What is a Feasibility Study?

A feasibility study is a planning-level assessment to determine if a future project is viable in terms of impacts, costs, and constructability. The US 93 Ninepipe Corridor Feasibility Study involved an evaluation of relevant conditions to determine if corridor right-of-way, wetland areas, wildlife presence and movements, cultural influences, and soil and groundwater constraints may hinder development of highway improvements.

Where is the corridor located?

The feasibility study focused on the Ninepipe segment of US 93 between Gunlock Road (Reference Point (RP) 40.0) and Brooke Lane (RP 44.5) near the Ninepipe and Kicking Horse Reservoirs in Lake County.

Who is conducting this study?

The Montana Department of Transportation conducted this study in partnership with the Confederated Salish and Kootenai Tribes (CSKT) and the Federal Highway Administration (FHWA). Collaboration with resource agencies, stakeholders, and the public was also an important part of the process.

What efforts were previously completed?

MDT completed a Final Environmental Impact Statement (FEIS) and Section 4(f) Evaluation in 1996 for the portion of US 93 between Evaro and Polson, MT. The Record of Decision (ROD) did not provide specific design details so MDT, the CSKT, and FHWA agreed to prepare a supplemental environmental study of the Ninepipe/Ronan section to further explore possible alternate alignments and perform a detailed study on the effects of highway improvements on wetlands and wildlife in the corridor. In 2008, MDT, the CSKT, and FHWA completed a Supplemental Environmental Impact Statement (SEIS) and a Section 4(f) Evaluation for the Ninepipe/Ronan section.

Why are improvements being considered in this corridor?

The 2008 SEIS noted that US 93 is important to local, regional, and nationwide transportation. With poor existing traffic operations, projected increases in traffic volumes, multiple safety concerns, and a lack of dedicated pedestrian and bicycle facilities, MDT and the CSKT supported improvements to address safety and mobility in the US 93 corridor. MDT and the CSKT also strived to minimize impacts to sensitive elements within the Ninepipe segment, including cultural and historic features, wetlands and waterways, wildlife and habitat, and other environmental resources.

What was identified as the 2008 preferred alternative for the corridor?

The 2008 SEIS identified a preferred alternative for the corridor consisting of a two-lane roadway (one lane in each direction), widened shoulders, wildlife crossing structures, and a separated bicycle/pedestrian path within the Ninepipe segment. The corridor would connect to a divided four-lane segment north of Brooke Lane and a passing lane segment south of Gunlock Road.

Why was the 2008 preferred alternative selected?

A two-lane configuration was selected for the Ninepipe segment to minimize impacts to sensitive natural resources within this portion of the corridor. The Ninepipe segment is characterized by numerous glacial pothole wetlands, providing valuable habitat for a wide range of wildlife species. Additionally, this segment is highly valued by the Tribes from a cultural standpoint. At the time of the 2008 SEIS, MDT, the CSKT, and FWHA elected to maintain the existing straight alignment and minimize the highway footprint through this segment.

Why did MDT conduct a feasibility study in the Ninepipe corridor?

Since completion of previous environmental documentation efforts, MDT has proceeded to develop projects in stretches of US 93 adjacent to the Ninepipe segment and has encountered multiple challenges relating to constructability, impacts, and costs. The intent of the US 93 Ninepipe Corridor Feasibility Study was to proactively address these challenges by identifying potential constraints and considering the viability of the preferred alternative previously identified in the 2008 SEIS before a formal project is nominated.

What steps were involved in the study?

The US 93 Ninepipe Corridor Feasibility Study involved three phases.

• Phase 1: An analysis of relevant conditions was completed in late 2021. The analysis involved conducting research and gathering field data relating to traffic and safety conditions, land ownership and corridor right-of-way, wetland areas, wildlife presence and movements, cultural influences, and soil and groundwater constraints.
• Phase 2: The feasibility evaluation occurred in 2022 to consider costs, impacts, and construction feasibility relating to roadway and bicycle/pedestrian path alignments and wildlife crossings.
• Phase 3: Feasibility study documentation was developed, with a final report completed in March 2023.
• Throughout: Public, stakeholder, and resource agency outreach was conducted during the entire process.

Did the study consider changes to the 2008 preferred alternative?

The study used the preferred alternative identified in the 2008 SEIS as a baseline starting point. At that time, MDT, the CSKT, and FHWA determined that the preferred alternative consisting of one travel lane in each direction and widened shoulders was best able to address the project purpose and need while minimizing impacts to cultural and natural resources. A four-lane section was previously evaluated but was not selected as the preferred alternative for this segment due to substantial resource impacts. The study did not revisit this decision.

As part of the feasibility study, MDT considered and incorporated modifications to the 2008 preferred alternative to improve highway function and reduce impacts and costs, including modified slopes and wildlife accommodations. Additionally, MDT intends to construct turn lanes associated with planned safety improvements at the Eagle Pass Trail intersection as a separate project.

How was the public involved in the study?

Members of the public were encouraged to participate in the process and offer feedback. Public informational meetings were held, with details pertaining to date and time announced in advance. Study materials were also posted to the website for public review.

What happens after the study?

Should a project be advanced into design, findings from this study will assist MDT in project development decisions and will support a future environmental re-evaluation of the Ninepipe segment, which will be needed to comply with the National and Montana Environmental Policy Acts and other state and federal regulations. The timeframe for development of a future project will be dependent on available funding. No funding has been secured at this time.