Every five years or so, I get the urge to share my thoughts on environmental issues…dirt, in particular. The stimulus this time came from a windborne dust cloud drifting in the lee of an abandoned construction site near where I live. Your guess is as good as mine as to how much soil was being transported downwind—I’ve been told that as much as 5 tons per acre per hour can disappear without being visible to the human eye—but I suspect there are a lot of variables at play, so I tend to take this figure with a grain of salt. Nonetheless, this cloud was highly visible well into the distance, so I’m comfortable with the belief that this was a significant soil-loss event.
So what’s the deal here? Dirt is dirt, after all. We bust it up, we dig it up, we push it around, we plow it, we mix different stuff into it, we compact it, and that’s nothing compared to what nature can do with its wind, water, ice, tectonics, volcanism, and an occasional meteor attack…all without the slightest bit of help from us. So why get upset by a little cloud of dust?
My concern is rooted well in the past…more than 50 years ago, during the opening day of Economics 101, a class presided over by the department head. As this was also my introduction to “College 101″ I could hardly wait for the mantle of knowledge to begin its descent upon my shoulders-something to which I still look forward-and thus recall with near perfect clarity his keynote declaration, outlining the purpose and scope of the course.
“Ladies and gentlemen,” he began, thrilling the 1,500 or so 18-year-olds seated in the auditorium with their instant elevation from lousy kid to responsible human in the space of three short words, “there are two kinds of goods in the world…[meaningful pause for heightened effect]…economic goods and free goods. Free goods are air, water, and dirt, and this is the last we’ll speak of them. Economic goods are all the rest.”
Well what was I-a seriously overmatched freshman-to do but slurp from the font of all knowledge. As value is based on availability (or perhaps more properly, scarcity), then air, water, and dirt clearly could be dismissed from further discussing…in 1954, that is.
But today? I don’t think that would fly, particularly with the heavy emphasis placed on cleaning up and protecting our precious air and water resources. The notions of public health and environmental sustainability have drawn air and water solidly into the supply-versus-demand world of economics, but what about dirt, other than its impact on air and water?
My Kingdom for an Inch of Topsoil
When was the last time you heard someone rail against the profligate waste of our soil resources? My guess is that for every mention of soil loss on the floor of Congress or in the output of our national media, there are at least a thousand each for air and water. And why? First, because the impacts are relatively easy to find and describe, and second, because they can—at a price—be remediated.
But dirt? That’s a different situation. While soil loss can indeed be measured-consider that much of the Midwest has lost half of its topsoil in the last 100 years—the impacts are less obvious to the naked eye, conservation efforts run headlong into land-use priorities, and as for remediation…well forget that.
Have you, as you’re busy moving a blade full of dirt from hither to yon, ever wondered how long it takes for nature to grow just one lousy inch of topsoil? Try 900 years, give or take a few depending on climate, geology, and whether a passing glacier is going to obliterate the progress. So when the soil beneath our feet—the same stuff that has sustained us since birth—is gone, for all practical purposes it’s really and truly gone.
Whether borne by wind, water, or the belly of a snail, fugitive topsoil has better than a 70% chance of ending up in the bottom of one ocean or another, where it gets recycled into rock before being thrust up or dragged down by earth’s colossal tectonic forces. Either way, you’re not going to be around to witness, much less benefit from, the process.
So the deal here is to recognize that it’s up to you-not the project owner, not the regulator, not some totally committed environmentalist-to minimize the export of dirt from each and every job site with which you’re involved.
A couple of our sister publications, Erosion Control and Stormwater, can help you with some great information on best management practices. Both can be accessed online, and complimentary subscriptions are available at www.erosioncontrol.com and www.stormh2o.com.
