Interior Secretary Calls For More High Colorado River Flows Through Grand Canyon National Park

These photos, taken at Mile 81 along the Colorado River in Grand Canyon National Park, in February 2008 and April 2008 show how high-flow releases can improve sandbar formation on the river corridor. Photos by Roderic Parnell, Northern Arizona University, via USGS.

Interior Secretary Ken Salazar is calling for more high-flow releases of the Colorado River down through Grand Canyon National Park and believes they can be done to benefit the national park's resources while also meeting energy and water needs.

The secretary, in Copenhagen to attend the global climate change conference, made his comments Thursday via video to the Colorado River Water Users Association, which is meeting in Las Vegas.

“We must find a way to protect one of the world’s most treasured landscapes – the Grand Canyon – while meeting water and clean energy needs in the face of climate change,” Secretary Salazar said.
“Today, I am directing the development of a protocol for conducting additional High Flow Experiments at the (Glen Canyon) Dam. These experimental high flows [like the one in 2008] send sediment downstream to rebuild sandbars, beaches and backwaters. The rebuilt areas provide key wildlife habitat, enhance the aquatic food base, protect archeological sites, and create additional camping opportunities in the canyon.”

In recent years there has been no small amount of friction between the National Park Service, which desires the high flow "washes" that scour the canyon, and the U.S. Bureau of Reclamation, which manages the Glen Canyon Dam and generally has opposed a regular series of releases that might mimic natural surges of the Colorado River that occurred before the dam went into service in 1963.

When the last high flow was allowed, in March 2008, BuRec officials proposed that it would be conducted just once, while September-October "steady" flows would be repeated for five years. At the time, strongly worded opposition from both park officials and the Grand Canyon Trust questioned how carefully BuRec officials had developed their flooding strategy and whether it really was intended to benefit the canyon's natural resources. Indeed, Trust officials contended the staged flood was aimed to benefit downstream water users and hydropower interests, not natural resources.

Park Superintendent Steve Martin said at the time that he didn't believe BuRec should be locking itself into one scenario for the next five years and that its plan should be more science-based. He said he'd prefer a situation where flooding is allowed in the spring on a more regular basis, perhaps every one or two years, depending on sediment conditions.

On Thursday, Assistant Interior Secretary Anne Castle told those attending the water users conference that, "We’ve put in place a comprehensive science program designed to figure out the complex processes at work downstream of Glen Canyon Dam, so that we can get better at managing the river for the benefit of all the various resources at stake. We can make [high flow releases of short duration] without affecting the overall amounts of water required to be released from Lake Powell by the 2007 interim guidelines and the Law of the River.”

Secretary Salazar also assured the audience that, "We will engage all our partners in this effort – from federal agencies and tribes to local and state governments and other stakeholders. We also recognize the need for additional experimental and management actions to protect the resources of Grand Canyon National Park, and these efforts will be implemented through the Glen Canyon Dam Adaptive Management Program.”

According to Interior and National Park Service officials, because the Glen Canyon Dam just upstream of Grand Canyon National Park traps approximately 90 percent of the sand once available to maintain Grand Canyon sandbars, high flows are a good tool to rebuild these important resources. The new protocol will allow for high flows to occur when Colorado River tributaries below the dam produce sufficient sediment to meet a threshold, or “trigger,” Interior said in a release. Timing of high flows would depend not only on sediment inputs from tributaries, but also other environmental considerations, such as impacts to the Lees Ferry trout fishery and riparian vegetation, the agency said.

The new protocol also will protect the interests of those relying on the Colorado River, as the water released during the high flow will not change the annual amount of water to be released to downstream users from Glen Canyon Dam, the release said. That water flows downriver to Lake Mead for use by the Lower Colorado River Basin States and the Republic of Mexico.

The most recent High Flow Experiment at Glen Canyon Dam was conducted in March 2008. During the experiment, the Bureau of Reclamation released water from both the powerplant and the bypass tubes to a maximum amount of approximately 41,000 cubic feet per second for about 60 hours.

Preliminary results of the 2008 experiment showed a robust sandbar building response and sandbar development throughout the river corridor, Interior officials said, adding that considerable erosion occurred following the experiment.

Research on the effects of the 2008 event on a range of resources—including native fish, vegetation, the Lees Ferry trout fishery, and more—will be completed by the U.S. Geological Survey in January 2010 and this additional information will be taken into consideration in the development of the new protocol pursuant to Thursday’s announcement by Secretary Salazar.

Comments

this proves the efficacy of periodic high flows to rebuilding the emaciated sandbars resulting from present flow regimes. a yearly high flow would restore the sand bars to their former glory.

Question: Do the flows actually contain any sediment from the Powell reservoir? If not, the they are, as some have suggested, merely scouring the upper reaches to increase bars in the lower. There is, of course, much dredging of main channel seds, but without some of that "90 percent of the sand once available" added back to the canyon, Lee's to Phantom will simply get bonier.