Thursday, March 31, 2005

Light Pollution

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Both of the elementary school students at my house are studying astronomy this month, which means, weather permitting, we’ll be outside three nights a week identifying constellations and tracking the progress of the moon and the planets. If you live in town and you’ve tried this yourself, you know we’ll be prevented from seeing much of what’s out there by the glow of artificial light in the sky.

Sky glow, which obscures our view of the heavens at night, is the most commonly recognized effect of bad lighting, or light pollution.

But bad lighting also causes a number of other problems. It creates glare, which is light that shines in our eyes rather than on things we need to see, and light trespass, unwanted light that strays into our yards and windows. Bad lighting is also the source of what some call light clutter, the unappealing and visually confusing nighttime environment so common in modern cities.

Beyond its undesirable visual effects, bad lighting also wastes energy—a lot of it! One reasonable calculation puts the cost of wasted light in the U.S. at one billion dollars a year. The energy used to produce that wasted light would equal at least six million tons of coal, or twenty-three million barrels of oil.

Why is such waste so widely accepted? Because we’ve come to equate more light with better safety and security. But that is simply not the case. In fact, overly bright, misdirected light can actually do more harm than good. Light that shines in our eyes prevents us from seeing hazards as we walk or drive at night. Widely scattered, bright light also creates hard shadows, which can conceal criminals while making victims visible. Worst of all, excessive, poorly designed lighting can make us feel safe when we should actually be on guard.

The principles of good lighting are really pretty simple. Good lighting shines down, only where it is needed, rather than sideways, where it causes glare, or up, where it causes sky glow. Good lighting is bright enough to light only what needs to be illuminated, and does not
create harsh transition zones between light and dark areas. Good lighting is also energy efficient and on only when it is needed.

It’s actually pretty easy to spot well-designed light fixtures once you know what to look for. They have the light source high, with a top and sides that direct light downward. It’s worth noting that you can illuminate even large areas such as parking lots and ball fields with such fixtures.

In poorly designed fixtures the light source is not fully shielded, either on the sides or at the top. The worst offenders are drop-lens cobra fixtures—the ones that loom over our arterial streets in town and the lighted portions of many interstates. Most locales have a policy of replacing these as they wear out with far superior flat lens fixtures that shine light only where it’s supposed to go. Other poorly designed fixtures include the super bright barn light fixtures found on power company poles, and decorative globes that shine light in all directions

You can do your part to reduce light pollution by replacing poorly designed fixtures on your property with well-designed ones. And remember as you do this that you’ll likely recover the cost of new fixtures with the money you save on electricity to operate them. If you want to go beyond that, check in with the Champaign-Urbana Astronomical Society or the U of I Astronomical Society concerning local efforts to promote dark skies.

With good lighting we’ve got nothing to lose, and an entire universe to gain.

Thursday, March 24, 2005

Mercury Pollution from Coal Burning Power Generation

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If you regularly buy a fishing license, or if you pay attention to reports about the healthfulness of eating certain foods, you’re likely aware that mercury from the environment accumulates in fish, and that eating contaminated fish can expose people to unhealthy levels of this toxic element.

At the levels we’re exposed to by eating fish, mercury poses the greatest danger to fetuses and young children, because it inhibits brain development. The impact is particularly severe for the fetus, which receives a concentrated dose of the mercury in its mother’s blood through the placenta. The impacts of prenatal exposure to mercury, which persist into adolescence and appear to be irreversible, include problems in balance and coordination, and deficits in memory, learning, and attention span.

According to calculations by one researcher at the U.S. EPA, nationally, as many as 630, 000 infants, or one in six babies, are born with unsafe levels of mercury in their blood each year.

One way to address the problem of human exposure to harmful levels of mercury is to advise people about how much or how little mercury contaminated fish they can safely eat. Like other states, Illinois does this through advisories issued by the Department of Public Health, which I quote:
In order to protect the most sensitive populations, pregnant or nursing women, women of childbearing age and children younger than 15 years of age are advised to eat no more than one meal per week of predator fish.
The predator fish referred to in the advisory include lots of favorite sport and food species, notabably bass, walleye, muskie and northern pike.

The Illinois advisory applies to fish taken from all rivers and streams, and all lakes within the state, as well as Lake Michigan. More restrictive advisories apply to certain bodies of water where tests have found higher concentrations of mercury.

Now, if we did not know how mercury got into the environment in the first place, or how to prevent mercury pollution at a reasonable cost, it would be reasonable to begin and end this discussion with fish consumption advisories. But the fact is, we do know how mercury gets into the environment, and we can reduce mercury pollution at a reasonable cost.

The largest single source of mercury emissions in Illinois is coal-fired power generation, which releases some four thousand pounds of mercury into the air annually. We’re currently 5th in national rankings for greatest mercury emissions by utilities.

Unfortunately, mercury emissions from coal-fired power generation are not currently regulated under federal clean air standards, and the U.S. EPA has recently reversed course on a policy that would have required ninety percent cuts in mercury emissions by the year 2008.

This refusal by the U.S. EPA to protect the public interest means that states are going to have to pick up the slack. We ought to be able to do this.

According to a report released in Fall 2004 by the National Wildlife Federation, mercury emissions from coal-fired power plants in Illinois could be reduced by 90%-- using existing technology--at a cost to residential customers of less than a dollar per month.

Thursday, March 17, 2005

The Other March Madness: American Woodcock

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One of the early season highlights of birding in east central Illinois is the return of American woodcocks in February and March, and most people who have made it a point to look for these birds have a story to tell. Indeed, for some of us, the return of woodcocks is March madness.

The woodcock belongs to the shorebird family, whose more familiar members include sandpipers and plovers. But unlike its cousins, the woodcock prefers habitat composed of moist woods, open fields, and brushy swamps. You won’t see a woodcock poking along beaches or mud flats the way other shorebirds do. Indeed, the woodcock is so secretive and so well camouflaged that unless you witness its courtship display, you’re likely to see one only if you come close to stepping on in it, and it flushes. Then you are startled by an explosion of wings at your feet, after which you’ll have five to ten seconds to watch the bird fly before it lands and takes cover again.

On the ground, the woodcock’s appearance suggests that it was constructed by a birdmaker who didn’t pay strict attention to the shorebird blueprint as he worked. It’s a plump bird, about eleven inches long altogether, although its bill accounts for three of those inches. This bill is highly sensitive to help the woodcock detect vibrations made by earthworms underground, and it features a flexible tip that can be opened to grasp worms even while the rest of the bill remains closed. The woodcock eats earthworms in quantities that equal its body weight in a day.

A woodcock’s eyes bulge out, like black stick-on doll-eyes that are attached in the wrong spot--just a little too high up, and too far back on its head. Odd as it may look, this arrangement allows the woodcock a super wide field of vision—nearly three hundred and sixty degrees—which is quite a useful adaptation for a bird that spends so much time with its nose to the ground.

Appearances aside, what endears the woodcock to birders is the strange and elaborate courtship ritual that the males perform at dusk and dawn in the spring. Many people have written to describe this behavior, although none so eloquently as Aldo Leopold, whose thought and writing are the foundation for so much of the modern conservation movement.

This is how Leopold describes what he terms the woodcock’s “sky dance”:

He flies in low from some neighboring thicket, alights on the bare moss, and at once begins the overture: a series of queer throaty peents spaced about two seconds apart, and sounding much like the summer call of the nighthawk.

Suddenly the peenting ceases and the bird flutters skyward in a series of wide spirals, emitting a musical twitter. Up and up he goes, the spirals steeper and smaller, the twittering louder and louder, until the performer is only a speck in the sky. Then, without warning, he tumbles like a crippled plane, giving voice in a soft liquid warble that a March bluebird might envy. At a few feet from the ground he levels off and returns to his peenting ground, usually to the exact spot where the performance began, and there resumes peenting

Depending on conditions, the male woodcock may repeat this performance for a half hour or more.

If you would like to see the sky dance for yourself, join members of the Champaign County Audubon Society for a woodcock walk at Meadowbrook Park in Urbana next Wednesday, March 23. They will meet at the Race Street parking lot south of Windsor Road at 6:00 p.m., and likely be out until 7:00. Details are available through Environmental Almanac website.

Thursday, March 10, 2005


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The most basic form of locomotion by humans, walking, has been the subject of much discussion on the U of I campus in recent weeks. As someone who loves to walk, I find this both gratifying and disconcerting: gratifying, because it reaffirms that others are interested in making room for walking in daily life, and disconcerting, because it suggests that walking has fallen so far as to need boosters.

A group from the School of Art and Design has organized a four-part symposium in order to explore the connections between walking and knowing and the creation of art associated with specific places. On a recent Friday morning, I joined up with participants from the first session of the symposium for a walk that began in Sadorus, a town of about thousand people, just southwest of Champaign.

At the edge of the Sadorus Community Park, where we gathered, a stone marker with a bronze plaque designates the location as a stop on the Potawatomi Trail of Death--the forced march of some 800 people by U.S. and Indiana officials from Plymouth, Indiana to eastern Kansas in 1838. One purpose of our walk was to commemorate the thirty-nine people who died along the way, and the suffering of those who survived.

From the park we walked out and back about a mile west on River Road, crossing and re-crossing the Kaskaskia as we went, and paralleling a high-traffic rail line. As we walked, the larger assemblage divided and regrouped the way migrating geese do, and members of the party gave impromptu lessons in the natural history of the region, or spoke of their experience walking elsewhere. The sun on our faces, the warm breeze from the southwest, and the natural lift that goes with walking outdoors promoted among us a pleasant feeling of connectedness.

Back on campus last week walking was also a prominent topic at a two-day institute hosted by the Department of Urban and Regional Planning. There keynote speaker Richard Killingworth from the Active Living by Design Program exhorted tomorrow’s planners to become public health practitioners by creating built spaces that foster physical activity: streets that are friendly to pedestrians and bicycles, neighborhoods where short trips can be made without cars.

Killingworth and others argue that as a society, we have become less healthy as we have become less active, and that we have become less active as a result of the car-oriented environments we have built for ourselves. By this logic one of the most significant things we can do to promote public health is to redesign where we live.

We have a lot to gain by going from place to place on foot when we can. Of course in walking we do our part as citizens of the world by leaving behind the need for fossil fuel and helping to keep the air clean. But we also benefit ourselves directly, both physically and psychologically, in ways that are perhaps by now well known enough not to need reciting here.

Given all of the reasons for walking, I’m tempted to appropriate a line from a commercial promoting seat belt use to end this piece, and so I do: what’s holding you back?

Thursday, March 03, 2005

The Mahomet Aquifer, an Underappreciated Resource

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Do you know where your water comes from? Most of us don’t think twice about that, as long as the water flows when we turn on the faucet. But here in east-central Illinois many of us draw our water from the Mahomet aquifer, a largely under appreciated natural resource.

The aquifer is a layer of sand and gravel whose top lies between one and two hundred feet beneath the ground we walk on. It was deposited there in the valley carved into bedrock by the prehistoric Mahomet river more than five hundred thousand years ago. The clay-rich sediments that now cover the aquifer and constitute the ground as we know it were left by glaciers that later came down from the north and trapped the sand and gravel in the Mahomet bedrock valley. The aquifer holds more water than the finer soils above it because the coarser grains of sand and gravel leave more in-between space for water to fill.

Its great size is one of the remarkable characteristics of the Mahomet aquifer. It stretches about a hundred and twenty-five miles long, from its eastern edge north of Danville to its western edge near Peoria, and it’s typically from four to fourteen miles wide. The aquifer lies beneath 1.26 million acres and crosses the boundaries of fifteen counties, as well as many other political entities. Geologists calculate that the Mahomet aquifer holds about four trillion gallons of water, about the volume of water that flows past St. Louis in the Mississippi river every two and a half weeks.

The water in the Mahomet aquifer is of remarkably high quality. Most of it is between one thousand and twelve thousand years old, which means it fell as rain at a time before it could pick up the industrial pollutants and synthetic pesticides that plague our surface water today. Water from the aquifer is also free of bacteria harmful to humans, having been isolated from the sources of such organisms for so long.

The only contaminant that poses an immediate concern for users of the aquifer is arsenic, which occurs naturally at concentrations high enough to pose a risk to humans at various sites throughout the region. Municipal systems remove arsenic, but well users must test for it.

The most pressing question concerning the Mahomet aquifer is how much water we can pump from this remarkable resource without depleting it. The frustrating non-answer to that question is, we don’t know—not yet, anyway. In order to find that answer, we’ve got to fund more science.

Beyond the issue of identifying sustainable levels of withdrawal from the Mahomet aquifer, we will eventually need to grapple with the question of how that water is allocated. That’s a complicated question since aquifers don’t conform to political boundaries. But it’s also one best addressed before anyone’s well runs dry.