Allowable uses and management actions that may impact NHTs and Other Historic Trails include changes in ownership, access, and proactive NHT and Other Historic Trails management actions. Any surface-disturbing activity, regardless of type, on or adjacent to NHTs or Other Historic Trails may cause adverse impacts to contributing segments of the trails. Visual impacts from development, such as windmills, or incompatible use, such as motorized vehicles on intact trails, also are possible.
Recreation and educational uses of the trails under any alternative may have both a beneficial and an adverse impact. Information about the trails may promote preservation, but also may encourage visitation and use, which may degrade trails.
Compliance with NHPA Section 106 is required for all alternatives and all types of activities, resulting in the mitigation of adverse impacts. Although resource avoidance is the preferred mitigation, other solutions may be reached.
Surface-disturbing activities under Alternative A have the potential to impact the Nez Perce NHT and Other Historic Trails. Actions that may physically affect the trails, however, would be limited because of the buffer zone required by existing management plans, and compliance with NHPA Section 106 provides protection from direct impacts. Furthermore, if direct impacts are unavoidable, NHPA compliance requires mitigation of those impacts.
Impacts to the Nez Perce NHT and Other Historic Trails from surface disturbance projected for Alternative A are anticipated to be primarily adverse. However, normal compliance with NHPA Section 106 before approving an action moderates the amount of actual disturbance. When an accommodation cannot be made, the BLM and the SHPO consult to develop and implement a treatment plan to mitigate adverse impacts to contributing segments. While this often results in project relocation, detailed recording and mapping or interpretation are some of the techniques that may be used for mitigation, depending on the specific trail segment and the nature of the potential adverse impacts.
Restrictions on surface-disturbing activities for the protection of other resources (e.g., soil, water, biological resources, and special designations) under Alternative A provide additional protection for trail resources.
Actions related to lands and realty actions on BLM-administered surface land can result in both beneficial and adverse impacts to the Nez Perce NHT and Other Historic Trails. The survey that would be required for NHPA Section compliance in the case of either disposal or acquisition would result in a beneficial impact to cultural resources because of data that furthers understanding of trail resources in the Planning Area. If contributing segments were identified during an inventory for disposal of lands, there would be an adverse impact due to a change in the protective measures for cultural resources. If the BLM acquired the land, the impact would be beneficial. Although land-tenure adjustment is classified as an adverse impact (in terms of Section 106), development of a treatment plan for contributing trail segments would mitigate that impact. The plan would be developed through consultation between the BLM and SHPO in compliance with Section 106 and BLM trail guidance.
Actions regarding linear resources, including ROWs, corridors, renewable energy projects, and recreational trails management may all impact the Nez Perce NHT and Other Historic Trails, not only adversely through direct disturbance of the trail, but indirectly because the routes traveled by trails may also be the best route for these other resource uses. Under Alternative A, the Nez Perce NHT and Other Historic Trails are provided with a maximum buffer from surface disturbance and visual impacts of ¼ mile. Renewable energy is one of the more problematic resource uses, because the infrastructure to exploit solar and wind energy may be highly visible, depending on the terrain, but the buffer to protect the trail viewshed is limited to ¼ mile. Some beneficial impacts may result from inventory and the identification of previously unrecorded segments. In all cases, adverse impacts must be mitigated in compliance with NHPA Section 106.
Travel management and recreation also may result in both direct and indirect, and adverse and beneficial impacts. Where recreational trails match or parallel the Nez Perce NHT and Other Historic Trails, use may degrade the surface of the trail or impact the viewshed from the trail. Improved access also may indirectly lead to impacts. Similarly, construction of trailheads and educational signs and/or kiosks may increase use of the trails and expose them to vandalism. Under all alternatives, motorized vehicle use is anticipated to increase in the Planning Area, bringing greater access and the potential for greater adverse impacts. Concentrated herbivory may adversely affect the Nez Perce NHT and Other Historic Trails. Impacts would be direct, through trampling, and indirect, through reduction in vegetation leading to increased erosion.
Special designations would tend to have beneficial impacts to the Nez Perce NHT and Other Historic Trails. The main exception would be back country byways, which would indirectly and adversely impact historic trails resources through increased access. Beneficial impacts to NHTs and Other Trails are anticipated under Alternative A from special designations.
The impact of fire and fuels management would be primarily adverse. Because of the unique nature of trails, there is little to distinguish between long- and short-term impacts, because once trail ruts or original markers are disrupted or destroyed, they cannot be restored. Use of a trail corridor to access a fire location for suppression, stabilization and rehabilitation, and creation of fire breaks, can all result in direct, adverse impacts. Approximately 70,000 acres of short-term disturbance from fire and fuels management are anticipated under Alternative A (Appendix T).
Cultural resources and VRM would both have direct and indirect beneficial impacts to the Nez Perce NHT and Other Historic Trails. Because management of both these resources overlaps with management of historic trails, the trails would benefit from protections and proactive activities for these other resources.
Proactive management actions under Alternative A generally result in beneficial impacts to the Nez Perce NHT and Other Historic Trails. Under existing management, an NSO stipulation is applied within ¼ mile of the Nez Perce NHT and Other Historic Trails. Because trails often comprise multiple traces, the ¼-mile buffer zone extends from the outer edges of the overall trace. Current management also avoids surface-disturbing activities in view within ¼ mile of both the Nez Perce NHT and significant segments of Other Historic Trails, including the Bridger Trail and Fort Washakie to Meeteetse to Red Lodge Trail.
Surface disturbance affects the fewest acres under Alternative B, and thus has the least direct impact on the Nez Perce NHT and Other Historic Trails compared to alternatives A, C, and D. As with Alternative A, actions that may physically impact the trails, particularly the Nez Perce NHT, would be limited through enforcement of a buffer zone. Under this alternative, the buffer zone would extend to in view within 5 miles of the Nez Perce NHT and Other Historic Trails, except within existing utility corridors. Additional protections come from an NSO restriction within 3 miles and a CSU stipulation in view within 5 miles of the Nez Perce NHT and Other Historic Trails. The same distances apply to mineral materials disposal.
As with the other alternatives, normal compliance with NHPA Section 106 before approving an action moderates the amount of actual disturbance. In addition, the BLM and the SHPO consult to develop and implement a treatment plan to mitigate adverse impacts to contributing trail segments.
Restrictions on surface-disturbing activities for the protection of other resources (e.g., soil, water, biological resources, and special designations) are greatest under Alternative B, providing more protection for trail resources than under alternatives A, C and D.
Impacts related to lands and realty actions on BLM-administered surface land are anticipated to be similar to those for Alternative A; however the intensity varies by alternative. Compliance with the NHPA would still be required. More acreage may be acquired under Alternative B than under alternatives A, C or D, with the result that there would be more survey and identification of potentially NRHP-eligible trail segments than under alternatives A, C or D.
Management of linear resource uses (e.g., ROWs, corridors, renewable energy projects, and travel and trails management) would result in similar, but of a reduced magnitude impacts, than under Alternative A. Alternative B provides a wider buffer zone than alternatives A, C, or D, and limits ROW authorizations within 5 miles for the Nez Perce NHT and Other Historic Trails (except within existing utility corridors). As with the other alternatives, renewable energy presents a special situation. Even the wider buffer zone required under Alternative B may need to be expanded as the trails’ viewsheds are considered on a case-by-case basis, depending on the terrain. In all cases, adverse impacts must be mitigated in compliance with NHPA Section 106.
Alternative B provides for more recreational options and more anticipated disturbance than Alternative A. Improved access also may indirectly lead to impacts. Livestock grazing under Alternative B would result in impacts similar to Alternative A, although more areas may be placed off limits to grazing based on site-specific environmental analysis, providing greater protection to the Nez Perce NHT and Other Historic Trails.
Alternative B designates more special designation areas and includes greater restrictions on surface-disturbing activity within these areas than alternatives A, C and D. These additional restrictions would result in the greatest beneficial impact to NHTs and Other Historic Trails. However, Alternative B also designates more back country byways than alternatives A, C, and D and develops more interpretative facilities than the other alternatives, which may increase adverse impacts through increased access. Adverse and beneficial impacts would be greatest under Alternative B.
The impact of fire and fuels management would be primarily adverse under Alternative B, but would have the least impact compared to the other alternatives due to the smallest projected acreage of related disturbance.
Alternative B provides more protection for cultural and visual resources than alternatives A, C, or D, resulting in greater beneficial impacts to NHTs and Other Historic Trails. For example, Alternative B manages more of the Planning Area as VRM Class I and II, which would close or limit motorized vehicle use to designated roads and trails.
Proactive management actions under Alternative B emphasize resource protection in the vicinity of the Nez Perce NHT and Other Historic Trails through a 3-mile NSO and 5-mile CSU buffer, and viewshed buffers. In addition, this alternative allows wider buffers on a case-by-case basis for certain types of development, such as wind-energy developments. Use of motorized vehicles also is limited to designated roads and trails in view within 5 miles of trails. Because trails often comprise multiple traces, the buffer zones extend from the outer edges of the overall trace. These buffer zones are larger under Alternative B than the other alternatives. Alternative B removes canals from the same type of consideration as trails, recognizing that the significance criteria for this resource type are different from those of other linear features, such as trails.
Alternative C is projected to result in the greatest acreage of surface disturbance and, consequently, the greatest potential to NHT and Other Historic Trails. As with the other alternatives, compliance with BLM management practices and the NHPA would limit adverse impacts through development of treatment plans and adherence to buffer zones.
Because management under Alternative C places a greater emphasis on resource use, there would be fewer restrictions on surface-disturbing activities for the protection of other resources (e.g., soil, water, biological resources, and special designations). Therefore, although there would be some additional protection for trail resources, it would be less than under alternatives A, B, or D.
The Nez Perce NHT and Other Historic Trails would be affected by lands and realty management similar to Alternative A. As under the other alternatives, the survey required for NHPA Section 106 compliance in the case of either disposal or acquisition would result in a beneficial impact to cultural resources because of data that furthers understanding of trail resources in the Planning Area. Less acreage is available for acquisition under this alternative than under alternatives A, B, and D, with the result that there would be less survey and identification of potentially NRHP-eligible trail segments than under the other alternatives.
Under Alternative C, the management of linear resource uses (e.g., ROWs, corridors, renewable energy projects, and recreational trails management) would have greater impacts on the Nez Perce NHT and Other Historic Trails than actions under alternatives A, B, or D. Under this alternative, an NSO restriction is applied, similar to Alternative A, but a 1-mile CSU stipulation is also added to protect the Nez Perce NHT. The areas around the Nez Perce NHT are closed to mineral materials disposal within ¼ mile or in view within 1 mile, and motorized travel is limited to designated roads and trails in view within ¼ mile. Similar restrictions are applied to Other Historic Trails, except within existing utility corridors where the trail lacks integrity or the viewshed has been compromised. Some beneficial impacts would result from the inventory and identification of previously unrecorded segments. In all cases, adverse impacts must be mitigated in compliance with NHPA Section 106.
Improved access, due to fewer limitations on motorized vehicle use, has the greatest potential to result in indirect adverse impacts under this alternative. Similarly, recreational development is greatest under this alternative, potentially leading to the greatest adverse impacts. However, installation of educational kiosks, diversion of traffic away from the historic trail to alternative routes, and general improved education would have a beneficial impact.
Beneficial impacts from special designations would be lowest under Alternative C. Having fewer special designations and, fewer restrictions within those areas would reduce the benefits to NHTs and Other Historic Trails. Back country byways, which may indirectly affect historic trails resources through increased access, are managed similar to Alternative A.
As under the other alternatives, impacts from fire and fuels management would be primarily adverse. A greater emphasis on commodity production would increase the potential for adverse impacts. Alternative C would cause the most disturbance related to fire and fuels management compared to alternatives A, B, and D.
Under Alternative C, cultural and visual resources management would continue to result in both direct and indirect beneficial impacts to the Nez Perce NHT and Other Historic Trails, although the impacts would be less than under alternatives B and D. For example, motorized vehicle use is not limited by VRM class under Alternative C, whereas Alternative B restricts motorized vehicle use in these areas.
Proactive management actions under Alternative C would result in beneficial impacts to the Nez Perce NHT and Other Historic Trails. Under existing management, an NSO restriction is added within ¼ mile of the Nez Perce NHT and Other Historic Trails, and a CSU restriction is added within 1 mile of the Nez Perce NHT and Other Historic Trails. Exceptions occur where the trail’s integrity or setting has been compromised. Areas within ¼ mile or in view within 1 mile also are closed to mineral materials disposal, and motorized vehicle use is limited to designated roads and trails, which would reduce access and associated impacts. As with the other alternatives, because NHT and Other Historic Trails often comprise multiple traces, the buffer zones extend from the outer edges of the overall trace. The buffer zones and restrictions under Alternative C are less than those required under alternatives B and D, but more than under Alternative A.
The amount of surface disturbance projected under Alternative D is similar to Alternative A, falling between the amount of disturbance projected under alternatives B and C. As with Alternative A, actions that would directly affect these trails, particularly the Nez Perce NHT, would be limited due to buffer zones that restrict certain resource uses. In contrast to the other alternatives, Alternative D does not contain management specific to mineral leasing (e.g., NSO or CSU restrictions) or mineral materials disposal, instead controlling these uses through a more generalized management approach to mitigate their impacts. Under this alternative, the BLM avoids surface-disturbing activities and protects the foreground of the trails up to 3 miles where setting is an important aspect of the integrity of the trail, and uses BMPs to avoid or mitigate adverse impacts.
As with the other alternatives, required compliance with NHPA Section 106 before approving an action would reduce disturbance or adverse impacts to these trails. Additionally, the BLM and the SHPO consult to develop and implement a treatment plan to mitigate adverse impacts to contributing trail segments.
Restrictions on surface-disturbing activities for the protection of other resources (e.g., soil, water, biological resources, and special designations) under Alternative D would result in impacts similar to Alternative A.
The types of impacts from lands and realty management are anticipated to be similar to those described under Alternative A, though the intensity of these impacts would be less than under alternatives A or C, and more than under Alternative B. In all cases, compliance with the NHPA is still required.
The management of linear resource uses (e.g., ROWs, corridors, renewable energy projects, and travel and trails management) would result in fewer adverse impacts than Alternative A. Alternative D provides protection via a wider buffer zone than either alternative A or C, but less than Alternative B. For Other Historic Trails, motorized vehicle use is constrained or guided by other resource management actions and does not have trails-specific requirements, in contrast to alternatives B and C. As with the other alternatives, renewable energy presents a special situation, whereby the trails’ viewsheds are considered on a case-by-case basis, depending on the terrain. In all cases, adverse impacts must be mitigated in compliance with NHPA Section 106.
For other resource uses, including recreation and livestock grazing, impacts from management under Alternative D would be similar to those under Alternative A.
Alternative D designates more special designation areas and includes greater restrictions on surface-disturbing activity within these areas, resulting in a greater beneficial impact than alternatives A and C. In all cases, improved access also may indirectly lead to impacts. Although Alternative D has fewer back country byways than Alternative B, it has more than alternatives A and C, and may increase access to historic trails in the vicinity of the byways.
The impact of fire and fuels management would be similar to that under Alternative A. Alternative D protects cultural and visual resources somewhat less than Alternative B, but more than either alternative A or C, resulting in beneficial impacts to NHTs and Other Historic Trails.
Proactive management actions under Alternative D emphasize avoidance of surface-disturbing activities and protection of the foreground of the Nez Perce NHT and Other Historic Trails. For the Nez Perce NHT, Alternative D requires the avoidance of surface-disturbing activity up to 3 miles where setting is an important aspect of the integrity for the trail. BMPs are to be used to avoid or mitigate adverse effects for the Nez Perce NHT and all Historic Trail segments. Motorized vehicle use is limited to existing roads and trails within 5 miles of the Nez Perce NHT. For Other Historic Trails, the foreground is to be protected up to 2 miles, and motorized vehicle use is constrained or guided by other resource management actions. In addition, consideration of wider buffers may be necessary on a case-by-case basis for certain types of development, such as wind-energy developments. Because trails often comprise multiple traces, the buffer zone extends from the outer edges of the overall trace. These buffer zones are larger under Alternative D than alternatives A and C, but smaller than Alternative B.