, the opportunity for rain water to soak into the ground or return to the atmosphere by evapotranspiration diminished.
To prevent flooding, Valley municipalities have relied on expensive engineered infrastructure, such as curb, getters and stormwater pipes, to divert rainwater into area creeks and streams, and sometimes directly into the K’omoks Estuary.
Along the way, that rain water has picked up oil, grease and engine coolants, copper from vehicle brakes, zinc from vehicle tires, animal feces and a variety of other contaminants that in some cases have killed all aquatic life in our waters and threatened public health.
Polluted stormwater regularly causes the Department of Fisheries and Oceans to ban shellfish harvesting in Baynes Sound (as it did in November), and for the Capital Regional District to declare waters at certain Victoria-area beaches a possible health risk (as it did on Dec. 29).
Municipalities around the world have moved toward systems that rely less on “grey” infrastructure and more on “green “infrastructure that attempts to mimic nature.
It also costs less. Curb, gutters and pipes create long-term, unfunded liabilities for taxpayers to repair and replace. The Comox Valley alone has hundreds of millions of dollars in unfunded infrastructure liabilities.
So, every community is looking for innovative stormwater solutions. Here are some of them.
The City of Victoria introduced a stormwater utility in 2016 to accomplish two goals: one, to fund its ongoing expense of replacing and repairing stormwater pipes; and, two, to encourage property owners to manage their own rainwater where it falls.
Before 2016, Victoria included stormwater fees in property taxes and based the charge on a property’s assessed value. Now, property owners pay fees based on the amount of rainwater estimated to run off their property.
In other words, the more impervious surfaces that cover a property and the fewer source control measures implemented — rain gardens, pervious pavers, etc. — the more a homeowner will pay.
“The stormwater utility is a funding model similar to how we fund water and sanitary services,” Brianne Czypyha, the city’s stormwater management specialist, told Decafnation. “The city uses the stormwater utility because it’s a more equitable user-pay system that bases the fees on the impact a property has on the system.”
Czypyha said grey infrastructure will always be an integral part of managing runoff in the city, but integrating green infrastructure will help build capacity of the system and improve the quality of stormwater runoff discharged into the environment. Using source controls is voluntary, for now, but not using them will cost property owners more.
“While the direction we have chosen is to use incentives to encourage the use of green infrastructure, particularly for retrofitting existing buildings,” Czypyha said. “I definitely see value in requiring new developments to meet more stringent rainwater management requirements.”
Richmond, BC, also has a stormwater utility, and it’s a common practice throughout Washington, Oregon and California.
“We’re aware of the problem, so why would we wait for someone else to tell us to fix it?”
Capital Regional District
The municipalities of Saanich, Victoria and Oak Bay have signed on to a multi-jurisdictional, multi-stakeholder 100-year watershed management plan for Bowker Creek. The plan identifies places to daylight and naturalize the creek.
“The plan is to move Bowker Creek back to a more natural stream, as opportunities arise,” Glenn Harris told Decafnation. Harris is the CRD’s senior manager for environmental protection and the Bowker Creek Initiative spokesperson.
Bird life and bio-diversity around the creek is already coming back, Harris said, especially around Oak Bay High School where a $750,000 grant restored and naturalized the creek, increased native plantings and created a creek-focused curriculum at the school.
“It provides an opportunity to restore islands of nature within the urban environment,” he said.
Elsewhere in Canada
Kitchener, Ontario has taken a direct action approach to stormwater management. For more than a year, the city has required all new development to capture the first 12.5 millimetres of rain — about a half-inch — every time it rains.
The rule applies to subdivisions, commercial buildings and even city-owned roads. It means that except for major storm events, all rain water must be managed onsite, and no water would reach stormwater pipes or ponds.
Kitchener took the action ahead of anticipated new provincial stormwater regulations based on its own climate change study that predicted a 20 percent increase in rainfall.
“We’re aware of the problem, so why would we wait for someone else to tell us to fix it?,” the city’s stormwater manager Nick Gollan told a Kitchener newspaper. “We should be putting strategies in place to adapt to the changes that are taking place.”
The City of Langley has created a Department of Green Infrastructure Services. It has standardized rain gardens instead of traditional curbs and gutters on all non-arterial roads.
Since 2009, the City of Toronto has required green roofs on all commercial, institutional and residential developments with a minimum floor area of 2,000 square metres (appx. 21,500 square feet), this includes any additions to buildings that increase the floor area to the minium.
Outside of Canada
Portland, Oregon has been the acknowledged leader of stormwater management regulations for more than two decades. It started in 1993 with a downspout disconnection program.
But since 1999, Portland’s Sustainable Stormwater Management Plan has required source control on any new redeveloped properties that add more than 500 square feet of impervious surface. That means property owners must manage and treat all the runoff from impervious surfaces with green infrastructure — rain gardens, green roofs, soaker trenches, drywell, pervious pavers, etc. — and in some cases may be required to install underground treatment devices to remove pollutants.
Now, other cities are catching up.
The City of Philadelphia is in the seventh year of a 25-year project to “detain it (rainwater), not convey it.” The city has committed $2.4 billion to recreate in the urban streetscape the kinds of pervious places where, instead of running into surrounding waterways, rainfall and the contaminants it carries can once again soak into and be cleaned by the earth.
Berlin, Germany adopted a Sponge City Strategy in 2017 to mitigate both heat and flooding problems expected to intensify with climate change. The goal is to increase the amount of surfaces within the city that allow water to soak into the ground and release it gradually, rather than a sudden rush into waterways, and more urban vegetation that cools the air through evaporation.
The manager of Berlin’s project says, “The key is to avoid sealing up too much of the ground surface with concrete or tarmac. Wherever possible, we want water-permeable surfaces.”
Berlin’s strategy borrows the term “sponge city” from a 2013 Chinese initiative that proclaimed urban areas should act like sponges, based on the work of landscape architect Kongjian Yu.
Yu’s motto for rainwater management is: retain, adapt, slow down and reuse. Others have since modified that slogan as: sink it, slow it, reuse it and move it.
The best educators have long-ago incorporated curriculum about the environment and, more recently, about climate change.
More than 30 years ago, Barry Thornton, the former principal of Brooklyn Elementary School in Comox, was a pioneer in teaching young students about conservation and the environment in general. Thornton was a advocate for the restoration of Brooklyn Creek and initiated several fish habitat improvement projects near the school.
He was also a co-founder of the schools Salmonids in the Classroom program that acquainted children with the life cycle of salmon and other aquatic life.
Today, students from elementary schools to high schools all over the globe are learning about the hydrological cycle, water balance and the need for better solutions to stormwater management. A quick search of the Internet brings up stormwater education programs from Kentucky to Rhode Island to Mississauga, Ontario.
The City of Mississauga has a stormwater outreach team that does presentations in K-12 classrooms that covers topics such as municipal stormwater management, water conservation, low-impact development and water quality and environmental health.
Students at Arcata High School in Humboldt County, Calif., recently started a project to create rain gardens around campus parking lots after an Environmental Science class found a high level of pollutants in the nearby Jolly Giant Creek.
In Kingston, Ontario, the city’s Fish and Frogs Forever program talks with local students about how polluted stormwater impacts local aquatic ecosystems and what they can do to reverse the negative effects.
What is the future?
Environmentalists and conservationists want improved stormwater regulations to happen quickly. But Brianne Cyzypyha, stormwater specialist at the City of Victoria, says that change in stormwater management is a multi-year, complex process, requiring involvement from many internal departments, and also feedback from experts and the public.
“In terms of the way forward, I see most municipalities as similar to a large ship changing course. It can be a bit of a slow process making changes to the old ways of doing business,” she said.
RELATED ARTICLES OF INTEREST
What to know more about the Sponge City concept?
This article describes modern stormwater management tools: sink it, slow it, reuse it and move it.
This article describes landscape architect Kongjian Yu who coined the term “sponge cities.”
This link takes you to Philadelphia’s guide for retrofitting properties to the city’s new stormwater regulations.
GLOSSARY OF STORMWATER TERMS
Bioswales — A stormwater conveyance system similar, but larger than a rain garden (see below).
Evaporation — As water is heated by the sun, surface molecules become sufficiently energized to break free of the attractive force binding them together, and then evaporate and rise as invisible vapour in the atmosphere.
Green infrastructure — Any natural or built system that provides ecological benefits and help to maintain pre-development hydrology. It encompasses natural features like streams, wetlands, forests and parks, as well as engineered systems that manage urban runoff.
Groundwater — Subterranean water is held in crack and pore spaces. Depending on the geology, the groundwater can flow to support streams. It can also be tapped by wells. Some groundwater is very old and may have been there for thousands of years.
Hydrologic cycle — The endless circulation of water. From the beginning of time when water first appeared, it has been constant in quantity and continuously in motions. The same water molecules have been transferred time and time again from the oceans and the land into the atmosphere by evaporation, dropped on the land as precipitation and transferred back to the sea by rivers and ground water.
Low-impact development (LID) — The systems and practices that use or mimic natural processes that result in the infiltration, evapotranspiration or use of stormwater in order to protect water quality and associated aquatic habitat.
Rain garden — A miniature wetland in a residential setting, lower than the adjacent grade to collect rainwater from roofs, driveways or streets, thus allowing infiltration into the ground.
Runoff — Excessive rain or snowmelt can produce overland flow to creeks and ditches. Runoff is visible flow of water in rivers, creeks and lakes as the water stored in the basin drains out.
Transpiration — Water vapour is also emitted from plant leaves by a process called transpiration. Ever day an actively growing plant transpires five to 10 times as much water as it can hold at once.
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