Project Background

Glen Canyon Dam/Smallmouth Bass Future Flow Options and High-Flow Experimental Protocol

Lake Powell water levels remain at historically low levels, which has contributed to increased fish passage through Glen Canyon Dam and warmer water being released through the dam. Below the dam, these warmwater releases are creating ideal spawning conditions for smallmouth bass, a predatory invasive fish species that poses a threat to the federally protected humpback chub and other native fish.

To respond to the threat of smallmouth bass establishment below Glen Canyon Dam, a targeted draft Environmental Assessment Link is to a PDF file was prepared that identified various flow options designed to disrupt smallmouth bass from spawning below the dam.

Based on the Comment Analysis Report Link is to a PDF file and the nearly 7,000 comments received, Reclamation concluded that additional analysis was warranted. Consistent with the National Environmental Policy Act process, Reclamation transitioned this analysis to an Environmental Impact Statement process that supplements the December 2016 Record of Decision for the Glen Canyon Dam Long-Term Experimental and Management Plan Final Environmental Impact Statement.

This process was formally initiated through a Notice of Intent in the Federal Register on Oct. 4, 2023. A 30-day scoping comment period was held from Oct. 4, 2023 through Nov. 3,2023. Reclamation hosted two open-house style virtual public webinars during the scoping comment period.

On Dec. 5, 2023 Reclamation released a Scoping Summary Report that includes, the scoping process, a summary of the scoping comments, and a summary of the key themes and resource issues identified during scoping.

Next Steps

A final supplemental EIS with Record of Decision, as appropriate, is anticipated to be available by early summer 2024.

Program Background

Since Glen Canyon Dam was completed in 1963, increasing concern was expressed by the public and federal and state agencies regarding how dam operations may be adversely affecting the downstream environment. To begin addressing these growing concerns, in December 1982, the Bureau of Reclamation initiated the multi-agency interdisciplinary Glen Canyon Dam Environmental Studies at the direction of the Secretary of the Interior.

In November 1989, the Secretary directed an Environmental Impact Statement be prepared on the operation of Glen Canyon Dam, and the Secretary designated Reclamation as the lead agency. This Final EIS, completed in March 1995, received broad and intense interest from water and power users, environmental and conservation groups, Federal and State agencies, Indian tribes, and private citizens across the country.

Findings from the EIS indicated that many uncertainties still exist regarding the downstream impact of water releases from Glen Canyon Dam. The EIS team consolidated the issues of public concern, identifying the significant resources and associated issues to be analyzed in detail. These resources include: water, sediment, fish, vegetation, wildlife and habitat, endangered and other special status species, cultural resources, air quality, recreation, hydropower, and non-use value.

In compliance with the Grand Canyon Protection Act of 1992 (Public Law 102-575), the EIS proposed a process of "adaptive management" whereby the effects of dam operations on downstream resources would be monitored and assessed.

The Act, and the EIS are the guiding documents for development of the Adaptive Management Program. The program meets the purpose and strengthens the intent for which the EIS was prepared, and ensures the primary mandate of the Act is met through future advances in information and resource management.

Section 1802 of the Act directed the Secretary to establish and implement long-term monitoring programs and activities to ensure the Glen Canyon Dam is operated "... in such a manner as to protect, mitigate adverse impacts to, and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established, including, but not limited to natural and cultural resources and visitor use."

In order to comply with the consultation requirement of the Act, Section 1805 of the Act, the EIS recommended formation of a federal advisory committee. The Transition Work Group was formed to operate until such time as a federal advisory committee could be formed, and a Record of Decision signed by the Secretary of the Interior to initiate a process of "management" (operating criteria for unbiased scientific research and data collection) whereby the effects of dam operations on downstream resources would be assessed. Meetings were held with representatives from the cooperating agencies and public interest groups who provided comments on the criteria for development of reasonable alternatives for the EIS.

The transition group worked on a variety of issues including a long-term monitoring and research program to ensure Glen Canyon Dam is operated in a manner consistent with protecting the downstream environment as well as implementation and management of operations and monitoring in consultation with broad-based interests.

The Record of Decision was signed by the Secretary of Interior in October 1996, and in January 1997, Interior Secretary Babbitt signed a Notice of Establishment of the Glen Canyon Adaptive Management Work Group, a federal advisory committee. The charter of this group was signed on January 15, 1997.

All of the elements are now in place for an effective, credible adaptive management effort. The Adaptive Management Work Group is the key; the Technical Work Group providing detailed guidance on issues and objectives; the Science Center to conduct the research and monitoring needed to evaluate operations; and the independent review panel, the outside review necessary to provide the credible science.

The AMWG continues public involvement in the decision-making process and incorporates those stakeholders with interest in the operation of Glen Canyon Dam and downstream resources. By blending the best science and management practices, the AMWG makes recommendations to the Secretary on how to protect the resources and meet the requirement of the law.

The Adaptive Management Program is administered through a senior Department of the Interior official — designee — and facilitated through the AMWG, which is organized as a federal advisory committee and chaired by the designee.

The AMWG held their first meeting on September 10-11, 1997, and officially formed the Glen Canyon Technical Work Group as a subgroup to work on tasks charged to them by the AMWG.