By Stephen Madden

A kayaker ponders the paddle power of the glass-bottomed Tahoe Queen.

Early one Sunday morning last spring, I perched, coffee mug in hand, atop a rock on the shore of Lake Tahoe and watched as the sunrise illuminated one of the most beautiful places in the United States. The Sierra Nevada, still snowcapped from a brief but intense winter, formed an amphitheater in which the lake, mirror calm this morning, was performing its timeless rhapsody of blue. Steller's jays, the ubiquitous bird of the Sierra Republic, chattered away in the trees behind me as I watched a Canada goose honk its way across the water. The cold air smelled faintly of wood smoke and strongly of pine and fresh water.

Nature abides, I thought, grateful for the glory of it all.

That, of course, was before I saw the garbage.

It looked like the detritus of a pretty good party. There was a beer bottle resting on the stones at the lake bottom about 20 feet offshore, Tahoe's legendary clarity ensuring that I could read its label—Corona Extra, La Cerveza Mas Fina—as clearly as if it were in my hand. A Marlboro wrapper and a few cigarette butts floated nearby.

And there you have it—all the problems and opportunities of the Tahoe Basin rolled into one writer-friendly moment: the astounding beauty of North America's largest alpine lake combined with the beast of modern population pressure.

No place in the West feels that pressure in quite the same way as the Tahoe Basin, the 500-square-mile area straddling the California–Nevada border that contains the lake as well as the more than 60 creeks and streams that feed it. Thirty-three million people live within 350 miles of Tahoe, and on summer weekends it feels as if all of them are on the 72 miles of primarily two-lane roads that ring the lake. Of course, millions do visit Lake Tahoe each year. Think you might get away from the crowds by heading into the mountains of the Desolation Wilderness Area, which rise just above the lake's lovely Emerald Bay? Think again. With its forests, granite peaks, and 130 jewel-like lakes, Desolation Wilderness is, per acre, the most heavily used wilderness in the country.

And it's not just visitors clogging that narrow road. According to a report in the Los Angeles Times, there were a mere 500 homes in the Tahoe Basin in 1960, the year the Winter Olympics at Squaw Valley brought the area's splendor to the world's attention. Today, there are more than 22,000 homes and nearly 53,000 residents in that same area (23,000 in South Lake Tahoe, Calif., alone), and the few parcels of lakefront land that ever trade hands have multimillion-dollar price tags.

You can't blame people for wanting a glimpse—or a piece—of the place. Mark Twain called Tahoe "the fairest picture the whole earth affords." The area abounds in recreational opportunities. Gamblers and those who love Vegas-style action flock to the casinos and strip malls of Stateline and South Lake Tahoe. The basin has the highest concentration of world-class ski areas in North America, with resorts whose mere names—Heavenly, Squaw, Alpine Meadows, Kirkwood, Royal Gorge—are enough to make nordies, alpine skiers, and snowboarders curse the summer.

Not that summer is anything to avoid. In warm weather, Tahoe offers a staggering array of recreational possibilities: hiking on the myriad trails (but especially the Pacific Crest Trail), mountain biking on the world-renowned 24-mile Flume Trail, rock climbing at Lover's Leap or Donner Summit, rafting on the Truckee River, and camping and backpacking in places too numerous to mention. In fact, summer is Tahoe's busiest season.

And there's the lake, a body of water so blue that it's a wonder Crayola doesn't produce a Tahoe Blue crayon.

Lake Tahoe gets its name from a mispronunciation of its Washoe Indian name Da ow a ga, which means "edge of the lake," but is often translated as "big water." Tahoe is truly huge—22 miles long, 12 miles wide, and 1,645 feet deep—and contains 37 trillion gallons of water. Its depth ensures that it never freezes, but it also ensures that it never warms up too much, which helps attract those fleeing the summer heat. Although certain kinds of personal watercraft (read: Jet Skis) have been banned, powerboats abound on Tahoe, as do canoes and kayaks.

Fearless souls can enjoy a bracing dip in the lake (68 degrees at its warmest) before drying out on the beach.

Yes, everybody loves Lake Tahoe. But it could be that we're loving it to death. The bellwether of the lake's health is its clarity, which scientists analyze by submerging a white, platelike device called a Secchi disk under a boat. The greater the depth at which the disk is visible, the healthier the lake. In 1968, limnologists on the surface could see the disk when it was submerged to 105 feet; today, it's visible at 66 feet, and scientists think that if current trends continue unabated, the disk will only be visible at 40 feet in 2030.

The decrease in the lake's clarity is largely the result of higher concentrations of algae, which feed on nitrogen put in the lake by auto emissions and on phosphorus from erosion and the road dust that is kicked up by the never-ending stream of cars circling the lake. Although more than 60 streams feed Tahoe, only one, the Truckee River, flows out of the lake. Experts estimate that a drop of water can remain in the lake for 700 years; nutrients, for 30 to 50 years.

So is Lake Tahoe half empty or half full? Some environmentalists tell you that the place is beyond repair, that a one-third reduction in water clarity in 30 years is an unhealable scar. Others tell you that the fight must and will go on. South Lake Tahoe has recently started an ambitious overhaul designed to reduce auto emissions and outflow from storm drains into the lake. A 1997 summit, which drew both President Bill Clinton and Vice President Al Gore, proposed a $906 million plan to maintain the clarity of the water and to sustain the environmental health of the entire basin.

I hope the plan works. I did my part. The beer bottle that ruined my morning was 20 feet offshore, but it was in shallow water. Shallow, very cold water, I discovered as I rolled up my pants and, in my own small way, lit a single candle.