CATARACT CANYON — Lake Powell has drastically shriveled during 20 years of drought, allowing dozens of miles of the Colorado River to become a river again in world-famous Cataract Canyon. But why have many of its legendary rapids failed to return?
Three men from Moab have made it their crusade to study that issue and to document a stunning after-effect of Lake Powell: a river struggling to cut its way through a monumental legacy of dried mud.
Mike DeHoff is a welder by trade, but on the river, he's a man on a mission.
"It's just a personal curiosity that's grown into this big old mess of a project," DeHoff said as he launched a small motorboat above Lake Powell and headed upriver.
He's one of three investigators in an effort called the Returning Rapids Project.
Another is Pete Lefebvre, a river-running guide who worships white-water.
"Getting splashed in the heat of the summer and running through the roller-coaster ride of the rapids, it's just a good old time and a lot of fun to be had," he said.
The third investigator is Chris Benson, a government geologist with a keen interest in long-lost rapids, such as Sheep Canyon Rapid, which was submerged for years by Lake Powell.
"Scary, yeah, people were very scared of this rapid," Benson said while floating over the invisible rapid. "And now today, it's a tranquil scene."
Today the three boaters can easily motor their boats upriver through 30 miles of canyons where the lake used to be. As the Colorado River has become a river again, the three men have been studying a frustrating — and fascinating — problem.
"Everything got exposed," DeHoff said. "But the rapids weren't coming back."
"In terms of major ones, there's at least 15 major rapids gone right now, and then a bunch of other smaller ones that weren't as consequential," Lefebvre said.
They've been comparing today's Cataract Canyon with old photos, collecting data on river-levels, running small rapids that once were big. What they're documenting is a river fighting its way down through an enormous deposit of dried mud left behind by Lake Powell.
DeHoff said the process began a half-century ago when the Glen Canyon Dam blocked the river 200 miles downstream.
"Moving water carries sediment," he said. "Still water can't carry sediment, and so when you put a dam in the way of the Colorado, that sediment drops out, and it all dropped out in Cataract Canyon."
Dozens of miles of river and many sets of rapids were buried by an enormous deposit of sediment.
"It's 35 to 40 miles long, it is 50 to 130 feet deep," DeHoff said.
During the last 20 years of drought, after Lake Powell withdrew from Cataract Canyon, the river has been cutting down through the sediment, leaving towering cliffs of dried mud, some 100 feet high or so.
Some of the old roller-coasters are slowly coming out to play, such as the partially restored Gypsum Canyon Rapid.
"This would be our sixth one coming back, and these are hold-on-tight, big fun, big rapids," said Lefebvre.
According to the three investigators, much of the old Cataract Canyon ecosystem also seems to be making a comeback.
"The beaver population has skyrocketed," said DeHoff.
Lefebvre noted other signs of recovery.
"The rapids and also some beaches and big native trees are starting to grow back, too," he said.
The three investigators produce a river guide each year to answer the questions of river-runners.
"What are the rapids doing?" Lefebvre said, describing the most frequently asked questions. "Do you need a motor to get out? Is there current? What do the camps look like?"
What resources are we going to prioritize and what resources are we going to sacrifice? We get to talk about some of those decisions again.
But DeHoff said there are more fundamental questions for the future: What if Nature makes more water available? Will humans decide to refill Lake Powell?
"I think that we're going to get faced with a similar decision that was made when the dam went in," DeHoff said. "What resources are we going to prioritize and what resources are we going to sacrifice? We get to talk about some of those decisions again."
The Returning Rapids Project is a volunteer, nonprofit organization. The three investigators have stepped up an effort to raise funds to cover their expenses.
Meanwhile, as their studies continue, the muddy Colorado is doing its best to move all that mud downriver and into what's left of Lake Powell.