By Tom Horton
10:12 AM EDT, June 24, 2013
Don't mess with Mother Nature, they say; but we do, perhaps must — hard-wired like steroidal beavers to be forever engineering our environment.
Some of our most emphatic "messing" is to pave and roof over the soft, vibrant skin of green earth. This obviously deadens it for the rest of life. Less obviously, by disrupting the natural flow of rain, it disrupts all manner of complex and vital communication between watersheds and waters.
We lump all this under "stormwater pollution," oversimplifying the problem, ensuring that we take too narrow an approach to solutions.
To be sure, stormwater even in the narrow sense is the fastest-growing source of pollution to the Chesapeake Bay. It has made news as federal requirements for restoring the bay force local jurisdictions to come up with big bucks to slow down, disperse and filter the polluted rainwater that rages off the millions of hardened acres where it used to soak in.
In Maryland, the legislature recently required large counties and Baltimore City to charge taxpayers a stormwater fee. Some politicians and conservative pundits have denounced this as a "rain tax."
They might as well call quarterly sewer bills "a bowel movement tax" or paint the food sales tax as government intrusion in "swallowing." So long as water runs downhill and connects "your" property to "our" bay, word games won't make the stormwater problem go away.
Unfortunately, neither will the latest round of expensive, new stormwater controls which we're all going to be paying for soon. They'll be, on balance, a real improvement, just as the stormwater holding ponds that dot the watershed were an improvement a couple of decades ago.
The new controls will require developers to mimic nature more, restricting how much land they harden, increasing places where the rain can soak into the soil and promoting natural buffers along streams.
All are good things to do — and they allow us to keep growing, developing in Maryland alone another half a million or so acres in the next couple of decades, with the illusion that we're restoring the bay.
Never mind the exceptions and exemptions and grandfathering and delayed timetables that will inevitably occur. Never mind that hugely understaffed stormwater inspection programs will have to deal with a huge increase in inspections.
Never mind that the focus remains relatively narrow, targeting nitrogen, phosphorus and sediment, the three main bay pollutants, rather than overall aquatic health of waterways.
This last is most concerning. The science makes it clearer every year that past a fairly low level of development, water quality in a given watershed begins to decline, regardless of stormwater control programs.
Native brook trout feel the impacts when as little as one half of 1 percent of the watershed around their streams is paved. That's the equivalent of a two-lane highway through an otherwise forested square mile of land.
In general, fish health and diversity are OK up to about 5 percent developed, or impervious; but by 10 percent most waterways have reached a tipping point, and by 15 percent they are clearly degraded.
And it's not clear you can go home again once a watershed passes from rural to suburban/urban. A recent Maryland study of urban streams found that while expensive restoration projects could make them look prettier, they weren't any healthier than unrestored streams.
It's not just little streams. Similar links between development and the aquatic health of the Chesapeake itself emerge in studies by the Smithsonian Environmental Research Center.
Why development inevitably tips waterways over the edge is only partly understood. In addition to measurable increases in polluted runoff, paving disrupts how rain moves naturally: seeping in, filtering through soils and feeding streams in drought; It may also short-circuit rainfall's conveyance of the organic matter from forested lands that nourishes the larvae of spawning fish.
Factor in other insults — from road salt to endocrine disrupters and other poisons that aren't taken out in sewage treatment — and one has what a scientist once called "urban stream syndrome."
"There's always another round of new solutions that will let us keep developing with less impact, but the burden of proof is always on the stream," said Scott Stranko, director of the Maryland Biological Stream Survey.
So what's the answer?
•Focus on aquatic health, not just a few pollutants of concern to a few parameters of bay health, important though these are.
•Consider triage — save resources to restore only streams that have a chance.
•Analyze whether growth as usual is cost-effective anymore if we really count all the costs, both to taxpayers and to the rest of nature. Might there be a limit on how many people you can put in a place and sustain a healthy and diverse natural environment?
If that sounds radical, consider the assumptions of the latest "rain tax": Developing another half-million acres in Maryland will lead to restored waters.
Tom Horton covered the Chesapeake Bay for 33 years for The Sun, and is author of six books about the bay. This article is distributed by Bay Journal News Service.
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