DOT&PF Notice of Proposed De Minimis Section 4(f) Finding - Avalanche Mitigation Alert Detection (AMAD) - (CGRNT01186)

The Alaska Department of Transportation and Public Facilities (DOT&PF) has assumed the responsibilities of the Federal Highway Administration under 23 U.S.C. 327 and is requesting public comments on an intended de minimis Section 4(f) finding for proposed impacts to Chugach State Park. The impacts are related to the purchase and installation of an avalanche detection system along the Seward Highway, which require the placement of equipment within the park. Chugach State Park is a popular recreation area under the jurisdiction of the Alaska Department of Natural Resources (ADNR) Division of Parks and Outdoor Recreation (DPOR) and is a protected resource under Section 4(f) of the U.S. Department of Transportation Act of 1966. The DOT&PF believes, after consultation with the Park Superintendent and consideration of impact avoidance, minimization, and mitigation or enhancement measures, that the proposed project will not adversely affect the activities, features, or attributes of the Chugach State Park that qualify it for protection under Section 4(f). The Superintendent of Chugach State Park must concur with this finding before it can be finalized.The purpose of the project is to improve safety, transportation reliability, and the ability to address significant avalanche risks on the Seward Highway. Impacts to Chugach State Park include the installation of a solar-powered infrasound detection system on Rohn towers with non-permanent bases in identified avalanche areas within the park. Only two eight-foot Rohn towers with non-permanent bases would be placed within Chugach State Park, near Mile Post 98.5 of the Seward Highway. No road closures are anticipated and developed park features, such as viewpoints, trails, interpretive sites, picnic shelters, and bathrooms would not be affected. The avalanche zones where the system would be installed are within the park and most are above the highway, outside of the DOT&PF right-of-way. However, DOT&PF believes that the impacts are de minimus because the towers have a small footprint (tower bases are approximately 4x4 ft.), the towers are temporary (the project involves trying out the new system for two years), and the towers would be installed in locations on avalanche slopes that should not impact recreation activities or facilities within the park. Unless public comment identifies significant factors not previously considered, the DOT&PF intends to formalize this finding.The infrasound systems would improve avalanche prediction accuracy, enable more timely warnings to avalanche staff (and subsequently the public) about avalanche-related road closures, and provide a more comprehensive view of conditions across different highway segments.Construction for the proposed project is anticipated to begin in the fall of 2025. To ensure consideration of all issues concerning the proposed work within the Chugach State Park, we request you submit comments no later than the close of business on October 3, 2025. Please send comments to: Heidi Zimmer, Regional Environmental ManagerDOT&PF Preliminary Design & EnvironmentalP.O. Box 196900Anchorage, Alaska 99519-6900heidi.zimmer@alaska.gov If you have any questions or require additional information, please contact Tim Glassett, Project Manager, at (907) 344-2615 or timothy.glassett@alaska.gov.The environmental review, consultation, and other actions required by applicable Federal environmental laws for this project are being, or have been, carried out by DOT&PF pursuant to 23 U.S.C. 327 and a Memorandum of Understanding dated April 13, 2023, and executed by FHWA and DOT&PF.It is the policy of the Alaska Department of Transportation & Public Facilities (DOT&PF) that no person shall be excluded from participation in, or be denied benefits of any and all programs or activities we provide based on race, religion, color, gender, age, marital status, ability, or national origin, regardless of the funding source including Federal Transit Administration, Federal Aviation Administration, Federal Highway Administration and State of Alaska Funds.The DOT&PF complies with Title II of the Americans with Disabilities Act of 1990. Individuals with a hearing impairment can contact DOT&PF at our Telephone Device for the Deaf (TDD) at (907) 269-0473