February 2006

By Eric de Place

My wife, Jill, and I recently bought our first house. We love it, but we have since realized that we got more than the pride of ownership, we also bought the nagging worries: Can we afford the mortgage? Should we get earthquake insurance? Why does a small lake appear in the backyard when it rains?

After 27 consecutive rainy days here in Seattle, that last one has been on our minds a lot lately. During wet periods our backyard gradually yields a daunting pool of water, a mini Everglades of swampy lawn and waterlogged roses. The soil is saturated and with more rain on the way this winter there’s little chance that it will dry up soon.

My dad suggested we stock it with trout. But I have a better idea: I'm going to landscape my way out of the problem.

There is new interest in sustainable landscaping that emphasizes storm-water management techniques. Landscaping for rainwater offers twin benefits. First, it ameliorates some of the environmental impacts of roofs, sidewalks, and other urban impervious surfaces. Good landscape design can help capture, filter, and use the water before it deluges the city drain system. That’s good, because when the system gets overloaded it discharges untreated sewage into local bodies of water such as Puget Sound. The second benefit is purely self-interested: I can concentrate on planting vine maple and our new shore pine (last year’s living Christmas tree) instead of worrying about my basement flooding.

The basics of landscaping for rain are simple. The first thing I’ll do is get my soil to drain better by digging out some wells and drains that I’ll fill with rock. I’ll leave shallow depressions in the landscaping, covered by mulch and sturdy native plants that can tolerate wet winters as well as summer droughts. These should help sequester the rainwater where I want it—in confined areas away from my house--and it will let the water soak in slowly, easing my burden on the city’s drain system and trapping pollutants to boot.

NEW’s managing director, Christine Hanna, and her husband Pete have already turned their soggy backyard into a rain-smart haven. In addition to a couple of dry wells and amending their soil with water-retaining organic matter, they’ve created swales that naturally divert runoff toward the more water-loving plants and trees like the Japanese painted ferns and the Sambucus “black beauty” that Christine just couldn’t resist.

Other innovators are highlighted on the Puget Sound Action Team website, such as one homeowner in Shoreline, Washington--similarly cursed with saturated soils—who created a bog garden. He built a retention pond and used a variety of plants to create a flourishing garden that can process an estimated 10,800 gallons of water a year on his quarter-acre lot. Total cost to the homeowner? Just $600.

It sounds like a no-brainer to me. I'm going to start digging right away. Just as soon as this rain stops.

Resources

• Native Plant Societies: The British Columbia, Oregon, Washington, and Idaho chapters have native plant guides, sustainable landscaping guidelines, and member activities. See especially the Portland Chapter. The Washington chapter offers ecologically friendly landscape and garden consultations for residents of King and Snohomish Counties through their “Growing Wild” program.

• Seattle Public Utilities: Provides landscape and plant identification guides for homeowners and showcases the city’s natural drainage projects like the Seattle’s SEA (Street Edge Alternatives) project. Also check out King County's info on storm water ponds.

• Puget Sound Action Team: Describes successful natural drainage techniques, including the bog garden.

• Rain Gardens Blossom as a Storm-water Management Tool: An article and research on rain gardens from the University of Connecticut by Lizz Thrall.

• Wisconsin Department of Natural Resources: A variety of resources, including how-to manuals and photos on their website.