Flooding the Grand
Paddlers on the Grand Canyon this spring got a surprise when they awoke the morning of March 5 (or later, depending on when they put in), when the Colorado River’s water level surged to over 40,000 cfs in a Department of Interior attempt to replicate flood-stage conditions for the first time in four years. If boats weren’t pulled high at camp beforehand, they were now tugging at their lines. If revelers passed out too close to shore after the night’s costume party, there was water lapping at their toes.
Of course, the real changes occurred on the water in such rapids as House Rock, Horn Creek, Hermit, Crystal and Lava Falls. Holes that might have been punchable at the normal fluctuation of 8,000 to 12,000 cfs were now raging monsters, thrashing the unprepared in their grasp.
Pioneered in 1996 and conducted again in 2004, the nearly three-day controlled flood was done to restore sediment on the banks of the river to promote the growth of native wildlife and river species. Since 1963 the Glen Canyon Dam has trapped sediment coming from upstream, changing the character of the river and altering its ecosystem. Following the dam’s construction, four fish species were driven to extinction and two others, including the humpback chub, have been threatened.
While the previous two floods yielded little gain, scientists of the Department of the Interior were optimistic about the results of this one, citing larger sediment deposits present in the corridor than there had been before the earlier experiments. In February sediment resources in the river were at a ten-year high—three times the amount present before the 2004 flood.
Environmentalists hope to use the results of the flood to determine if the plan is successful enough to continue and draft a flooding plan that would restore the river’s ecosystem. Some groups believe that the infrequent floods do little for the river but serve as a means to delay more aggressive corrective action; they are in favor of a flooding regimen that would occur seasonally to better replicate the natural cycle.
Local outfitters are skeptical of the results. “I was there at super high water and in my opinion they’re just a big boondoggle about replacing the sand,” says Donnie Dove, owner of Flagstaff, Ariz.’s Canyon REO, who has been unimpressed with the results of this and the previous flooding experiments. “The upper half of the river gets stripped and the lower half gets sand, and it all gets undermined when they turn on the water again.” The problem, he adds, is that not enough of the sediment in the reservoir makes it through the dam, and the section of river just below the dam is eroded by the higher flow.
“The power company says they’re losing millions in the flood,” he says. “If they want a quick-fix they should put that money to get a dredge and pump the sand up over the dam. There’s no sand right below the dam! Get the damn sand from the top to the bottom!”
While data from this year’s flood is still being gathered and analyzed, supporters remain confident that the flood served to restore sand bars and keep debris fans from obstructing the flow of the river, rejuvenating the banks of the Colorado. It also rejuvenated the river-running skills of the instant big-water boaters on the river at the time.