Friday, June 24, 2011


            Oak Island racked up another .08” of rain from a Thursday night storm that skirted us to the north, bringing our 35-day total to .58”. The good news is, my rain barrels have water in them again.
Fitzgerald rain barrel # 1

            An old-fashioned “new” idea, storing rainwater for future use is once again popular. Driven by a sharp awareness of the need to conserve water following several seasons of drought, I’d asked Tim to install a 55-gallon black pickle barrel under the back-porch downspout. (It was my anniversary present for 2008: am I a lucky girl or what? And why a pickle barrel? We live near Mount Olive, NC, the Pickle Capital of the U.S.) He raised it on blocks so my watering can slides easily under the barrel’s spigot. I love the virtuous feeling I get when I use it, and angled for another one. Tim said, “Would you please stop fluttering your eyelashes like that and just call the [rain barrel] guy?” So I did, and Number Two now sits on the north side of the outside shower, convenient to the vegetable garden.

Fitzgerald rain barrel # 2
             Easy to install—requiring only an “S” modification of a downspout—rain barrels are available at garden centers, hardware stores and occasionally from Cooperative Extensions or as garden club promotions. Cost varies—my first one, from a garden center, ran about $130; the Boiling Spring Lakes Garden Club delivered the second one, setting us back just $45. For those of you with flamboyant tastes for whom basic black won’t do, expect to pay a premium for hand-painted models. (One advantage of black is that it helps slow down huge ice-cylinder formation in winter by absorbing warmth from the sun. If you live in a cold-winter area, you’d probably best empty and store yours from first frost to last, no matter what color it is.) If you have a frugal or a do-it-yourself bent, many magazines published directions in their spring issues over the past few years: and of course, googling “rain barrel” will deluge you with plans.

Three rain-barrel factoids:

·         It only takes one-tenth of one inch of rain running off just 1000 square feet of roof to fill a 55-gallon rain barrel. Most barrels are manufactured so that they can be connected to other barrels to capture the excess, if you have the space and desire. (I have the desire. Unfortunately, I lack the space.)

·         Only allow rainwater in your rain barrel. I started pouring grey water (water saved after use in cooking, bathing or washing dishes) in mine, resulting, after a few warm days, in 55 gallons of really stinky liquid. I had to drain the barrel and scrub it before refilling it. If you collect grey water—which I sometimes do, although not to a fanatic extent, mostly from kitchen chores, when I’m in the mood—pour it directly on your plants to keep your barrel smelling rainwater fresh.

·         A rain barrel never fully empties because the spigot is about nine inches above its bottom. Over time, algae and bacteria grow, causing the decanted water to smell unpleasant. Your plants won’t care, but you might. It’s okay to address the problem with the very occasional dollop of Clorox. Chlorine is volatile, meaning it evaporates into the atmosphere, which is why swimming pools go through tons of it in a summer. A half-cup of the stuff poured into 55 gallons of water at the beginning and again at the end of the growing season can’t do too much harm. And please—somebody correct me if I’m wrong.   

Ninety-Mile Beach,
near Cape Reinga, New Zealand
           When our town demonstrated its firm resolve to install a sewer system, indicated by digging up our street, Tim and I considered converting our septic tank into a cistern to store excess runoff from our roof. The details proved onerous, however, as the tank lies directly beneath my vegetable garden. We shelved the project until we win the lottery. In which case, we’re immigrating to New Zealand anyway.

Everybody loves rain… except when there’s too much or too little of it. It often seems no middle ground exists—we’re either inundated or parched, or, as in the case of one recent year, the Mississippi River put the Midwest under water at the same time Atlanta’s reservoirs were down to a frightening 90-day supply and California was on fire. As the concept of limitless clean water goes the way of eight-track tapes and VCRs, it behooves gardeners to adapt so that our precious plots may continue to thrive.

List of common runoff contaminants,
courtesy of Virginia Tech's website
(Click on the picture
to make it readable) 

Storm-water run-off poses big problems for city-dwellers because urban areas are notoriously lacking in spaces for water to seep into the ground. This is one of those rings-around-the-pebble-tossed-in-the-pond situations. During storms, water flows off roofs and over hard surfaces at great speed, causing erosion when it hits dirt. Along the way, it picks up heavy metals from paved surfaces, fertilizers and pesticides from the land it courses through, and sundry other pollutants you wouldn’t want coming out of the kitchen tap before ending up in the closest stream, river, lake or ocean.

So what am I expected to do about that? you ask.

I’ve got two sets of two words for you: permeable paving, and rain gardens.

Permeable paving example # 1

Although it sounds oxymoronic, permeable paving is a hard surface that allows water to go through it. Think of unsealed dry-laid paver patios and sidewalks, wide-spaced flagstone paths, and driveways made of concrete panels with cutouts that grass grows through. There are rumors abroad of actual permeable asphalt and concrete, mostly being used in the Northwest U.S. Other seepage-friendly driveway materials that abound in my childhood memories include gravel, oyster shells, and those parallel tracks with grass or gravel or oyster shells between them.

Permeable paving example # 2

If you’re building a house, the most important thing you can do is to make sure the house actually fits on the lot without resorting to oddly angled garages, tiny setbacks, or shoehorns, so there’s some open land left into which rain water can run. (It really annoys me to see McMansions crammed onto lots so small the side setbacks are ten feet or less. They not only look ridiculous, they are impossible to landscape well—scale is out of kilter from the get-go.)  Minimize or consider alternatives to usually impervious surfaces, like driveways and patios. Any up-front expense will be more than recouped both aesthetically and by lack of future drainage problems. 

Sand to China on Oak Island

Our house on Oak Island doesn’t have drainage problems. Besides sitting on sand-to-China, the structure, driveway and sidewalk only occupy about 1900 of the 6000 square feet that is our property. That works out to less than one-third impervious to two-thirds pervious, a good ratio. But if I lived on swamp-muck or clay or other dense soil, I would consider adding a rain garden to my landscape.


A rain garden/bioretention area
schematic drawing
Rain gardens are another one of those trendy “new” phenomena that date back centuries. When the only way folks knew how to manage their land was sustainably, they sensibly dealt with occasional excess surface water by giving it a place to go. Grandma called these areas “the pond,” or “the low spot,” or “the bottom”: today we say “rain garden” and “bioretention area.” The objectives are the same: to slow down runoff in order to minimize erosion; and to filter out pollutants before the water reaches rivers or other surface features and the water table. Modern techniques for channeling urban runoff include green roofs, permeable paving, residential rain gardens and—for commercial applications—bioretention facilities (rain gardens on steroids). All of these enhance the “catchment” of rain following the principles of the natural water cycle, instead of relying on increasingly overtaxed storm drains. It’s certainly an idea worth studying, despite the florid vocabulary. 

An actual parking-lot
bioretention area at NCSU
Ideally sited in an already-low spot, a rain garden is an area dedicated to an array of plants that prefer boggy conditions (or at least don’t mind occasional wet feet): to reiterate, the idea is to slow down runoff so that it can be absorbed into the ground, and cleansed by percolating through roots and soil before reentering the water table. A rain garden can also spiff up reedy, weedy, marshy places on your property, making it look like you planned them that way.


 Tim and I haven’t been called upon to design a rain garden yet, though I suspect the day is coming. But since I have no direct experience with the process, I’ll share with you the book I read. Rain Gardens: Managing Water Sustainably in the Garden and Designed Landscape by Nigel Dunnett and Andy Clayden is a basic overview of the concept and a primer for constructing a rain garden of your own (see Good Reads at right). And of course the Internet is chockablock with helpful sites as well.

            Okay, enough for one session. After the June Wrap-Up, we’ll celebrate the Fourth by taking a look at garden water features.

            Thanks for dropping by.


P.S.--On Thursday, 23 June, the Wilmington, NC, StarNews ran an op-ed essay I wrote rebutting a piece extolling agricultural biotechnology. Check it out at the link I've provided.