Northwest Rain Garden DIY

Rain gardens. Rain barrels. French drains and swales. Green solutions to stormwater runoff sound fancy and complicated, but they’re not. And I’ve got a list of rain garden how-to resources to prove it.

The basic principal for controlling stormwater in an earth-friendly way: keep the water where it falls and help it soak into the ground. Homeowners can do that by following any or all of these low-impact development strategies:

1. Channel your roof’s downspout into a rain garden
2. Install pervious pavement for pathways and patios (LID expert Tom Holz recommends Turfstone from Mutual Materials)
3. Instead of paving a whole driveway, install two tracks of pavement or paving tiles just where you drive (this is sometimes called “California strips”) and leave the rest of the driveway in gravel or vegetation
4. Install a vegetated or green roof
5. Connect your downspout to a rain barrel

There are even programs in Portland, Seattle, and elsewhere to help pay for these stormwater fixes, and there are a variety of free classes to show you how to do LID.

(If you still need convincing that stormwater is a serious environmental and economic problem, keep in mind that in a single storm in the Puget Sound region, 10 bathtubs worth of water pour off a single home’s roof. For more on stormwater’s harm check out our report Curbing Stormwater Pollution.)

Ready to take the next step?

Let’s start with a little elaboration on these five strategies.

What is a rain garden? In it’s simplest form, it’s a shallow depression, like a little pond, that a roof downspout empties into. Most of the time, the pond is empty. When it rains, it fills with water that slowly soaks into the ground. That soaking process is helped by digging the pond an extra few inches or feet deep, then lining it with a few inches of sand, gravel, and soil that soak up water better than the average patch of dirt in your yard. The depression is usually planted with grasses and shrubs that can tolerate wet soil. (Also note the depression can be called a swale or bioswale, and a French drain is akin to a buried rain garden.)

Pervious pavement is just what it sounds like—it has small holes like a sponge or Swiss cheese that allows water to pass through it to the ground beneath.

Building a driveway with tracks is a straightforward solution, and dramatically cuts down on the amount of pavement that repels water.

A green or vegetated roof is going to be the most costly, complicated of these strategies. It’s a roof covered with soil and vegetation that trap and hold water (that’s a ridiculously simplified explanation, and frankly I have less knowledge about this solution—Sunset Magazine this month offers a simple green roof how to, but I’m skeptical that it’s that easy.).

Rain barrels are getting pretty ubiquitous in the Northwest. The idea is to plug your downspout into a barrel or cistern, then use the water on plants during the summer (if you have a composite roof, those tiles are made from asphalt and the water isn’t safe for using on edibles). The thing is, these barrels fill up FAST. Basically, one good November storm will fill the barrel, and then for the rest of winter the water just spills out of the barrel or runs back into the stormwater system. So if you really want to help the environment, let the barrel slowly drain into your yard after the storm when the ground is less saturated so that it can fill again with the next rain.

Rain Garden Guides

That’s the quick and dirty rundown. Here are some great publications walk you through the specific hows and whys of rain gardens, rain barrels, and other strategies:

• The Oregon Rain Garden Guide from Sea Grant Oregon. This illustrated guide helps you figure out exactly how and where to build a rain garden, including cutaway diagrams and photos that are nothing short of landscaping eye-candy—look at those fuzzy sedges and meandering rock streams. Also check out Rob Emanuel’s blog for more on stormwater and LID.
• The Rain Garden handbook from Washington State University on Seattle Public Utilities’ RainWise website also provides step-by-step rain garden instructions. It also tells you how to install rain barrels and other less labor-intensive means of dealing with runoff.
• The Waterbucket website has stormwater info that’s BC centric, but it’s also more technical.
• And this Oregon Metro website has still more Oregon-oriented info.

Free classes and workshops

If this still seems daunting, check out these free classes on installing a rain garden and rain barrels:

• The East Multnomah Soil and Water Conservation District website lists upcoming classes in Portland, Beaverton, and other cities.
• In the Puget Sound area, check out the Stewardship Partners website for classes happening right now.

Free rain gardens

And finally, let’s talk about cost. Lately, new programs keep cropping up to help pay for rain gardens and the like.

• Residents of Puyallup, Eatonville, and the Broadview neighborhood of Seattle have a shot at getting a free rain garden.
• Seattle residents in the Ballard neighborhood could be eligible for a separate rain garden program.
• Gresham residents can get $100 grants for installing a rain garden.
• Portland residents who disconnect their downspout from the sewer system can get a discount on their utility bill.

I’m certain there are resources, classes, and incentives that I’ve missed in this roundup, so be sure to add a comment to this post to share any additional information!