Red Lodge Clearinghouse

The 41,500-cubic-feet-per-second test flow, which began March 5 and ran for 60 hours, is part of a federal program aimed at reversing some of the degradation to Grand Canyon resources caused by the dam, erected in 1963.

The experiment, which follows similar test flows in 2004 and 1996, already shows some encouraging signs, said Ted Melis, chief of the USGS Grand Canyon Monitoring and Research Center, which conducts research in how to restore the Grand Canyon ecosystem as part of a mandate under the Grand Canyon Protection Act. The test flow was timed to take advantage of unusually high sediment loads in Colorado River tributaries churned up by recent rains, and the torrent of muddy water has succeeded in creating sandbars and beaches within certain areas of the Colorado River's 277-mile reach through the park, although areas closest to the dam lost sediment, he said.

Analyzing time-elapsed photos taken from two separate areas in the river, at 3 and 45 miles downstream, respectively, USGS scientists said the surge eroded sandbars closer to Glen Canyon Dam in Arizona, where the flood gates were opened, and built them farther down the river (E&E Daily, April 7).

The main question now, Melis said, is whether the sediment boost will last. Dam operations have now returned to normal, and those low fluctuating flows could erode the gains from the experiment, which is what happened in 2004, he said.

"In the last experiment, we saw [sand] bar building, but in the upper part of the canyon," Melis said. "During the higher summer and winter, those bars were then eroded back. So over 18 months to two years, a lot of the gains were returned back to the mainstream river."

A flow regime change

Regardless of what the final results of the new experiment are, though, the overall body of science conducted during the 10-year-old program suggests that it is time for a flow regime change, said Steve Martin, superintendent of Grand Canyon National Park.

"We've spent an inordinate amount of money and time studying the effects of the different flow regimes on the resources of Grand Canyon," he said, referring to the $80 million spent on the science program over the past decade. "The science has shown that these high flows -- when there's enough sediment in the system -- is the only chance we have to restore the natural beaches and systems that were there before the dam. We should be doing this every time there's adequate sediment in the system."

Martin emphasized that scientific study of Grand Canyon resources is always welcome but added that enough is already known to support a change in dam operations to begin to restore the endangered humpback chub, a native fish, native vegetation, beaches used by rafters, and other canyon resources, as required under the Grand Canyon Protection Act.

"We're not saying abandon the science, we're just saying the science is clear," Martin said.

High flow tests should be conducted every year or two, when sediment loads in the Colorado River and its tributaries are high enough to effectively build sandbars and beaches, Martin said. Those high flows should be followed by periods of steady flows, ideally in the summer months, to maintain those sediment gains and minimize the risk of erosion, he added.

"The preliminary information we have from this flow suggests that it was highly successful," Martin said. "The other thing that's very clear is that dam operations will erode whatever gains we've had."

But Bureau of Reclamation officials said they have no plans to revise dam operations any time soon. They note that their actions are guided by a suite of laws and Interior decisions, including the environmental assessment finalized in February, which authorized the March test and calls for a thorough analysis of the experiment's effects on the canyon. Any change in how the dam is managed needs the approval of the secretary of Interior, who takes his cue from the recommendations of the Glen Canyon Dam Adaptive Management Working Group, a group of stakeholders from the National Park Service, Fish and Wildlife Service, Reclamation and other agencies, as well as power interests, environmental groups, tribes and others.

"I haven't seen any indication from Reclamation or within the department that we ought to deviate from the plan that exists," said Barry Wirth, a spokesman for Reclamation's Upper Colorado River office. "Fully analyzed means fully analyzed."

Any change in dam management would likely meet resistance from hydropower generators, which lose revenue every time Reclamation conducts a high flow test. The most recent experiment cost power generators $4 million in revenues -- twice as much as they lost during the 2004 test.

"We wouldn't support high flows that are too frequent," said Brad Warren, manager of the Colorado River Storage Project, who represents WAPA on the Glen Canyon Dam Adaptive Management Working Group. Furthermore, following such surges with a couple of months of steady flows in the summer to preserve newly created beaches and sandbars would conflict with peak demand, which requires fluctuating flows, he added.

"Obviously high flows do impact power, so our objective is to comply with the laws but have the least impact on supply," Warren said. "We see it as a balancing act."

Some advocate decoupling the experiments from power revenues. "The easiest way is if Congress appropriated the money to conduct these experiments," Warren said.

Reclamation's Wirth declined to say whether the bureau would support shifting the financial burden from power interests to Congress, saying that would be a decision that Congress would have to make.

Steady flows?

While FWS's 1994 biological opinion called for steady flows during certain times of the year to benefit the humpback chub, the agency's most recent biological opinion suggested that steady flows may not be necessary for recovery. But Nikolai Lash, who represents the Grand Canyon Trust on the working group, said that was an arbitrary reversal not based on science. The group is suing FWS over the biological opinion, he said.

"Reclamation has never run a seasonally adjusted steady flow, so FWS had no basis to say, 'Look, they don't work,' or 'We don't really need them,'" Lash said. And while chub numbers have recently increased to 6,000 fish, the population still has a long way to go toward recovery, he added.

"They're still in a perilous state," Lash said.

The Grand Canyon ecosystem faces a myriad of other problems as well, Lash and river managers note. Today, the Colorado River, named for its historic reddish hue, is a very different river. The water in the river is cooler and clearer than it was historically, because most of the water that flows downstream has languished in the deep, cool reservoir behind the dam before being released. When the water slows as it reaches the dam, the sediment falls out, settling to the bottom of the reservoir.

Those changes, along with the invasion of exotic fish, are largely responsible for the extinction of four species of native fish and for the endangered status of the four remaining native fish species in the Grand Canyon, including the humpback chub (Land Letter, Dec. 2, 2004).

Martin said he recognizes that the Grand Canyon can probably never be restored to its pre-dam condition. But a new flow regime could go a long way toward making the best of current circumstances, so that the park's river resources are improved without compromising power generation too much, he said.

"We recognize that we will not be able to fully restore the river," he said. "But when the science shows we should be moving forward with a way to begin to negate the effects, it's important that we do that."

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