The Nez Perce (Neeme‐poo or Nimi’ipuu) NHT is the only NHT in the Planning Area. A number of Other Historic Trails also pass through the Planning Area, including trails of importance to Native Americans, routes from the early historic period, such as the Bridger Trail, and roads and highways from the late 19th and early 20th centuries. Map 73 illustrates the Nez Perce NHT and Other Historic Trails.
NHTs and Other Historic Trails are fragile, nonrenewable resources that provide a direct and tangible link to human history in the Planning Area. As resources on public land under the jurisdiction of a federal agency, the BLM is responsible for their protection and interpretation, and must consider their value when making land use decisions.
Adverse impacts to trail resources are primarily the result of direct impacts from actions that disturb the soil or alter characteristics of the surrounding environment that contribute to the trail’s significance. This includes the introduction of visual elements out of character with the existing scenery, or other actions that alter the setting or result in neglect of the resource to the extent that it deteriorates or is destroyed. For example, surface-disturbing activities that impact trail ruts are considered adverse impacts because the trail segments are nonrenewable. In contrast, actions that result in data collection and preservation of NHTs and Other Historic Trails can be considered beneficial impacts. Beneficial impacts also include proactive trail management, such as the preservation of buffer zones.Indirect impacts to NHTs and Other Historic Trails primarily result from project-related increases or decreases in activity in the Planning Area. For example, the construction of a recreational facility may increase visitor use, which would result in an indirect impact to previously undisturbed trail segments. Recreation in particular is a complex issue, because actions taken to preserve historic values can result in both beneficial and adverse impacts for the resource, and for heritage tourism and trail enthusiasts. Construction in an area some distance from a trail also can result in erosion or deposition at a trail location.
Because of the nonrenewable nature of NHTs, there is little distinction between short-term and long-term impacts. An exception to this would be visual impacts related to temporary construction or fire-related impacts. For example, a change in vegetation resulting from fire or clearing would be a temporary impact, as long as it did not lead to erosion of the trail. Similarly, if construction activity temporarily intruded into the trail’s viewshed, this would be a temporary impact, as long as the construction itself did not directly affect the trail or result in a condition that may lead to indirect impacts.
For all federal undertakings that may impact NHTs and Other Historic Trails, the BLM complies with NHPA Section 106 before implementing the undertaking. Section 106 compliance typically includes inventory, evaluation, and consultation with the SHPO. The existing plans considered the maintenance of a ¼-mile buffer zone adequate protection in most trail situations, with the occasional application of a 5-mile buffer zone a generous allowance that would provide protection to the viewshed of the Nez Perce NHT. However, with the introduction of new technology, particularly wind turbines that are often grouped into wind farms, this distance does not protect the Nez Perce NHT’s resource values. As setting has gained importance in determining the NRHP eligibility of significant trails, trail management must approach the application of viewshed criteria with flexibility, considering the distance from the resource and the type of intrusion when determining the impact. On a case-by-case basis, and as appropriate for some projects, project decisions will consider the importance of viewshed in a resource’s eligibility, and the distance necessary to protect its NRHP significance.
Application of the standards specified in BLM trail management guidance, and in the 1986 historic trails plan (BLM 1986b), also will limit adverse impacts to trail resources. These standards include:
Avoid impacts to all physical remains with good integrity.
Avoid impacts to locales with good environmental integrity.
Cross the setting where the integrity of setting has already been compromised.
Avoid running a linear project parallel to a trail.
Cross at 90 degrees using a dog-leg or S-curve.
Relocate the proposed disturbance where it will be less visible from the trail (i.e., behind a rise).
Restrict the width of a working ROW within a visual buffer on either side of a trail.
Avoid any blading on a ROW within the buffer zone if a track can do the job.
Consider special rehabilitation measures (such as revegetation) which will help reestablish the integrity of the trail.
Consider special interpretive measures (such as signing) which will help mitigate the impact of the project.