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###### Department of the Interior

###### Bureau of Reclamation

          - [RR040U2000, 23XR0680GB, RXN5570007.3200000]

# AGENCY:

Bureau of Reclamation, Interior.

# ACTION:

Notice and request for comments.

# SUMMARY:

On June 6, 2023, the Secretary of the Interior's Acting Designee to the Glen Canyon Dam Adaptive Management Work Group (AMWG), a Federal advisory committee, directed the Bureau of Reclamation (Reclamation) to prepare a Supplemental Environmental Impact Statement (SEIS). The supplement is to the December 2016 Record of Decision for the Glen Canyon Dam Long-Term Experimental and Management Plan (LTEMP) Final Environmental Impact Statement and will analyze flow options to prevent smallmouth bass and other warmwater invasive nonnative fish from establishing below Glen Canyon Dam (by preventing additional spawning) and will analyze new information regarding the sediment accounting window associated with the LTEMP High-Flow Experiment (HFE) protocol.

# DATES:

                        This                         **Federal Register**                         notice initiates the public scoping process for the SEIS. Reclamation requests that the public submit comments concerning the scope of specific operational guidelines, strategies, and any other issues that should be considered on or before November 3, 2023.                    

                        Reclamation will host two public webinars to provide summary information and receive oral comments. For specific information concerning the dates, times, and links to the webinars, click on the link provided in the                         **ADDRESSES**                         section of this notice.                    

# ADDRESSES:

                        Please send written comments pursuant to this notice to                         *LTEMPSEIS@usbr.gov*                         or by mail to Bureau of Reclamation, Attn: LTEMP SEIS Project Manager, 125 South State Street, Suite 800, Salt Lake City, UT 84138. For information on the upcoming webinars, go to                         *https://www.usbr.gov/​uc/​progact/​amp/​index.html.*

# FOR FURTHER INFORMATION CONTACT:

                        Kathleen Callister, Adaptive Management and Water Quality Division Manager, Bureau of Reclamation, at (801) 524-3867, or by email at                         *LTEMPSEIS@usbr.gov.*                         Please also visit the Glen Canyon Dam Adaptive Management website at                         *https://www.usbr.gov/​uc/​progact/​amp/​index.html*                         for updates. Individuals in the United States who are deaf, deafblind, hard of hearing, or have a speech disability may dial 711 (TTY, TDD, or TeleBraille) to access telecommunications relay services. Individuals outside the United States should use the relay services offered within their country to make international calls to the point-of-contact in the United States.                    

# SUPPLEMENTARY INFORMATION:

                    This document provides notice that Reclamation intends to prepare an SEIS and a modified Record of Decision for the 2016 LTEMP. Reclamation is issuing this                     **Federal Register**                     notice pursuant to the National Environmental Policy Act of 1969, as amended (NEPA), 42 U.S.C. 4321*et seq.;*                     the Council on Environmental Quality's regulations for implementing NEPA, 43 CFR parts 1500 through 1508; and the Department of the Interior NEPA regulations, 43 CFR part 46.                

## Background

The Colorado River Basin has been in a prolonged period of drought and low-runoff conditions, and despite current projections of 2023 runoff being above average, the period from 2000 through 2023 is currently estimated as the second driest period in more than a century and one of the driest periods in the last 1,200 years.

                    As the water elevation at Lake Powell has declined, the epilimnion (upper layer of water) where most fish reside has become closer to the dam's intakes, which move water from the reservoir, into the dam through the turbines for hydropower production, and downstream into the Colorado River. The decrease in water elevation means that nonnative fish in Lake Powell are now more likely than in prior years to become entrained, passing through the dam and downstream into the Colorado River. While some level of fish mortality occurs during passage through the turbines, some fish survive. As Lake Powell elevations decline, warmer water from the epilimnion is discharged, resulting in releases of water with warmer temperatures. Warm water temperatures below the dam create conditions that are suitable for warmwater nonnative fish to reproduce and eventually establish populations. This is a concern because smallmouth bass and other predatory invasive fish pose a threat to federally listed fish species and other native fish downstream of Glen Canyon Dam. Although invasive fish, including smallmouth bass, have been detected                           ( print page 68668)                        below the dam previously, the thermal conditions in the river (that is, warmer waters) are now conducive for smallmouth bass reproduction and establishment.                

To respond to the changing conditions, the Secretary of the Interior's Acting Designee to the AMWG directed Reclamation in August 2022, through the AMWG, to identify and analyze operational alternatives at Glen Canyon Dam that may serve to disrupt spawning of smallmouth bass and other warmwater invasive fish that pass through the dam.

Reclamation undertook an environmental assessment (EA) in August 2022. The draft EA entitled Glen Canyon Dam/Smallmouth Bass (SMB) Flow Options was released for public comment on February 24, 2023. Based on the EA analysis and nearly 7,000 comments received, Reclamation concluded that additional analysis was warranted.

Additionally, the increased temperatures of water releases, entrainment of warmwater nonnative fish, and lower Lake Powell elevations have resulted in the Department deciding to not implement fall HFEs in 2015, 2021, and 2022, despite reaching input triggers for sediment HFEs. The absence of spring HFEs during the first 10 years of the HFE protocol, coupled with analyses documenting reduced transport of fine sediments in years with low release volumes and low Lake Powell elevations, have prompted the researchers to reassess aspects of the scientific information supporting the HFE protocol. Assessment of the protocol from its use over the past 11 years indicates a need to evaluate the potential for longer sediment accounting periods and implementations windows as described in the LTEMP Record of Decision. The successful implementation of a spring HFE in April 2023 gives preliminary credence to altering sediment accounting windows.

The LTEMP SEIS will also consider modifying the LTEMP HFE protocol to incorporate the latest scientific information available. Over the past 25 years, scientific information on the use and timing of HFEs has improved understanding of how best to manage tributary-derived sediment supplies below the dam. Refined evaluation of opportunities and impediments for HFEs over the past decade under lower Lake Powell reservoir levels warrants review of the HFE implementation protocols. The LTEMP SEIS will re-evaluate the HFE sediment accounting period and implementation window to more fully achieve the LTEMP goals as they relate to using HFEs.

## Purpose and Need

The purpose of the LTEMP SEIS is for Reclamation to analyze additional flow options at Glen Canyon Dam in response to invasive smallmouth bass and other warmwater nonnatives recently detected directly below the dam. The need is to prevent the establishment of smallmouth bass below the Glen Canyon Dam (by preventing additional spawning), which could threaten core populations of threatened humpback chub in and around the Little Colorado River and its confluence with the Colorado River mainstem.

The LTEMP SEIS will also consider the HFE protocol by including the latest scientific information to improve Reclamation's ability to implement HFEs as originally intended in the LTEMP EIS. Specifically, Reclamation is considering adjusting sediment accounting periods and HFE implementation windows.

## Preliminary Proposed Action

Reductions in water temperature combined with changes in flow velocity may be vital tools that can be used to disrupt smallmouth bass from successfully spawning and establishing a population. As such, Reclamation has determined that an SEIS is necessary to pursue implementation of additional flow options at Glen Canyon Dam. A range of reservoir releases with temperature and flow velocity combinations will be analyzed to determine efficacy of their ability to disrupt and prevent smallmouth bass spawning behavior. Reclamation will also analyze the sediment accounting periods and implementation windows associated with the HFE protocol analyzed in LTEMP.

## Alternatives To Be Considered

During the EA process, nearly 7,000 public comments were received. Many of the substantial comments focused on the effects to hydropower generation and revenues as well as the effects on Tribal resources. Upon direction from the Secretary of the Interior's Acting Designee, Reclamation is transitioning to an SEIS analysis.

For the LTEMP SEIS scoping process, Reclamation anticipates the following preliminary alternatives will be considered:
    - No Action.
    - Four actions initially analyzed in the Glen Canyon Dam/Smallmouth Bass Flow Options Draft Environmental Assessment (February 2023). The Draft EA can be accessed at this web address: https://www.usbr.gov/​uc/​DocLibrary/​EnvironmentalAssessments/​20230200-GCDSmallmouthBassFlowOps_​Draft%20EA_​508.pdf. 
    - Hydropower flow option that does not include the use of bypass to reduce water temperatures.
    - Included in all but the No Action alternative will be a revised annual sediment accounting period and implementation window associated with the HFE protocol.

## Summary of Expected Impacts

The LTEMP SEIS will analyze reasonably foreseeable impacts from the alternatives considered. An initial analysis of impacts was done as part of the Glen Canyon Dam/Smallmouth Bass Flow Options Draft Environmental Assessment (February 2023). This initial analysis and alternatives considered will be further informed by comments received during the public EA comment process, the current SEIS scoping process and analysis of the current hydrology. These analyses will build upon and utilize information described in the 2016 LTEMP Final EIS and relevant analyses. The analyses in the SEIS will consider potential effects on the resources below Glen Canyon Dam, including natural and cultural resources, endangered species, recreation, water resources, hydropower resources, and other resources and uses. Reclamation will use an interdisciplinary approach incorporating expertise in the relevant resource fields.

## Schedule

Reclamation is planning to provide opportunities for public participation consistent with the NEPA process, including a 30-day scoping period and a 45-day public comment period on the draft LTEMP SEIS. The draft LTEMP SEIS is anticipated to be made available for public review in the winter of 2023-2024 and the final LTEMP SEIS with a Record of Decision, as appropriate, is anticipated to be available during the early summer 2024. The proposed duration of the flow options would potentially run through 2027. Any decisions regarding revisions to the HFE protocol are anticipated to run through duration of the LTEMP Record of Decision.

## Cooperating Agencies

                    Reclamation will be inviting the cooperating and co-lead agencies that participated in the LTEMP EIS to be cooperating agencies on the current LTEMP SEIS. Federal agencies with jurisdiction by law or with specialized expertise include the National Park Service, U.S. Fish and Wildlife Service,                           ( print page 68669)                        Bureau of Indian Affairs, and Western Area Power Administration.                

## Public Disclosure of Comments

Before including your address, phone number, email address, or other personal identifying information in your comment, you should be aware that your entire comment—including your personal identifying information—may be made publicly available at any time. While you can ask us in your comment to withhold your personal identifying information from public review, we cannot guarantee that we will be able to do so.

Wayne Pullan,

Regional Director, Bureau of Reclamation, Upper Colorado Basin Region.

[FR Doc. 2023-22077 Filed 10-3-23; 8:45 am]

BILLING CODE 4332-90-P