Officials from the U.S. Bureau of Reclamation hoped the flood, which reached a maximum of 42,300 cubic feet of water per second, would rebuild sandbars, beaches and backwaters along the river. They said in a news release that it would enhance the aquatic food base, protect archaeological sites, and create new camping sites in the canyon.
Paul Grams, a research hydrologist with the Grand Canyon Monitoring Research Center, said some sediment moved downstream as hoped and some new beaches were built.
The center, part of the U.S Geologic Survey, is the science provider for the Glen Canyon Dam Adaptive Management Program. It released its analysis of the November flood last week.
Meanwhile, a news release from Moab-based Living Rivers and Colorado Riverkeeper, indicates the project showed little benefit.
Only 55 percent of the target beaches were improved while 36 percent stayed the same and 9 percent were degraded, according to the news release.
Grams acknowledged during an interview that those numbers are correct. He added that more sandbars were built during a 2008 flood than during the recent one.
The environmental groups also assert that only 25 percent of the sediment that scientists hoped to mobilize and distribute downriver actually moved. Grams said “a large part but not all of it went downstream,” and declined to characterize the flood as success or failure.
John Weisheit, director of Moab-based Living Rivers, said the results were not surprising.
“[Interior Secretary] Ken Salazar claimed that this was going to be ‘a milestone in the history of the Colorado River,’ but like the three previous experiments in 1996, 2004 and 2008, it too has shown that, at best, some beaches are temporarily improved, but the long-term prognosis for the Grand Canyon is a system without sediment,” Weisheit said.
He added that 95 percent of sediment inflows to the Grand Canyon National Park’s river corridor since 1963 have been trapped behind Glen Canyon Dam. Weisheit said that has damaged habitat conditions for the river’s native fish – leading to the extinction of the Colorado pikeminnow, razorback sucker, bonytail chub and roundtail chub, and the endangerment of the humpback chub.
“Far too much public time and money is wasted on preparing for, publicizing, executing and monitoring these useless floods that do nothing but perpetuate a science welfare program masquerading as an endangered species recovery effort,” Weisheit said.
The only two solutions to the Grand Canyon’s sediment deficit, he said, are transporting sediment around Glen Canyon Dam or decommissioning the structure.
The Bureau of Reclamation’s news release in November quoted Salazar as saying the water release would show “that the goals of water storage, delivery and hydropower production are compatible with improving and protecting the resources of the Colorado River.”
Bureau of Reclamation spokeswoman Lisa Iams told The Times-Independent prior to the flush that new long-term plans for managing the river allow for twice-annual high-flow events.
George Went, president and CEO of OARS Outdoor Adventure River Specialists, applauded the Department of Interior’s project just before the five-day water release began. He said in a news release the move would “improve the canyon experience for boaters supporting a $26 billion recreation economy that depends on the Colorado River.”