LEES FERRY, Ariz. The federal Bureau of Reclamation is gradually opening turbines and bypass tubes at Glen Canyon Dam as part of a government program to restore the Grand Canyons ecosystem.
The river has run at about 8,000 cubic feet per second this fall but will ramp up to 42,300 cubic feet for 24 hours from Monday night into today, and the river will run high for five days.
The goal is to wash millions of tons of sediment downstream to create beaches and improve habitat for plants and animals.
Parks officials have contacted visitors with backcountry or river permits and advised them to camp on high ground this week.
Its an experiment that could hurt next years fishing and complicate hydropower production and water storage in the name of a more environmentally correct river.
Fisherman Jim Simpson didnt care about the protected humpback chub and his reaction crystallizes the dilemma of whether to maximize the dams gifts or turn some of them back in favor of primordial nature.
Simpson is more into rainbow trout, the non-native beauty that has fueled a trophy fishery since the dam started clearing and cooling the formerly muddy river in the 1960s. The game fishs ascent has coincided with the collapse of the chub, a large native minnow that now thrives mainly where the undammed Little Colorado River meets its larger namesake about 62 miles below Lees Ferry, Ariz.
Im going to die in a few years, Simpson said. But wouldnt it be nice for my grandkids to come up here and catch a monster fish, hook him and let him go? What are they going to do, go down to the Little Colorado and catch a little chub?
Many environmentalists and park managers feel differently, and they have fought for decades to be sure future generations will recognize a river shaped by the millennia instead of by the Bureau of Reclamation.
For them, this rush of water churning up sand for new beaches and backwater sandbars signals the rivers best chance. Its the fourth experimental flush since 1996, and the first since Interior Secretary Ken Salazar in May decreed them routine in a 10-year protocol that, weather permitting, could mean mini-floods every year.
This is a great victory, said Nikolai Lash, program director with Grand Canyon Trust. Previous experiments in 1996, 2004 and 2008 were one-time fact-finding missions instead of fundamental shifts in river management. This (Obama) administration can be patted on the back and thanked for doing what weve been trying to do, seriously, for 15 years.
The river gets only a tenth of the sediment that historically washed into it before the dam was completed in 1966, and this years release is timed to capitalize on summer storms that loaded the Paria River with sand that it dumped below the dam.
Mimicking annual springtime floods that once pushed river sand onto the banks, the flush is meant to create new beaches; shelter warm backwater fish habitat with sandbars; cover archaeological sites to prevent erosion; and shore up wind-blown soil for canyon plants such as mesquite.
Critics see little environmental benefit and that it comes at a cost. In comments submitted to the Interior Department before the decision to go forward with regular flushes, the Colorado River Energy Distributors Association, a group of nonprofit energy utilities, noted that previous springtime flood experiments helped the trout, not the chubs, putting more mouths into the river to compete with and eat young chubs.
Those flushes apparently helped the trout spawn by clearing sand from gravel beds on the river bottom, and they may have stimulated food growth at critical times.
Association Director Leslie James said shell be watching again to see if this flood has lasting benefits.
The previous experiments affected the associations 4 million customers, from Arizona and New Mexico to Wyoming, because their providers must buy power from alternate sources. The association predicts this weeks release will cost $1.4 million.
The Bureau of Reclamation notes that the reduced output is a fraction of 1 percent of the power generated at the dam. The agency will adjust later releases to even out the water budgets between upper and lower Colorado River Basin states, so the flood wont affect annual deliveries downstream to Lake Mead.
Unlike springtime releases, this one comes at a bad time for trout. Their food chain, from algae to insects, has been largely exposed by low fall flows. The flood will scour away whats left, said Wendy Gunn, owner of Lees Ferry Anglers.
She said its not a natural time of year for a flood. Pre-dam floods, which the U.S. Geological Survey says maxed out at 50,000 cubic feet per second in high-water years, typically came in June.
This is the most unnatural time for a flood on this river, Gunn said.
Previous attempts didnt improve the river, she said, and park managers would be better off manually stabilizing the beaches they already have.
But then a whole lot of government people and scientists would be out of work, she quipped.
Grand Canyon National Park never expected the beach-building benefits to last without regular repetition, said Jan Balsom, the parks deputy chief of resource management. And as for the appropriateness of high flows in fall, she said its necessary to act while theres a good sand supply, whatever the season.
We have very little to work with, she said, so weve got to make the most of it.
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