Gifford Pinchot National Forest; Washington; Spirit Lake Outflow Safety Improvement Project

SUPPLEMENTARY INFORMATION:

Purpose and Need for Action

The purpose of the Spirit Lake Outflow Safety Improvement Project is to provide for the safety of downstream communities by reducing the risk of flooding and mudflows from a failure of the Spirit Lake debris blockage. Following the 1980 eruption of Mount St. Helens, Spirit Lake's natural outlet to the Toutle River system was blocked by the landslide and debris flow from the eruption. The Spirit Lake tunnel was constructed under emergency conditions to address the imminent public safety threat posed by rising water levels in Spirit Lake. The tunnel is in an area with volcanic, geologic, hydrologic, and seismic hazards. The geological pressures on the tunnel have caused rock heave, compression, cracking, and support failures, necessitating periodic repairs. As the tunnel ages, it will require more frequent and longer closures for repair to prevent failure. It is not expected to remain serviceable without significant repair and/or upgrade. A failure would result in rising lake levels that could exceed the maximum safe operating level, at which point pressure from rising water levels could force the breaching of the natural debris blockage, putting the downstream population of approximately 50,000 people at risk of catastrophic flooding and mudflows.

The actions proposed for this project are needed to:

• Accommodate lake level rise from a flood event without exceeding a designated maximum safe level. The current average operating level is 3,440 feet ± 4 feet, with a maximum safe level of 3,460 feet elevation. Reduced tunnel diameter from shear led to a reduction in the maximum design discharge of the tunnel. Reduction in design discharge leads to faster lake level rise during storm events. For this reason, the tunnel is no longer functioning at optimal capacity, which increases the risk of debris blockage failure as lake levels approach the maximum safe level of 3,460 feet elevation.
• Improve access reliability to outflow infrastructure. Current travel to the existing intake infrastructure takes an average of 4.5 hours and requires a combination of travel modes including high-clearance passenger vehicle, utility terrain vehicle, and boat. This access does not allow for mobilization of heavy equipment to the inlet for necessary repair. A moving, floating, 40-acre log debris mat can prevent boat access depending on weather conditions. The site is under snow a significant portion of the year, which precludes year-round access to the inlet. Helicopter access is often not viable throughout the year due to poor weather conditions.
• Provide outflow redundancy. There is currently only one outflow configuration with the existing tunnel, and any reduction in outflow capacity increases the risk of debris blockage failure. Two previous tunnel repairs that required tunnel closure have led to lake levels approaching the maximum safe level of 3,460 feet elevation. A redundant outflow that accommodates design discharge will allow for extended closure of the primary outflow for repair, while maintaining a safe operating level.
• Reduce long-term outflow operation and maintenance burden. The existing outflow infrastructure needs significant repair to operate at optimal design capacity. The existing tunnel has not been a long-term, resilient outflow solution over the last 30 years as repeated necessary repairs have been a significant maintenance burden.

Proposed Action and Alternatives

In 2016, the Gifford Pinchot National Forest commissioned the National Academies of Science, Engineering and Medicine (NASEM) to develop Decision Making Framework for Managing the Spirit Lake and Toutle River System. NASEM recommended a multi-criteria decision-making approach that considers a range of alternatives. Based on a preliminary study conducted by the Forest Service and Army Corps of Engineers, extensive working group coordination, and subsequent engineering feasibility analyses, the Forest Service has identified six potential outflow improvement, as follows, that the environmental impact statement will consider:

• constructing an open outlet channel, which maintains Spirit Lake at its current elevation, with the redundant measure of rehabilitating the existing outlet tunnel;
• constructing an open outlet channel that drains Spirit Lake, with the redundant measure of upgrading the existing outlet tunnel and modifying its intake depth;
• rehabilitating the existing outlet tunnel in shear zones (areas in volcanic tuffs decomposed to weak rock and swelling clays) with the redundant measure of a permanent pumping station;
• constructing a new pressure tunnel parallel to the existing tunnel, with a redundant measure of rehabilitating the existing outlet tunnel in shear zones;
• rehabilitating the existing outlet tunnel in shear zones, with a redundant measure of a buried conduit within the debris blockage that releases water during storm events or during maintenance of the primary outlet; and
• converting the existing tunnel into a pressure tunnel, with the redundant measure of lake storage with an updated maximum safe lake level.

To align with NASEM guidance this NOI does not specify a preferred alternative.

As required under the National Environmental Policy Act (NEPA), the Forest Service will also evaluate a no action alternative in which no changes to current Spirit Lake outflow tunnel or lake level management strategies would be made.

Expected Effects

The draft environmental impact statement will identify and describe the potential effects of the alternatives on the human environment. Those potential effects must be reasonably foreseeable and must have a reasonably close causal relationship to the alternatives. Such effects include those that occur at the same time and place as the alternatives and those that are later in time or occur in a different place. The Project is expected to result in potential impacts to the following resources: air quality; aquatic, plant, and terrestrial biological resources; cultural resources; fire and fuels; floodplains; hydrology, and water quality; forestry and land use; geology and soils; heritage resources; public safety; recreation; roads and access; and scenic and visual resources. The level of review of the identified resources for the environmental impact statement will be commensurate with the anticipated effects to each resource and will be governed by the statutory or regulatory requirements protecting those resources.

Lead and Cooperating Agencies

The U.S. Department of Agriculture's Forest Service is the lead agency. U.S. Army Corps of Engineers and U.S. Geological Survey will likely be cooperating agencies; work is ongoing to complete cooperating agency agreements.

Responsible Official

The Responsible Official is the Gifford Pinchot National Forest Supervisor.

Scoping Comments and the Objection Process

This notice of intent initiates the scoping process, which guides the development of the environmental impact statement. The Agency is requesting comments on potential alternatives and impacts, and identification of any relevant information, studies, or analyses of any kind concerning impacts affecting the quality of the human environment. A public scoping meeting will be held at the Cowlitz County Event Center located at 1900 7th Avenue, Longview, Washington from 4 to 8 p.m. on Wednesday October 23, 2024. The Forest Service will accept written comments at the scoping meeting.

Reviewers should provide their comments at such times and in such manner that they are useful to the agency's preparation of the final environmental impact statement; therefore, comments should be provided prior to the close of the comment period and should clearly articulate the reviewer's concerns and contentions. Commenting during scoping and any other designated opportunity to comment provided by the Responsible Official as prescribed by the applicable regulations will also govern eligibility to object once the final environmental impact statement and draft record of decision has been published. Comments received in response to this solicitation, including names and addresses of those who comment, will be part of the public record for this proposed action. Comments submitted anonymously will be accepted and considered; however, they will not be used to establish eligibility for the objection process.

Objections will be accepted only from those who have previously submitted specific written comments regarding the proposed Project during scoping or other designated opportunity for public comment in accordance with 36 CFR 218.5(a). Issues raised in objections must be based on previously submitted timely, specific written comments regarding the proposed Project unless based on new information arising after designated opportunities.

Permits, Licenses or Other Authorizations Required

A U.S. Army Corps of Engineers Section 408 review and permission for any project activities that may cause downstream sedimentation or have the potential to affect a U.S. Army Corps of Engineers Civil Works project such as the Sediment Retention Structure or levees will be required. Depending on project details for the chosen alternative Section 401 and Section 404 permits through the U.S. Army Corps of Engineers may also be required.

Nature of Decision To Be Made

Given the purpose and need, the Responsible Official will determine whether the proposed actions comply with all applicable laws governing Forest Service actions and with the applicable standards and guidelines found in the Forest Plan; whether the EIS has sufficient environmental analysis to make an informed decision; and whether the proposed action meets the purpose and need for action. With this information, the Responsible Official must decide whether to select the proposed action and what, if any, additional actions should be required.

Substantive Provisions

Guidance for management of the Monument comes from the 1985 Mount St. Helens National Volcanic Monument's Comprehensive Management Plan, which is fully incorporated into the 1990 Gifford Pinchot National Forest Land and Resource Management Plan (Forest Plan), as amended by the 1994 Record of Decision for Amendments to Forest Service and Bureau of Land Management Planning Documents within the Range of the Northern Spotted Owl.

All actions authorized by the Forest Service on National Forest System lands must be consistent with the Forest Plan. If a proposed project-specific action is not consistent with the Forest Plan, the Responsible Official may modify the proposed action to make it consistent with the plan, reject the proposed action, or amend the plan such that the action will be consistent with the plan, as amended. When proposing a forest plan amendment, the planning regulations require the Responsible Official to identify in this notice which specific substantive requirements (36 CFR 219.8 through 219.11) are directly related to the plan direction being modified by the amendment based on the purpose of the amendment or the effects of the amendment (36 CFR 219.13(b)(5)).

The substantive requirements that are likely directly related to the purpose of the forest plan amendments are 36 CFR 219.8(a)(3)(i)(B), 219.8(a)(3)(i)(G), and 219.8(b)(1).

An amendment to Management Area A Recreation—Planning and Inventory standard and guideline 2 may be needed to allow project activities within the Monument and for potential road upgrades along the road corridors of FS-99 and FR-25 to exceed the Retention VQO during project implementation. The substantive requirements that are likely directly related to the effects of this forest plan amendment are 36 CFR 219.8(b)(2), 219.10(a)(1), and 219.10(b)(1)(i).

An amendment to Management Area A Recreation—Use Administration standard and guideline 2 may be needed to allow for off-road vehicle during the summer during project implementation. The substantive requirements that are likely directly related to the effects of this forest plan amendment are 36 CFR 219.8(a)(2)(ii), 219.10(a)(1), and 219.10(a)(5).

An amendment to Management Area A Facilities—Road Operations standard and guideline 1 may be needed to add National Forest System road(s) in the area. The substantive requirement that is likely directly related to the effects of this forest plan amendment is 36 CFR 219.10(a)(3).

An amendment to Management Area A Facilities—Road Operations standards and guidelines 2 and 3 may be needed to allow for road and off-road vehicle use on Deer and Elk Winter Range from December 1 to April 1 during project implementation. The substantive requirements that are likely directly related to the effects of this forest plan amendment are 36 CFR 219.9(a)(1), 219.10(a)(1), and 219.10(a)(5).

[FR Doc. 2024-22159 Filed 9-27-24; 8:45 am]

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