Targhee Pass Environmental Assessment


Why is the Environmental Assessment (EA) being done?

The U.S. 20 Corridor Plan has identified a need for safety improvements, pavement restoration, and wildlife-vehicle collision improvements within the Targhee Pass area.

ITD is now initiating an EA to evaluate risks, benefits, opportunities and costs associated with reconstruction of Targhee Pass (U.S. 20 between its junction with Idaho 87 and the Montana state line). The Federal Highway Administration (FHWA) is the lead agency on this study and will be signing the final study document. This study will be completed in accordance with the National Environmental Policy Act (NEPA).

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What has been done up to this point?

Since 2004, ITD has engaged in an extensive safety corridor planning effort for U.S. 20 from Chester to the Montana state line – Idaho’s gateway to Yellowstone National Park. The U.S. 20 Corridor Plan is a long-range planning effort examining land uses, existing infrastructure, traffic, and environmental conditions along U.S. 20. ITD has been working with the IDFG as the state's wildlife specialist, per a Memorandum of Understanding (MOU). The purpose of the plan is to assess the condition of the U.S. 20 corridor and to identify the necessary improvements to meet the corridor’s system and user needs for the next 20 years.

Please visit the U.S. 20 Corridor Plan Story Map for additional information.

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Why this project? Why now?

ITD is proposing transportation improvements for U.S. 20 from Idaho 87 to the Montana state line (Targhee Pass).

As described in the corridor plan, U.S. 20 must accommodate local traffic, heavy tourist traffic, and the majority of the truck freight moved between West Yellowstone, southern Montana, and the communities of the Snake River Plain. When the corridor plan was first being developed, much of the roadway within Idaho was falling behind in serving its function as a component of the National Highway System (NHS). U.S. 20 within Idaho remained a two-lane rural highway, with four-to six-foot-wide shoulders along the majority of its length. Since that time, improvements have been made for many of the segments of the corridor, with Targhee Pass being one of the remaining sections to receive attention. At the present time, pavement condition in this segment of the corridor is beyond routine repair and requires reconstruction as well as consideration of upgrades to meet current design safety standards.

In October 2016, the ITD board approved use of federal funds for making improvements to this segment of the corridor.

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What is an Environmental Assessment?

The National Environmental Policy Act (NEPA) process begins when a federal agency develops a proposal to take a major federal action or (as in this case) when federal funds would be utilized to implement a project. By deciding to prepare an Environmental Assessment (EA), ITD and the Federal Highway Administration (FHWA) will be evaluating whether the proposed action or other alternatives would cause significant environmental effects. If the effects are determined to be less than significant (including avoidance and mitigation measures), then a Finding of No Significant Impact (FONSI) will be prepared and an action alternative will be selected for implementation. Generally, the EA includes a brief discussion of:

  • The need for the proposal
  • Alternatives (when there is an unresolved conflict concerning alternative uses of available resources)
  • The environmental impacts of the proposed action and alternatives
  • A listing of agencies and persons consulted

When completed, the EA document will be made available to the public, and a public meeting will be scheduled and advertised.

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How can I participate in the process?

The study team is working through an open process to complete a thorough environmental study that considers and evaluates a range of potential solutions.

We are publicizing this effort through traditional, electronic and social media, while working diligently to provide multiple ways for the public to comment. We welcome any comments and discussion through the following avenues:

Phone: 208-220-5937
Email: targheepass@langdongroupinc.com

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What is the Environmental Assessment considering?

  • Change in Vehicular Access or Vehicular Access Control: No substantial changes to vehicle access are proposed for this part of the corridor; private and public land access would be preserved and traffic flow may be improved by addition of turning lanes in several locations.
  • Land Use and Property Acquisition: None of the alternatives being considered would require relocations of residences or businesses, but some alternatives may require a property easement or minor addition to the existing highway right-of-way.
  • Social and Economic Impacts: The highway is an integral component of the local economy and community. The Targhee Pass Segment of U.S. 20 is used by locals to commute and for movement of goods and services. Tourists who visit the area access local services (restaurants, lodging, destinations) by using the corridor. Residents of the corridor are concerned about economic, property value, visual, noise, and land use changes of project alternatives.
  • Visual Resources: Potential visual changes to the corridor will be evaluated in the EA and efforts to minimize visual impacts of alternatives will be described.
  • Noise: A highway traffic noise analysis is being completed for the EA.
  • Recreation Resources: Winter and summer trail accesses are located in the area. For the Targhee Pass segment of U.S. 20, project design elements to maintain recreation access will be described in the EA and potential impacts will be evaluated.
  • Cultural Resources and Native American Consultations: Literature and data searches and site surveys were conducted to inventory potentially eligible resources in the area of potential effects for the project alternatives. The Nez Perce Tribe and the Shoshone Bannock Tribe expressed interest in the Environmental Assessment and will be consulted throughout the NEPA process.
  • Water Resources: The watershed supplies water for local residences and Howard Creek flows into Henry’s Lake just below the crossing of SH 87. Howard Spring is an important ecological and community resource. Impact avoidance and minimization will be described in the EA.
  • Wetlands, Riparian Areas, and Stream Alteration: A jurisdictional wetland delineation was completed during project planning to identify resources. Impact avoidance and minimization will be described in the EA.
  • Wildlife and Fisheries: The impact analysis will utilize available data and research literature to evaluate effects of alternatives on wildlife-vehicle collisions and migratory, dispersal, and daily movements of wildlife. Potential effects to fish in Howard Creek will also be evaluated.
  • Soils and Geology: The EA will summarize slope stability, near-surface groundwater, and other potential constraints and design considerations
  • Construction Impacts: Short-term impacts that can result from road construction (air quality impacts, potential to encounter previously contaminated soils, utility service disruption, soil erosion, water quality impacts, invasive species introductions, and economic disruption) will be evaluated.
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    Will access to bordering federal lands be changed as a result of any of the proposed alternatives for Targhee Pass?

    For alternatives involving wildlife fence, ITD would preserve access to public and private lands by providing appropriate vehicle and pedestrian accesses. Frequent vehicle access locations such as private driveways and entrances to Big Horn Hills Estates would have open access through a wildlife fence. Some less frequently used access locations may be appropriate for a gated entrance. Pedestrian access gates, such as sportsmen's accesses, could be placed at key locations or periodically at some determined distance. ITD would work with landowners, the Forest Service, Fremont County, and Idaho Department of Fish & Game to finalize access locations upon selection of any alternative that would involve installation of wildlife fence. The Forest Service has no immediate plans to change land use or its current travel management plan, regardless of the alternative selected.

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    Are speed limits being assessed as part of the Targhee Pass Environmental Assessment?

    Seasonal advisory speeds will be assessed as part of the EA.

    ITD is currently working on a complete review of the speed limits in the Island Park area (from Ashton to the Montana state line) later this fall, weather permitting. This work is not part of the Targhee Pass EA. This review includes collecting speeds of vehicles and reviewing roadway conditions. ITD will also review crash history and check sight distance at intersections. From this study, ITD will determine if all speed zones are correct and if the changes between the zones are posted at the correct locations. Also outside of the scope of the Targhee Pass EA, ITD is reviewing speeds at night to see if a nighttime speed limit could be implemented, as well as assessing truck speeds to see if a separate speed limit should be implemented for trucks.

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    I am concerned about wildlife along this section of U.S. 20. How will this be addressed in this process?

    Wildlife collisions are a known issue, examined in the corridor planning effort and corridor wildlife studies. ITD has worked closely with Dr. Patty Cramer, an independent wildlife researcher, to collect data and compile a wildlife study as part of the U.S. 20 planning effort. Our study team has also spent the past several months having one-on-one conversations with local agencies, municipalities, tribes and other key stakeholders, which has shed even more light on this important issue.

    Study data previously gathered through the U.S. 20 safety corridor plan and our ongoing work with area stakeholders is being used for the Targhee Pass Environmental Study. ITD is looking at options for a solution along with funding opportunities to reduce wildlife-vehicle collisions. ITD has an existing MOU with IDFG designating IDFG as the state's wildlife specialist, as per the MOU.

    A common comment received in the scoping phase was specific to WVC reduction measures that would decrease wildlife-vehicle collisions and help promote motorist and wildlife safety.

    Starting in January 2017, ITD began working with IDFG to develop a Cooperative Agreement under the existing MOU to conduct additional work above and beyond the work already completed by these two agencies in the overall corridor planning and wildlife migration pattern studies. The agreement would lead to additional work by a consultant to evaluate the ITD District 6 Wildlife Study in order to increase the safety along U.S. 20 by identifying and implementing measures to reduce the WVC rate and provide for wildlife connectivity throughout the corridor.

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    How is this project funded?

    Right now, the $22.2 million project budget is cost shared with Federal Aid Highway Funds at the rate of 92.66% Federal Aid with 7.34% matching State funds (typical for Idaho).

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