Because cultural resources are fragile, often unique, nonrenewable resources that occupy relatively small areas, almost any management action has the potential to affect the resource. Actions under each alternative may directly or indirectly affect cultural resources, and impacts may be beneficial or adverse. Except for setting, there is little distinction between short- and long-term impacts. Section 4.7.4 National Historic Trails and Other Historic Trails in this chapter analyzes historic trails in detail. This section and Section 4.8.5 Tribal Treaty Rights identify Native American concerns.

Direct adverse impacts to cultural resources from RMP alternatives typically result from actions that disturb the soil or physically alter, damage, or destroy all or part of a resource; alter characteristics of the surrounding environment that contribute to resource significance; introduce visual or audible elements out of character with the property or alter its setting; or result in neglect or physical exposure of the resource to the extent that it deteriorates or is destroyed. Surface-disturbing activities would result in direct adverse impacts because, once a cultural resource has been disturbed, it cannot be replaced and the potential for collecting or preserving meaningful data is compromised. Actions resulting in data collection and preservation of cultural resources are considered to be neutral or not adverse impacts, as the actions merely maintain the status quo. Indirect impacts to cultural resources result from project-induced increases or decreases in activity in the Planning Area, such as an interpretive area that increases visitor use. A beneficial impact to cultural resources enhances their value (for example, constructing interpretive signs). Paradoxically, the same actions that can result in direct or indirect adverse impacts also may result in beneficial impacts. The discovery of previously unknown cultural resources, or the facilitation of data collection, preservation, or public education are possible beneficial impacts.

Once a cultural resource is physically altered, the impact is permanent; therefore, there is no difference between short- and long-term direct impacts from surface disturbance. Stabilization can halt deterioration, and restoration may be possible in unique situations; however, the disruption of cultural deposits on archeological sites and the deterioration of rock art, for two examples, are irreversible. For indirect impacts, the duration of a disturbing element or activity can be short or long. As examples, a pipeline construction corridor that results in erosion to or deposition on a cultural resource may be a short-term disturbance, because normal reclamation ultimately stabilizes the soil. A disturbance lasting more than 5 years is considered long-term.

The BLM complies with NHPA Section 106 for all actions with the potential to adversely impact historic properties (cultural resources eligible for listing or listed on the National Register of Historic Places [NRHP]). Section 106 compliance typically includes a cultural resources inventory and evaluation of any resources found. If historic properties are present, the BLM consults with the State Historic Preservation Office (SHPO), interested Native American tribes, and other interested parties to develop measures to mitigate adverse impacts to affected historic properties.

Under all alternatives, the BLM continues its obligation to engage in government-to-government consultations with interested tribes regarding sensitive resources in the Planning Area. Impacts to Native American traditional resources or sacred sites are identified in consultation with the affected tribes. Alterations to the important characteristics of traditional or sacred resources can adversely impact traditional use of the area. While temporary disturbances, such as construction activities, may not be of major concern, long-term increases in noise, changes in visual setting and smells, and increases in motion and activity, all have the potential to detract from a site’s setting. In addition, physical impacts to traditional or sacred sites and limitations on tribal access can impact traditional uses.

The BLM initiated contact with the following tribes, listed alphabetically, to identify potential impacts of the alternatives to sites of cultural concern on BLM lands: