Early Notice and Public Review of a Proposed Activity in a Federal Flood Risk Management Standard Designated Floodplain or Wetland

To: All interested Agencies, Groups and Individuals

This is to give notice that Beaverhead County has determined that the following proposed action under Community Project Funding B-24-CP-MT-1305 is located in the Federal Flood Risk Management Standard (FFRMS) floodplain/wetland, and Beaverhead County will be identifying and evaluating practicable alternatives to locating the action within the floodplain/wetland and the potential impacts on the floodplain/wetland from the proposed action, as required by Executive Order 11988, as amended by Executive Order 13690 and/or Executive Order 11990, in accordance with HUD regulations at 24 CFR 55.20 in Subpart C Procedures for Making Determinations on Floodplain Management and Protection of Wetlands. The proposed project location is 45°18’18.65″N, 112°33’48.46″W in Dillon, Beaverhead County. The extent of the FFRMS floodplain was determined using 0.2 percent flood approach. The Anderson Lane Bridge over the Beaverhead River is a single-lane, load-limited, bridge that provides primary access to numerous residential users, agricultural operations, and recreationalists. Beaverhead County proposed to replace the structure with a new prestressed concrete structure on driven pile foundations. The new Anderson Lane Bridge will provide a two-lane crossing, increase safety, ensure long-term access, handle legal loading requirements, and maintain waterway adequacy.

In terms of floodplain and wetland considerations, the project may impact 0.61 acres of floodplains and 0.08 acres of wetlands located at the current bridge location, which are classified under the FFRMS and have a wetlands classification of Palustrine Emergent and Palustrine Scrub-Shrub. The project site encompasses the area of the current bridge, which includes approximately 0.332 acres of floodplain and wetlands classified under the Federal Flood Risk Management Standard (FFRMS). The wetland types identified in this area include Palustrine Emergent and Palustrine Scrub-Shrub. The existing natural and beneficial functions of the impacted floodplain and wetland include floodwater storage and conveyance, groundwater discharge and recharge, erosion control, and maintenance of water quality. Additionally, these areas provide vital habitat for various flora and fauna, contributing to the region’s biodiversity. The intrinsic values of the floodplain and wetland include recreational opportunities for activities such as fishing and wildlife observation and educational prospects for local schools and organizations.

To protect the wetland and floodplain from the Anderson Lane Bridge project, several measures will be taken. Comprehensive planning will minimize the construction footprint and preserve wetland functions, maintaining natural hydrology and ecosystem integrity. During construction, strict erosion control measures will be implemented to prevent sediment runoff, following best management practices to protect water quality and ensure natural water flow patterns are maintained. Environmental monitoring will occur before, during, and after construction to assess impacts and ensure regulatory compliance. If any issues arise, immediate corrective actions will be implemented. Community engagement will be prioritized to raise awareness about the project. These strategies aim to keep the wetland and floodplain healthy and vibrant during construction.

There are three primary purposes for this notice. First, people who may be affected by activities in the floodplain and wetlands, as well as those who have an interest in the protection of the natural environment, should be given an opportunity to express their concerns and provide information about these areas. Commenters are encouraged to offer alternative sites outside of the floodplain and wetlands, alternative methods to serve the same project purpose, and methods to minimize and mitigate project impacts on the floodplain and wetlands. Second, an adequate public notice program can be an important public educational tool. The dissemination of information and request for public comment about the floodplain and wetlands, can facilitate and enhance Federal efforts to reduce the risks and impacts associated with the occupancy and modification of these special areas. Third, as a matter of fairness, when the Federal government determines it will participate in actions taking place in the floodplain and wetlands, it must inform those who may be put at greater or continued risk.

Written comments must be received by Beaverhead County at the following address on or before May 8, 2026: Beaverhead County, 2 S Pacific #4, Dillon, MT 59725, Attention: Michael McGinley, Chairman. A full description of the project may also be reviewed from Monday through Friday, 8:00 a.m. to 5:00 p.m. at 2 South Pacific Street, Suite 3, Dillion, MT 59725, and beaverheadcountymt.gov. Comments may also be submitted via email at bhankinson@beaverheadcountymt.gov.

Date: April 23, 2026

The Beaverhead County Road Department will be closing Browne’s Bridge between Glen and Melrose from April 22 thru April 29, 2026 to replace decking.  Please use an alternate route for this time frame.

Browne’s Bridge – Google Maps

Lemhi Pass Road will be closed to vehicle traffic beginning December 1, 2025 reopening May 15, 2026 weather permitting.

Road closure will be from the Bar Double T ranch to Lemhi Pass on the Idaho border.

The Pioneer Mountains Scenic Byway will be closed to vehicle traffic beginning December 1, 2025 reopening May 15, 2026 weather permitting.

Byway closure will be from Elkhorn Hot Springs to the Pettengill Campground.

Final Notice and Public Explanation of a Proposed Activity in a Federal Flood Risk Management Standard Designated Floodplain or Wetland

 To:  All interested Agencies, Groups and Individuals

This is to give notice that Beaverhead County has conducted an evaluation as required by Executive Order(s) 11988, as amended by Executive Order 13690, and/or Executive Order 11990, in accordance with HUD regulations at 24 CFR 55.20 in Subpart C Procedures for Making Determinations on Floodplain Management and Wetlands Protection. The activity is funded under Community Project Funding B-24-CP-MT-1305. The proposed project location is 45°18’18.65″N, 112°33’48.46″W in Dillon, Beaverhead County, and is located in the Federal Flood Risk Management Standard (FFRMS) floodplain / wetland. The extent of the FFRMS floodplain was determined using 0.2 percent flood approach. The existing Anderson Lane Bridge over the Beaverhead River is a single-lane, load-limited, bridge that provides primary access to numerous residential users, agricultural operations, and recreationalists. Beaverhead County proposed to replace the structure with a new prestressed concrete structure on driven pile foundations. The new Anderson Lane Bridge will provide a two-lane crossing, increase safety, ensure long-term access, handle legal loading requirements, and maintain waterway adequacy.

Beaverhead County has considered the following alternatives and mitigation measures to minimize adverse impacts and to restore and preserve natural and beneficial functions and intrinsic values of the existing floodplain/wetland: no action, relocation, replacement in existing location, and closure. A no-rise analysis was completed for the new structure to demonstrate no increase in base flood elevations or velocities in compliance with State and local regulations. Replacing the bridge in the existing location was selected to prevent the acquisition of private property and minimize effects to undisturbed adjacent wetlands and floodplain. Both upstream and downstream reaches of the Beaverhead River are also located in a mapped floodplain.

Beaverhead County has reevaluated alternatives to building in the floodplain/wetland and has determined that it has no practicable alternative to floodplain/wetland development. Environmental files documenting compliance with Executive Order 11988, as amended by Executive Order 13690, and/or Executive Order 11990, are available for public inspection, review and copying upon request at the times and location delineated in the last paragraph of this notice for receipt of comments.

There are three primary purposes for this notice. First, people who may be affected by activities in floodplain/wetland and those who have an interest in the protection of the natural environment should be given an opportunity to express their concerns and provide information about these areas. Second, an adequate public notice program can be an important public educational tool. The dissemination of information and request for public comment about floodplain/wetland can facilitate and enhance Federal efforts to reduce the risks and impacts associated with the occupancy and modification of these special areas. Third, as a matter of fairness, when the Federal government determines it will participate in actions taking place in floodplain/wetland, it must inform those who may be put at greater or continued risk.

Written comments must be received by the Beaverhead County at the following address on or before June 26, 2025: Beaverhead County, 2 S Pacific #4, Dillon, MT 59725, Attention: Michael McGinley, Chairman. A full description of the project may also be reviewed from Monday through Friday, 8:00 a.m. to 5:00 p.m. at 2 South Pacific Street, Suite 3, Dillion, MT 59725, and beaverheadcountymt.gov. Comments may also be submitted via email at ssetzer@beaverheadcountymt.gov.

See the Preliminary Engineering Report document for more information.

Date: June 17, 2025