U.S. Department of the Interior Record of Decision for the Glen Canyon Dam Long-Term Experimental and Management Plan Final Environmental Impact Statement December 2016 U.S. Department of the Interior Bureau of Reclamation Upper Colorado Region Salt Lake City, Utah National Park Service Intermountain Region Lakewood, Colorado Record of Decision Glen Canyon Dam Long-Term Experimental and Management Plan 1. SUMMARY OF ACTION The U.S. Department of the Interior (DOI), through the Bureau of Reclamation, Upper Colorado Region (Reclamation) and the National Park Service (NPS) have jointly published a Final Environmental Impact Statement (FEIS) for the Glen Canyon Dam Long-Term Experimental and Management Plan (L TEMP). Reclamation and NPS are joint-lead agencies for the L TEMP EIS because of their roles in operating Glen Canyon Dam (Reclamation's role) and managing the resources of Glen Canyon National Recreation Area (GCNRA), Grand Canyon National Park (GCNP), and Lake Mead National Recreation Area (LMNRA) (NPS 's role). As joint leads, both agencies were equally involved in the development of all aspects of the L TEMP FEIS. There were 15 Cooperating Agencies for the FEIS, which included the Bureau of Indian Affairs (BIA), U.S. Fish and Wildlife Service (FWS), Western Area Power Administration (WAP A), Arizona Game and Fish Department (AZGFD), Colorado River Board of California, Colorado River Commission of Nevada, Upper Colorado River Commission, Salt River Project, Utah Associated Municipal Power Systems, Havasupai Tribe, Hopi Tribe, Hualapai Tribe, Kaibab Band of Paiute Indians, Navajo Nation, and the Pueblo of Zuni. Throughout the process, the U.S. Geological Survey (USGS) Grand Canyon Monitoring and Research Center (GCMRC) provided technical advice and managed peer review processes. The proposed Federal action considered in the L TEMP FEIS is the development and implementation of a structured, Jong-term experimental and management plan for operations of Glen Canyon Dam. The LTEMP will provide a framework for adaptively managing Glen Canyon Dam operations and other management and experimental actions over the next 20 years, consistent with the Grand Canyon Protection Act (GCPA) and other provisions of applicable Federal Jaw. The L TEMP identified specific options for dam operations (including hourly, daily, and monthly release patterns), non-flow actions, and appropriate experimental and management actions that meet the GCP A's requirements, and maintain or improve hydropower production to the greatest extent practicable, consistent with improvement of downstream resources, including those of importance to American Indian tribes. Under the L TEMP, water will continue to be delivered in a manner that is fully consistent with and subject to the Colorado River Compact, the Upper Colorado River Basin Compact, the Water Treaty of 1944 with Mexico, the decree of the Supreme Court in Arizona v. California, and the provisions of the Colorado River Storage Project Act of 1956 (CRSPA) and the Colorado River Basin Project Act of 1968 that govern allocation, appropriation, development, and exportation of the waters of the Colorado River Basin, and consistent with applicable determinations of annual water release volumes from Glen Canyon Dam made pursuant to the Long-Range Operating Criteria (LROC) for Colorado River Basin Reservoirs, which are currently implemented through the 2007 Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lake Powell and Lake Mead. The area potentially affected by the L TEMP includes Lake Powell, Glen Canyon Dam, and the Colorado River downstream to Lake Mead. More specifically, the scope primarily encompasses the Colorado River Ecosystem (CRE), which includes the Colorado River mainstream corridor 2 and interacting resources in associated riparian and terrace zones, located primarily from the forebay of Glen Canyon Dam to the western boundary ofGCNP. The CRE specifically consists of the area where dam operations impact physical, biological, recreational, cultural, and other resources. This section of the river runs through Glen, Marble, and Grand Canyons in Coconino and Mohave Counties in northwestern Arizona. Although the FEIS focuses primarily on the CRE, the affected area varies by resources and extends outside of the immediate river corridor for some resources and cumulative impacts. For resources such as socioeconomics, air quality, and hydropower, the affected region is larger and includes areas potentially affected by indirect impacts of the LTEMP. The FEIS and this Record of Decision (ROD) have been prepared in accordance with the National Environmental Policy Act (NEPA), the Council on Environmental Quality's NEPA regulations (Title 40, Code ofFederal Regulations, Parts 1500 to 1508 [40 CFR 1500-1508]), and DO I regulations (4 3 CFR 46). The decision made here is based on the FEIS filed with the U.S. Environmental Protection Agency (EPA) (FES 12-01) on October 7, 2016, and noticed by the EPA in the Federal Register on October 14, 2016. For this ROD, DOI selected Alternative D without modification, which was identified in the L TEMP FEIS as both the preferred and the environmentally preferred alternative. This alternative will use the monthly release volumes as specified in Table I. Within a year, monthly operations may be increased or decreased based on factors referenced in Sections 1.2 and 1.3 of Attachment B of this ROD. Alternative D best meets the purpose and need and the broadest set of objectives and resource goals of the LTEMP. Alternative D provides the best balance of performance among downstream resources to comply with the GCPA to protect, mitigate adverse impacts to, and improve the natural and cultural resources and visitor use in the GCNP and GCNRA park units while continuing to comply with GCPA 1802 (b) applicable laws. TABLE 1 Monthly Release Volumes of the Selected Alternative Monthly Release Volume (thousand ac-ft)' Total Annual 7,000 7,480 8,230 9,000 9,500 10,500 11,000 12,000 13,000 14,000 October 480 480 643 643 643 643 643 643 643 643 November 500 500 642 642 642 642 642 642 642 642 December 600 600 716 716 716 716 716 716 716 716 January 664 723 763 857 919 1,041 1,102 1,225 1,347 1,470 February 587 639 675 758 813 921 975 1,083 1,192 1,300 March 620 675 713 801 858 973 1,030 1,144 1,259 1,373 April 552 601 635 713 764 866 917 1,019 1,121 1,223 May 550 599 632 710 761 862 913 1,014 1,116 1,217 June 577 628 663 745 798 905 958 1,064 1,171 1,277 July 652 709 749 842 902 1,022 1,082 1,202 1,322 1,443 August 696 758 800 899 963 1,091 l, 156 1,284 1,413 1,537 Seetember 522 568 600 674 722 819 867 963 1,059 1,160 3 a Within a year, monthly operations may be increased or decreased based on factors referenced in Section 1.2 and 1.3 in Attachment B of this ROD. 2. PURPOSE AND NEED The purpose of the proposed action is to provide a comprehensive framework for adaptively managing Glen Canyon Dam over the next 20 years consistent with the GCPA and other provisions of applicable Federal law. The proposed action will help determine specific dam operations and actions that could be implemented to improve conditions and continue to meet the GCP A's requirements and to minimize------consistent with law-adverse impacts on the downstream natural, recreational, and cultural resources in the two park units, including resources of importance to American Indian Tribes. The need for the proposed action stems from the need to use scientific information developed since the 1996 ROD to better inform DOI decisions on dam operations and other management and experimental actions so that the Secretary of the Interior may continue to meet statutory responsibilities for protecting downstream resources for future generations, conserving species listed under the Endangered Species Act (ESA), avoiding or mitigating impacts on National Register ofHistoric Places (NRHP)-eligible properties, and protecting the interests of American Indian Tribes, while meeting obligations for water delivery and the generation of hydroelectric power. 3. ALTERNATIVES CONSIDERED The FEIS assesses the potential environmental effects of seven alternatives to meet the purpose and need of the proposed action: The No-Action Alternative (Alternative A), and six action alternatives (Alternatives B, C, D, E, F, and G), which are summarized below (see LTEMP FEIS, Section 2.2). Alternative A (No-Action Alternative): Alternative A represents continued operation of Glen Canyon Dam as guided by the 1996 ROD for operations of Glen Canyon Dam, that is, Modified Low Fluctuating Flow (MLFF), as modified by recent DOI decisions, including those specified in the 2007 ROD on Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operations for Lakes Powell and Mead (Interim Guidelines) (until 2026); the High-Flow Experiment Environmental Assessment (HFE EA); and the Nonnative Fish Control EA (both expiring in 2020). Alternative B: The objective of Alternative B is to increase hydropower generation while limiting impacts on other resources and relying on flow and non-flow actions to the extent possible to mitigate impacts of higher fluctuations. Compared to the No-Action Alternative, Alternative B would increase within-day fluctuations and include experimental hydropower improvement flows, but would retain the monthly water release pattern of Alternative A. Alternative B focuses on non-flow actions and experiments to address sediment resources, nonnative fish control, and on native and nonnative fish communities. 4 Alternative C: The objective of Alternative C is to adaptively operate Glen Canyon Dam to achieve a balance ofresource objectives with priorities placed on humpback chub, sediment, and minimizing impacts on hydropower. Compared to the No-Action Alternative, Alternative C would decrease within-day fluctuations, reduce water releases in the late summer and fall, and provide more even releases in other months.