What We've Done

Challenges and Accomplishments of the Glen Canyon Dam Adaptive Management Program

The Colorado River ecosystem is remarkably complex, having evolved under changing influences through geologic time. The many animals and plants have adapted to a variety of influences from human and natural causes. The construction and operation of Glen Canyon Dam is one of the more significant recent changes and its long-term effects are unknown. For that reason, the scope of the Adaptive Management Program is long-term and continues to challenge society to make important management decisions for the benefit of the ecosystem. Without question, the interconnected ecosystem that exists in Glen and Grand Canyons cannot be adequately understood without the ability to experiment and test hypotheses over time. From that perspective, the Adaptive Management Program has been in place for a relatively short period of time when one contrasts the experiments recommended by the program to the forces of nature that created these ecosystems over eons of time.

Since the Adaptive Management Program’s official implementation in September 1997, various operational changes and management decisions have occurred, and studies have been conducted, as part of the long-term process of experimenting, studying, and adjusting to improve the resources of Glen and Grand Canyons. The following is a chronological list of significant activities conducted under the Glen Canyon Dam Adaptive Management Program:

In March/April 1996, the first Beach Habitat-Building Flow (BHBF), or controlled flood, was conducted to determine if this operational scenario could be a useful tool in restoring the river ecosystem. It was a bold and innovative experiment that produced an enormous volume of useful scientific information.
In the late 1990's, the Adaptive Management Work Group (AMWG) and the Technical Work Group (TWG) developed a comprehensive strategic plan and monitoring program and honed their operating procedures. In addition, management of the Grand Canyon Monitoring and Research Center (GCMRC) was transferred from the Bureau of Reclamation to the U.S. Geological Survey.
During this same period, scientific evidence indicated that new dam operations meant to conserve natural resources were not accomplishing that goal. The AMWG requested the development of additional scientific experiments for dam releases that could better conserve the essential components of the river ecosystem. In response, the GCMRC provided a comprehensive long-term test flow plan divided into four-year blocks. In 2002, the AMWG recommended the first two years of the plan, environmental compliance was completed by Reclamation, and the experiment began in October 2002.
The experimental plan had several components:

Steps to reduce competition and predation by non-native fishes on the endangered humpback chub.
A mechanism for triggering a controlled flood (BHBF) in sediment-enriched conditions to optimize the re-building of sand bars and beaches.
Studies of wind-blown sand to determine the effect of wind deposits for protecting archeological sites.
High fluctuating flows in the winter months designed to reduce trout spawns to limit competitive pressures on the downstream humpback chub and produce a healthier trout population above Lees Ferry.
Mechanical removal of non-native fishes near the mouth of the Little Colorado River designed to reduce predation on the humpback chub.

The first sediment-triggered BHBF occurred in November, 2004 immediately following the accumulation of large sediment inputs from the Paria River. Monitoring of wind blown sand was initiated at several archeological areas throughout the river corridor.
In the summer of 2005, GCMRC conducted a Knowledge Assessment Workshop that gathered many scientists together to determine a collective sense of what had been learned over many years of work.
The GCMRC produced a comprehensive report on the State of the Colorado River Ecosystem (SCORE) that summarized 10 years of scientific effort and presented it at the GCMRC Science Symposium in October 2005.
The results of the 2004 BHBF experiment that became available in 2005 were presented at the GCMRC Science Symposium.
Currently, the scientific experimental plan is being adjusted to accommodate initial results and the effects of the sediment-triggered BHBF. In addition, a science advisory panel is working with the AMWG members to apply the best available scientific results to refine the experiment. The AMP goal is to have the refined experimental plan in place beginning with the new water year that starts on October 1, 2006.

The goal of the Adaptive Management Program is to provide a scientifically credible framework to continually refine and, if necessary, modify the operations at Glen Canyon Dam to satisfy the intent of the Grand Canyon Protection Act. Achieving this goal involves the challenges of a collaborative stakeholder process that integrates experiments and the testing of alternatives based on data collected through long-term monitoring, modeling and research. The science and the extensive monitoring of the resources in Grand Canyon are being incorporated back into the decision-making process. Each new experiment builds on knowledge gained from those done previously. Even though it may appear slow moving, we are on a long science-based learning curve in which we hope to reach some sort of equilibrium with societal values and expectations of the public, such that the state of the downstream resources are finally acceptable and sustainable over the long term.