When Seattle was planning its first extreme-green makeover of a city block, residents competed for the honor. And in 1999, the winning street in the Broadview neighborhood got a gorgeous facelift complete with new sidewalks and verdant roadside rain gardens with shrubs and grasses.
But when the city recently tried going green in the Ballard neighborhood, homeowners there felt like they got stuck with the booby prize.
The rain gardens installed by the city last summer and fall haven’t worked as planned. The gardens, which look sort of like shallow, sparsely-planted ditches running between the road and sidewalk, fill with water — and stay filled up. Some of the rain gardens drain over the course of hours or days, but some become mini ponds until the city comes to pump out the water.
Many of the residents are not pleased. They worry that the swamped gardens are a drowning hazard for young children, a breeding ground for mosquitoes, and will lower their property values. There’s even a neighborhood blog calling for their removal.
“We feel badly,” said Nancy Ahern, deputy director for utility-systems management for Seattle Public Utilities, the department that installed the rain gardens. “It’s been hard on this community.”
More is at stake than the ire of residents. Seattle, like metropolitan areas nationwide, has a century-old legacy of streets, driveways, parking lots, and roof tops that create massive volumes of runoff. Rain gardens are a key technology for curbing stormwater, which can trigger overflows of raw sewage, trash salmon streams with torrents of water, or scoop up and dump millions of pounds of toxic pollutants into Puget Sound, Lake Washington, the Columbia and Willamette rivers, and beyond. Scientists say that controlling these flood waves of stormwater is essential to recovering salmon and cleaning up the environment.
And so cities and counties nationwide have been eager to install rain gardens, which are viewed as environmentally friendly and often less expensive than traditional stormwater solutions that rely on pipes and drains.
This week, Washington State University and the nonprofit Stewardship Partners launched the 12,000 Rain Gardens campaign with the goal of getting 12,000 of the stormwater gardens installed in the Puget Sound region by 2016. Along with Seattle, Portland has committed to the widespread installation of rain gardens, and smaller cities including Puyallup and Lacey are promoting their use. The Washington State Department of Ecology is working on an update of requirements spelling out when and how rain gardens and other green stormwater technologies — also called low-impact development — must be used.
But Ballard’s rain garden fiasco is a very visible reminder that green solutions aren’t always quick, easy, and predictable. The project offers a cautionary tale to be heeded nationwide: rain gardens have limitations.
“Low-impact development technologies are very site specific,” said Art Castle, interim executive vice president at the Building Industry Association of Washington, an organization representing the housing industry. Castle, who served on an advisory committee that helped the state craft its low-impact development rules, says he believes rain gardens work, but worries about mandates for their use.
The Ballard rain gardens were meant to specifically help with the problem of sewage spills triggered by heavy rainfalls. Seattle is planning to spend $500 million over the next 14 years to reduce the sewage overflows by repairing the existing system, building large storage systems to handle the stormwater runoff, and installing green infrastructure. Portland has spent $1.4 billion on the “Big Pipe” projects to curb its storm-sewer problems through more conventional means, in combination with greener solutions. Port Angeles is working on plans for a $40 million fix to its overflows with new sewage lines and a storage tank.
The combined sewer overflows — also called CSOs — can contaminate lakes and bays with disease-causing pests including salmonella bacteria, the parasite giardia, and Norwalk-like viruses. People can get sick by inhaling small droplets of the polluted water, or through contact with skin, eyes, ears, and cuts. Exposure can cause diarrhea, vomiting, stomach cramps, fever, hepatitis, bronchitis, pneumonia, and swimmers itch.
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