Potential impacts to cultural resources are similar under all alternatives; however, the BLM anticipates that the intensity of impacts will vary. Therefore, impacts to cultural resources from surface-disturbing activities related to management of other resources are described for individual alternatives. Essentially, any activity that disturbs or has the potential to disturb the surface, regardless of the resource program with which the activity is associated, has the potential to affect cultural resources. Other types of disturbance also can affect cultural resources, including the adverse interaction of vibration impact, dust and airborne chemicals on rock art sites.
A number of management actions are common to all alternatives. These fall into several categories. Reactive actions include the investigation of all alleged violations of the Archeological Resources Protection Act; emergency site stabilization and long‐term protection projects on important sites as appropriate, including the Hanson Site and several rock art occurrences; and assignment of an archeologist to all fires with heavy equipment employed beyond Minimum Impact Suppression Techniques (see Glossary ) to assist in determinations of appropriate suppression strategies.
Native American consultation actions, which can affect how the BLM manages cultural resources, include continuing existing relationships and development of new relationships with Native American tribes to identify sites, areas, and resources important to them; documenting and maintaining confidentiality of sites, areas, and resources worthy of protection and the incorporation of information obtained from the tribes into the planning system; identifying resource conflicts in the earliest stages; avoiding these conflicts whenever possible; and managing identified areas of tribal importance to minimize disturbance to them and to ensure continued access. The BLM must ensure that areas important to Native American communities are not transferred from federal ownership, physically modified, or affected by management actions in ways that restrict or deny access and/or use. The BLM also must inventory potentially sensitive cultural places identified during Native American consultations independent of specific land use actions and apply tools (such as site avoidance and buffer areas) to protect sensitive cultural sites, as necessary.
Under all alternatives, all cultural properties will be categorized according to the six use allocations defined in BLM Manual 8110 (BLM 2004d) – scientific use, conservation use, public use, traditional use, experimental use, and discharged from public use.
Under all alternatives, compliance with NHPA Section 106 before an action is approved serves to moderate the amount of actual disturbance to cultural resources. In cases in which there can be no accommodation, the BLM and the SHPO consult to develop and implement a treatment plan to mitigate adverse impacts to historic properties. Often, this results in data recovery, which can take the form of planned excavation, detailed recording and mapping, or Historic American Buildings Survey/Historic American Engineering Record documentation. Other options include interpretation, one of many techniques that can be used for impact mitigation, depending on the type of site and the nature of the potential adverse impacts.
Exploration and development of locatable minerals may result in adverse impacts to cultural resources from the discovery and inadvertent destruction or degradation of cultural resources during project activities. Current regulations require operators to notify the BLM if cultural resources are discovered to reduce potential impacts to those resources. Under current policy, the BLM must allow mining operations to proceed within 10 working days after notification to the authorized officer of a discovery of cultural resources that might be altered or destroyed on BLM-administered lands by operations (43 CFR 3809.420(b)(8)(ii)). This requirement also applies to not only a plan of operations that requires an approval of an action, but also for operations under a 3809 notice, which does not require agency approval before commencing actions.
For all alternatives, the BLM identified proactive management actions that would have a beneficial impact on cultural resources. These actions include preparation of activity plans for important sites, as appropriate (including the Hanson Site and several rock art occurrences), Ten Sleep Raid, Minick Sheep Camp Raid, historic trails (including the Bridger Trail), and the Fort Washakie to Red Lodge stage route; management of the Legend Rock Petroglyph Site for public education in cooperation with the state of Wyoming; and initiation of work to acquire the private land portions of the Legend Rock Petroglyph Site from willing landowners, preferably through a land exchange. The BLM also will develop additional cultural resource interpretive sites employing scenic overlooks, signs, and walking trails. Surface‐disturbing activities associated with the construction and use of sites and facilities are subject to appropriate mitigation developed through implementation of the National Programmatic Agreement (BLM, Advisory Council on Historic Preservation, and National Conference of State Historic Preservation Officers 1997) and the State Protocol (BLM and Wyoming SHPO 2006). Based on analysis and assessment, the BLM may need to apply additional restrictions beyond those specifically described in the alternatives.
Proactive management actions that protect cultural resources include prohibiting the use of bulldozers in areas of significant cultural resources or historic trails for fire suppression unless an archeologist is present, and restricting or prohibiting the use of fire-retardant chemicals to protect rock art. All alternatives apply an NSO restriction on the Legend Rock Petroglyph Site and pursue withdrawals on a case-by-case basis for the protection of important cultural sites. The BLM also limits the use of motorized vehicles to designated roads and trails in areas with significant cultural and paleontological resources to reduce the potential for looting and resource degradation.
Any action that results in surface disturbance or subsurface disturbance (as identified in Appendix T) through culture-bearing strata may impact cultural resources. However, the net potential adverse impact to historic properties is limited because compliance with NHPA Section 106 requires the application of some type of mitigation to historic properties before any disturbance. The relative amount of surface disturbance projected for each alternative defines the level of potential to impact cultural resources. Under Alternative A, the BLM anticipates that impacts to cultural resources from surface-disturbing activities would increase with a greater intensity of surface disturbance, represented by the reasonable foreseeable actions shown in Appendix T. Moreover, the BLM anticipates that impacts to cultural resources from surface disturbance under Alternative A would primarily be adverse.
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 cultural resources.
Resource exploration, development, and extraction can result in a long-term, direct adverse impact. Associated resources in the Planning Area, including locatable minerals, leasable minerals, mineral materials disposal, and forest products, all can lead to surface disturbance that may affect cultural resources. In addition to the actions required to develop these resources, associated actions, such as the creation and use of roads and other utilities, may impact cultural resources. Dust and vibration from some methods of resource exploration can result in a direct impact to rock art. The dust accumulates on the panels and can degrade the paint, and vibrations from blasting can cause spalling and rock fall that also adversely affects rock art. The BLM anticipates that these actions will occur under Alternative A.
Under Alternative A, the BLM pursues leasable mineral and mineral material restrictions to protect cultural resource sites on a case-by-case basis. The allowance for more case-by-case management under Alternative A, while providing discretionary protection, increases the chance of adverse impacts to cultural resources. Development of locatable minerals may result in adverse impacts to cultural resources if activities degrade or destroy resources. Pursuing mineral withdrawals would result in beneficial impacts to cultural resources by prohibiting mineral activities that may degrade or destroy resources. Under Alternative A, the BLM pursues withdrawals on a total of 174,354 acres.
Land exchanges may result in both beneficial and adverse impacts. The survey required for compliance with NHPA Section 106 in the case of either disposal or acquisition would result in a beneficial impact because of data that furthers understanding of cultural resources in the Planning Area. In addition, if the BLM acquires land with sensitive resources for the purpose of managing that resource, that would be beneficial. However, if historic properties are identified during the inventory, it may result in an adverse impact because once in private ownership, there are no protective measures for cultural resources. For that reason, Section 106 classifies land-tenure adjustment as an adverse impact. Alternative A identifies 116,800 acres as available for disposal, resulting in the potential for adverse impacts.
Any resource use that includes road development has the potential to result in direct impacts to cultural resources because the road may pass through or over a site. These resource uses may include any resource use already mentioned, but also invasive species and pest management, CTTM, and recreation. An indirect impact from this type of development occurs when the road provides access to a previously remote and/or inaccessible location. People who gain access may inadvertently damage fragile resources, or may vandalize or loot sensitive sites, particularly rock art and rock shelters. The BLM anticipates that Alternative A would result in 3,199 acres of short-term disturbance from new road construction and motorized vehicle use (Appendix T).
ROWs and corridors, renewable energy, CTTM, and recreation can result in similar impacts. The linear nature of corridors means they can reach far into areas where remoteness previously provided protection for the cultural resources. Balancing the needs of recreation with preservation presents a challenge because increased recreational use of an area exposes the cultural resources there to inadvertent damage and potential vandalism and looting. Under Alternative A, the BLM manages 941,778 acres as ROW avoidance/mitigation areas and 61,416 acres as ROW exclusion areas. Renewable energy development is considered on a case-by-case basis, consistent with applicable policy and guidance and other resource management objectives, including cultural resource objectives. CTTM designations that place fewer restrictions on access to portions of the Planning Area, such as limiting travel to existing roads and trails (2,332,355 acres under Alternative A), would result in indirect adverse impacts to cultural resources by increasing the possibility of looting and vandalism. In contrast, CTTM that places greater restrictions on the routes available for use (e.g., limiting travel to designated roads and trails; 787,626 acres) or closes these routes altogether (59,192 acres) may reduce such impacts. Prohibiting and avoiding surface-disturbing activities in specified recreation areas would benefit cultural resources.
Livestock trampling and wallowing in areas of concentrated livestock use can directly affect cultural artifacts and features on or just below the surface by breaking or scattering these artifacts. Placing salt blocks increases the local adverse impact because cows lick the soil as the salt block melts into the ground. Alternatively, cattle trails and other heavily trampled and exposed areas can unearth otherwise undetected cultural resources and allow them to be identified and recorded, resulting in a beneficial impact. However, in most cases concentrated livestock grazing would result in adverse impacts. Properly managing livestock grazing can mitigate these impacts by improving the distribution of livestock and reducing instances of concentrated use by these animals. Restrictions on livestock grazing also can help reduce impacts by limiting the area in which livestock can graze, and closures under Alternative A would generally benefit cultural resources. However, even in areas closed to livestock grazing, the presence of wildlife or wild horses may result in some impacts from trampling and wallowing.
Under Alternative A, the BLM manages three ACECs (Sheep Mountain, Little Mountain, and Upper Owl Creek) for their cultural values (among other values). Managing these areas as ACECs would provide additional protection to cultural resources and reduce the potential for adverse impacts.
Management actions related to other resources have the potential to impact cultural resources. As discussed above, compliance with BLM regulations and guidance and NHPA Section 106 would prevent some of the impacts and mitigate others. However, impacts are still possible, and most would be adverse. There may be some beneficial impacts. For example, standards for air quality that reduce dust and chemicals in the air would reduce adverse impacts to rock art and improve the viewshed for cultural resources where setting is an integral part of NRHP eligibility. Similarly, protecting cave and karst resources would benefit cultural resources in these areas.
Fire, fuels, and vegetation management may result in adverse or beneficial impacts. Protecting resources from fire reduces adverse impacts from heat, such as spalling at rock art sites. Protecting resources from fire also protects against the loss of vegetative cover, which protects cultural resources from the effects of erosion and provides camouflage for sensitive resources, protecting them from inadvertent and purposeful damage. However, fire management also can result in adverse impacts from loss of cover, firebreak construction, clearing vegetation, and revegetation activities (e.g., reseeding) and deployment of fire retarding chemicals. Prescribed fire is used on approximately 40,000 acres in the Planning Area over the life of the plan.
Wild horse management under Alternative A allows visitor access to HMAs and recreational use of some HMAs, which may result in greater access to remote areas and put cultural resources at risk.
Under Alternative A, the BLM manages cultural resources proactively in compliance with BLM regulations and guidelines and the NHPA. The BLM strives to meet its Section 110 responsibility through inventory, and Section 106 compliance through identification, evaluation of cultural resources and mitigating impacts to those resources. Proactive management includes further exploration of the Hanson site, with the goal of nominating it as a National Historic Landmark. Alternative A emphasizes the management of rock art and other archeological sites for research and interpretation, and for preservation for future study. As previously noted, this alternative pursues restrictions on leasable minerals to protect sites on a case-by-case basis and takes similar actions for mineral materials disposal and the location of renewable energy development.
Alternative A manages portions of the town of Gebo and adjacent coal mining areas for preservation and interpretation of cultural and historic values and emphasizes management of historic oil and gas fields for scientific and public use.
As for all the alternatives, any action that results in surface disturbance or subsurface disturbance through culture-bearing strata may affect cultural resources. Overall, Alternative B would involve the least surface disturbance; therefore, it would result in the fewest impacts to cultural resources associated with surface and subsurface disturbances.
Under Alternative B, there are more restrictions on surface-disturbing activities for the protection of other resources (e.g., soil, water, biological resources, and special designations), providing additional protection for cultural resources and reducing adverse impacts. Paradoxically, because less surface disturbance would result in less Section 106 compliance and therefore less cultural resources surveying, the beneficial impacts from such surveys would be lowest under this alternative.
Activities associated with resource exploration, development, and extraction that can have a long-term, direct adverse impact on cultural resources will be less under Alternative B than under the other alternatives. Not only will these activities be reduced from Alternative A, Alternative B provides more avoidance protection, including larger buffer zones (see the Proactive Management section, below).
Alternative B applies an NSO restriction for leasable minerals within 3 miles of important cultural sites and a CSU stipulation within 5 miles, in contrast to management under Alternative A, which pursues restrictions on a case-by-case basis. Alternative B also provides a larger buffer zone than Alternative D, which protects the foreground of important cultural sites up to 3 miles where setting is an important aspect of the integrity of the site, and Alternative C, which applies an NSO restriction within ¼ mile of important cultural sites and a CSU stipulation within 1 mile of important cultural sites. Under Alternative B, mineral materials disposal are prohibited within 3 miles or in view within 5 miles of important cultural sites. These mineral restrictions would benefit cultural resources by prohibiting surface disturbance from mineral activities in areas with cultural sites or resources that may degrade or destroy these resources. Impacts to cultural resources from locatable mineral development would be similar to those described for Alternative A, although to a lesser degree because withdrawals are pursued in more area (325,102 acres) than under Alternative A.
The types of impacts from land exchanges under Alternative B are the same as those under Alternative A, although the intensity varies by alternative. Under all alternatives, land available for disposal would be surveyed for the presence of cultural resources, but after disposal it would not necessarily be protected from adverse impacts. Alternative B identifies more area for disposal (including special disposal and disposal for specific uses) than Alternative A, resulting in a greater potential for adverse impacts. However, the BLM expects that most adverse impacts associated with land tenure adjustments would be mitigated through Section 106 compliance and because disposal in areas available for special disposal (Zones 1B and 1C; most of the area available for disposal under Alternative B) would occur only rarely and only under special circumstances.
As described for Alternative A, any resource use that includes road development can result in direct impacts to cultural resources. The BLM anticipates that Alternative B would result in the least amount of new road construction compared to the other alternatives, with the result that Alternative B would result in the fewest impacts to cultural resources.
The types of impacts associated with ROWs and corridors, renewable energy, CTTM, and recreation are the same as described for Alternative A, although the intensity varies under Alternative B. Alternative B is anticipated to result in fewer ROW authorizations than the other alternatives and a greater degree of ROW consolidation to limit impacts. In contrast, it has more than twice the trails and recreational development of Alternative A, but half that of Alternative D, and about one-fifth that of Alternative C. The BLM manages areas within 5 miles of trails and sites eligible for the NRHP and traditional cultural properties (TCPs) as renewable energy (specifically, wind turbine) exclusion areas, unless the structures are screened from the site by intervening topography. Under Alternative B, this requirement is more specific and more protective of these resources than under Alternative A, which has no specific management for such development and manages it on a case-by-case basis. CTTM under Alternative B includes a greater amount of area limited to designated road and trails or closed (2,054,228 acres and 136,474 acres respectively), and less area limited to existing roads and trails than under Alternative A. Adverse impacts from looting and trespassing due to increased access may be less under this alternative than Alternative A.
The types of impacts from livestock grazing under Alternative B are similar to those described under Alternative A, although grazing under Alternative B has more restrictions than all the other alternative, resulting in less potential for adverse impacts to cultural resources.
Under Alternative B, the BLM manages the three Alternative A ACECs that include cultural resources among their values of concern (Sheep Mountain, Little Mountain, and Upper Owl Creek) and expands the Carter Mountain ACEC to include cultural resources. Expansion of the Carter Mountain ACEC would result in the greatest beneficial impacts to cultural resources in relation to other alternatives, particularly Alternative C, under which the BLM does not manage any of the previously mentioned areas as ACECs.
In contrast to Alternative A, under Alternative B, the BLM designates all LWCs as Wild Lands and manages them to protect their wilderness characteristics, which would benefit cultural resources by limiting access and travel, imposing more restrictive VRM, and limiting minerals leasing. The only action in Wild Lands that results in direct impacts to cultural resources is the restriction that excavation of cultural resource sites is allowed only where scientific information would be collected under permit, with minimum site disturbance.
As described for Alternative A, management actions related to other resources have the potential to result in both adverse and beneficial impacts to cultural resources. Measures that protect other resources and that may, in turn, protect cultural resources are similar under all four alternatives, with slightly more protection under Alternative B than under the other alternatives.
Impacts from fire and fuels management under Alternative B would be similar to those under Alternative A. However, under Alternative B, the BLM would initiate less prescribed fire than under any of the other alternatives; therefore, Alternative B would present less potential for adverse impacts. The same is true for silvicultural treatments and timber harvesting, both of which would occur less frequently under Alternative B, resulting in less potential for adverse impacts.
Wild horse management under Alternative B includes more restrictions to HMAs than under the other alternatives, which would have the added beneficial impact of limiting access to remote areas that may contain significant cultural resources.
In addition to the BLM managing cultural resources in accordance with its regulations and federal laws, Alternative B would augment existing plans and add a number of proactive measures. The overall approach would implement projects for the investment of maximum cultural resources protection. For further exploration of the Hanson site with the goal of nominating it as a National Historic Landmark, Alternative B would identify and test other deposits of similar age to determine the full extent of Folsom-age deposits. Compared to the Alternative A emphasis on managing rock art and other archeological sites for research and interpretation, and preservation for future study, Alternative B would explicitly avoid surface-disturbing activities and ROW authorizations in view within 5 miles of important cultural sites where integrity of setting is a contributing element of NRHP significance, except within designated utility corridors. In contrast to the case-by-case management approach under Alternative A, Alternative B applies an NSO restriction for leasable minerals within 3 miles and a CSU stipulation in view within 5 miles of important cultural sites, and follows a similar plan for mineral materials disposal. Alternatives B, C, and D identify exclusion areas for renewable energy development. Alternatives B and C also impose visual restrictions, depending on the topography, for sites eligible for the NRHP (including trails) and TCPs; Alternative A does not, and Alternative D specifies that important sites must have setting as an important aspect of their integrity. On a case-by-case basis, visual restrictions may exceed the 5-mile buffer to avoid adverse impacts to cultural resources, where structures are not screened from the resource by intervening topography.
Under Alternative B, the BLM manages portions of the town of Gebo and adjacent coal mining areas for preservation and interpretation, emphasizing a pedestrian trail rather than a road, thereby reducing access and associated indirect adverse impacts. This alternative also will provide comprehensive information about the site on the BLM website.
Finally, under Alternative B, the BLM limits motorized vehicle use to designated roads and trails on BLM‐administered land along the Bighorn Slope, Bridger, Owl Creek, and Absaroka foothills to manage (minimize issues such as looting) for cultural and paleontological resources. Alternative B is similar to alternatives C and D in terms of travel restrictions. Alternative A, which does not restrict motorized vehicle use in these areas to designated roads and trails, provides less protection than Alternative B.
Alternative C allows the most surface disturbance compared to the other alternatives, with the consequence that there would be the greatest potential for disturbance of cultural resources. As with the other alternatives, however, potential adverse impact to cultural resources would be limited through compliance with NHPA Section 106.
Because Alternative C places more emphasis on resource use, there are fewer restrictions on surface-disturbing activities for the protection of other resources (such as soil, water, biological resources, and special designations), so that although there is some additional protection for cultural resources, it is less than under the other alternatives. However, the potential for more surface-disturbing activities under Alternative C also may result in the identification of more cultural resources and their subsequent protection than under any of the other alternatives.
Actions associated with resource exploration, development, and extraction are the most extensive and would have the greatest adverse impact on cultural resources under Alternative C. For leasable minerals, Alternative C applies an NSO restriction within ¼ mile and a CSU stipulation within 1 mile of important cultural sites. Similarly, there is a prohibition on mineral materials disposal within ¼ mile, or in view within 1 mile of these sites. Under Alternative C, adverse impacts to cultural resources from management of mineral leasing and mineral materials disposal would be similar to those under alternatives B and D, although to a greater degree because of the smaller area of restriction around important cultural sites. Impacts to cultural resources from locatable mineral development would be similar to those described for Alternative A, although to a greater degree because withdrawals are pursued over a smaller area (47,846 acres) than under the other alternatives.
The types of potential impacts due to land exchanges under Alternative C are the same as those for the other alternatives. The survey required for compliance with NHPA Section 106 in the case of either disposal or acquisition would result in a beneficial impact because of data that furthers understanding of cultural resources in the Planning Area. However, more area is identified for disposal (including special disposals and disposal for specific uses) and less area is identified for retention than under any other alternative, resulting in the greatest potential for adverse impacts.
Alternative C results in more road and trail construction, thereby accommodating more recreational and other uses in the Planning Area than under the other alternatives, exposing more cultural resources to impacts. For example, managing the Basin Gardens Play Area as open to cross-country motorized travel would expose known cultural sites to potential damage caused by off-trail motorized recreation.
Under Alternative C, the types of impacts associated with ROWs and corridors, renewable energy, and recreation would be the same as described for Alternative A, although the intensity would vary; impacts from CTTM would be the same as described for Alternative B. Alternative C is projected to result in the greatest extent of ROWs development, potentially providing the most potential survey acreage and the most access to previously remote cultural resources. The location of renewable energy development is subject to similar restrictions, but compliance with NHPA Section 106 may impose greater visual restrictions to reduce the visual impact of developments such as wind farms on all types of sites, including sites of importance to Native Americans, NRHP-listed and/or eligible sites, and trails. CTTM designations under Alternative C are similar to Alternative A except that a greater area is open to cross-country motorized travel (14,873 acres compared to 1,320 acres) and a smaller area is closed to travel, which may increase impacts in certain areas under this alternative.
Livestock grazing under Alternative C has the least restrictions and therefore the greatest potential adverse impact.
Under Alternative C, the BLM would not manage the Sheep Mountain, Little Mountain, and Upper Owl Creek areas as ACECs, removing any beneficial impacts to cultural resources from the application of restrictions on surface-disturbing activities specific to these special designations.
Under Alternative C, management for resources (e.g., soils and special status species) is less restrictive than under the other alternatives, which may result in the greatest impact on cultural resources by increasing resource use and the potential for degradation of cultural resources.
Impacts from fire and fuels management and vegetative treatments would be similar to those for alternatives A and D, although there is greater disturbance from prescribed fire under Alternative C than the other alternatives. The same relation is true for forest, woodlands, and forest products.
Wild horse management under Alternative C is similar to alternatives A and D, and applies fewer recreational restrictions that allow more access to HMAs than under Alternative B. Management under this alternative may result in greater access to remote areas, which may put cultural resources at increased risk than under Alternative B.
Proactive management under Alternative C is closer to that under Alternative B than under Alternative A, reflecting current understanding of the importance of cultural resources and the potential impacts of other management actions. Proactive measures include further exploration of the Hanson site and nearby deposits, although Alternative C does not seek World Heritage nomination. Alternative C also emphasizes management of rock art and other archeological sites for research and interpretation, but imposes a smaller buffer zone than alternatives B or D, avoiding ROW authorizations in view within ¼ mile of important cultural sites where integrity of setting is a contributing element of NRHP significance, except within designated utility corridors. As previously mentioned, management of mineral leasing and mineral materials disposal under Alternative C results in smaller buffers than under alternatives B and D. Alternative C imposes visual restrictions, depending on the topography, within 5 miles of sites eligible for the NRHP and TCPs, and specifies avoidance/mitigation areas (in contrast to the exclusion areas under Alternative B), unless structures are screened from the site by intervening topography.
Under Alternative C, the BLM manages portions of the town of Gebo similar to alternatives A and D. Alternative C also emphasizes interpretation of historic oil and gas fields, providing interpretive signs in safe viewing areas, which would increase beneficial impacts to these historic resources compared to alternatives A or B. Alternative C emphasizes implementation of projects for the investment of maximum public recreation and access to cultural sites, subject to consultation and required resources protection, in contrast to Alternative B, which stresses resources protection. Overall, this may result in greater adverse impacts to cultural sites in relation to other alternatives. As with Alternative B, Alternative C would restrict motorized vehicle use to designated roads and trails on BLM-administered land along the Bighorn Slope, Bridger, Owl Creek, and Absaroka foothills to minimize issues such as looting.
Although Alternative D allows more surface disturbance than alternatives A or B, it results in approximately half the disturbance of Alternative C (Appendix T); there is more potential to disturb cultural resources under this alternative than under alternatives A or B, but considerably less than under Alternative C. As with the other alternatives, adverse impacts to historic properties would be limited through BLM compliance with NHPA Section 106.
Restrictions on surface-disturbing activities for the protection of other resources (such as soil, water, biological resources, and special designations) would provide additional protection for cultural resources on a level overall greater than under Alternative C, and similar to that under alternatives A and B.
Impacts from resource exploration, development, and extraction under Alternative D would be similar to impacts under alternatives A and C. Restrictions on mineral leasing and mineral materials disposal are more stringent than under Alternative C, but less restrictive than Alternative B in relation to determining the importance of setting and the use of BMPs to avoid or mitigate adverse impacts. As with the other alternatives, withdrawals would benefit cultural resources by prohibiting mineral activities that may degrade or destroy resources. Under Alternative D, withdrawals would be less than under all other alternatives except Alternative C.
Under Alternative D, beneficial and adverse impacts from land exchanges are the same as for other alternatives, with beneficial impacts resulting from information gathered through compliance with Section 106 and adverse impacts resulting from the loss of mandatory compliance with NHPA once the land has left public ownership. Alternative D allows disposal on more land than Alternative B, but less than alternatives A and C; the adverse impacts from disposal under Alternative D also are less than under alternatives A and C and more than under Alternative B.
Linear projects that include ROWs and corridors, renewable energy, CTTM, and recreation can result in similar adverse impacts. Potential adverse impacts from ROWs for road development are similar to impacts under Alternative A, but less than under Alternative C (Appendix T). Managing more area as ROW avoidance/mitigation or exclusion areas than under Alternative A may consolidate ROWs and limit adverse impacts to cultural resources to a greater extent. However, the affected area from open cross-country motorized travel under Alternative D is greater than under alternatives A or B, and approximately half that under Alternative C. CTTM designations under Alternative D are similar to Alternative A, but limiting off-road travel to within 300 feet of roads and trails would limit route proliferation and associated impacts to cultural resources. Additionally, management under Alternative D limits motorized vehicle use to existing roads and trails along the Bighorn Slope, Bridger, Owl Creek and Absaroka foothills. As for alternatives B and C, management of these areas is designed to minimize looting and facilitate management of cultural resources; however, management of motorized travel in these areas under Alternative D is less restrictive than under alternatives B and C and would result in fewer beneficial impacts to cultural resources.
Under Alternative D, impacts from livestock grazing would be similar to those under Alternative A, with management focused on maximizing multiple use while requiring buffer zones and managing livestock grazing to support other resource uses. Furthermore, Alternative D would mitigate new resource uses to minimize or avoid conflicts with livestock grazing where appropriate. Alternative D presents more potential for adverse impacts than Alternative B because of the much smaller area closed to livestock grazing and greater reliance on case-by-case evaluations of impacts.
As for Alternative A, under Alternative D, the BLM would manage the Sheep Mountain Anticline, Little Mountain, and Upper Owl Creek areas as ACECs for their cultural values (among other values), and would manage the Little Mountain ACEC expansion area discussed for Alternative B as the Craig Thomas Little Mountain SMA. Unlike Alternative B, Alternative D would not expand the Carter Mountain ACEC. Management of these areas as ACECs or SSMAs provides additional protection for cultural resources and reduces the potential for adverse impacts.
Under Alternative D, the BLM designates 52, 485 acres as Wild Lands and manages them to maintain their wilderness characteristics. Similar to Alternative B, this management would benefit cultural resources by limiting access and travel, imposing more restrictive VRM, and limiting minerals leasing. Adverse impacts to cultural resources would result from restrictions on the excavation of cultural sites in Wild Lands.
Fire and fuels management under Alternative D is similar to that under Alternative A and provides fewer restrictions than Alternative B. Prescribed fire would be implemented on approximately 40,000 acres in the Planning Area over the life of the plan.
Wild horse management under Alternative D is similar to that proposed under Alternative B. Alternative D promotes public viewing and education, similar to Alternative C. However, compared to Alternative C, Alternative D limits access and SRPs to some areas, providing additional protection to remote areas that may contain significant cultural resources.
As with alternatives B and C, Alternative D proactively recognizes the current understanding of cultural resources management practices. Proactive measures are a mix of alternatives A, B and C. The BLM would investigate and nominate the Hansen site as a National Historic Landmark, but would not pursue World Heritage nomination. Rock art and other prehistoric and historic sites and districts are managed for scientific, public and sociocultural use, and research and preservation for future study and use. Known important cultural sites are protected from surface-disturbing activities. For resources where setting is important to the site’s integrity, the site’s foreground is to be avoided (in contrast to prohibited under Alternative B) with buffers that may be up to 3 miles wide. This buffer is smaller than the buffer under Alternative B, but larger than the buffers under alternatives A and C, and applies to mineral leasing and mineral materials disposal actions for all site types (e.g., trails, sites eligible for the NRHP, and TCP). In addition, implementing BMPs would avoid or mitigate adverse effects.
Similar to Alternative B, Alternative D implements projects for the investment of maximum cultural resource protection, but is more similar to Alternative C in its management of historic resources in oil and gas fields, including the installation of interpretive signs. Under Alternative D, the BLM would manage the town of Gebo and adjacent coal mining areas as it would under Alternative A.