Rain Drain
Make a swale and settle the problem of nasty storm water
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 MIKE SIEGEL / THE SEATTLE TIMES The eco-swales between cottages at Danielson Grove in Kirkland blend in with the landscape, yet are a low-impact, low-cost way to tame storm-water runoff. The gardens at Danielson Grove were designed and planted by developer Linda Pruitt and Todd Paul of City Gardening Services. |
Echeveria 'Orange Bouquet' is a showy succulent for a hot, dry spot in the garden or to grow in a pot you can move inside for the winter. Its blue-green rosette of fleshy leaves is topped with wavy spikes holding aloft little bell-shaped golden-orange flowers. Grow 'Orange Bouquet' as an annual or bring it inside before first frost to overwinter on a bright windowsill.
Danielson Grove is private, but you can visit the city of Seattle's Street Edge Alternatives program in the Pipers Creek watershed in Northwest Seattle. This is Seattle's first Natural Drainage System project. The project is on Second Avenue Northwest, between Northwest 117th and 120th streets. See www.seattle.gov/util/naturalsystems and www.raingardennetwork.com for more information.
The University of Washington Center for Urban Horticulture has a rainwater garden, runnel and swale, as well as native plantings alongside the swale in Goodfellow Grove. For more information, visit the Miller Library in Merrill Hall, at 3501 N.E. 41st St. You can check www.depts.washington.edu/hortlib.And just out from Timber Press: "Rain Gardens: Managing Water Sustainably in the Garden and Designed Landscape," by Nigel Dunnett and Andy Clayden ($34.95), is the first book on the subject for home gardeners.
Last November we were doused with nearly 16 inches of rain, the wettest month ever in Seattle. The weather gods followed up with a couple more feet of rain before winter blew out of town. Where does all that water go, anyway, besides settling into the soil and drowning our plants?
At Danielson Grove, a cottage community in Kirkland, storm runoff is handled aesthetically, eco-sensitively and inexpensively. The side yards between the cottages are low-impact storm-water swales, though you'd never know it to look at them. These homegrown water-retention facilities, more poetically called rain gardens, boast meandering rivers of gravel and stone, surrounded by ornamental grasses, perennials, trees and shrubs. Native and ornamental plants that enjoy wet feet, such as shrubby dogwoods, iris, sedges and rushes, absorb and filter storm water. The city of Kirkland is looking at the innovative idea of eco-swales, or bio-swales, as ornamental landscape features that will be a model for storm-water mitigation.
The idea is to use the garden to slow the passage of water off roofs and paved areas like driveways and sidewalks. When storm water is filtered through gravel, rock and plants, pollutants are removed, and the water table is recharged. The storm sewers aren't overburdened, and lakes and streams aren't flushed with water full of nasty pollutants. You might think the water gushing down city streets during a rainstorm is harmless, but in fact it's loaded with gasoline, oil, insecticides, pet waste — OK, OK, enough. The point is to tame the gush by filtering it through our gardens, thus protecting endangered salmon.
Danielson Grove is private, but you can visit the city of Seattle's Street Edge Alternatives program in the Pipers Creek watershed in Northwest Seattle. This is Seattle's first Natural Drainage System project. The project is on Second Avenue Northwest, between Northwest 117th and 120th streets. See www.seattle.gov/util/naturalsystems and www.raingardennetwork.com for more information.
The University of Washington Center for Urban Horticulture has a rainwater garden, runnel and swale, as well as native plantings alongside the swale in Goodfellow Grove. For more information, visit the Miller Library in Merrill Hall, at 3501 N.E. 41st St. You can check www.depts.washington.edu/hortlib. And just out from Timber Press: "Rain Gardens: Managing Water Sustainably in the Garden and Designed Landscape," by Nigel Dunnett and Andy Clayden ($34.95), is the first book on the subject for home gardeners.
One way to think of rain gardens is as the mirror image of raised beds. You know how you heap soil up to create healthy gardens with good drainage? Rain gardens are the reverse. They're convex, shaped like shallow basins to capture water. Kansas City, Mo., has a grassroots plan to create 10,000 such gardens within five years. With our salmon and record rainfall, shouldn't we be the city with the ambitious horticultural solution to such problems?
Here's the non-techie version of how the eco-swales work at Danielson Grove, explained by developer Linda Pruitt of The Cottage Company. The water from each home's downspouts is piped to the rear of the lot, where it's directed into a sunken catch basin. Then the water flows out of the catch basin and down the swale's slight grade, through gravel and rocks, where it's gradually absorbed and soaked up by thirsty plants. If there's a big storm, water that makes it through the swale is captured in the detention system.
All in all, it's a system both sensible and sustainable. Now, let's get busy and give Kansas City a run for its money.
Valerie Easton is a Seattle freelance writer and author of "A Pattern Garden." Her e-mail address is valeaston@comcast.net. Mike Siegel is a Seattle Times staff photographer.
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