A Man, A Plan, A Natural Drain

The rains have set in. And with the approach of the holidays, the waning of the light, and the inevitable existential angst, Northwest homeowners turn their thoughts to the season’s verities: turkey dinners, Christmas lights, and flooded basements.

But not me. This season it’s all eggnog and overeating for me. (And existential angst, of course. That goes without saying.)

That’s because in a fit of uncharacteristic virtue, my wife, Jill, and I embarked on a backyard landscaping project last summer that’s already paying dividends. And I think it’s helping ease my home’s environmental impact to boot.

Last January, I wrote a bit about my backyard and how soggy, even lake-like, it became in the rain. The heavy clay soil allowed worrisome amounts of water to pool up, turning the lawn into something resembling the Everglades. But rather than stocking my backyard lake with trout, as my Dad suggested, we vowed to landscape our way out of the problem.

So with the aid of a pick axe I started digging. First, I tore up chunks of lawn. Together with pieces of the lawn that I’d already cut up to make way for a patio we built, I began creating berms along two sides of my backyard.

Beneath these berms, I began digging out a series of drainage ditches than feed into two larger drainage catchments. We piled the diggings from the ditches—mostly awful clay soil—in with the sod cuttings to make the berms larger. (We’re sort of hoping that the organic matter in the decaying sod will mix with the lousy soil from the ditches and magically create decent dirt. Time will tell.)

Then, after we had the ditches leveled and lined with landscape sheeting, Jill and I embarked on a rather hilarious Saturday morning of filling the big drainage catchments with rubble. This involved driving around our neighborhood and repeatedly filling our Civic’s trunk with scavenged demolition debris, bricks, and other items from places like the Re-Store and from that “free” sign on the sidewalk.

Once the catchments were loosely filled with big chunks of rubble—with plenty of spaces for water to trickle in and wait while it soaks into the ground—we tackled the ditches by laying down drain rock and perforated pipe to move water toward the catchments and away from the house. Then we covered everything with a layer of landscape sheeting (permeable to water, but not to dirt) and had a cold drink or five.

We cheated on the next stage. Not having the courage to tackle shoveling and hauling 10 cubic yards of topsoil, we had it installed on top of the berms we’d built, and in a thinner layer over the ditches. We even found a place, Cedar Grove, that could blow it in using an engine and a big blower hose. Interestingly, Cedar Grove is the outfit that composts all of Seattle’s yard waste. So it’s possible that our own pizza crusts and leaf rakings were returning to our yard as soil. Ah, the cycle of life.

You can imagine my delight—and my back’s relief—to return home from work and find 10 yards of excellent topsoil neatly applied around our yard, just where Jill had told them to put it. The only problem was the smell—the topsoil was about 50 percent compost—which gave off a distinct “barnyard” scent even from a ways off. (Sorry neighbors!)

But we were almost done. The most satisfying day by far was planting our new vine maples, Chinese dogwood, shore pine (last year’s living Christmas tree), limelight cypress (awesome!), and a number of shrubs, ferns, bushes, and bulbs. Many of these will help retain water in the berms where they’re planted. And many are native: so they can easily withstand the Northwest’s seasonal cycle of saturation and drought. We didn’t finish all our planting in the fall because we ran out of money and season. Plus, we wanted see how things fared over the winter before we completed our planting.

The last stage was covering things over with several cubic yards of bark mulch. Then we waited to see if it would actually drain. And we didn’t have to wait long until we hit the wettest month in Seattle’s history.

The crazy thing is, it actually worked. The worst that’s happened so far it that for a single 8 hour period, we had standing water visible above the buried ditches and catchments. But that was after an extremely wet stretch and by morning it had all absorbed into the ground and well away from the house. Last winter, by contrast, we could routinely see standing water.

As I pointed out in an earlier post about my rain barrel, there’s an awful lot of water falling from the sky. In November alone, nearly 44,000 gallons of water fell on our property, maybe half of that in the backyard. And our home-built natural drainage system somehow managed to process all that water without sending it into my neighbor’s yard, (as it used to), making me worry about my basement (as it also used to), or adding to the strain on the city’s drainage infrastructure. Pretty cool.

Even better, the whole thing was extremely cheap, if you don’t count our labor. I bet we didn’t spend more than $250 on the entire drainage portion of the project. (We did, however, spend a bunch more on the topsoil, plants, and mulch.) At the close of the wettest month on record, I’m pretty pleased with our summer project.

Now, to the eggnog!

Photos of the whole project in process here.