Experimental High Flow Releases Promise "Hugely Beneficial" Impacts to River Ecology

Native News Network Staff in Native Currents. Discussion »

PAGE, ARIZONA – Secretary of the Interior Ken Salazar yesterday triggered the first "high-flow experimental release" at Glen Canyon Dam since 2008, as part of a new experimental long term protocol announced in May by the Secretary to better distribute sediment to conserve downstream resources, while meeting water and power needs and allowing continued scientific experimentation, data collection, and monitoring to more fully address the important resources in the Colorado River below Glen Canyon Dam.

Releasing the requisite water needed downstream in large pulses.

The new protocol calls for experimental releases from the dam through 2020 to send sediment downstream to rebuild sandbars, beaches, and backwaters. The rebuilt areas would provide key wildlife habitat, enhance the aquatic food base, protect archeological sites, and create additional camping opportunities in the canyon.

“This is truly an exciting day in the history of the Colorado River Basin, in the history of Grand Canyon National Park, and in the history of the Department of the Interior,”

said Salazar.

“It was an honor to open the river tubes as we opened the door to a new era for Glen Canyon Dam operations and the ecology of Glen Canyon National Recreation Area and Grand Canyon National Park - a new era in which we realize that the goals of water storage, delivery and hydropower production are compatible with improving and protecting the resources of Glen Canyon and Grand Canyon.”

The new protocol is built on more than 16 years of scientific research and experimentation conducted under the Glen Canyon Dam Adaptive Management Program. The Department translated the research into a flexible framework that enables scientists to determine, based on the best available science, when the conditions are right to conduct these releases to maximize the ecosystem benefits along the Colorado River corridor in Glen Canyon National Recreation Area and Grand Canyon National Park.

With the Glen Canyon Power plant running at full capacity, Secretary Salazar opened the river outlet tubes at noon, releasing additional flows that will increase throughout the day until a maximum release of approximately 42,300 cubic feet per second is reached. These releases will continue for nearly five days based on the parameters specified in the protocol and the volume of sediment deposited by the Paria River since late July, which scientists estimate is approximately 500,000 metric tons, enough to fill a football field 230 feet deep.

Glen Canyon Dam Yesterday

Through the foundation laid by the protocol, annual experiments can be conducted through 2020 to evaluate the effectiveness of multiple high flow experimental (HFE) releases in rebuilding and conserving sandbars, beaches, and associated backwater habitats that have been lost or depleted since the dam's construction and operation. The protocol identifies the conditions under which a high flow release will likely yield the greatest conservation and beneficial use of sediment deposited by inflows from Colorado River tributaries as a result of rainstorms, monsoons, and snowmelt.

"Favorable sediment conditions in the system only occur periodically, so the ability to respond quickly and make the best use of those deposits when the time is right is essential,"

said Anne Castle, Assistant Secretary of the Interior for Water and Science.

"Today's experimental release under the new protocol represents a significant milestone in our collective ability to be nimble and responsive to on the ground conditions for the benefit of respond quickly to change dam operations to improve downstream resources conditions."

High-flow experimental releases simulate natural flood conditions that suspend and redeposit sand stored in the river channel to provide key wildlife habitat - including habitat for the endangered humpback chub, protect archaeological sites, enhance riparian vegetation, maintain or increase recreation opportunities, and improve the wilderness experience along the Colorado River in Glen and Grand canyons. Single experimental releases were conducted in 1996, 2004, and 2008, and included extensive scientific research, monitoring, and data collection by the US Geological Survey's Grand Canyon Monitoring and Research Center, the Bureau of Reclamation, the National Park Service, and the US Fish and Wildlife Service.

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posted November 20, 2012 9:20 am est