Anchorage Daily News

The Anchorage area averages less than 16 inches of precipitation a year: That's rain, drizzle, dew, ice and snow -- less than 16 inches a year -- and why, green as things seem, our area is considered an arctic desert by those who classify these things.

Click to enlarge

Story tools

Comments

E-mail a friend

Print

Share on Facebook

Digg this

Seed Newsvine

Send link via AIM

Follow on Twitter

Font size : A | A | A

Doesn't it make sense to capture what little moisture we get and keep it for ourselves and our plants?

This is an old problem in dry country but one now with a relatively new fix: the rain garden, a solution the Municipality of Anchorage believes in so strongly that it's offering to pay homeowners half of their costs, up to $750, to put one in.

Rain gardens aren't water gardens or bog gardens, wetlands or mosquito incubators. They're carefully planted, thought-out depressions in landscapes that capture runoff from hard surfaces like roofs, sidewalks, driveways, decks -- and even lawns in which the turf has gotten dense enough to act like felt instead of a sponge.

Their purpose is to hold water long enough for it to percolate through the soil, losing pollutants and sediment on its way to recharging the groundwater and replenishing subsurface flow paths.

We can't see them, but underground waterways course beneath our feet and homes. When things are working the way they should, we're all standing on living water.

Think of a sponge on top of a filter: That's how the rain garden at Taku Park on 76th Avenue, west of Old Seward Highway, works. Tammie Wilson, a municipal engineer, designed the city's demonstration project there last year.

She was out there in early June with a squad from Youth Employment in Parks, weeding, replacing plants that didn't make it through the winter and giving the place a general spruce-up.

"The city stocks the lake with fish, and in summer, kids swim in it," she says. "We want to keep the lake clean for them."

The Taku Lake rain garden extends from a gravel trough and sand-set pavers next to the parking area to a wooden bridge adjacent to the lake. It's flat and level on the bottom to stop and hold water feeding it from slopes from all sides. Perimeter boulders break the rush of water, and native plants like ferns, alpine currants, high bush cranberries, joe-pye weed and iris, plus a few tough-guy ornamentals like ligularia, absorb what doesn't percolate into the soil.

"We watered it last year when it was getting started," says Wilson, "and we'll water it this year to make sure it's established, but starting next year, it'll be on its own."

'NO TARMAC'

The same ideas can be applied to individual yards, like the one at the family home of Bonnie Lembo and husband Bob Bundy, near downtown.

"We've tried to make every surface we can porous, so the water is purified as it slowly filters through," Bonnie says. "In most places runoff from lawns and roofs and driveways goes straight into the sewer system and then our waterways, all the herbicides, pesticides, the stuff in the streets, oil spills, gasoline, and dog poop. Our children used to play in Campbell Creek -- until the city warned everybody to stay out because of the fecal coliform bacteria. A rain garden stops and cleans this."

Anchorage had 69,000 dogs at last count, all pooping. If the owners don't pick up after them, the poop and other untreated runoff eventually sluice into the storm drains on their way to the nearest creek. (Waste in the sewer system goes to the city's sewage treatment plant, which uses a sedimentation process to separate solids from liquids, then flushes the liquids into Cook Inlet.)

"Other than the footprint of our house, the garage and one path, everything here is porous," Lembo says. "We were aware of the eco-disaster of paved cities like Los Angeles and New York. They really distort the climate because there's no place for water to go, so they have a lot of flooding, pollution and heat retention. About 10 years ago, we made an environmental decision and went on from there."

Even the pavers at the Lembos' home are set in sand so water drips between them, and a vine arbor in front rests on a gravel bed. The driveway is covered with shredded tree bark -- "no tarmac" -- and mostly native plants have replaced much of a once-dense lawn -- "a lawn with a thick root system does not absorb much water."

The slow drip through the natural rain garden also keeps sediment out of salmon streams, a good thing for salmon.

NEIGHBORHOOD APPROACH

The U.S. model of leveling everything, hard-surfacing it and then shooting whatever flows off into concrete sewers to the nearest creek is fairly new. Before things got so congested and fast, roadways tended to be bordered with gentle earthen swales that served as natural runoff sponges.

A Maryland developer, Dick Brinker, decided in 1990 to try something different from level-and-pave in his new housing subdivision, Somerset, in Prince George County. Brinker took the idea of swales and ran with it. Every house he built in Somerset had a 300- to 400-square-foot rain garden, beautifully planted. His experiment turned out to be a huge money saver. It cost about $100,000 back then to do the rain gardens. Conventional curbs, sidewalks and gutters to handle the same runoff would have set him back about $400,000.

Other municipalities and groups noticed -- Portland, Ore.; Atlanta; Maplewood, Minn.; Kansas City, Mo. (the "10,000 Rain Gardens" project); and various groups in Delaware and West Michigan.

Seattle had an eye-opening experience. In 2001, Seattle Public Utilities took three blocks in the Pipers Creek watershed in the northwest part of the city to try as a prototype. The street was changed from ruler-straight to gentle curves, and most edges were made into rain gardens. A hundred new evergreen trees went in, and 1,100 shrubs. Parking areas were part of the plan, and places to walk or bike. Residents agreed to take care of the plantings. and a new neighborly sense of pride and community sprang up.

The benefits weren't just touchy-feely and aesthetic, though. A three-year study after all that work showed 98 percent of wet-season and 100 percent of dry-season storm-water runoff into the watershed had been eliminated.

It's called the SEA Street . A Web search for Street Edge Alternatives Seattle will bring up the public utilities Web site and a virtual tour. The final photos, before and after shots, are telling. The "before" is Anyplace, USA. The "after" looks like someplace people would pay premiums to live.

The Municipality of Anchorage is hoping more citizens here get into rain gardening. To that end, it's willing to help pay for installing one. It offers a rain garden brochure, a Web site and a how-to manual for homeowners who'd like to put one in, or several, or convert their whole yards.

"We haven't had many applicants," says Wilson, "and we have a lot of money just sitting there waiting to be given away."

MUNICIPAL RAIN GARDEN INFORMATION is available at www.anchorageraingardens.com. The reimbursement application is also available online, or call 343-8008.

www.anchorageraingardens.com

ADVERTISEMENT