The following analysis focuses on potential short-term and long-term impacts to surface water and groundwater quality and quantity as a result of allowable uses and management actions proposed under each alternative. The proposed management of the following resource programs has the highest potential to beneficially or adversely affect water resources: locatable minerals, oil and gas (including, but not limited to the handling of produced water), soils (including restoration of healthy plant communities), fish and wildlife, CTTM, livestock grazing, and ACECs and other special designations. Other resource programs that have the potential to affect water resources include recreation (particularly the recreational use of OHVs), ROW improvements, watershed enhancement, invasive species, and forests, woodlands, and forest products (though these activities are usually small scale and do not totally denude the surface or alter root masses). Emphasis on the Wyoming Standards for Healthy Rangelands (Appendix N) would moderate impacts to water resources.
The principal factors used to differentiate between alternatives are the acres of projected surface disturbance for each alternative and the limitations of allowable uses and management actions. Alternatives with higher projected disturbance areas may lead to greater potential impacts to surface and groundwater (as described below under Impacts Common to All Alternatives). Similarly, greater or fewer allowable uses under an alternative would lead to a similar change in the potential for impacts to surface and groundwater. Due to the programmatic nature of the RMP alternatives, the timing and specific location of project actions that may affect resources are not defined. Alternative A is the primary point of comparison for all other alternatives.
Actions that remove vegetation and loosen surface soil may cause surface runoff, resulting in soil erosion and sedimentation in the surface water system. Eroded soil that reaches surface water channels is a principal source of impaired surface water quality. The amount of sediment delivered to a stream depends on many factors (e.g., slope length and gradient, vegetative cover and type, and density of the drainage network), all of which may result in deposition of the sediment before it reaches a drainage (also called buffering). For example, large runoff events can lead to gully erosion, which can deliver large amounts of sediment in a small period.
Analysts used the WEPP analysis model, described in Section 4.1.3 Soil of this chapter, to estimate average runoff as a result of surface disturbances in the Planning Area. Analysts used the same assumptions they used to estimate soil erosion (see Section 4.1.3 Soil and Appendix V) to calculate the mean annual average runoff. The WEPP model estimates that areas affected by short-term surface disturbance would experience 0.34 inches of runoff per year. Once these areas are stabilized and reclaimed, the average runoff would drop to 0.19 inches per year in the long term. In comparison, the WEPP model estimates that with no disturbance there would be only trace amounts of annual runoff. The scale of impacts from runoff is anticipated to vary by alternative based on the amount of surface disturbance anticipated under each alternative. Therefore, if there is more acreage of surface disturbance, there is more impact to water resources in the Planning Area.
The highest potential for long-term surface disturbance under all alternatives would result from the development of minerals, fire and fuels management, forest management, ROW development (roads, pipelines, and powerlines), motorized vehicle use, and recreational site development. Soil disturbance may also result from invasive species and pest management, motorized vehicle use, livestock and wildlife grazing, and the reclamation of disturbed areas. Alternatives with greater projected surface disturbance would result in increased sedimentation. Livestock and wildlife also may introduce fecal coliform, NO3, and sediment to surface waters, which would contribute to water quality impairment.
Roads intercept surface water runoff on the landscape and often direct flows to drainages through ditches and culverts. If roads are unsurfaced, runoff flowing down a road often picks up sediment that is then deposited in the surface water system at stream crossings or at culverts and water bars. Alternatives that increase the density of roads in a watershed, especially unsurfaced roads, may increase sedimentation. Roads may also act as conduits for directing contaminants from vehicles and resource management activities (e.g., pesticide applications) into the surface water system (Furniss et al. 2000).
Short-term and long-term surface disturbance (e.g., from oil and gas and other minerals development, or travel and transportation management) and herbivory within the Planning Area also may affect surface water quality. Those watersheds with the greatest proportion of highly erodible soils have the most potential for contributing sediment to the surface water system with the presence of surface-disturbing activities. Under all alternatives, implementation, inspection, and maintenance of BMPs and the development and implementation of Stormwater Pollution Prevention Plans, as required under the WYPDES Stormwater Program would minimize sedimentation within watersheds. Water management plans for surface discharges of produced water would include reclamation strategies, mitigation, and monitoring to track changes in receiving channels and to minimize adverse impacts to watershed health. The BLM monitors rangeland health to determine livestock grazing management actions necessary to control erosion and other water-quality issues, such as contamination by fecal coliform bacteria, that affect surface waters. Proper management of livestock grazing can mitigate sediment delivery from erosion. WYPDES permits required by the state of Wyoming would regulate water quality changes associated with point source discharges (Wyoming DEQ 2004).
Management that reduces the production of sediment (e.g., through the enhancement of vegetative ground cover, proper livestock grazing management, or watershed improvement projects that reduce sediment transport into waterways) would have a beneficial impact on efforts to reduce sedimentation of Bighorn Lake. A 2009 study by the Bureau of Reclamation (BOR) and U.S. Army Corps of Engineers states that implementing BMPs in the Bighorn Basin could reduce the total sediment load entering this reservoir. The study notes, however, that such an approach might not be a practical way to achieve substantial sediment reductions given conditions in the area, noting that it would require considerable time to achieve results noticeable in the northern portion of Bighorn Lake that are important for recreational access (USACE and BOR 2009).
The Wyoming DEQ permits surface discharges of produced water from oil and gas wells through a WYPDES permit that requires compliance with specific water-quality standards. The quality of produced water discharged on the surface must be suitable for designated uses, such as agriculture and livestock, and cannot result in a violation of water-quality standards in the receiving stream. Produced water discharged into streams generally is hotter than the naturally occurring surface water and, although it is subject to applicable Wyoming DEQ water quality standards, it can contain dissolved compounds that may affect water quality. Due to prolonged contact with the formations that contain oil and gas and contamination from chemical additives used in well drilling and production, this water may be more saline and contain higher concentrations of organic compounds (e.g., oil and other hydrocarbons) and various inorganic compounds than the receiving surface waters (Veil 2004). Adverse impacts on surface water quality from the introduction of these components of produced water would be minimized, but not eliminated, under all alternatives by following standard practices, BMPs, and guidelines for surface-disturbing activities. The properties of produced water can vary depending on the location of the producing well and the oil and gas formation, which will influence the application of BMPs and other measures intended to safeguard water quality.
When watersheds lack vegetation, surface infiltration into the soil decreases, causing more runoff to reach stream systems. As surface disturbance increases, so does the amount of bare soil, compacted soils, and possibly less-pervious areas in a watershed. As a result, more surface water runoff reaches streams in a shorter period of time, which increases the potential for sedimentation and the frequency of flooding or erosive velocities from high flows in channels. Conversely, activities such as reclamation would improve vegetative cover and would have a beneficial impact. Healthy vegetative cover increases infiltration of surface water flows, filters out sediment before it reaches drainages, reduces runoff, and lowers peak flows in the surface water system. Prescribed fire would reduce vegetation cover and increase sedimentation in the short term, but restoring fire-adapted ecosystems would increase vegetation cover and decrease the potential for large catastrophic fires in the long term. Concentrated grazing by livestock, wild horses in HMAs, and wildlife may contribute to soil compaction and damage to the vegetative cover and soil crust, thus increasing surface water runoff, erosion, and sedimentation.
Produced water from oil and gas wells sometimes is discharged to surface waters, thereby contributing to surface water flows. Beneficial impacts from produced water discharges include increased availability of surface water, although there may be adverse impacts from altering natural flow regimes, such as increased channel erosion. This would be the case under all alternatives, including Alternative B, under which the BLM would prohibit new surface discharge of produced water on public lands. Surface discharges previously authorized by the state of Wyoming would be allowed to continue.
Potential sources of groundwater contamination may come from point sources, such as chemical spills, chemical storage tanks (above ground and underground), industrial sites, landfills, household septic tanks, oil and gas well sites, oil and gas detention and retention ponds, well stimulation and hydraulic fracturing, and mining activities. Other possible sources of groundwater contamination may come from nonpoint sources, such as roadways and agricultural activities. Groundwater quality is most susceptible to pollution where the aquifer is shallow (within 100 feet of the surface), very permeable, or connected directly to a surface water system, such as river gravels. Produced water from oil and gas wells and, potentially, coalbed natural gas (CBNG) would have the greatest potential to affect groundwater quality and quantity where the wells are in areas with shallow depth to groundwater. Water produced from future CBNG wells in the Planning Area is expected to be of essentially the same quality and quantity as produced water from conventional or deep oil and gas wells.
Management actions that would protect or enhance water resources, regardless of the alternative, include, but are not limited to: using BMPs, watershed improvement and conservation practices, and Stormwater Discharge Plans to reduce impacts; restoring healthy plant communities and vegetative cover after surface disturbance in a timely fashion; conforming BLM actions to Wyoming DEQ water quality standards, enforcement, and remediation; and participating in the development and implementation of local watershed management plans and/or total maximum daily loads (TMDLs) with interested stakeholders and the Wyoming DEQ. The BLM designates the Spanish Point Karst ACEC under all alternatives, which would protect important groundwater recharge areas from surface-disturbing activities and other resource uses that may affect water quality.
The BLM projects approximately 15,710 acres of long-term surface disturbance from BLM-authorized actions and approximately 136,415 acres of short-term surface disturbance (Table 4-1). Surface-disturbing activities would result in adverse impacts to water quality due to erosion, runoff, sedimentation, and potential changes in the chemical characteristics of water resources. Erosion rates, calculated using the WEPP model (Appendix V), are estimated to be 568,166 tons per year in the short term. After reclamation, long-term erosion rates would average 25,167 tons per year. The BLM analyzes all surface-disturbing activities for suitability and potential impact, which may reduce adverse impacts from surface disturbances by allowing the BLM to impose additional mitigation to reduce erosion on some projects.
Resource uses such as locatable minerals operations, oil and gas operations, travel and transportation management, and livestock grazing may result in both direct and indirect adverse impacts to water resources. Direct adverse impacts resulting from such activities include accidental chemical releases and water disposal. Under Alternative A, the BLM allows the aerial application of pesticides near water on a case-by-case basis subject to label requirements, which would result in potential but limited direct adverse impacts to water quality. Indirect adverse impacts may result from surface disturbance, soil erosion, and resultant sedimentation. Alternative A would result in new roads from ROW development and user pioneered roads in areas open to cross-country motorized travel (Appendix T). The amount of new roads would result in proportional adverse impacts to soils, described under Impacts Common to All Alternatives. The BLM conducts the least extensive monitoring of grazing allotments under this alternative, which may result in less documentation of impacts to water quality, compared to the other alternatives. Alternative A prohibits the placement of salt, mineral, or forage supplements within ¼ mile of water, which would reduce the potential for soil compaction and vegetation removal adjacent to waterways from concentrated livestock grazing.
Under Alternative A, the BLM authorizes new activities resulting in the surface discharge of produced water if it meets state of Wyoming water quality standards. As described under Impacts Common to All Alternatives, such discharges would result in adverse impacts to surface water quality through the addition of sediment, heat, and chemical compounds and to groundwater quality and quantity through aquifer contamination and drawdown. Such discharges could increase in-stream flow, thereby benefitting surface water quantity.
Special designations, such as ACECs, would restrict surface-disturbing activities and resource uses that may adversely impact water quality and quantity, which generally would result in beneficial impacts to water resources. Under Alternative A, ACECs, WSAs, and WSR eligible waterways would encompass 49, 22, and 89 miles of streams, respectively. Due to their size and management, special designations under Alternative A would result in the third-greatest beneficial impact to water resources, compared to the other alternatives.
Reclamation requirements to manage soil resources would result in beneficial impacts to water quality in the short term by reducing erosion and associated sedimentation, and water quality and quantity in the long term by reestablishing vegetation to reduce runoff. Under Alternative A, the BLM routinely seeds, or requires permittees and operators to seed, disturbed areas with native plant species or approved seed mixtures and reestablishes vegetative cover over disturbed areas within 5 years of initial seeding, but does not require temporary protective surface treatments for mechanically disturbed areas. The BLM considers stabilization of heavily eroded or washed-out roads as well as trail stabilization on a case-by-case basis. These management actions would result in beneficial impacts to soils and ultimately water quality under Alternative A.
Alternative A would result in disturbance from fuels treatments and prescribed fire that would result in adverse impacts to surface water quality and quantity, but the small area of these treatments and the use of BMPs would minimize these impacts. Alternative A would also result in long-term beneficial impacts from restoring fire-adapted ecosystems by reducing the potential for catastrophic fires that may cause greater adverse impacts to water resources.
Forests, woodlands, and forest products may result in adverse impacts to water quantity and quality under Alternative A. The BLM allows clear cuts of up to 300 yards in any direction under this alternative. Clear cuts would increase sedimentation from increased erosion and runoff in clear-cut areas and result in adverse impacts to water resources. Spur roads generally are closed after completion of timber management, allowing vegetation to return, which would minimize long-term impacts to water resources from erosion in these areas.
To protect fish habitat, the BLM applies an NSO restriction and prohibits unnecessary and unmitigated surface-disturbing activities within 500 feet of surface water and riparian areas. This management would reduce adverse impacts to water quality from oil and gas development.
Proactive management actions under Alternative A that would result in beneficial impacts to surface water quality and quantity include implementing watershed improvement practices in Wyoming’s Bighorn Basin water quality plans, encouraging the maintenance of natural flow regimes in streams supporting fisheries, and fencing streams and reservoirs as necessary. This alternative also benefits surface water quality and quantity by stabilizing existing failed watershed improvement projects to benefit watershed stability and by assessing erosion and soil stability during rangeland health evaluations.
Over the long term, it is projected that BLM actions under Alternative B would disturb approximately 10,882 acres, the smallest area of disturbance of any alternative, and would result in 17,432 tons per year of soil erosion. Projected short-term surface disturbance would affect approximately 73,919 acres (Table 4-1), resulting in an average of 307,873 tons of erosion per year. Alternative B requires additional analysis of soils for erosion potential, and therefore more information to prevent erosion than the other alternatives, by requiring mapping of the soils in areas to be disturbed and elsewhere on BLM-administered lands to a series level, collecting soil samples, and evaluating current erosion conditions. Unlike alternatives A and C and similarly to Alternative D, reclamation plans are required prior to surface-disturbing activities, increasing the chances for successful reclamation and reducing the chances for watershed decline. Compared to the other alternatives, surface-disturbing activities under Alternative B would reduce the potential for erosion and sedimentation in surface waterbodies resulting in less impervious surface to diminish groundwater recharge.
Conservation measures under this alternative would improve water quality and quantity compared to the other alternatives by reducing erosion and sedimentation, and increasing infiltration. Under Alternative B, the BLM prohibits the aerial application of pesticides within ½ mile of aquatic habitats, which would result in the least potential for adverse water quality impacts, compared to the other alternatives. Alternative B would result in the least acreage of new roads from ROW development and user pioneered roads in areas open to cross-country motorized travel (Appendix T) with proportional adverse impacts to water quality described under Impacts Common to All Alternatives.
The BLM conducts the most extensive monitoring of grazing allotments, all those that do not meet the Wyoming Standards for Healthy Rangelands (Appendix N), which would result in the greatest beneficial impact to water quality by monitoring erosion. Alternative B prohibits the placement of salt, mineral, or forage supplements within ½ mile of water. The additional grazing constraints under Alternative B may reduce the potential for fecal coliform and NO3 reaching surface waters when compared to the other alternatives. In addition, reduced grazing in riparian areas under Alternative B would reduce erosion and sedimentation in surface waters, and reduced well development would reduce groundwater withdrawals when compared to all other alternatives.
Alternative B places the greatest restrictions on motorized vehicle use in the Planning Area of any alternative, which would result in the least potential vegetation removal, soil compaction, and fewest water crossings and associated adverse impacts to water resources.
Additionally, new surface discharge of produced water on public lands is prohibited, which would result in fewer potential adverse impacts to surface water quality and groundwater quality and quantity, and fewer beneficial impacts to surface water quantity than alternatives A, C, and D.
Alternative B designates an additional eight ACECs, the Absaroka Front Management Area and all LWCs as Wild Lands to protect their wilderness characteristics. Under this alternative, ACECs, WSAs, WSR eligible waterways, the Absaroka Front Management Area, and Wild Lands would encompass 62, 22, 89, 38, and 91 miles of streams, respectively. The relative size and additional restrictions on surface-disturbing activities and resource uses in these areas would result in additional protection for surface and groundwater versus alternatives A, C, and D.
Alternative B would result in the least adverse impacts to water resources from short-term surface disturbance because it applies the most stringent requirements to minimize erosion. The BLM reestablishes native plant communities in disturbed areas; requires temporary protective surface treatments of disturbed areas, such as mulch, matting, netting, or tackifiers; requires interim and final reclamation of disturbed areas at the earliest feasible time; and closes or relocates heavily eroded or washed out roads and trails. Specifically, Alternative B requires the reestablishment of 50 percent of pre-disturbance levels of desired vegetative cover within three growing seasons following surface disturbance and 80 percent within 5 years of initial seeding to prevent erosion.
Alternative B would result in the least disturbance from fuels treatments and prescribed fire. This disturbance would result in the least short-term adverse impacts to surface water quality and quantity, but the least long-term beneficial impacts of restoring fire-adapted ecosystems to reduce the potential for catastrophic fires.
Forests, woodlands, and forest products management practices under Alternative B would result in the least adverse impact to water resources. The BLM prohibits clear cuts and closes timber access and haul roads not required for existing uses, which would result in the least potential for erosion and sedimentation.
To protect fisheries and riparian/wetland areas, the BLM applies an NSO restriction and prohibits surface-disturbing activities within ¼ mile of riparian/wetland areas, any Wyoming Game and Fish Department (WGFD)-rated Class 1 or 2 waters, and many major rivers in the Planning Area. The BLM allows sediment reduction structures on a case-by-case basis. These management practices under Alternative B would reduce adverse impacts to water quality from oil and gas development the most, compared against the other alternatives.
Under Alternative B, the BLM manages water resources with an emphasis on conservation. Proactive management actions under Alternative B that would result in beneficial impacts to surface water quality and quantity include completing a greater number of watershed enhancement projects; maintaining natural flow regimes in priority streams; and cooperating with adjacent landowners and managers to address impaired waterbodies on the state of Wyoming 303d list. Watershed improvement projects are stabilized to prevent release of stored sediment if the project no longer meets resource objectives. Proactive management actions under Alternative B would result in the greatest beneficial impacts to water resources, compared to the other alternatives.
Long-term (41,545 acres) and short-term (245,783 acres) surface disturbance under Alternative C constitute more acreage than under the other alternatives (Table 4-1). Similarly, erosion rates under Alternative C are the highest among the alternatives. Erosion rates would average 1,023,686 tons per year in the short term and 66,555 tons per year in the long term, over twice as high as the long-term erosion rate under Alternative A. Additional analysis of soils for erosion potential, which is required under Alternative B, is performed only on a case-by-case basis under Alternative C, reducing the relative potential benefits to soils. The BLM requires reclamation plans only on a case-by-case basis, which may reduce the beneficial impacts of this action compared to Alternative B. Overall, Alternative C would have the greatest potential for erosion and sedimentation in surface waterbodies and result in the most impervious surface to diminish groundwater recharge.
Alternative C would have the most acreage available for surface disturbance when compared to the other alternatives, and, therefore, the greatest potential for adverse impacts to water resources among the alternatives. Alternative C prohibits the aerial application of pesticides within 100 feet of aquatic habitats, which would result in less potential water quality impact from the associated chemicals than alternatives A and D, but more than Alternative B. Alternative C would result in the most acreage of new roads from ROW development and user pioneered roads in areas open to cross-country motorized travel (Appendix T) with proportional adverse impacts to water quality described under Impacts Common to All Alternatives.
Potential impacts from grazing allotment monitoring would be similar to those under Alternative A. Alternative C allows the placement of salt, mineral, or forage supplements to maximize livestock use. This management action would result in the greatest potential impact to surface water from soil compaction and vegetation removal in riparian/wetland areas and from potential fecal coliform and NO3 introduction, compared to all other alternatives.
Alternative C would allow the most motorized vehicle use in the Planning Area, including the most acreage open to cross-country motorized travel, which would result in the greatest potential vegetation removal, soil compaction, and water crossings and the associate impacts to water resources.
Alternative C would result in the same types of adverse and beneficial impacts from produced water disposals as described under Impacts Common to All Alternatives and Alternative A. However, expanded oil- and gas-well development projected under this alternative would result in the greatest intensity of these impacts, because groundwater withdrawals would increase compared to the other alternatives.
Except for travel restrictions, Alternative C proposes no specific management for the Absaroka Front Management Area, and also designates fewer ACECs than alternatives A, B or D, manages all WSR eligible waterway segments as unsuitable for inclusion in the National Wild and Scenic Rivers System (NWSRS), and does not manage any LWCs to protect their wilderness characteristics. Under Alternative C, ACECs and WSAs encompass 20 and 22 miles of streams, respectively. Generally, Alternative C would protect fewer areas from surface-disturbing activities than the other alternatives and therefore would be the least beneficial to surface and groundwater.
To prevent erosion, Alternative C requires 30 percent of pre-disturbance vegetation cover within three growing seasons of initial seeding. However, unlike Alternative B, Alternative C does not institute long-term vegetation cover requirements. Alternative C would result in the greatest adverse impact to water resources from short-term surface disturbance due to the greater acreage disturbed under this alternative and because it applies the second-least stringent requirements to minimize erosion. Alternative C does require reclamation plans on a case-by-case basis and stabilizes heavily eroded or washed out trails, which are a major source of runoff and sediment.
Alternative C would result in the greatest disturbance from fuels treatments and prescribed fire. This disturbance would result in the greatest short-term adverse impacts to surface water quality and quantity, but would have the greatest long-term beneficial impact of restoring fire-adapted ecosystems to reduce the potential for catastrophic fires.
Forests, woodlands, and forest products management practices under Alternative C would result in similar impacts to water resources as under Alternative A. The BLM allows clear cuts of up to 100 acres (more area than under Alternative A) and permits timber access and haul roads to remain open to meet other resource goals and objectives, maintaining impervious surfaces in these areas.
Alternative C applies similar NSO restrictions as Alternative A, but allows surface-disturbing activities in floodplains or riparian/wetland areas on a case-by-case basis. These management practices under Alternative C would result in the greatest potential adverse impacts to water quality from oil and gas development, compared to the other alternatives.
Under Alternative C, the BLM manages resources with an emphasis on resource uses. This alternative manages for the stabilization of watersheds through maintenance of existing watershed improvement projects. Under Alternative C, the BLM does not implement or develop new watershed improvement practices and only fences springs and their associated wetlands. Overall, proactive management actions under Alternative C would result in the fewest beneficial impacts to water resources, compared to the other alternatives.
Under Alternative D, short- and long-term surface disturbance from BLM-authorized actions would disturb more acreage than alternatives A and B but less than Alternative C. Short-term surface disturbance of approximately 140,507 acres (Table 4-1) would result in an erosion rate of 585,214 tons per year. After reclamation, long-term surface disturbance (18,443 acres) would result in an erosion rate of 29,546 tons per year. Impacts from surface disturbance and erosion would be similar to those described under Alternative A although to a slightly higher degree due to more acreage of surface disturbance and greater erosion potential. However, more stringent reclamation standards and a requirement for reclamation plans, stipulations, or measures would provide a greater beneficial impact to surface water than both alternatives A and C by increasing the potential for successful reclamation and reducing the potential for long-term erosion. Soil and erosion evaluations are conducted in a similar manner as under Alternative A, although a slightly greater benefit may occur by conducting soil surveys as funds become available.
Alternative D allows more resource use that would result in greater surface disturbance than alternatives A and B, creating a greater potential for watershed health degradation than those two alternatives. However, for certain resource programs, such as minerals development, Alternative D is projected to result in less disturbance than alternatives A and C. The BLM allows the aerial application of pesticides near water on a case-by-case basis, which would result in the same impacts as Alternative A. Alternative D is estimated to result in more new roads from ROW development and user-pioneered roads than alternatives A and B, resulting in proportional impacts.
Potential impacts from grazing allotment monitoring would be similar to Alternative A. Alternative D prohibits the placement of salt, mineral, or forage supplements within ¼ mile of water, reducing the potential for adverse impacts from concentrated livestock grazing similarly to Alternative A.
Alternative D opens more area to cross-country motorized travel than alternatives A and B, creating mores areas that could be adversely affected by concentrated motorized vehicle use through increased runoff and erosion.
Disposal of produced water under Alternative D would be authorized for new activities where compatible with other resource objectives and in consultation with stakeholders. The impacts, both adverse and beneficial, from produced water disposals would be the same as those described under Impacts Common to All Alternatives and Alternative A. However, because the number of new federal wells projected under Alternative D would be less than under alternatives A and C, adverse impacts to water may be reduced overall.
Alternative D designates more acreage as ACECs than alternatives A and C, designates the Absaroka Front Management Area, and designates 52,485 acres of LWCs as Wild Lands, which would limit surface disturbance and adverse impacts to water in these areas. However, like Alternative C, Alternative D manages all WSR eligible waterway segments as unsuitable for inclusion in the NWSRS. Under this alternative, ACECs, WSAs, and the Absaroka Front Management Area would encompass 42, 22, and 44 miles of streams, respectively, which would provide greater beneficial impacts to water resources than alternatives A and C but less than Alternative B.
Alternative D would help to reduce erosion and subsequent sediment loading in streams by reestablishing native or desired plant communities in disturbed areas; requiring temporary protective surface treatments of disturbed areas when appropriate; requiring interim and final reclamation of disturbed areas at the earliest feasible time; and closing and reclaiming heavily eroded roads and trails if other stable roads and trails are available. While Alternative D does not specify timing requirements for achieving vegetative cover after surface disturbance, a potential adverse impact, it also does not consider successful final reclamation of vegetative cover to be achieved until conditions are equal to or better than pre-disturbance site conditions, a potential beneficial impact. Overall, measures to prevent erosion under Alternative D would result in a greater beneficial impact to surface water than under alternatives A and C, but less than under Alternative B.
Disturbance from fuels treatments and prescribed fire is projected to be the same as Alternative A with similar impacts.
In general, impacts from forests, woodlands, and forest products management would be similar to Alternative A. Spur roads would be assessed for closure on a case-by-case basis while clear cuts would be limited to 100 yards, potentially resulting in greater adverse impacts to surface water than under Alternative A by increasing runoff and erosion.
To protect riparian/wetland areas, the BLM applies an NSO restriction and manages to avoid surface-disturbing activities within 500 feet of riparian/wetland areas and up to ¼ mile if needed to protect sensitive resources, which would provide a greater beneficial impact to water than alternatives A and C. In addition, surface disturbance is avoided within ¼ mile of all WGFD-rated Class 1 or 2 fisheries, while all other fisheries are subject to a 500-foot buffer.
Proactive management actions that would benefit surface water quality and quantity include developing watershed improvement practices; applying BMPs to reduce sediment loading; and fencing streams, wetlands, reservoirs, and riparian areas as necessary. The BLM conducts the same amount of watershed enhancement projects as under Alternative A while also stabilizing existing watershed improvement projects to prevent the release of stored sediment and protect watershed health. Similar to Alternative A, Alternative D would encourage the maintenance of natural flow regimes in priority streams supporting fisheries.