Lee's Ferry, Paria Confluence

Lake Powell Water Level to Drop 2.5 feet

It’s SCIENCE!

From November 18-23, 2012, the Department of Interior will conduct the first High Flow Experiment under a multi-year High Flow Protocol announced earlier this year by Secretary Salazar. Under this Protocol, high flow releases are linked to sediment input and other resource conditions below Glen Canyon Dam.

Beginning on the evening of November 18th, releases from Glen Canyon Dam will begin ramping up to full power plant capacity (approximately 27,300 cfs). At midday on November 19th, bypass tubes at Glen Canyon Dam will be opened and releases will continue to increase up to full power plant and bypass capacity (approximately 42,300 cfs) by the evening of November 19th. Releases will be maintained at peak release for 24 hours and then begin ramping back down. Releases will return to normal operations in the evening of November 23rd. The entire experiment, including ramping is expected to last 5 days, with 24 hours at peak release. November releases from Glen Canyon Dam prior to and after the High Flow Experiment are expected to fluctuate between 7,000cfs and 9,000cfs. The elevation of Lake Powell is expected to decrease approximately 2 ½ feet during the 5-day experiment.

For additional information please visit the 2012 High Flow Experiment webpage.

Transcript:

Hello.
I’m Anne Castle, Assistant Secretary of the Interior for Water and Science. As the Assistant Secretary for the past three years, I’ve had the privilege of overseeing the Bureau of Reclamation and the U.S. Geological Survey. I also serve as the chair of the Glen Canyon Dam Adaptive Management Work Group. The Adaptive Management Program for the Glen Canyon Dam was established in 1996.


It was part of a new era of refined dam operations that began after the passage of the Grand Canyon Protection Act in 1992.

After that legislation was enacted, the Department of the Interior did an extensive environmental analysis of the impacts of the operations of Glen Canyon Dam on the resources downstream in Glen and Grand Canyons.

That analysis was then used to determine a new method of operating the dam that dampened down the wide fluctuations in flow that had occurred previously.

We also adopted an adaptive management strategy that features an on-going cycle of learning through scientific experimentation, learning through doing, and improvement over time.

That is exactly what we’ve been doing over last the 16 years.

One of the components of the adaptive management strategy has been experimental high flow releases from the dam.

We’ve done three of those, first in 1996, then in 2004, and again in 2008.

These high flow experiments were designed to mimic the pre-dam natural flooding of the Colorado River to conserve and redistribute sediment and improve the resources downstream of the dam.

Before, during, and after each one, we’ve monitored the condition of the various resources, like fish, and sand, and habitat, to get a better handle on what effect the releases were having.

Today, we have a wealth of scientific knowledge and insight that we simply didn’t have back in 1996, and we’ve used that information to improve our stewardship of the Colorado River downstream from the Dam.

This year we completed two important efforts that represent milestones in the history of the River.

The first is a program that provides a framework for actions and research to protect
endangered native fish in the Colorado River downstream of the dam.

Protecting the native fish includes disadvantaging or removing non-native fish that prey
on the natives, so the program includes a lot of detail about how we’re going to do that.

We listened to the Native American tribes who have concerns about the taking of life in the Grand Canyon, which they consider a sacred place, and we adjusted the program to take those concerns into account.

The second milestone was the establishment of a protocol for conducting experimental high-flow releases from the dam when conditions are right to help the resources downstream.

Because the dam and the reservoir behind it trap the sediment that used to flow down the River, the reaches of the Colorado River in Grand Canyon are sediment starved.

That has adverse impacts on beaches and backwaters and habitat for fish and other aquatic creatures.
What we’re trying to do with the high flow releases is redistribute sediment that’s provided by tributaries below the dam, and prevent or slow down further erosion of the sediment.

The protocol outlines the conditions that need to exist to make the high flow release beneficial, and specifically what that means is that there has to be a substantial amount of sediment in the mainstem of the River that’s been provided by tributaries as a result of rainstorms.

The Secretary of the Interior approved the implementation of these two programs, the non-native fish control and the High Flow Experimental Protocol, in May of 2012.

We think that these two programs lay the foundation for the next generation of refined operations and management strategies.

And, as it turns out, we’ve had significant rain this summer and fall that has brought a lot of sediment into the Colorado River below the Dam.

So we’re going to implement the high flow protocol.

On November 19, we’ll do the first experimental high flow release from Glen Canyon Dam under the new protocol.

The release from the dam will get up to 42,000 cubic feet per second for somewhere between 1 and 4 days, and that will mobilize the sediment in the River and redistribute it higher up on the banks and floodplain.

The water that’s released isn’t wasted because it all goes down to Lake Mead and it’s stored there.

And the annual release from Lake Powell won’t change – we’re just altering the timing a little.

Everything we learn from this release will be used to refine our future management actions on the River.

We intend to continue to advance our scientific knowledge so that we can make better decisions and better preserve the resources in the Grand Canyon.

On behalf of Secretary Ken Salazar, I want to express our appreciation to all the Glen Canyon Dam Adaptive Management Program partners and the Colorado River Basin States and sovereign tribal nations and all the stakeholders for their support.

These are exciting times in the history of the Colorado River.

And we’re all working together to provide water and power to millions of Americans in the West and, at the same time, provide greater protection to that incomparable natural treasure, the Grand Canyon.

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