In the most extensive assessment of river conditions in the Grand Canyon since the creation of the Grand Canyon Protection Act in 1992, the U.S. Geological Survey study says endangered native fish species are still struggling, while sandbars and backwaters that serve as habitat for the fish as well as anchors for vegetation, havens for cultural resources and campsites for human visitors continue to decrease.

The report, produced by the agency's Grand Canyon Monitoring and Research Center, stopped short of calling federal attempts to restore the river and its shorelines a failure. But it makes clear there is still a long way to go to bring the environment back to anything close to what it looked like before Glen Canyon Dam and Lake Powell were created some four decades ago.

"We've learned a helluva lot, but we've also learned is that this is really, really hard," said Jack Schmidt, an aquatic, watershed and earth resources professor at Utah State University, who attended a symposium in Phoenix unveiling the study. "It's a real challenge to adaptively manage the river [and restore habitat] while also focusing on producing electricity and providing water for California. It's just damn hard."

Others were more blunt. At least one environmental group labeled the report proof that efforts by the Bureau of Reclamation - which manages Glen Canyon Dam - to revive the Colorado River below the dam have been a flop.

"When you add up all the numbers, over $200 million has been spent on this, and 13 years after all this money has been spent, they have absolutely nothing to show for it," said John Weisheit, conservation director of the Moab-based Living Rivers, which has called for the decommissioning of Glen Canyon Dam. "The Grand Canyon, in my opinion, is worse off. There's less fish. Less sand. Fewer archaeological resources. The dam has become more of a liability than an asset."

Attempts to reach Bureau of Reclamation officials for comment were unsuccessful Wednesday.

Built in 1963, Glen Canyon Dam has provided water and power for the West, but also transformed the Colorado River below it from muddy and warm to clear and cold, and altered and moderated its natural flows. The long-term results have been a gradual disappearance of sandbars and backwaters throughout the canyon, as well as the decline of native fish species, such as the humpback chub, and the emergence of new, non-native fish such as rainbow trout.

The Geological Survey study focused on efforts by federal managers since the creation of the Grand Canyon Protection Act, and specifically the establishment of the Glen Canyon Dam Adoptive Management Program - an attempt to reintroduce beaches and other native fish habitat into the Grand Canyon's bottom. The focus of those efforts: a series of high-flow test experiments, the most recent last November, that were designed to push more sediment downstream.

The big picture is not encouraging. According to the report, sandbars "continue to erode," and new sand brought downstream by the test flows have not accumulated in the main channel.

Likewise, the humpback chub's population has decreased between 30 percent and 60 percent. Now on the endangered species list, it is one of four native fish species that survive in the Colorado River below the dam out of the original eight.

But there also have been positive signs. Warmer water coming out of Lake Powell - depleted because of the drought - combined with a program to eradicate non-native fish from the river has resulted in an increase in juvenile humpback chubs, though it's unclear now how many will make it to adulthood.

And last November's flow test, which came following heavy October rains, succeeded in pushing more sediment and creating sandbars in the upper reaches of Marble Canyon, even though it was shorter in duration than previous flow tests.

"We saw a limited restoration scenario in an area that had been subject to significant erosion," said Ted Melis, executive director of the Grand Canyon Monitoring Center. "We didn't see a larger impact because of the limits in sand, but with more supply, we might have seen more restoration throughout the system. That's a real positive outcome."

All sides agree on one point: The sediment issue will have to be resolved - both because its need in the Grand Canyon, and because the buildup of sediment in Lake Powell will eventually threaten the reservoir. A sediment pipeline, or dredging Lake Powell, could be in the offing at some point.

Temperature controls at the dam could also become a fixture, if they are proven to enhance native fish populations without introducing new problems.

"It might be hard and it might be costly," said Schmidt, the USU professor. "In fact, it might be so costly that the public might decide that we shouldn't try. Maybe we should tell the public that the cost of providing water and power is the decline of the Grand Canyon and the public will accept that. But the public might also say the Grand Canyon is too important and we should spend whatever it takes."

jbaird@sltrib.com

Grand Canyon health report

* The Grand Canyon ecosystem hasn't been repaired despite a long, costly effort.

* The disappearance of sandbars and native fish declines haven't been reversed by experimental releases from Glen Canyon Dam.