And there, in the center, a river that changes colors almost as quickly as a chameleon, from deep green to chocolate brown to frothing white and then back to flowing green, giving off a perfect reflection of the reddish-toned cliffs when calm.

That changes when the flows speed up and the riverbed turns once-calm water into a churning, frothing field of rapids.

The Colorado River is, this year, a very different river than many of today's boatmen remember.

And, what it does, said Merrill, aside from putting them up against the larger waves, is put a real premium on boating skills.

The key to a good ride in high water, he noted, "is timing. Everything happens so much faster. In mid- to low-water, you may go from rapid to rapid with a break in between. In high water it can be just one continuous ride, so you need to be prepared."

Experienced boatmen learn to read the river, know its habits and can anticipate its ever-changing movements.

The entry into a rapid, for example, is at the "tongue" or "V" formed as the waters narrow. From there the boatman positions the boat in the rapids that will allow him to "ferry" right or left, as required.

The introduction of new and safer equipment, complimented by an experienced corps of boatmen over the years, has made it so today's runs, even at high water, are exciting but safe.

There are, of course, other advantages to the higher flow, among them the fact that the higher water levels cleanse the beaches and speed the ride, which allows for more time for things like hiking and camping along the water's edge.

The Cataract Canyon river trip is roughly 120 miles of untamed river running through the very heart of Canyonlands National Park,

Along the way there are roughly 20 miles of water where boaters encounter some of the fiercest rapids in America. During high water, they are often ranked among the world's roughest.

The rapids begin a few miles below the confluence and end near the northeastern-most tip of Lake Powell at the Hite Marina.

In all, there are 28 separate rapids. The most formidable of the rough water stretches is Big Drop One, Two and Three. In less than a mile the river drops 30 feet, which is one of the river's steepest sections. On a scale of one to five, Big Drop is typically ranked a five.

Once floating the canyon took a minimum of three days. Today, thanks to high-tech boats and the quiet four-stroke motors, people can make a Cataract trip in a day — put-in to take-out.