Each year, nearly 5 million people visit the Grand Canyon, most of them traveling to the South Rim, where they spend as much time looking for a parking place as they do looking at the canyon. Only a small fraction venture below the rim on a trail.

Another 22,000 people a year see the canyon from the bottom up, enjoying a week or more of spectacular scenery while running rapids, hiking to waterfalls hidden in side canyons, and sleeping on sand next to the river under a sky studded with stars.

For most, life on the river is an earthly paradise. Surrounded by "the best wallpaper in the world," as my fellow guide Kevin Johnson describes it, your body is assaulted by sensations — the warmth of a breeze, splash of cool water, roar of a rapid, song of a canyon wren, smell of coffee at sunrise, the yipping of a pack of coyotes.

Absent are clocks, television, newspapers and phones that ring. A hundred miles down the river you don’t know, or care, what day it is.

It’s not for everyone. But for some, the experience beats most pleasures known to man. And there’s the rub: Interest in whitewater boating has grown steadily over the years, and there’s not enough room in the canyon for everybody to be there at once.

In the century before the completion of Glen Canyon Dam, 1,100 people floated through the Grand Canyon. Five years later, it was a thousand a year; in five more years, it was 10,000 a year. Recognizing that people have impacts on the canyon, and on each other’s experience, the National Park Service "stabilized" use in 1973, by saying, in effect, "No more people."

A decade later, a new plan called for the elimination of motorized boating but more than doubled use levels, in an effort to appease both commercial and noncommercial users. A rider attached to the Park Service appropriations bill axed the controversial elimination of motorboats, but left the increased use levels. Complaints about crowding and competition for campsites soon followed. As interest in do-it-yourself trips grew, the Park Service established a waiting list for future trips, a list that grew ever longer.

Today, canyon resources are in a tailspin. The downstream impacts of Glen Canyon Dam, which began operations in 1963, have increased. Camping beaches, deprived of new sediment, grow smaller and disappear; some native fish species exist on the brink of extinction, while others are gone for good. Footprints evolve into trails, then metamorphose into backcountry highways. Non-native plants and animals proliferate while ancient artifacts disappear into the pockets of tourists.

Nobody is trying to wreck anything, but the changes accumulate over the years, many of them in direct proportion to the number of visitors. Almost everybody has a great time in the canyon, so they tell their friends about it, and even more people want to go the next year. There’s no end in sight. Professionally outfitted trips book far in advance, and when the waiting list for a private trip got to be 20 years long, the agency stopped taking names.

A planning process intended to straighten all this out got so bogged down in controversy it was terminated by the agency in 2000. After a lawsuit got the process started again, the controversy over who gets to go on the river, on their own or with an outfitter, resumed. Outfitters just want to do what they’ve done for years — make a living showing folks a good time in the canyon. Private boaters just want to get on the river soon, not in 20 years. The Park Service wants the controversy to go away, so it can get on to other issues: managing the backcountry for hikers, for example, or dealing with aircraft noise. The agency’s latest plan, aimed at getting cars away from the rim, lacks funding and appears stalled.

Now, the Park Service has proposed a new plan for the river, but sad to say, it increases river use by 23 percent, reaching a level two and a half times what was "enough" 30 years ago. The agency assures the public that if more use creates more problems, it will cut back. Experience says that will never happen. Simply monitoring the impacts of this proposed plan, for example, will have to depend on "additional funding" from unspecified sources. The final plan is due out next fall.

For three decades, I’ve watched the Park Service struggle to please everyone, while crowds and congestion increased and the river experience diminished. That is why most river guides oppose further use increases, even if it means less work and smaller incomes for us. We believe that the canyon, and the experience, are too precious to destroy.

Drifter Smith lives in Flagstaff, Arizona, where he is president of Grand Canyon River Guides, a nonprofit group with 1,800 members in 48 states and 10 foreign countries.