CHAPTER 4: 

 ENVIRONMENTAL CONSEQUENCES 

 Air Resources and Climate 

 through 

 Fish and Wildlife, Aquatics 

Miles City Field Office 

Resource Management Plan and 

Environmental Impact Statement 

BLM
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

4-1

CHAPTER 4: ENVIRONMENTAL 

CONSEQUENCES, SECTION 1

INTRODUCTION

Chapter 4 presents the likely direct, indirect, and cumulative impacts on the human and natural environments 

in terms of environmental, social, and economic consequences projected to occur when the alternatives 

presented in Chapter 2 are implemented. Because the alternatives generally describe overall management 

emphasis, the environmental consequences are most often expressed in comparative general terms. 

Impact analyses and conclusions are based on the interdisciplinary team’s knowledge of the resources and 

planning area, information provided by Bureau of Land Management (BLM) experts or those from other 

agencies, and information contained in pertinent existing literature. The current condition or situation as 

described in Chapter 3, Affected Environment was the baseline used for the impact analysis. Analysis 

assumptions have also been developed to help guide the determination of impacts (see Analytical 

Assumptions). Because this resource management plan (RMP) provides a broad management framework and 

because exact locations of development or management are often unknown, the analysis in this chapter 

represents best estimates of impacts. Impacts are quantified to the greatest extent practical with available 

data. In the absence of quantitative data, best professional judgment provides the basis for the impact 

analysis.

AVAILABILITY OF DATA AND INCOMPLETE INFORMATION

Although programmatic planning efforts typically utilize site-specific data to the extent possible, site-specific 

data is not always available. Some information was unavailable for use in developing the RMP, primarily 

because resource-specific inventories have not been conducted or completed. Data unavailable for 

development of this RMP included:

 regional oil and gas emission inventories appropriate for photochemical grid modeling,

 certain cultural surveys,

 planning-area-wide vegetation by species,

 detailed soil surveys for lands,

 certain wildlife inventory data (e.g., peregrine falcon nest sites or other sites),

 wildlife monitoring data,

 100-year floodplain mapping,

 certain American Indian traditional use areas, 

 detailed climate change impact data at the local level, and

 visitor use trend data for recreational areas.

As a result, some impacts could not be quantified in relationship to the proposed management actions. Where 

data is insufficient to quantify the potential impacts, the impacts are projected in qualitative terms or, in some 

cases, described as unknown. Subsequent project-level analysis of impacts would provide the opportunity to 

collect and examine site-specific inventory data necessary to determine appropriate application of the RMP 

programmatic level guidance. Ongoing inventory efforts by the BLM and other agencies within the planning 

area would be used to continually update and refine the information used to implement this plan. 

ANALYTICAL ASSUMPTIONS

To estimate the impacts of the alternatives, several assumptions are made (Table 4-1). These are made only 

for the purpose of analysis and do not represent potential RMP decisions; however, the assumptions do 

provide reasonably foreseeable, projected levels of development that could occur within the planning area. 

These assumptions should not be interpreted to be constraining or redefining Chapter 2 management 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

4-2

objectives and actions proposed for each alternative. The following are the general assumptions applicable to 

all resource categories. Specific resource assumptions are provided in the subheading for that resource.

 Decisions and implementation of actions from any of the RMP alternatives would be in compliance 

with all valid existing rights, federal regulations, Bureau policies, and other requirements.

 Acre figures and other numbers used in the analysis are approximate projections for comparison and 

analytical purposes only. Readers should not infer that they reflect exact measurements or precise 

calculations.

Throughout the planning area, BLM-authorized activities associated with all resource and all resource use 

programs would be subject to mitigation and minimization guidelines and best management practices (BMPs)

(see the Best Management Practices Appendix) including those specific Mitigation Measures, Conservation 

Actions, and Best Management Practices for greater sage-grouse (see the Best Management Practices 

Appendix). For analysis purposes, it has been assumed that these measures and conservation actions would be 

implemented during site-specific project planning, where appropriate.

TYPES OF IMPACTS

DIRECT AND INDIRECT

Consistent with direction provided 

in 40 Code of Federal Regulations 

(CFR) 1502.16, direct, indirect, and 

cumulative impacts were considered 

in this impact analysis. Direct 

impacts are caused by 

implementation of an action or 

alternative and occur at the same 

time and place. Indirect impacts also 

result from implementation of an 

action or alternative but usually 

occur later in time or further 

removed in distance. Indirect 

impacts are reasonably certain to 

occur.

Impacts were quantified, where 

possible, primarily using geographic 

information systems (GIS) 

applications. In the absence of 

quantitative data, best professional 

judgment prevailed; subsequently, 

impacts are sometimes described 

using ranges of potential impacts or 

qualitative terms.

Only management programs with 

impacts were included in Chapter 4. 

The standard definitions for terms 

referring to impact duration used in 

the impact analysis are as described 

below, unless otherwise stated.

TABLE 4-1.

ASSUMPTIONS FOR THE ANALYSES (SHORT- AND LONGTERM EFFECTS TO BLM-ADMINISTERED ACRES)

Resource Acres Affected in the 

Short-term (5 years)

Acres Affected in the 

Long-term (20 

years)

Vegetation 17,500 prescribed fire 70,000 prescribed fire

Vegetation 

Treatments 12,000 mechanical 80,000 mechanical

Recreation Facilities N/A 50 to 500 (10 to 50 

facilities)

Livestock Grazing

(range 

improvements) Pits 

or Reservoirs

49.5 198 

Wells 6.75 27 

Pipelines 6 24

Fences <1 (0.7) 2.8 

Oil and Gas 3,524 1,352

Coal Bed Natural 

Gas (CBNG)

139 134

Locatable Minerals 100 100

Mineral Material 50 50

ROWs 550 2,200 

Overhead Power 

lines <1 (0.12) <1 (0.12)

Major Pipelines (5) 600 1,440 

Major Power line (1) 60 480

Railroad Right-ofWay (ROW)

140 N/A

Carbon Sequestration 

Test 6 15

2920 Permits 3 150

Wind Energy 50 to 75 350 to 525

Solar Energy N/A 500 
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ENVIRONMENTAL CONSEQUENCES

4-3

 Short-term impact: The impact occurs only during implementation or immediately after 

implementation of the alternative. For the purposes of this RMP, short-term impacts would occur 

during the first 5 years.

 Long-term impact: The impact could occur for an extended period after implementing the 

alternative. The impact could last several years or more and could be beneficial or adverse. For the 

purposes of this RMP, long-term impacts would occur beyond the first 5 years.

CUMULATIVE IMPACTS

Cumulative impacts are defined as the direct and indirect impacts of a proposed project alternative’s 

incremental impacts in combination with other past, present, and reasonably foreseeable actions, regardless of 

who carries out the action (40 CFR Part 1508.7). Guidance for implementing the National Environmental 

Policy Act (NEPA) requires that federal agencies identify the timeframe and geographic boundaries within 

which they would evaluate potential cumulative impacts of an action and the specific past, present, and 

reasonably foreseeable projects that would be analyzed. Impacts of past actions and activities on resources are 

manifested in the current condition of the resource, which is described in Chapter 3, Affected Environment,

for resources on BLM-administered lands.

Actions anticipated over the next 20 years on all lands in the planning area, including those with private, state 

(Montana Fish, Wildlife, and Parks [MFWP] and the Montana Department of Natural Resources and 

Conservation [MDNRC]), and federal (United States Forest Service [USFS], Bureau of Reclamation, 

National Park Service, and the United States Fish and Wildlife Service [USFWS]) ownership or 

administration, have been considered in the analysis to the extent reasonable and possible, by resource and 

program area. The analysis remains general because decisions about other actions in the planning area could 

be made by many other public and private entities, and the location, timing, and magnitude of such actions 

cannot be predicted. Actions outside of the BLM’s jurisdiction considered in the cumulative impacts analysis 

include:

 those pertaining to the Tongue River Railroad Project (near Colstrip and Decker, Montana);

 an increase in the number of conservation easements within the planning area to prevent 

subdivisions and development;

 increased purchase or operation of private land for purposes other than commodity production 

(including recreational, philosophical, and quality of life values);

 continued vegetation manipulation on private lands, which might lead to a decrease in sagebrush

canopy;

 continued timber harvest on MDNRC lands;

 the continuation and maintenance of commercial saw log harvest by the USFS;

 the increased use of prescribed and natural ignition fires by the USFS;

 the expectation that large-scale, stand-replacing wildfires would be expected to cross into lands 

under the jurisdiction of the Miles City Field Office (MCFO);

 the continuation of livestock and wildlife grazing on state lands;

 increased use of communication sites and corridors;

 continued development of unincorporated areas;

 continued county maintenance of roads under the jurisdiction of counties within the RMP area; 

 those pertaining to the Nelson Creek Project (near Circle, Montana, in McCone County) 500-

megawatt, lignite-burning, coal-fired power plant;

 an increased number of concentrated animal feeding operations;

 an annual average of 90 wildfires that burn an average of 34,582 total acres of federal surface (the 

average fire size is 400 acres in grass/shrub fuel types and 25 acres in forested fuel types) in the 

Eastern Montana Fire Zone (20-year average as of December 31, 2006), which includes BLMadministered, USFS, USFWS, and state lands;

 increasingly consolidated private land holdings to form larger private land ownership holdings;

 an increase in private lands leased for outfitted hunting opportunities, resulting in more pressure to 

BLM-administered lands;
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ENVIRONMENTAL CONSEQUENCES

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 the continuation of increased demands for energy (oil, gas, coal, and alternative sources such as 

wind) on federal, state, and private mineral estate; and

 continued alteration of hydrologic function on and off public lands due to reservoir and pit 

construction and implementation or continuation of fish passage projects to restore historic 

migratory patterns on the Tongue and Yellowstone rivers and important tributary streams.

For a description of the impacts from management actions in Chapter 2, see below or, for electronic drafts, click 

on the following link to take you to a specific resource: 

Air Resources and Climate; Fish and Wildlife (Aquatics, including Special Status Species); Soils; Vegetation –

Invasive Species; Vegetation - Riparian and Wetland Areas; Vegetation (including Special Status Species –

Plants); and Water Resources.

RESOURCES

This section of Chapter 4, Environmental Consequences, contains a description of potential impacts to existing 

biological and physical resources of the planning area and follows the order of topics addressed in Chapter 2 as 

follows:

 Air Resources and Climate,

 Soil,

 Water Resources,

 Vegetation,

o Riparian and Wetland Areas,

o Invasive Species, and

 Fish and Wildlife,

o Aquatics (including Special Status Species).

See Volume II for the rest of Chapter 4, Environmental Consequences.

AIR RESOURCES AND CLIMATE

ASSUMPTIONS AND METHODOLOGY

The air resources impact analysis includes emission inventories for each alternative, quantitative analysis for 

near-field air resource impacts from oil and gas activity, and qualitative descriptions of potential far-field

impacts to air pollutant concentrations and air quality related values (AQRV), including visibility and 

deposition.

Emission inventories include BLM sources and non-BLM sources within the planning area. Criteria pollutants

include carbon monoxide (CO), nitrogen oxide (NOx), ozone (O3), fine particulate matter (PM2.5), particulate 

matter (PM10), and sulfur dioxide (SO2), as well as volatile organic compounds (VOCs), which are ozone

precursors. Hazardous air pollutants (HAPs), such as benzene and toluene, are also included in the inventories. 

Lead emissions were not estimated because there are few lead-emitting sources in the planning area. As 

described in Chapter 3, Affected Environment, ozone is not emitted directly into the atmosphere; instead, it is 

formed in atmospheric reactions involving nitrogen oxide and VOCs. Emissions of greenhouse gases (GHGs)

(carbon dioxide [CO2], methane [CH4], and nitrous oxide [N2O]) are described in the climate change impact 

analysis. An emissions inventory was completed for the planning area and is included in the Miles City Field 

Office Resource Management Plan Air Resource Technical Support Document (BLM 2013).

Proposed management activities would cause GHG emission increases from many types of sources. This 

section quantifies GHG emissions from each alternative and provides a qualitative discussion of potential 

climate impacts. As described in Chapter 3, Affected Environment, climate change is occurring and will 

continue to occur for many years because of the longevity of GHGs that are already in the atmosphere. 

Approximate atmospheric lifetimes for carbon dioxide, methane, and nitrous oxide are 50 to 200 years, 12 
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years, and 120 years, respectively (USEPA 2010i). Consequently, GHG emissions would cause long-term 

climate change impacts.

Ongoing scientific research has identified the potential impacts of GHG emissions on climate change. Through 

complex interactions at regional and global scales, atmospheric GHG concentrations cause a net warming of the 

atmosphere (which makes surface temperatures suitable for life on Earth), primarily by decreasing the amount 

of heat energy Earth radiates back into space. Although GHG concentrations in the atmosphere and climatic 

conditions have varied throughout Earth’s history, industrialization and combustion of fossil fuels have caused 

global atmospheric carbon dioxide concentration to increase dramatically (NRC 2006). Global atmospheric 

concentrations of carbon dioxide are expected to increase from 385 parts per million (ppm) in 2008 to more 

than 400 ppm by 2020 and may plateau at 450 ppm if emissions are stabilized at current or reduced levels (Karl, 

Melillo, and Peterson 2009). 

The global increase in carbon dioxide concentrations is due primarily to fossil fuel use and land use change, 

while those of methane and nitrous oxide are due to agricultural soil management, animal manure management, 

sewage treatment, and mobile and stationary combustion of fossil fuels (IPCC 2007). According to climate

change researchers, the impacts of climate change are expected to vary by region, season, and time of day (NRC 

2006; Karl et al. 2009). Computer model forecasts indicate that increases in temperature will not be evenly or 

equally distributed but are likely to be accentuated at higher latitudes.

The lack of scientific tools (models with sufficient spatial and temporal resolution) to forecast climate change at 

local scales limits the ability to quantify many future impacts of climate change in the planning area. The 

following paragraphs describe potential future impacts of climate change that can be reasonably anticipated for 

the region; some of these impacts are known to already be occurring. However, over the next 20 years, tools 

may become available that will allow for better local analysis of climate change impacts and for better 

capability to predict carbon storage. The United States Geological Survey (USGS), for example, is developing 

GIS-based tools to determine the carbon storage of specific soils. Ongoing research is analyzing the response of 

different vegetation types to increasing carbon dioxide, longer growing seasons, higher heat, and more 

unpredictable rain patterns.

The Earth’s atmosphere is warming and these warming trends are expected to continue through the life of this 

plan. Climate changes predicted for the region include the changes described below.

 Surface temperature: average annual temperatures may increase 3 to 5 degrees (°) Fahrenheit (F) from 

the 1960 to 1979 baseline years by the mid-21

st century (Karl et al. 2009). The largest increase in 

average temperature is likely to occur in the winter months. Relatively cold days in the region are 

becoming less frequent and relatively hot days are becoming more frequent (Karl et al. 2009).

 Precipitation: regional precipitation is expected to increase during winter and spring, decrease during 

summer, and remain relatively stable during fall (Karl et al. 2009).

Within North America, warming is predicted to affect many resources and human health. In western mountain 

areas, warming is projected to cause decreased snowpack, more winter flooding, and reduced summer river and 

stream flows, which would exacerbate competition for water resources and could cause declining water quality. 

The warming of lakes and rivers would adversely affect the thermal structure and water quality of hydrological 

systems, which would add additional stress to water resources in the region (IPCC 2007). The region depends 

on springtime snowpack to meet demand for water from municipal, industrial, agricultural, recreational uses, 

and BLM-authorized activities. The USGS notes that mountain ecosystems in the western United States are 

particularly sensitive to climate change, particularly in the higher elevations, where much of the snowpack 

occurs. Some of these areas have experienced three times the global average temperature increase over the past 

century (USGS 2010a). Higher temperatures are also causing more winter precipitation to fall as rain rather than 

snow, which would contribute to earlier snowmelt. Additional declines in snowmelt associated with climate 

change are projected, which would reduce the amount of water available during summer (Karl et al. 2009). 

Rapid spring snowmelt resulting from sudden and unseasonal temperature increases could also lead to greater 

erosive events and unstable soil conditions.
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Increasing temperatures could also increase the amount of water vapor in the atmosphere, the timing and 

amount of precipitation, and the intensity of storm systems. Climate models predict continued increases in the 

heaviest rainfall events, while the lightest precipitation is predicted to decrease. Heavy downpours that are now 

1-in-20-year occurrences are predicted to occur approximately every 4 to 15 years by the end of this century, 

depending on location, and the intensity of heavy downpours is also expected to increase.

There is evidence that recent warming is affecting aquatic biological systems (IPCC 2007). Increases in algal 

abundance in high-altitude lakes have been linked to warmer temperatures, while range changes and earlier fish 

migrations in rivers have also been observed (IPCC 2007). Increased temperatures would raise water 

temperatures in lakes, reservoirs, rivers, and streams. Fish populations are expected to decline due to warmer 

waters, which could lead to the closure of fishing waters (Saunders, Montgomery, Easley, and Spencer 2008).

Climate change is likely to combine with other human-induced stress to further increase the vulnerability of 

ecosystems to pests, invasive species, and loss of native species. Warming temperatures are leading to earlier 

timing of spring events such as leaf-unfolding, bird migration, and egg-laying (IPCC 2007). The range of many

plant and animal species is shifting north and to higher elevations, as the climate of these species’ traditional 

habitat changes (Lawler et al. 2009). Warming temperatures are also linked to longer thermal growing seasons 

(IPCC 2007). Climate change is likely to affect wildlife breeding patterns, water and food supply, and habitat 

availability to some degree. Sensitive species in the planning area, such as sage-grouse, which are already 

stressed by declining habitat, increased development, and other factors, could experience additional pressures as 

a result of climate change.

Increases in average summer temperatures and earlier spring snowmelt in the region are expected to increase the 

risk of wildfires by increasing summer moisture deficits (Karl et al. 2009). Studies have shown that earlier 

snowmelts can lead to a longer dry season, which increases the incidence of landscape-level fire (Westerling, 

Hidalgo, Cayan, and Swetnam 2006b). Together with historic changes in land use, climate change is anticipated 

to affect the variability in the occurrence of wildfire throughout the western United States. Although the impact 

of climatic factors varies by ecosystem type and from year to year, drought, low winter precipitation, wind 

conditions, and high summer temperatures are positively associated with wildfire occurrence (Ashton 2010). 

During the last 20 years, research has shown that these factors have led to an increase in the frequency of very 

large wildfires and total acres burned throughout the region (Ashton 2010).

Climate change also poses challenges for many resource uses on BLM-administered land. Increased 

temperatures, drought, and evaporation may reduce seasonal water supplies for livestock and could impact 

forage availability. However, in non-drought years, longer growing seasons resulting from thermal increases 

may increase forage availability throughout the year. In the next few decades, moderate climate change is 

projected to increase aggregate yields of rain-fed agriculture by 5 to 20 percent, but with important variability 

among regions (NRC 2011). Major challenges are projected for crops that are near the warm end of their 

suitable range or which depend on highly utilized water resources. Shifts in wildlife habitat due to climate 

change may influence hunting and fishing activities, and early snowmelt may impact winter and water-based 

recreational activities. Drought and resulting stress on vegetation could increase the frequency and intensity of 

mountain bark beetle and other insect infestations.

Climate change science and predictions of climate change impacts are a continually growing and emerging 

science. Additional and recent information on climate change and regional predictions can be found at the 

United States Global Change Research Program (http://www.globalchange.gov/) and the Intergovernmental 

Panel on Climate Change (http://www.ipcc.ch/).

MANAGEMENT COMMON TO ALL ALTERNATIVES

BLM emission sources include fluid mineral development (conventional natural gas, CBNG, and oil), solid 

mineral development (primarily coal), fuels management (prescribed fire, mechanical vegetation treatment),

resource road maintenance, forest and woodland treatments, livestock grazing, vegetation management,

recreation, and general BLM travel. These emissions would be long-term emissions because most activities 

would be expected to occur over the life of the plan. However, if activities ceased, concentrations of criteria air 
CHAPTER 4

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Air Resources and Climate

4-7

pollutants and HAPs would decrease through emission reductions. In this respect, air resource impacts would be 

short-term, reversible impacts. BLM-authorized emissions of criteria pollutants and HAPs are shown in Figure 

4-1.

FIGURE 4-1.

CRITERIA AND HAZARDOUS AIR POLLUTANT EMISSIONS 

FROM BLM SOURCES IN THE PLANNING AREA

For each of the alternatives, the largest BLM criteria pollutant and HAP emission sources would be associated 

with coal mining, fluid mineral development, and fire management. Detailed emission breakdowns by resource 

are included for each of the alternatives. For most of these resources, emissions would be similar to emissions 

associated with current levels of activity. For example, forestry management and general BLM travel would not 

be expected to increase over current activity levels and emissions from these activities would remain relatively 

constant. Consequently, emissions from these ongoing resource management activities would not represent 

increases to regional emissions. However, oil and gas activity emissions would reflect increased activity in 

future years and would add to regional emissions. Oil and gas emission estimates reflect the year with the 

greatest total emissions from development and production activities.

Oil and gas emission inventories were generally based on emission standards required by the Montana 

Department of Environmental Quality (MDEQ) and United States Environmental Protection Agency (USEPA). 

An exception is emission estimates based on the use of Tier 4 nonroad engine standards for diesel drill rig 

engines, which would be required under BMPs and as an initial mitigation measure. A list of initial mitigation 

measures to be applied upon issuance of the ROD is included in the air resource management plan (ARMP) 

provided in the Air Resources and Climate Appendix. For drill rig and completion engines greater than 750 

horsepower, generator set engines with low emission rates were assumed when developing the emission 

inventories. With regard to other oil and gas emission sources, emissions were estimated conservatively because 

they do not include more stringent emission controls mandated by the USEPA on August 16, 2012, nor do these

inventories account for the use of newer, cleaner non-drill-rig engines that will replace older engines. The 

USEPA’s August 16, 2012 New Source Performance Standards and National Emission Standards for 

Hazardous Air Pollutants would substantially decrease emissions from many types of oil and gas equipment 

(USEPA 2012). For example, the final rule is expected to decrease national oil and gas VOC emissions by 

approximately 25 percent and substantially decrease HAP emissions. Some of these emission reduction 

requirements apply only to sources with emissions exceeding specified levels. For those types of sources, the oil

and gas emission inventories assume no control in order to be conservative. Because some of these sources 

 -

 1,000

 2,000

 3,000

 4,000

 5,000

 6,000

CO NOx VOC SO2 PM10 PM2.5 HAPs

Emissions (tons per year)

Criteria and Hazardous Pollutants

Alternative A

Alternative B

Alternative C

Alternative D

Alternative E
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4-8

would be subject to control, the emission inventories presented in this chapter overestimate emissions. The 

VOC and HAP portions of the oil and gas emission inventories will be updated in the final RMP to address

these regulatory changes.

Emissions associated with each of the alternatives represent a fraction of the USEPA’s National Emission 

Inventory emissions reported for 

calendar year 2008 (Table 4-2). 

Criteria pollutant emissions 

associated with management actions 

included in this RMP would be 

between 1.1 percent and 51.9 percent 

of total emissions in the planning 

area (Carter, Custer, Daniels, 

Dawson, Fallon, Garfield, Prairie, 

Richland, Roosevelt, Rosebud, 

Sheridan, Treasure, and Wibaux

counties). Although National 

Emission Inventory emissions 

include stationary sources, non-road 

sources, and vehicle sources, 

National Emission Inventory 

emissions do not necessarily include 

all existing oil and gas emissions 

since some small sources and many 

fugitive emissions have not been 

included historically. The oil and gas

activity emissions represent a 

potential increase in county 

emissions because these emissions 

are associated with additional 

authorized activity. Emission 

increases associated with oil and gas

activity vary from less than 0.01 

percent to 47.1 percent of National 

Emission Inventory emissions.

Near-field Criteria Air Pollutant Concentrations from Oil and Gas Activities

Near-field dispersion modeling was performed for oil and gas development for drilling and completion of wells, 

in addition to well pad construction activities. The USEPA guideline model for estimating near-field impacts is 

the AERMOD dispersion model. AERMOD is suitable for modeling discrete sources of emissions to a distance 

of 50 kilometers from the source, and provides conservative estimates of potential air quality impacts from such 

sources. Receptors were placed in the modeling domain, which extended 3 kilometers from the center of the 

central well pad. Information describing AERMOD meteorology, modeling parameters, and data processing is 

provided in the Near-Field Air Quality Assessment Protocol for Resource Management Plans and 

Environmental Impact Statements: Billings Field Office, HiLine District, Miles City Field Office, South Dakota 

Field Office (BLM 2012c). Emission inventories for each alternative and detailed near-field modeling results 

are provided in the Miles City Field Office Air Resource Technical Support Document (BLM 2013) and 

summarized below.

Three well pad development scenarios (construction, drilling, and completion) were modeled at a central well 

pad. Well development activities would be temporary and occur at different times. Well pad construction would 

occur first over a period of up to 3 days of active site construction involving soil movement (e.g., digging and 

TABLE 4-2.

ESTIMATED MAXIMUM ANNUAL CRITERIA POLLUTANT 

EMISSIONS AS A PERCENTAGE OF EXISTING EMISSIONS

Alternative

Percentage of Total Emissions Within Planning 

Area Counties (%) 1

CO NOx VOC SO2 PM10 PM2.5

Alternative Emissions for Multi-Resource Activities Excluding 

Wildfire Smoke 2, 3

A 15.1 6.2 51.9 1.1 21.6 18.1

B 11.8 4.9 7.2 1.1 21.2 17.3

C 12.7 5.3 19.1 1.1 21.3 17.5

D 13.5 5.6 30.3 1.1 21.4 17.7

E 13.3 5.5 27.1 1.2 21.4 17.6

Increase Due to Oil and Gas Activity Emissions 4

A 3.4 1.3 47.1 0.01 0.4 0.8

B 0.2 0.1 2.4 <0.01 0.0 0.05

C 1.0 0.5 14.2 <0.01 0.1 0.3

D 1.9 0.7 25.4 <0.01 0.2 0.5

E 1.6 0.6 22.2 0.01 0.2 0.4

1 Counties included in the National Emission Inventory comparison include 

Carter, Custer, Daniels, Dawson, Fallon, Garfield, Prairie, Richland, Roosevelt, 

Rosebud, Sheridan, Treasure, and Wibaux counties.

2 Wildfire smoke is excluded since it is caused by natural events and is not included 

as part of the National Emission Inventory.

3 A large share of these emissions are from activities that are already occurring; 

therefore, they do not necessarily represent an increase in emissions over current 

emission inventories.

4 Oil and gas emissions represent an increase above National Emission Inventory

emissions because they are associated with new well development and production.
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4-9

grading). Drilling would occur next, with up to 15 days of active drilling. Then well completion would occur for 

up to 5 days. Once well development is complete, a long-term production phase typically begins. The 

construction modeling scenario has the greatest short-term (24-hour) emission rates for particulate matter 

(PM10) and fine particulate matter (PM2.5). Temporary drilling activities account for the greatest short-term (1-

hour) emission rates for all non-particulate criteria air pollutants. Completion activities have greater nonparticulate emissions than the construction phase. In order to represent production activities at nearby wells, 

estimated oil and gas production emissions were modeled at four producing wells surrounding the central pad. 

Production emissions at outlying pads were modeled concurrently with each of the three well development 

scenarios (construction, drilling, and completion).

Modeled concentrations were compared to National Ambient Air Quality Standards (NAAQS), Montana 

Ambient Air Quality Standards (MAAQS), and Prevention of Significant Deterioration (PSD) increments. 

Comparisons to the NAAQS and MAAQS were performed by summing modeled concentrations with 

background concentrations (representing current air quality) and comparing the total concentrations to the 

standards. The results of the near-field modeling performed for Alternative A are shown in Table 4-3. 

Alternative A near-field modeling represents dense well pad and equipment spacing that could occur in 

localized areas within high potential oil and gas activity areas; because this dense spacing could also occur 

under Alternatives B, C, D, and E, the Alternative A modeling results conservatively predict impacts that could 

occur in localized areas under each of the alternatives.

Table 4-3 summarizes modeled results by showing the largest modeled and total concentrations based on the 

three scenarios and 5 years (2005 through 2009). Additional modeling results are included in the air resource 

technical support document (BLM 2013). For example, the maximum total 1-hour carbon monoxide

concentration of 7,534 micrograms per cubic meter (μg/m3) was predicted during the drilling scenario using 

2009 meteorology. Predicted concentrations were below the NAAQS and MAAQS, as shown by the 

percentages in the last column of the table. Total concentrations of 50 percent of a NAAQS or greater were

predicted for the 1-hour nitrogen dioxide (NO2), 24-hour particulate matter (PM10), and 24-hour fine particulate 

matter (PM2.5)standards. The maximum 1-hour nitrogen dioxide impacts were due to heavy-duty construction 

equipment exhaust during the brief well construction period. Maximum 24-hour particulate matter (PM10) and 

fine particulate matter (PM2.5) impacts occurred during short-term construction-related activities. Predicted 

ambient concentrations associated with production activities were much less than emissions associated with 

temporary activities.

Modeled concentrations can also be compared to PSD increments, which are designed to prevent good air 

quality from deteriorating to the level set by the NAAQS. In areas attaining the NAAQS, PSD increment 

analysis is required prior to construction of a major stationary source of air pollutants that have the potential to 

emit at least 100 tons per year (tpy) or 250 tpy of a criteria air pollutant. The sources included in this near-field 

modeling analysis do not meet the definition of a major source of criteria air pollutants and would not be 

required to undergo PSD analysis. The following PSD analysis is not a regulatory analysis; its purpose is to 

provide context for evaluating potential air quality impacts.

The USEPA established PSD increments for Class I areas (e.g., national parks and large wilderness areas) and 

Class II areas (all non-Class I areas). Oil and gas activities are expected to occur within Class II areas and the 

modeled (not total) concentration can be compared directly to the Class II increment. Temporary 24-hr 

particulate matter (PM10) and fine particulate matter (PM2.5) concentrations greater than the Class II PSD 

increments are predicted to occur during construction and completion activities. Temporary concentrations 

above the Class I increments for particulate matter (PM10) and fine particulate matter (PM2.5) are also possible 

during construction, drilling, and completion if these activities were located very close to a Class I area.

Air pollutant concentrations generally decrease as distance from the source increases. Figure 4-2 provides an 

illustration of 24-hr particulate matter (PM10) modeled concentrations during construction activity. At the center 

of the figure is a well pad with short-term construction activities. The four surrounding well pads are modeled 

with emissions representing production activity. Red markers indicate emission sources and green markers 

indicate receptors (points at which concentrations are calculated). Shaded areas indicate the extent of the area 

for which particulate matter (PM10) concentrations are predicted to be greater than the PSD Class I increment 
CHAPTER 4

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4-10

(8 μg/m3) or Class II increment (30 μg/m3) on the day with the second-highest particulate matter (PM10) 

modeled concentration during 2005. Wells would be located in Class II areas and concentrations above the 

Class II PSD increment are predicted to extend up to approximately 300 meters from the well pad boundary. In 

order for concentrations to exceed the Class I increment, well pad construction activity would need to be within 

approximately 1,500 meters of a Class I area. Concentrations of these magnitudes could occur only on days 

when well pad construction activity is concurrent with meteorological conditions causing high ambient 

particulate matter (PM10) concentrations. 

TABLE 4-3.

NEAR-FIELD NAAQS MODELING SUMMARY FOR ALL ALTERNATIVES

Pollut. Avg. 

Period

Model 

Output 

Rank

Value (μg/m3)

Percentage

of NAAQS

(%)

Modeled 

Conc.

PSD 

Increment Bckgrnd 

Conc.1

Total 

Conc.

NAAQS

or 

MAAQS Class 

I

Class 

II

CO 1-hour H2H 321 None None 7,213 7,534 26,450628

8-hour H2H 231 None None 2,175 2,406 10,000 24

NO2 1-hour H8H 289.7 None None 40 129.7 188 69

Annual H1H 32.8E-02 2.5 25 6 6.28 9467

PM10 24-hour H2H 108.0 8 30 30 138.0 150 92

Annual H1H 0.6 4 17 8 8.6 50617

PM2.5 24-hour H8H 4

(H2H)7 9.2 2 9 22.5 31.7 35 91

Annual H1H 0.86 1 4 5.5 6.36 15 42

SO2 1-hour H4H53.3 None None 35 38.3 196 20

24-hour H2H30.58 5 91 11 11.58 36564

Annual H1H21.12E-03 2 20 3 3.00 8066

H1H = highest-first-high

H2H = highest-second-high

H4H = highest-fourth-high

H8H = highest-eighth-high

1 Background concentrations were provided by the MDEQ (MDEQ 2012a; MDEQ 2012b).

2 5

-year average of the 98th percentile (H8H) 1-hour modeled NO2 concentrations. Post processed using the 1-hour and annual 

NO2 Tier 2 method using 80 percent conversion of modeled NOx to NO2.

3 Post processed using the annual NO2 Tier 2 method using 75 percent conversion of modeled NOx to NO2.

4

5-year average of the 98th percentile (H8H) 24-hour modeled PM2.5 concentrations.

5

5-year average of the 99th percentile (H4H) 1-hour modeled SO2 concentrations.

6 This is a Montana standard.

7 The H2H rank provided in parentheses is used to compare to the PSD increments, while the H8H rank is compared to the 

NAAQS.

Near-field Hazardous Air Pollutant Concentrations from Oil and Gas Activities

Near-field modeling was also conducted to determine predicted ambient air quality impacts of HAP emissions. 

HAPs are defined by the USEPA as toxic air pollutants known or suspected to cause cancer or other serious 

health effects, such as reproductive effects, birth defects, or adverse environmental effects. Similar to the 

NAAQS modeling, HAP modeling consisted of construction, drilling, and completion of wells. Modeled 

impacts were compared to established health-based thresholds to determine the incremental increase in risk 

associated with the proposed activities. Health-based thresholds are established for both short-term (acute, 

typically 1-hour) and long-term (chronic, 1-year) exposures. The short-term thresholds used in the analysis 

consisted of acute reference exposure levels and are defined as short-term concentrations at or below which no 

adverse health effects would be expected. The long-term non-carcinogenic thresholds used in the analysis 

consisted of chronic reference concentrations and are the threshold at which no long-term, non-carcinogenic 

adverse health effects would be expected. The long-term carcinogenic thresholds used in the analysis consisted 

of unit risk factors to estimate the increased risk of developing cancer associated with the ambient concentration 

of the HAP being analyzed. Six HAPs were modeled (benzene, ethyl benzene, formaldehyde, n-hexane, toluene, 

and xylene) (Table 4-4). 
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4-11

FIGURE 4-2.

EXTENT OF PM10 CONCENTRATIONS ABOVE 

PSD INCREMENTS DURING WELL CONSTRUCTION

To estimate the incremental increase in risk, the modeled impacts were compared directly to reference exposure 

levels. Table 4-5 presents the results of the acute HAP modeling. The maximum acute impacts for benzene, 

formaldehyde, n-hexane, toluene, and xylene were associated with drilling operations. The maximum impacts 

for ethyl benzene were associated with well completions. Acute HAP modeling impacts were well below the 

reference exposure levels. Table 4-6 presents the results of HAP modeling of potential chronic effects and 

compares them to reference concentrations. 

Of the HAPs evaluated, only benzene, ethyl benzene, and formaldehyde are identified by the USEPA as being 

carcinogens. Unit risk factors for this analysis were derived based on assuming a person is exposed to the HAP

for a 70-year lifetime. Cancer risk was estimated by calculating the annual model-predicted concentrations by 

the unit risk factor for each carcinogen. The resulting calculations were then scaled by adjustment factors to 

represent the most likely exposure and maximally exposed individual risks. The maximally exposed individual 

adjustment takes into account the lifetime of the project, which was assumed to be 50 years. The most likely 

exposure adjustment takes into account the average duration that a family remains at a residence as well as the 

time spent at home versus time spent elsewhere. Table 4-7 presents the results of the carcinogenic HAP

modeling for both the most likely exposure and maximally exposed individual exposure assumptions. The 
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4-12

maximum cancer risks were associated with drilling operations and were well below an incremental increase in 

cancer risk of 1 per million.

TABLE 4-4.

HEALTH EFFECTS OF MODELED HAZARDOUS AIR POLLUTANTS

HAP

Shortterm

(Acute)

Long-term

(Non-carcinogen)

Long-term

(Carcinogen)

Benzene X X X

Ethyl Benzene X X X

Formaldehyde X X X

N-Hexane X X

Toluene X X

Xylene X X

Far-field Criteria Air Pollutant Concentrations

Far-field photochemical grid modeling would be performed in the future, as explained in the ARMP in the Air 

Resources and Climate Appendix. Photochemical grid modeling would assess ozone and other criteria pollutant 

concentrations and would be performed when adequate regional oil and gas emission inventories become 

available.

TABLE 4-5.

ACUTE SHORT-TERM HAZARDOUS AIR POLLUTANTS MODELING 

RESULTS FOR ALL ALTERNATIVES

HAP

Modeled 1-Hour 

Concentration 

(μg/m3)

Reference Exposure 

Levels

(μg/m3)

Percentage of 

Reference 

Exposure Level 

(%)

Benzene 1.37 1,300 0.11

Ethyl Benzene 2.91 350,000 <0.1

Formaldehyde 7.49 55 14

N-Hexane 9.98 390,000 <0.1

Toluene 1.05 37,000 <0.1

Xylene 0.72 22,000 <0.1

Based on the highest-emitting alternative (Alternative A), a qualitative description of potential air quality 

impacts is provided below for each criteria air pollutant. Impacts to air pollutant concentrations would be direct 

impacts with durations similar to the duration of emission-producing activities. The impacts would be reversible 

because they decline or disappear when emissions cease. For each criteria air pollutant, impacts would be 

expected to be below the NAAQS and MAAQS based on recent monitoring in oil and gas areas. The Sidney 

monitor in Richland County had quality assured data for years 2009 to 2011 for most criteria air pollutants 

except sulfur dioxide (2011 data only). The Birney (Rosebud County) and Broadus (Powder River County) 

monitors had quality assured data for 2010 to 2011, with the exception of sulfur dioxide concentrations which 

were not monitored at these sites. Data for 2012 have not yet been quality assured by MDEQ.
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TABLE 4-6.

CHRONIC NON-CARCINOGENIC HAZARDOUS AIR POLLUTANT 

MODELING RESULTS FOR ALL ALTERNATIVES

HAP

Modeled Annual 

Concentration 

(μg/m3)

Reference 

Concentration

(μg/m3)

Percentage of 

Reference 

Concentration 

(%)

Benzene 0.02 3

<10.2

Ethyl Benzene 0.06 1,000

Formaldehyde 0.02 9.80

N-Hexane 0.36 700

Toluene 0.03 5,000

Xylene 0.01 100

TABLE 4-7.

CARCINOGENIC HAZARDOUS AIR POLLUTANT MODELING RESULTS FOR ALL 

ALTERNATIVES

HAP

Modeled 

Annual 

Concentratio

n (μg/m3)

Unit Risk 

Factor

(μg/m3) -1

Adjustment 

Factor

Cancer Risk

(Per 

Million)

Risk 

Exceeds

1 Per 

Million?

Most Likely Exposure 

Benzene 0.025 7.80×10-60.0949 0.02 No

Ethyl Benzene 0.064 2.50×10-60.0949 0.02 No

Formaldehyde 0.018 1.30×10-50.0949 0.02 No

Maximally Exposed Individual

Benzene 0.025 7.80×10-60.71 0.14 No

Ethyl Benzene 0.064 2.50×10-60.71 0.11 No

Formaldehyde 0.018 1.30×10-50.71 0.17 No

 Carbon monoxide: carbon monoxide concentrations are not monitored within the planning area 

because expected concentrations are low. A 3.4-percent emission increase (based on oil and gas

activities under the highest-emitting alternative) in the planning area would cause a negligible increase 

in carbon monoxide concentrations.

 Nitrogen dioxide: nitrogen dioxide monitors in Birney and Broadus measured 2-year average 98th

percentile 1-hour nitrogen dioxide concentration from 2010 to 2011 of 8 percent and 20 percent of the 

NAAQS. Based on 2009-2011 data, 1-hour nitrogen dioxide concentrations at Sidney were 9 percent 

of the NAAQS. An emission increase of approximately 1.3 percent in the planning area would cause a 

negligible increase in nitrogen dioxide concentrations in most areas. A larger increase in ambient 

concentrations may occur in some localized areas in which large engines operate continuously.

 Sulfur dioxide: the sulfur dioxide monitor in Sidney measured a 2011 average 99th percentile 1-hour 

concentration equivalent to 8 percent of the NAAQS. Because increased sulfur dioxide emissions 

would be less than 1 percent of planning area emissions and would be dispersed over large areas, these 

emissions would cause a negligible increase in sulfur dioxide concentrations.

 Particulate matter (PM10): From 2010 to 2011, 24-hour second maximum particulate matter (PM10)

concentrations were approximately 37 percent and 66 percent of the NAAQS at the Birney and 

Broadus monitors, respectively. At Sidney, the 2009 to 2011 average was 64 percent of the standard. 

An emission increase of up to 0.4 percent would cause a negligible or minor increase in particulate 

matter (PM10) concentrations. At locations with construction activities, vehicle traffic on unpaved 
CHAPTER 4

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4-14

roads, or off-road travel, temporary particulate matter (PM10) concentration increases may be moderate 

or high if adverse weather conditions occurred.

 Fine particulate matter (PM2.5.): The 2010 to 2011 average fine particulate (PM2.5) concentrations were

approximately 31 percent and 44 percent of the 24-hour NAAQS at the Birney and Broadus monitors, 

respectively. At Sidney, the 2009 to 2011 average was 39 percent of the NAAQS. For the fine 

particulate matter (PM2.5) annual NAAQS, monitored values were 27 percent, 37, percent, and 40 

percent of the NAAQS at the Birney, Broadus, and Sidney monitors, respectively. An emission 

increase of up to 0.8 percent in the planning area could cause a minor increase in fine particulate 

(PM2.5) concentrations. At locations with construction activities, vehicle traffic on unpaved roads, or 

off-road travel, temporary fine particulate (PM2.5) concentration increases may be moderate or high if 

adverse weather conditions occurred.

 Lead: lead emissions would be negligible.

Compared to the other pollutants described above, current ozone concentrations are closest to the NAAQS. 

Ozone concentrations are variable and highly dependent on weather conditions. Consequently, compliance with 

the ozone NAAQS is based on a 3-year average of the fourth-highest daily maximum 8-hour concentration. The 

Sidney monitor measured a 3-year average fourth-highest 8-hour ozone concentration of 0.056 ppm, which is 

equivalent to approximately 74 percent of the standard. At Birney and Broadus, the 2010 to 2011 2-year 

average fourth-highest daily maximum 8-hour concentrations were 74 and 73 percent of the NAAQS, 

respectively.

NOx and VOC emissions contribute to ozone formation. BLM-authorized emission increases would be 

estimated to increase by up to 1.5 percent for nitrogen oxide and by 2.4 percent to 47.1 percent for VOCs, 

depending on the alternative. However, recent USEPA regulations imposing more stringent VOC emission 

controls will cause future VOC emission increases to be significantly less than predicted. Based on current 

monitoring data, cumulative emissions would be unlikely to cause or contribute to a violation of the ozone

NAAQS.

Far-field AQRV Impacts

The best modeling method to determine far-field AQRV impacts for large modeling domains is photochemical 

grid modeling, which can model long-range regional transport of air pollutants that cause atmospheric 

deposition and visibility impacts. Reliable photochemical grid modeling requires comprehensive regional 

emission inventories and ambient monitoring data throughout the 48 contiguous United States. As described in 

the ARMP in the Air Resources and Climate Appendix, the BLM is actively acquiring data needed to perform 

photochemical grid modeling, which is expected to be completed after this RMP is finalized. For the Draft

RMP, the following qualitative analysis is provided for atmospheric deposition and visibility. A request from 

the USFWS and the National Park Service (NPS) prompted a limited modeling effort using the CALPUFF 

model that would be performed to assess visibility impacts at the UL Bend Wilderness Class I area and the 

Medicine Lake Wilderness Class I area, and at nearby potential sensitive Class II areas. The CALPUFF 

modeling effort would include estimated emissions from BLM-authorized oil and gas activities. This modeling 

would be completed prior to publication of the Final Proposed RMP/EIS.

Sulfur and nitrogen deposition impacts would likely be minor at Class I and sensitive Class II areas. Increases in 

nitrogen oxide and sulfur dioxide emissions would be less than 10.5 percent and 0.01 percent, respectively. 

Potential total nitrogen and sulfur deposition would likely remain below the levels of concern (3.0 kg/ha/yr and 

5.0 kg/ha/yr, respectively). Precipitation pH would be unlikely to become acidified because of predicted 

emission increases. The closest federally mandated Class I areas to oil and gas development areas are the 

Medicine Lake Wilderness in the planning area, the UL Bend Wilderness adjacent to the planning area, and 

Theodore Roosevelt National Park in North Dakota. Tribal Class I areas include the Northern Cheyenne and 

Fort Peck Indian Reservations. With regard to potential sensitive Class II areas listed in Table 3-5, some of 

these areas could experience small increases in deposition. As part of a future photochemical modeling effort, 

deposition impacts would be assessed as described in the ARMP included in the Air Resources and Climate 

Appendix.
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4-15

Small increases in sulfur and nitrogen deposition would potentially cause minor potential lake acidification

impacts at Class I and potential sensitive Class II areas. As part of a future photochemical modeling effort, lake 

acidification impacts would be assessed as described in the ARMP included in the Air Resources and Climate 

Appendix.

A qualitative analysis of visibility impacts based on the relative emission increase is provided below. Potential 

visibility impacts are likely to be small for the following reasons:

 increases in emissions of sulfur dioxide, nitrogen oxide, and fine particulate matter (PM2.5) would be 

relatively low; and

 emission sources would be spread over a large geographic area that would likely lead to relatively low 

concentration increases of haze-inducing pollutants.

Under the highest-emission alternative, total emissions of nitrogen oxide and sulfur dioxide from existing and 

future activities would be approximately 2,668 tons per year, compared to National Emission Inventory

emissions of 38,914 tons per year (Figure 4-3). This represents a regional emission increase of 7 percent; 

however, in localized areas with oil and gas activities, the percentage increase in emissions would be greater. As 

part of the future photochemical modeling effort mentioned above, visibility impacts at Class I and sensitive 

Class II areas would be assessed as described in the Air Resources and Climate Appendix.

Air Resource Management Plan and Adaptive Management Strategy for Oil and Gas Resources

The ARMP for oil and gas activities is provided in the Air Resources and Climate Appendix. The ARMP 

describes the air quality adaptive management strategy that would be used to assess future air quality and 

AQRVs. The goal of the strategy is to maintain the good air quality that the population in the planning area 

currently enjoys. By assessing monitored and modeled air resource and AQRV impacts, the BLM can identify 

mitigation measures to address unacceptable impacts that may be associated with future oil and gas 

development. As described in the ARMP, the BLM would work with the MDEQ and the AQTW to identify 

successful strategies to address air quality and AQRV concerns.

The adaptive management strategy focuses on oil and gas activity because aggregated emissions from multiple 

small sources at well sites can potentially cause significant air quality and AQRV impacts under certain 

circumstances. Many of these small oil and gas emission sources are not required to obtain air quality permits 

from the MDEQ, unlike large stationary sources such as coal mines that are permitted and inspected by the 

MDEQ. The oil and gas adaptive management strategy was prepared in collaboration with the USEPA and 

three federal land management agencies under the Understanding Among the U.S. Department of Agriculture, 

U.S. Department of the Interior, and U.S. Environmental Protection Agency, Regarding Air Quality Analyses 

and Mitigation for Federal Oil and Gas Decisions Through the National Environmental Policy Act [NEPA] 

Process (USDA, USDI, and USEPA 2011). This Memorandum of Understanding (MOU) is summarized in the 

ARMP.

The ARMP includes both near-term actions and long-term actions. In the near-term, the ARMP sets forth initial 

mitigation measures to maintain good air quality until regional photochemical grid modeling can be performed 

to further assess potential impacts to air quality (including ozone) and AQRVs. Additional monitoring data and 

regional emission inventory data are being acquired to support photochemical grid modeling, which is expected 

to be completed in 2015. In the longer term, the ARMP provides ongoing management strategies to assess and 

adapt to new air quality and AQRV ambient monitoring and modeling data during the life of this RMP.

The ARMP includes a multifaceted approach involving the following activities:

 oil and gas activity assessment,

 ambient air quality monitoring support,

 air quality and AQRV assessment,

 future air quality and AQRV modeling, and

 mitigation.
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4-16

FIGURE 4-3.

GREENHOUSE GAS EMISSIONS IN TERMS OF CARBON DIOXIDE 

EQUIVALENT FOR ALL ALTERNATIVES

Pollutants addressed by the ARMP include nitrogen dioxide, O3, particulate matter (PM10), and fine particulate 

matter (PM2.5). The ARMP also addresses modeling and mitigation for the following AQRVs:

 deposition of sulfur and nitrogen,

 lake acid neutralizing capacity, and

 visibility.

The adaptive management strategy for oil and gas resources provides the flexibility to respond to changing 

conditions that could not have been predicted during RMP development. The strategy also allows for the use of 

new technology and methods that may minimize or reduce impacts.

Air Quality Impacts from Climate Change

Air quality impacts from climate change may include increases in ambient ozone concentrations and increases 

or decreases in particulate matter concentrations (USEPA 2009d). Increased temperatures associated with 

climate change have the potential to increase ground-level ozone formation, although this effect would be more 

pronounced in regions with relatively high ozone concentrations rather than in regions with relatively low ozone

concentrations. Climate change also has the potential to increase emissions of ozone precursors, such as 

increased biogenic and fugitive source VOC emissions although there is much uncertainty in this regard. The 

potential cumulative impact of climate change on particulate matter (PM10) and fine particulate matter (PM2.5) is 

less well understood. A range of increases and decreases in particulate matter (PM10) and fine particulate matter

 -

 500

 1,000

 1,500

 2,000

 2,500

 3,000

 3,500

 4,000

 4,500

 5,000

Alternative

A

Alternative

B

Alternative

C

Alternative

D

Alternative

E

Emissions (mtpy)

CO2

CH4

N2O
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

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4-17

(PM2.5) concentrations may occur in different regions, and for different component chemical species in the same 

region. For example, climate changes that involve increased precipitation would decrease fugitive dust

emissions while drier soils (particularly during the summer and fall) would increase fugitive dust emissions.

Because of the inability to accurately model the effects of local GHG emissions on climate change, this analysis 

provides a summary of GHG emissions associated with the alternatives and a comparison of these emissions to 

other GHG inventories. GHG emissions were estimated using methodologies similar to those used for criteria 

air pollutants and included GHG emission that would be directly emitted from sources related to fluid mineral

development, coal mining, fuels management, resource road maintenance, BLM travel, forest and woodland

treatments, vegetation treatments, and livestock grazing. The emission estimates reflect GHG emissions from 

BLM-authorized activities occurring within the planning area. GHG emissions from activities outside the 

planning area were not included because insufficient data exist to accurately quantify these emissions. For 

example, combustion emissions associated with oil and natural gas produced within the planning area and 

combusted outside the planning area were not included in the inventory. GHG emissions from wildfires were 

not included in the emission inventories because these emissions would be beyond the BLM’s control and occur 

every year (although wildfire intensity and magnitude can vary greatly from year to year). GHG emissions from 

prescribed fire and fire prevention activities were included in the inventory since these activities result from 

BLM-authorized activities. GHG emission inventories are included in the Air Resources and Climate Appendix.

GHG emission sinks caused by sequestration and changes in land use were not estimated because insufficient 

data and methodologies exist for estimating carbon uptake in vegetation and soils. BLM activities that improved 

forest and vegetation health would tend to increase carbon dioxide uptake from the atmosphere and reduce 

atmospheric concentrations. Increased carbon sequestration on land administered by the BLM would offset 

GHG emission increases from other BLM sources.

GHG emission inventories developed as part of this analysis are expressed in short tons per year because 

emission factors used to calculate emissions were available in units of pounds and short tons. However, state, 

national, and global emission inventories are typically provided in terms of metric tons per year (mtpy). 

Consequently, GHG emissions provided in this section are also given in terms of mtpy in order to compare 

alternative emissions with other GHG inventories.

Differences in cumulative GHG emission impacts among the alternatives would be negligible when considered 

on state, national, or global scales. GHG emissions under the highest-emitting alternative would be a small 

percentage of Montana, United States, and global emissions. Based on emission inventory data included in 

Table 4-8, Alternative A carbon dioxide equivalent (CO2e) emissions would be less than 1.07 percent of 

Montana emissions, 0.01 percent of United States emissions, and 0.002 percent of global GHG emissions. 

GHG emissions from multiple activities would likely decrease in future years as a result of future federal 

regulation of GHGs. The USEPA’s August 16, 2012 New Source Performance Standards and National 

Emission Standards for Hazardous Air Pollutants rule is expected to decrease national CH4 emissions from 

affected oil and gas systems by approximately 26 percent (USEPA 2012). A previous light-duty vehicle 

regulation imposed carbon dioxide emission standards for new vehicles. As new vehicles replace existing 

vehicles, carbon dioxide emissions will decline on a per-mile basis. The USEPA is collecting GHG emission 

data and is considering additional future regulation.

Several federal initiatives have been launched to improve the ability to understand, predict, and adapt to the 

challenges of climate change. The Secretary of the Interior signed Secretarial Order 3289 on February 22, 2010, 

establishing a Department-wide, science-based approach to increase understanding of climate change and to 

coordinate an effective response to impacts on managed resources. The order reiterated the importance of 

analyzing potential climate change impacts when undertaking long-range planning issues, and also established 

several initiatives including the development of eight Regional Climate Science Centers. Regional Climate 

Science Centers would provide scientific information and tools that land and resource managers can apply to 

monitor and adapt to climate changes at regional and local scales (Secretarial Order 3289, February 22, 2010). 

The North Central Climate Science Center, which will incorporate the planning area, was established in 2011.
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4-18

Given the broad spatial influence of climate change that requires response at the landscape-level, the USDI also 

established Landscape Conservation Cooperatives, which are management-science partnerships that help to 

inform management actions addressing climate change across landscapes. These cooperatives are formed and 

directed by land, water, wildlife, and cultural resource managers and interested public and private organizations, 

to increase the scope of climate change response beyond federal lands.

In addition to efforts being undertaken to better respond and adapt to climate change, other federal initiatives 

are being implemented to mitigate climate change. The Carbon Storage Project was implemented to develop 

carbon sequestration methodologies for geological (i.e., underground) and biological (e.g., forests and 

rangelands) carbon storage. The project is a collaboration of federal agency and external stakeholders to 

enhance carbon storage in geologic formations and in plants and soils in an environmentally responsible 

manner. The Carbon Footprint Project is a project to develop a unified GHG emission reduction program for the 

USDI, including setting a baseline and reduction goal for the Department’s GHG emissions and energy use. 

More information about the USDI’s efforts to respond to climate change is available at http://www.doi.gov/wha

twedo/climate/cop15/index.cfm.

In addition to emissions of GHGs regulated by the USEPA under climate change regulations, emissions of 

diesel combustion particulate and other black carbon emissions from forest fires contribute to climate change by 

reducing the reflectivity of the earth’s surface. This effect is greatest when black carbon is deposited on snow 

because the darker surface absorbs more sunlight, melts the snow more quickly, and heats the earth’s surface. 

Current and future air quality regulations will reduce emissions of carbon dioxide, methane, and nitrous oxide

from many types of sources including oil and gas equipment and operations, vehicles, and many types of 

engines.

Soil management occurs as an integral part of many activities, including oil and gas development, road 

maintenance, mining, fire management, forestry and woodland management, livestock grazing, and vegetation 

management. Consequently, emissions related to soil management are included in emission inventories for 

these specific types of activities.

Management of soil resources throughout the planning area would require submission of an approved 

reclamation plan before beginning surface-disturbing activities. These plans would reflect the complexity, 

environmental concerns, and reclamation potential of the site. Reclamation would reduce fugitive dust

emissions by revegetating areas after project completion. Additionally, although projects to promote soil 

TABLE 4-8.

BLM SOURCE GREENHOUSE GAS EMISSIONS UNDER ALTERNATIVE A 

Resource or Resource Use Emission (Tons per Year) CO2e (mtpy) CO2 CH4 N2O CO2e

Oil and Gas Development and 

Production

Oil 69,637 414 0 78,464 71,169

Natural Gas 28,786 384 0 36,657 33,249

Coal bed Natural Gas 10,282 197 0 14,433 13,091

Coal Mining 104,029 1 1 104,365 94,662

Vegetation Management 34 0 0 35 32

Fire Management 1289,046 121 24 298,944 271,151

Forestry and Woodland Products 178 0 0 179 163

Livestock Grazing 1,382 2,666 0 57,377 52,043

Recreation – Trails and Travel 

Management 78 0 0 83 76

General Purpose BLM Fleet Travel 285 0 0 297 269

Road Maintenance 147 0 0 147 134

BLM Emission Total 503,884 3,783 25 590,981 536,039

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.
CHAPTER 4

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4-19

stabilization, including emergency stabilization and rehabilitation following wildfire, would have a beneficial 

long-term impact to air quality by reducing susceptibility to wind erosion, they could create short-term increases 

in fugitive dust and exhaust emissions during and immediately following project implementation.

Soil management occurs as an integral part of many activities, including oil and gas development, road 

maintenance, mining, fire management, forestry and woodland products, livestock grazing, and vegetation 

management. GHGs, primarily carbon dioxide, are stored in soil and in plant mass (foliage and roots). Activities 

that disturb soil and remove vegetation can release soil carbon dioxide into the atmosphere and reduce future 

carbon dioxide sequestration in plant matter. However, once site reclamation occurs and new vegetation is 

planted, carbon dioxide uptake into plant matter increases. GHG emission inventories for surface-disturbing 

activities include GHG emissions released by equipment and vehicles but do not include estimates of GHG

emissions from soil or plant matter. Methods for accurately estimating soil and plant matter GHG releases to the 

atmosphere and uptake from the atmosphere are not available.

Vegetation treatments improve overall land health using manual, mechanical, chemical, and biological 

treatment techniques. Emissions associated with vegetation management activities were calculated based on the 

amount of surface disturbance and primarily reflect fugitive dust and equipment exhaust emissions. Emissions 

from chemical substances (such as herbicides) were not estimated. Vegetation management projects would have 

a long-term beneficial air quality impact by reducing susceptibility to wind erosion. However, short-term 

increases in fugitive dust and equipment exhaust emissions would occur during and immediately following 

vegetation management activities. 

Vegetation treatments improve overall land health and may increase long-term soil and vegetative uptake of 

carbon dioxide from the atmosphere. However, short-term increases in carbon dioxide and nitrous oxide

emissions from equipment exhaust would occur during vegetation management activities. Short-term decreases 

in carbon dioxide uptake may also occur if vegetation is removed during treatment activities.

Management activities to protect wildlife and special status species would typically reduce air quality impacts 

or relocate them to other areas. Habitat protection activities that limit vehicle and human access, surfacedisturbing activities, and noise would reduce engine exhaust and fugitive dust emissions in locations subject to 

these limitations. In some cases, emission-producing activities would be relocated to other areas and total 

emissions would not change. In other cases, these activities might not occur or might occur on state or private 

land. Emission calculations generally do not account for habitat protection management actions because 

insufficient data are available to determine the likelihood of emission source relocation to other areas.

Management activities to protect wildlife and special status species would typically decrease GHG emissions or 

relocate them to other areas. Habitat protection activities that limit surface-disturbing activities and vehicle and 

human access would reduce engine exhaust emissions in locations subject to these limitations. In some cases, 

GHG-producing activities would be relocated to other areas and total GHG emissions would not change. In 

other cases, these activities might not occur. GHG emission calculations generally do not account for habitat 

protection management actions because insufficient data are available to determine the likelihood of emission 

source relocation to other areas.

Fire management and ecology activities include preventive activities such as forest thinning and prescribed 

fires, as well as fighting wildfires. Smoke contains all criteria air pollutants (carbon monoxide, nitrogen oxide, 

VOC, sulfur dioxide, particulate matter [PM10], and fine particulate matter [PM2.5]), many HAPs, and large 

quantities of GHGs, primarily carbon dioxide. Prescribed burns are begun only when atmospheric conditions 

provide safe fire control conditions and when ambient concentrations of fire-related pollutants would be 

acceptable. The size of the prescribed fire, and the current and expected weather conditions, including the 

predicted wind speed and direction, would be reviewed prior to burning to assure good smoke dispersal. 

Prescribed burns would be completed in a manner that is consistent with procedures established by the 

Montana/Idaho Airshed Group under the authority of the Montana Open Burning Regulations (Administrative 

Rules of Montana [ARM] Title 17, Section 8, Subchapter 6). Wildfire smoke quantities and pollutant 

concentrations would vary with the amount and type of fuel burned and atmospheric conditions. Wildfires 

would cause short-term emissions from smoke and the use of heavy equipment during fire suppression 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-20

activities. Long-term wildfire impacts include increased fugitive dust emissions from lack of vegetation. In 

addition, intense wildfires would alter soil chemistry and reduce natural vegetative growth. Fire mitigation 

activities following wildfires would cause increased equipment exhaust and fugitive dust emissions.

During large wildfires, fine particulate matter (PM2.5) could spread over many miles and affect areas outside the 

planning area, including Class I areas and sensitive Class II areas. In addition to increased concentrations of 

particulate, carbon monoxide, VOCs, and HAPs, large wildfires adversely affect visibility. Individual wildfire

impacts can last from a few days to several weeks, while impacts from multiple fires within the region can 

occur throughout the fire season.

Fire management and ecology activities include preventive activities such as forest thinning and prescribed 

burning, as well as fighting wildfires. Smoke from prescribed burning and wildfires contain large quantities of 

carbon dioxide. In addition to emissions from smoke, vehicle and equipment exhaust emissions contribute small 

amounts of carbon dioxide and nitrous oxide to the atmosphere.

Short-term fugitive dust emissions would occur primarily while woodland treatments are in progress. Emissions 

of carbon monoxide, nitrogen oxide, particulate matter (PM10), fine particulate matter (PM2.5), sulfur dioxide, 

VOCs, and HAPs would be released from vehicles and equipment used during these activities. Over the long 

term, revegetation and land reclamation would reduce fugitive dust.

Short-term vehicle exhaust emissions would occur while woodland treatments are in progress. Carbon dioxide

emissions would increase if woodland slash was burned.

Livestock grazing has the potential to affect air quality through land disturbance from grazing animals, land 

disturbance for range improvements, wind erosion, and vehicle usage to access and transport livestock. 

Rangeland health standards would be used to determine if soil and site stability was achieved. Adjustments to 

the grazing authorization would be made as needed to ensure that fugitive dust emissions were not excessive. 

Livestock grazing releases large quantities of methane, which is approximately 21 times more potent than 

carbon dioxide in terms of global warming potential (according to USEPA regulations). Methane has a short 

atmospheric lifetime of 12 years.

Coal mining is the largest solid mineral mining activity within the planning area and it would be expected to 

continue at rates similar to those experienced in the past. This activity would contribute to the generation of 

fugitive dust (PM10 and PM2.5) at surface facilities from material handling, wind erosion from material 

stockpiles, and vehicle traffic. Additional pollutants would include carbon monoxide, nitrogen oxide, sulfur 

dioxide, VOCs, and HAPs from engine exhaust.

Coal mining is the largest solid mineral mining activity within the planning area and it is expected to continue at 

rates similar to those experienced in the past. This activity would contribute to the generation of GHG emissions 

associated with exhaust from vehicles and equipment. Fugitive coal dust also contributes to climate change if it 

is deposited on snow or other highly reflective surfaces.

Fluid mineral development and production activities in the planning area would increase criteria air pollutant

and HAP emissions through engine exhaust, fugitive organic emissions, and fugitive dust. 

Oil and gas development and production activities in the planning area would increase GHG emissions, 

particularly emissions of carbon dioxide and methane. GHG emissions from oil and gas activities were 

estimated conservatively and did not include emission reductions that may be mandated by future USEPA 

regulations. For example, the USEPA’s proposed oil and gas sector National Emission Standards for Hazardous 

Air Pollutants regulation is expected to reduce methane emissions by approximately 26 percent. 

Relatively few developed recreation sites are located within the planning area. Limited hunting, dispersed 

limited camping, hiking, and off-road travel occur within the area. Recreational uses may cause minor localized 

emission increases through vehicle exhaust and small areas of surface disturbance. Because of the relatively 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-21

small quantity of air pollutants associated with recreational activities, emissions from recreational activities 

were not included in the emission inventory.

GHG emissions from recreational activities are caused primarily by vehicle emissions of carbon dioxide and 

nitrous oxide.

Air quality and AQRV impacts from vehicle travel, including road maintenance and OHV use, would result 

from fugitive dust and exhaust emissions attributable to vehicle travel, including road maintenance and OHV 

use. Travel-related impacts depend on the route or trail surface material and condition, type of vehicle, size of 

vehicle, and vehicle speed. Although the alternatives differ in terms of the number of routes that would remain 

open, open with restrictions, or closed, emissions would depend largely on total vehicle miles traveled. Because 

the public may shift use to other roads in the same area or move to a different area, emissions may remain 

consistent for the planning area regardless of road closure and restrictions.

Fugitive dust from wind erosion would decrease in areas in which road closures allowed native plants to 

recolonize previously disturbed areas. Limiting authorized travel to administrative use would reduce traffic and 

emissions on these routes. 

Construction or maintenance of higher standard unpaved routes has the potential to allow greater travel speeds 

and increased fugitive dust. Unimproved and unmaintained routes generally reduce speeds and fugitive dust. 

Emissions from trails and travel management are largely represented in the alternative emission inventories in 

the following categories: BLM travel, BLM road maintenance, and resource-specific management activities, 

such as fire management and vegetation management.

Vehicle travel, road maintenance activities, and OHV use would cause exhaust emissions of carbon dioxide and 

nitrous oxide. 

Air quality and AQRV impacts from land use authorizations are expected to be minor. New road rights of way 

(ROWs) cause short-term (construction) and long-term (use) impacts and emissions depend on the type of road 

surface, length and width of the road, and the number of vehicles and speed at which they travel. Utility ROWs 

generally have smaller long-term air quality impacts than road ROWs because vegetation is restored and only a 

small number of vehicles would travel through the ROW for maintenance purposes.

Emissions from ROW authorizations were not calculated because land disturbances are expected to be small. 

Emissions for surface-disturbing activities associated with roads for oil and gas activities are included in the oil

and gas emission calculations.

New ROWs would cause short-term (construction) and long-term (vehicle use) increases in GHG emissions. 

GHG emissions from ROW authorizations were not calculated because land disturbances are expected to be 

small. However, GHG emissions for surface-disturbing activities associated with roads for oil and gas activities 

are included in the oil and gas emission calculations.

ALTERNATIVE A

Alternative A would allow new oil and gas development of up to 100 percent of the RFD. Impacts in specific 

areas of the planning area would depend on the location of fluid mineral activity.

Fluid mineral development and production activities in the planning area would increase criteria air pollutant

and HAP emissions through engine exhaust, fugitive organic emissions, and fugitive dust. 

Resource-specific emissions are provided in Tables 4-8 and 4-9. 

Alternative A would have carbon dioxide equivalent emissions of 536,038 mtpy. 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-22

TABLE 4-9.

BLM SOURCE EMISSIONS UNDER ALTERNATIVE A 

Resource or Resource Use Emissions (Tons per Year)

CO NOx SO2 PM10 PM2.5 VOC HAP

Oil and Gas Development and 

Production

Oil 734.5 321.3 0.6 74.1 20.7 2,563.1 161.9

Natural Gas 288.8 119.4 0.3 18.6 6.7 82.5 8.3

Coal Bed Natural Gas 126.3 63.9 0.1 13.6 4.2 43.7 8.3

Coal Mining 2,121.0 1,817.4 179.8 4,448.

4

444.8 144.2 14.4

Vegetation Management 11.3 0.1 0.0 10.7 1.4 3.1 0.3

Fire Management 11,741.9 58.3 13.6 210.7 151.1 97.3 9.7

Forestry and Woodland

Products 0.9 1.3 0.0 3.6 0.4 0.1 0.0

Livestock Grazing 11.3 9.3 0.2 136.9 14.3 4.2 0.4

Recreation – Trails and Travel 

Management 26.6 0.1 0.0 292.6 30.1 27.1 2.7

General Purpose BLM Fleet 

Travel 4.4 1.6 0.0 74.7 7.5 1.9 0.2

Road Maintenance 0.5 1.2 0.0 1.4 0.2 0.1 0.0

BLM Emission Total 5,067.5 2,393.8 194.6 5,285.

3

681.4 2,967.3 206.2

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.

ALTERNATIVE B

Alternative B would allow new oil and gas development of up to 5 percent of the RFD. Impacts in specific areas 

of the planning area would depend on the location of fluid mineral activity.

Resource-specific emissions are provided in Tables 4-10 and 4-11. 

TABLE 4-10.

BLM SOURCE EMISSIONS UNDER ALTERNATIVE B

Resource or Resource Use Emissions (Tons per Year)

CO NOx SO2 PM10 PM2.5 VOC HAP

Oil and Gas Development and 

Production

Oil 39.5 16.6 0.0 4.2 1.1 129.3 8.2

Natural Gas 15.1 6.2 0.0 1.0 0.4 4.2 0.4

Coal bed Natural Gas 6.7 3.4 0.0 0.9 0.2 2.3 0.4

Coal Mining 2,121.0 1,817.4 179.8 4,448.4 444.8 144.2 14.4

Vegetation Management 11.3 0.1 0.0 10.7 1.4 3.1 0.3

Fire Management 11,741.9 58.3 13.6 210.7 151.1 97.3 9.7

Forestry and Woodland Products 0.2 0.1 0.0 0.5 0.1 0.0 0.0

Livestock Grazing 11.3 9.3 0.2 136.9 14.3 4.2 0.4

Recreation – Trails and Travel 

Management 26.6 0.1 0.0 292.6 30.1 27.1 2.7

General Purpose BLM Fleet Travel 4.3 1.6 0.0 73.7 7.4 1.9 0.2

Road Maintenance 0.5 1.3 0.0 1.5 0.2 0.1 0.0

BLM Emission Total 3,978.4 1,914.4 193.6 5,181.1 651.1 413.7 36.7

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-23

TABLE 4-11.

BLM SOURCE GREENHOUSE GAS EMISSIONS UNDER ALTERNATIVE B

Resource or Resource Use Emissions (Tons per Year) CO2e (mtpy) CO2 CH4 N2O CO2e

Oil and Gas Development and 

Production

Oil 4,016 21 0 4,470 4,055

Natural Gas 1,529 20 0 1,950 1,769

Coal bed Natural Gas 545 11 0 778 706

Coal Mining 104,029 1 1 104,365 94,662

Vegetation Management 34 0 0 35 32

Fire Management 1289,046 121 24 298,944 271,151

Forestry and Woodland Products 9 0 0 9 8

Livestock Grazing 1,382 2,458 0 53,010 48,082

Recreation – Trails and Travel 

Management 78 0 0 83 76

General Purpose BLM Fleet Travel 282 0 0 293 266

Road Maintenance 154 0 0 154 140

BLM Emission Total 401,104 2,632 25 464,091 420,948

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.

ALTERNATIVE C

Alternative C would allow new oil and gas development of up to 30 percent of the RFD. Impacts in specific 

areas of the planning area would depend on the location of fluid mineral activity.

Alternative C would potentially result in relatively low carbon dioxide and methane emissions. 

Resource-specific emissions are provided in Tables 4-12 and 4-13. 

ALTERNATIVE D

Alternative D would allow new oil and gas development of up to 54 percent of the RFD. Impacts in specific 

areas of the planning area would depend on the location of fluid mineral activity.

Oil and gas activity would be approximately 54 percent of the RFD. 

Resource-specific emissions are provided in Tables 4-14 and 4-15. 

ALTERNATIVE E (PREFERRED ALTERNATIVE)

Alternative E would allow new oil and gas development of up to 47 percent of the RFD. Impacts in specific 

areas of the planning area would depend on the location of fluid mineral activity.

Alternative E would have mid-range emissions resulting from oil and gas activity that would be approximately 

47 percent of the RFD. 

Resource-specific emissions are provided in Tables 4-16 and 4-17.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-24

TABLE 4-12.

BLM SOURCE EMISSIONS UNDER ALTERNATIVE C

Resource or 

Resource Use

Emissions (Tons per Year)

CO NOx SO2 PM10 PM2.5 VOC HAP

Oil and Gas Development and 

Production

Oil 223.1 97.2 0.2 22.7 6.3 772.9 48.8

Natural Gas 87.9 36.1 0.1 5.8 2.1 24.9 2.5

Coal bed Natural 

Gas 38.4 19.4 0.0 4.7 1.3 13.3 2.5

Coal Mining 2,121.0 1,817.4 179.8 4,448.4 444.8 144.2 14.4

Vegetation 

Management 11.3 0.1 0.0 10.7 1.4 3.1 0.3

Fire Management 11,741.9 58.3 13.6 210.7 151.1 97.3 9.7

Forestry and 

Woodland Products 1.6 2.3 0.1 6.4 0.8 0.3 0.0

Livestock Grazing 11.3 9.3 0.2 136.9 14.3 4.2 0.4

Recreation – Trails 

and Travel 

Management

26.6 0.1 0.0 292.6 30.1 27.1 2.7

General Purpose 

BLM Fleet Travel 4.6 1.7 0.0 71.3 7.2 2.0 0.2

Road Maintenance 0.5 1.4 0.0 1.6 0.2 0.1 0.0

BLM Emission 

Total 4,268.2 2,043.3 194.0 5,211.8 659.6 1,089.4 81.5

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.

TABLE 4-13.

BLM SOURCE GREENHOUSE GAS EMISSIONS UNDER ALTERNATIVE C

Resource or Resource Use Emissions (Tons per Year) CO2e (mtpy) CO2 CH4 N2O CO2e

Oil and Gas Development and 

Production

Oil 21,343 125 0 24,012 21,779

Natural Gas 8,818 117 0 11,259 10,212

Coal bed Natural Gas 3,137 62 0 4,440 4,027

Coal Mining 104,029 1 1 104,365 94,662

Vegetation Management 34 0 0 35 32

Fire Management 1289,046 121 24 298,944 271,151

Forestry and Woodland Products 314 0 0 316 287

Livestock Grazing 1,382 2,659 0 57,243 51,921

Recreation – Trails and Travel 

Management 78 0 0 83 76

General Purpose BLM Fleet Travel 300 0 0 312 283

Road Maintenance 161 0 0 161 146

BLM Emission Total 428,642 3,085 25 501,170 454,576

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-25

TABLE 4-14.

BLM SOURCE EMISSIONS UNDER ALTERNATIVE D

Resource or Resource Use Emissions (Tons per Year)

CO NOx SO2 PM10 PM2.5 VOC HAP

Oil and Gas Development and 

Production

Oil 399.0 174.0 0.3 40.5 11.2 1,384.6 87.5

Natural Gas 157.1 64.8 0.1 10.2 3.7 44.8 4.5

Coal bed Natural Gas 68.6 34.7 0.0 7.7 2.3 23.7 4.5

Coal Mining 2,121.0 1,817.4 179.8 4,448.4 444.8 144.2 14.4

Vegetation Management 11.3 0.1 0.0 10.7 1.4 3.1 0.3

Fire Management 11,741.9 58.3 13.6 210.7 151.1 97.3 9.7

Forestry and Woodland Products 2.7 3.9 0.1 10.7 1.3 0.4 0.0

Livestock Grazing 11.3 9.3 0.2 136.9 14.3 4.2 0.4

Recreation – Trails and Travel 

Management 26.6 0.1 0.0 292.6 30.1 27.1 2.7

General Purpose BLM Fleet Travel 4.6 1.7 0.0 72.7 7.3 2.0 0.2

Road Maintenance 0.5 1.4 0.0 1.6 0.2 0.1 0.0

BLM Emission Total 4,544.6 2,165.7 194.1 5,242.7 667.7 1,731.5 124.2

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.

TABLE 4-15.

BLM SOURCE GREENHOUSE GAS EMISSIONS UNDER ALTERNATIVE D

Resource or Resource Use Emissions (Tons per Year) CO2e (mtpy) CO2 CH4 N2O CO2e

Oil and Gas Development and Production

Oil 38,079 224 0 42,857 38,872

Natural Gas 15,673 209 0 20,025 18,163

Coal bed Natural Gas 5,593 108 0 7,871 7,139

Coal Mining 104,029 1 1 104,365 94,662

Vegetation Management 34 0 0 35 32

Fire Management 1289,046 121 24 298,944 271,151

Forestry and Woodland Products 524 0 0 527 478

Livestock Grazing 1,382 2,663 0 57,320 51,991

Recreation – Trails and Travel 

Management 78 0 0 83 76

General Purpose BLM Fleet Travel 304 0 0 316 287

Road Maintenance 161 0 0 161 146

BLM Emission Total 454,903 3,326 25 532,504 482,997

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires

CUMULATIVE

Alternative A

Most criteria air pollutant and HAP emissions from BLM sources would be less than non-BLM emissions in the 

planning area. Increases in coal mining on federal solid mineral estate instead of nonfederal solid mineral estate 

would result in BLM particulate emissions that were greater than non-BLM particulate emissions. Figure 4-4 

shows criteria pollutant and HAP emissions from BLM and from non-BLM sources. Cumulative impacts from 

BLM sources; projected future non-BLM oil, gas, and coal mining sources; and existing sources would not be 

expected to exceed the NAAQS or MAAQS for any pollutant. As described in the ARMP in the Air Resources 

and Climate Appendix, ambient concentrations would be monitored to assess impacts. Furthermore, pollutant 

concentration impacts as well as deposition and visibility impacts would be predicted using future 

photochemical grid modeling.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-26

TABLE 4-16.

BLM SOURCE EMISSIONS UNDER ALTERNATIVE E

Resource or Resource Use

Emissions (Tons per Year)

CO NOx SO2 PM10 PM2.5 VOC HAP

Oil and Gas Development and 

Production

Oil 347.8 151.7 2.3 34.8 9.3 1,207.5 76.3

Natural Gas 136.1 56.3 0.1 8.8 3.2 38.9 3.9

Coal bed Natural Gas 59.6 30.1 0.0 6.7 2.0 20.6 3.9

Coal Mining 2,121.0 1,817.4 179.8 4,448.4 444.8 144.2 14.4

Vegetation Management 11.3 0.1 0.0 10.7 1.4 3.1 0.3

Fire Management 11,741.9 58.3 13.6 210.7 151.1 97.3 9.7

Forestry and Woodland Products 2.7 3.9 0.1 10.7 1.3 0.4 0.0

Livestock Grazing 11.3 9.3 0.2 136.9 14.3 4.2 0.4

Recreation – Trails and Travel 

Management 26.6 0.1 0.0 292.6 30.1 27.1 2.7

General Purpose BLM Fleet Travel 4.6 1.7 0.0 72.7 7.3 2.0 0.2

Road Maintenance 0.5 1.2 0.0 1.4 0.2 0.1 0.0

BLM Emission Total 4,463.4 2,130.1 196.1 5,234.4 665.0 1,545.4 111.8

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.

TABLE 4-17.

BLM SOURCE GREENHOUSE GAS EMISSIONS UNDER ALTERNATIVE E

Resource or Resource Use

Emissions (Tons per Year)

CO2e (mtpy)

CO2 CH4 N2O CO2e

Oil and Gas Development and Production

Oil 33,176 195 0 37,342 33,871

Natural Gas 13,516 181 0 17,278 15,672

Coal bed Natural Gas 4,862 94 0 6,843 6,207

Coal Mining 104,029 1 1 104,365 94,662

Vegetation Management 34 0 0 35 32

Fire Management 1289,046 121 24 298,944 271,151

Forestry and Woodland Products 524 0 0 527 478

Livestock Grazing 1,382 2,656 0 57,173 51,857

Recreation – Trails and Travel 

Management 78 0 0 83 76

General Purpose BLM Fleet Travel 304 0 0 316 287

Road Maintenance 147 0 0 147 134

BLM Emission Total 447,098 3,248 25 523,053 474,427

1 Excludes smoke emissions from wildfires, but includes smoke emissions from prescribed fires.

Alternative B

Figure 4-5 shows criteria pollutant and HAP emissions from BLM and from non-BLM sources. Cumulative 

impacts from projected future BLM and non-BLM sources would not be expected to exceed the NAAQS or 

MAAQS. As described in the ARMP in the Air Resources and Climate Appendix, pollutant concentrations 

would be monitored to assess impacts. Furthermore, pollutant concentration impacts as well as deposition and 

visibility impacts would be predicted using future photochemical grid modeling.

Alternative C

Figure 4-6 shows criteria pollutant and HAP emissions from BLM and non-BLM sources. Alternative C 

cumulative pollutant concentrations are expected to be less than the NAAQS and MAAQS. As described in the 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-27

ARMP in the Air Resources and Climate Appendix, pollutant concentrations would be monitored to assess 

impacts. Furthermore, pollutant concentration impacts as well as deposition and visibility impacts would be 

predicted using future photochemical grid modeling.

Alternative D

Figure 4-7 shows criteria pollutant and HAP emissions from BLM and from non-BLM sources. Cumulative 

pollutant concentrations would be expected to be less than the NAAQS and MAAQS. As described in the 

ARMP in the Air Resources and Climate Appendix, pollutant concentrations would be monitored to assess 

impacts. Furthermore, pollutant concentration impacts as well as deposition and visibility impacts would be 

predicted using future photochemical grid modeling.

Alternative E (Preferred Alternative)

Figure 4-8 shows criteria pollutant and HAP emissions from BLM and from non-BLM sources. Cumulative 

pollutant concentrations are expected to be less than the NAAQS and MAAQS. As described in the ARMP in 

the Air Resources and Climate Appendix, pollutant concentrations would be monitored to assess impacts. 

Furthermore, pollutant concentration impacts as well as deposition and visibility impacts would be predicted 

using future photochemical grid modeling.

FIGURE 4-4.

LONG-TERM EMISSIONS FROM BLM AND NON-BLM 

SOURCES IN THE PLANNING AREA UNDER ALTERNATIVE A 

BLM emissions include emissions from multiple resources, including BLM-authorized oil and gas emissions. 

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

CO NOx VOC SO2 PM10 PM2.5 HAPs

Emissions (tons per year)

Criteria and Hazardous Pollutants 

BLM

Non-BLM
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-28

Non-BLM emissions include emissions from oil and gas activities on state and private mineral estate.

FIGURE 4-5.

LONG-TERM EMISSIONS FROM BLM AND NON-BLM 

SOURCES IN THE PLANNING AREA UNDER ALTERNATIVE B

BLM emissions include emissions from multiple resources, including BLM-authorized oil and gas emissions. 

Non-BLM emissions include emissions from oil and gas activities on state and private mineral estate.

FIGURE 4-6.

LONG-TERM EMISSIONS FROM BLM AND NON-BLM 

SOURCES IN THE PLANNING AREA UNDER ALTERNATIVE C

BLM emissions include emissions from multiple resources, including BLM-authorized oil and gas emissions. 

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

CO NOx VOC SO2 PM10 PM2.5 HAPs

Emissions (tons per year)

Criteria and Hazardous Pollutants 

BLM

Non-BLM

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

CO NOx VOC SO2 PM10 PM2.5 HAPs

Emissions (tons per year)

Criteria and Hazardous Pollutants 

BLM

Non-BLM
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Air Resources and Climate

4-29

Non-BLM emissions include emissions from oil and gas activities on state and private mineral estate

FIGURE 4-7.

LONG-TERM EMISSIONS FROM BLM AND NON-BLM 

SOURCES IN THE PLANNING AREA UNDER ALTERNATIVE D

BLM emissions include emissions from multiple resources, including BLM-authorized oil and gas emissions. 

Non-BLM emissions include emissions from oil and gas activities on state and private mineral estate.

FIGURE 4-8.

LONG-TERM EMISSIONS FROM BLM AND NON-BLM 

SOURCES IN THE PLANNING AREA UNDER ALTERNATIVE E

BLM emissions include emissions from multiple resources, including BLM-authorized oil and gas emissions. 

Non-BLM emissions include emissions from oil and gas activities on state and private mineral estate.

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

CO NOx VOC SO2 PM10 PM2.5 HAPs

Emissions (tons per year)

Criteria and Hazardous Pollutants 

BLM

Non-BLM

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

10,000

CO NOx VOC SO2 PM10 PM2.5 HAPs

Emissions (tons per year)

Criteria and Hazardous Pollutants 

BLM

Non-BLM
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-30

SOILS

ASSUMPTIONS

Acre figures and other numbers used in this analysis are approximate projections for comparison and analytical 

purposes only. Readers should not infer that they reflect exact measurements or precise calculations. GIS 

analysis is based on a 1:24,000-scale 2009 Natural Resources Conservation Service (NRCS) Soil Survey 

Geographic Database (also known as SSURGO) for each county in the planning area. Acre figures in all tables, 

except where noted, may overlap, and adding these figures will not result in accurate total acreage values.

Naturally functioning soils sustain biotic productivity and maintain water and air quality. Important components 

of the soil system include physical properties (e.g., bulk density, texture, structure, parent material, and 

porosity), chemical properties (e.g., pH, salts, calcium carbonate, clay, and humus), and biotic properties (e.g., 

microorganisms, macroorganisms, and organic matter). Soils within the planning area are rejuvenated by natural 

disturbances such as fire and grazing. See Chapter 3, Soils for further discussion on natural soil structure and 

function.

Controlled uses of resources (controlled surface disturbance and controlled surface use) would provide for the 

conservation of soil resources by reducing impacts to soils. Prohibiting surface-disturbing activities and 

surface use would provide for the maintenance of soil resources and allow soils to recover from past 

disturbances (natural or anthropogenic).

MANAGEMENT COMMON TO ALL ALTERNATIVES

Management actions that promoted organic soil carbon storage would inherently improve soil quality by 

increasing vegetative ground cover, soil development, soil organic matter, fertility, water-holding capacity, and 

by reducing soil loss from wind and water erosion. Various ecosystem processes are influenced by the carbon 

cycle; therefore, management of soil carbon would affect other ecosystem processes, such as nutrient and water 

cycles. Management actions that maintained or improved habitat would promote organic soil carbon storage. 

For example, applying a rest-rotation regime in order to enhance vegetative carbon stocks would also increase 

soil carbon stocks. Reclaiming or improving existing degraded areas would also improve organic carbon stocks 

in soils.

Surface-disturbing actions, such as vegetation or fuels treatments (up to approximately 18,000 acres in the short 

term and 70,000 acres in the long term), range or habitat improvements (up to approximately 420 acres 

annually), mechanical invasive species (vegetation) control (up to approximately 12,000 acres in the short term 

and 80,000 acres in the long term), fire suppression activities (up to approximately 15 acres in the short term 

and 60 acres in the long term), excavation of cultural and paleontological sites (up to approximately 45 acres in 

the short term and 150 acres in the long term), minerals exploration and extraction (up to approximately 8,900 

acres in the short term and 51,000 acres in the long term), vehicle use, infrastructure, and lands and realty or 

renewable energy projects (up to approximately 1,600 acres in the short term and 5,700 acres in the long term) 

would result in reduced ground cover or soil mixing, compaction, or removal; exposure of the soil resource to 

accelerated wind and water erosion; and the irretrievable loss of topsoil and nutrients. Surface disturbances 

would potentially result in mass movement or sedimentation. Surface disturbances would also change soil 

structure, heterogeneity (variable characteristics), temperature regimes, nutrient cycling, biotic richness, and 

diversity. Mixed soils would have decreased bulk density and altered porosity, infiltration, air-water 

relationships, salt content, and pH (Perrow and Davy 2003; Bainbridge 2007). Soil compaction would result in 

increased bulk density and reduced porosity, infiltration, moisture, air, nutrient cycling, productivity, and biotic 

activity (Logan 2001; Perrow and Davy 2003; Bainbridge 2007). Altering such characteristics would reduce the 

soil system’s ability to adapt to climate change and withstand future disturbances.

Soils would take decades to hundreds of years to recover from the impacts of altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen

content (Perrow and Davy 2003). Mixed or removed soil horizons are perpetually altered by the disturbance; 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-31

including texture class, rock fragment content, structure, and depth to bedrock. Soil recovery following 

disturbance would be accelerated by mitigation and reclamation to reduce natural recovery rates, typically 

hundreds of years, to within several decades (Perrow and Davy 2003). Within 2 to 5 years of reclamation, 

vegetative cover and rates of erosion would return to pre-disturbance conditions (BLM 2008g). Exceptions to 

this timeline would include sites poorly suited to reclamation (1.6 million acres, 57 percent of the planning 

area), which would require unconventional or site-specific reclamation measures.

Management actions that prohibited surface-disturbing activities would maintain soil resources (Table 4-18). 

Prior to authorization, activities would be evaluated on a case-by-case basis, and the project would be subject to 

mitigation measures, relocation, or denial to maintain the soil system. Although surface-disturbing actions on 

BLM-administered lands on up to approximately 50,000 acres in the short term and up to 330,000 acres in the 

long term would potentially occur, all land uses under all alternatives would meet the Standards for Rangeland 

Health.

The application of BMPs (see the Best Management Practices Appendix) would provide for sustainable land use 

methods or relocation of the surface-disturbing activity to a more suitable soil type. Mitigation would 

potentially include limiting the total area of disturbance, rapid reclamation (see the Reclamation Appendix), 

erosion or sediment control, soil salvage, decompaction, revegetation, weed control, slope stabilization, surface 

roughening, and fencing. 

Monitoring soil systems (see the Monitoring 

Appendix) would promote sustainable use of the 

soil resource. Meeting Rangeland Health 

Standards would maintain soil health, and 

Standards 1 and 2, which promote soil biota, 

stability, nutrient cycling, and water storage, 

would be particularly important. Maintaining 

proper functioning condition (PFC) for riparian

and wetland areas would sustain soil stability and 

hydric function on approximately 110,000 acres of 

hydric soils, which is 4 percent of the planning 

area. Activities that met water quality standards 

would reduce accelerated streambank erosion and 

sedimentation.

Management actions that maintained, conserved, 

or improved vegetation conditions, including 

managing for PFC, riparian buffers, forest

resilience, special status species plants, and range 

improvements, or wildlife habitat would promote natural soil structure and function (up to approximately 420 

acres annually). Although some treatments would cause surface disturbance in the short term, such treatments 

would promote nutrient cycling, soil development, soil biodiversity, and site stability in the long term.

Using an integrated approach for controlling invasive vegetation species (e.g., weed-free forage; vehicle 

washing; and mechanical, biological, and chemical control) would promote a natural soil system. Although 

soil disruption from treatments would cause short-term, localized impacts the treatment would promote longterm soil health (up to approximately 5,000 acres disturbed in the short term and 50,000 acres in the long 

term). Herbicides with residual soil activity would inhibit soil biodiversity and biotic activity (BLM 2007d). 

Biological control using sheep and goats would cause compaction through trampling and trailing. Following 

standard operating practices designed to reduce impacts to soils from weed management actions would 

promote sustainable use of the soil resource (BLM 2007d). Use of vehicle wash stations would minimize the 

transport and establishment of invasive weeds.

TABLE 4-18.

BLM-ADMINISTERED SOIL RESOURCES

MAINTAINED UNDER MANAGEMENT 

COMMON TO

ALL ALTERNATIVES

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Oil and gas closures 

(discretionary and those under 

Management Common to all 

Alternatives)

56,000 24,000

Oil and gas, no surface 

occupancy (NSO) 29,000 3,800

WSAs 76,000 24,000
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-32

The use of wildland fire chemicals (foam and retardant) would cause short-term, localized imbalances in soil 

nutrient levels because such chemicals would potentially contain nitrogen, phosphorous, and boron (USFS 

2012; Finger 1997).

Using fertilizer to accomplish vegetation community restoration would alter nutrient cycling in the short term 

and promote natural soil system conditions in the long term. The addition of nitrogen fertilizer would 

potentially favor annual bromes (Wight 1976), which would lead to alteration of the soil environment 

(Radosevich, Holt, and Ghersa 2007). Nitrogen fertilization would increase soil organic matter (and soil carbon 

stocks) from enhanced vegetative growth. Improper application of ammonium-based fertilizer would cause soil 

acidification (Brady and Weil 2004).

Developing minerals in conjunction with other resource uses would co-locate surface disturbances, which 

would promote sustainable use of the soil resource and reduce soil system fragmentation. However, the 

combined effects to the soil resource would amplify impacts to the soil system within those areas.

Coal extraction and the associated removal and replacement of overburden would cause surface disturbance and 

depress surface elevation, which would alter soil-water relationships (up to approximately 1,600 acres 

annually). Land application of water with high salt content, which is typical of coal seams, would reduce 

infiltration and productivity, increase overland flow, accelerate erosion, or cause toxic impacts to biota (see the 

Soils Appendix for further discussion on salt-affected soils) (Table 4-19). Coal development would be mitigated 

by a screening process that included sensitive soils in the unsuitability criteria (see the Minerals Appendix for 

further discussion of the screening process).

Geothermal extraction would include the risk of soil contamination from spills, leaks with concentrated 

metals, and low or high pH values. However, no federal geothermal leasing would likely occur in the short or 

long term.

There would be approximately 3,700 acres of oil and 

gas developed in the long-term. Applying the 

following BMPs would maintain soil resilience; and 

reduce soil system fragmentation, wind and water 

erosion, and the total area of surface disturbance:

 utilizing plans of development (a priority in 

the Carter MLP area),

 removing vegetation in the smallest area 

possible,

 co-locating infrastructure,

 using a single trench for utilities and piping, 

 employing multiple completions per well 

bore and directional drilling,

 ensuring reclamation of all new roads at the 

end of the life of the well, 

 preventing degradation of the watershed 

from produced water,

 designing impoundments or water disposal 

methods to minimize impacts to soil, and

 initiating interim reclamation within 25 

days of drilling the well.

The risk of accelerated erosion following bentonite extraction would be compounded by the site’s poor 

reclamation suitability, which is typically high in clay and salt content (up to approximately 40 acres 

annually). Segregating suitable topsoil material and the addition of soil amendments would improve 

TABLE 4-19. 

BLM-ADMINISTERED SOIL RESOURCES AT 

RISK OF DEGRADATION 

UNDER MANAGEMENT COMMON TO ALL 

ALTERNATIVES

Area or Resource

Acres of 

Sensitive 

Soils

Acres of 

Slopes 

25% or 

Greater

Coal, high and moderate 

development areas 140,000 11,000

Coal, further study areas, 

pending further study 11,000 2,100

Coal, further study areas

Current oil and gas leases

74,000

350,000

11,000

39,000

High reasonably foreseeable 

development (RFD), oil and 

gas development

220,000 27,000

Moderate RFD, oil and gas

development 380,000 39,000

Low RFD, oil and gas

development 1,200,000 39,000

Carter MLP Area 96,000 850
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-33

vegetation recovery (see the Soils Appendix for a discussion of suitable topsoil characteristics and suggested 

soil amendments).

Uranium extraction would include the risk of soil contamination from spills, leaks, or land application of treated 

wastewater, which would result in accumulated radionuclides, selenium, salt content, and other metals and 

potentially cause the soil to become toxic to biota (USNRC and WDEQ 2009). Although impacts would 

potentially be severe in the short-term, the required rapid response (including remediation) and routine 

monitoring would cause minimal long-term impacts (USNRC and WDEQ 2009).

Although infrastructure construction and use would cause accelerated erosion, increased overland flow, and 

sedimentation (up to approximately 1,000 acres in the long term for recreational purposes); road and 

infrastructure maintenance would reduce such impacts. Considering constraints of the soil resource and colocating ROWs when constructing infrastructure would encourage sustainable use of the soil resource, which 

would include avoiding sensitive soils. Designing infrastructure on stabile, high-bearing-strength locations 

with proper drainage would avoid destabilizing erosive soils. Developing roads with gentle grades and along 

contours would reduce accelerated erosion from overland flow. Closing and restoring unauthorized usercreated roads or trails and closing dispersed camping within 300 feet of roads or trails in degraded, 

ecologically sensitive areas would promote natural soil structure and function.

Vehicles would act as vectors for weeds and cause ground cover loss, compaction, and rutting, which would 

result in increased overland flow, accelerated erosion, and sedimentation, particularly in areas of rough or 

erosive terrain. Wet soils would be especially susceptible to rutting, which would lead to braiding of roads 

and trails, channeling, and accelerated water erosion. Avoiding vehicle use during conditions causing ruts 

greater than 4 inches deep would reduce such impacts. Although disturbing areas prone to producing dust 

would result in the loss of topsoil and nutrients and inhibit biotic production, dust would potentially be 

controlled by biodegradable dust suppressants or water with low salt content. 

Areas of concentrated Open off-highway vehicle (OHV) use would result in compaction, accelerated erosion, 

and reduced ground cover, infiltration, nutrient cycling, and organic matter (BLM 2003m; Bainbridge 2007), 

particularly in areas of highly erodible soils. OHV use on slopes greater than 25 percent would have a severe 

risk of accelerated water erosion (NRCS 1998). Soils with biotic, physical, or chemical crusts in areas with 

low vegetative cover would be particularly susceptible to destabilization from cross-country travel, which 

would result in accelerated erosion. Disturbance of areas dependent on biotic crusts for nutrient cycling would 

result in reduced fertility (Evans and Ehleringer 1993).

Acquired lands that improved habitat connectivity would promote the soil system’s resilience to climate change

and future disturbances (e.g., wildfire, and drought) (Perrow and Davy 2003).

ALTERNATIVE A

Land uses proposed under Alternative A, such as vegetation or fuels treatments, range or habitat improvements,

mechanical invasive species (vegetation) control, oil and gas exploration and extraction, geophysical 

exploration, vehicle use, infrastructure development, and ROW activities, would cause surface disturbance. 

Surface disturbances would result in reduced ground cover or soil mixing, compaction, or removal; exposure of 

the soil resource to accelerated wind and water erosion; and the irretrievable loss of topsoil and nutrients. 

Surface disturbances would potentially result in mass movement or sedimentation. Surface disturbances would 

also change soil structure, heterogeneity (variable characteristics), temperature regimes, nutrient cycling, biotic 

richness, and diversity. Mixed soils would have decreased bulk density and altered porosity, infiltration, airwater relationships, salt content, and pH (Perrow and Davy 2003; Bainbridge 2007). Soil compaction would 

result in increased bulk density and reduced porosity, infiltration, moisture, air, nutrient cycling, productivity, 

and biotic activity (Logan 2001; Perrow and Davy 2003; Bainbridge 2007). Altering such characteristics would 

reduce the soil system’s ability to adapt to climate change and withstand future disturbances.

Soils would take decades to hundreds of years to recover from the impacts of altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-34

content (Perrow and Davy 2003). Mixed or removed soil horizons are perpetually altered by the disturbance; 

including texture class, rock fragment content, structure, and depth to bedrock. Soil recovery following 

disturbance would be accelerated by mitigation and reclamation to reduce natural recovery rates, typically 

hundreds of years, to within several decades (Perrow and Davy 2003). Within 2 to 5 years of reclamation, 

vegetative cover and rates of erosion would return to pre-disturbance conditions (BLM 2008g). Exceptions to 

this timeline would include sites poorly suited to reclamation (1.6 million acres, 57 percent of the planning 

area), which would require unconventional or site-specific reclamation measures.

Reserve, brine, and water disposal pits would contain material (e.g., drilling fluids, mud, cuttings, and salts) 

that altered soil chemistry and created soil toxic to biota if the material leaked out of the pit. Implementing 

closed-loop drilling or other pitless methods would avoid such impacts and reduce the total area of 

disturbance. Disposal of water with high salt content using land application or seepage ponds would result in 

reduced infiltration and productivity, increased overland flow, accelerated erosion, or cause impacts toxic to 

biota. Discharge of produced water would result in gullying, headcutting, and sedimentation (ALL 2001a; 

BLM 2008g). Spills or leaks of produced hydrocarbons, fuels, or produced water high in salt content would 

create soil toxic to biota (BLM 2008g). Early detection, containment, and cleanup would keep such impacts 

localized.

As slopes approached 30 percent, the risk of soil instability following disturbance would increase, particularly if 

cover, structure, permeability, or bulk density had been altered (Monsen, Stevens, and Shaw 2004). 

Reclamation suitability would be low for slopes greater than 20 percent (Monsen et al. 2004). Activities on 

slopes greater than 30 percent within the Big Dry RMP area (48,000 acres, 2 percent of the planning area) 

would require mitigation to ensure sustainable use of the soil resource (Table 4-20). 

Mechanical treatment of vegetation on slopes greater than 15 percent (280,000 acres, 10 percent of the planning 

area) and highly erodible soils (160,000 acres, 6 percent of the planning area) within the Big Dry RMP area 

would require mitigation to ensure sustainable use of the soil resource. 

Under this alternative, oil and gas extraction would require mitigation on slopes 30 percent or greater (90,000 

acres, 3 percent of the planning area) to ensure sustainable use of the soil resource. 

Management actions that prohibited surface-disturbing activities would maintain soil resources, particularly 

hydric function in floodplains, waterbodies, riparian, wetland, and aquatic wildlife habitat (Table 4-21). 

Prohibiting such activities within designated wildlife habitat and paleontological areas would inhibit treatment 

strategies that would improve soil resources.

Management actions designed to maintain, conserve, or improve vegetation conditions (including managing for 

PFC, fencing new spring developments, using timber harvest or salvage for habitat improvement, haying, fuels 

management, approximating natural disturbance regimes, and supporting forest resilience) would promote 

natural soil structure and function. Although some treatments would cause surface disturbance in the short term, 

such treatments would promote nutrient cycling, soil development, soil biodiversity, and site stability in the 

long term. 

Impoundments would accumulate sediment flows that would have been deposited naturally downstream in 

other areas, which would alter natural erosion and deposition rates at the impoundment and downstream (Zelt, 

Boughton, Miller, Mason, and Gianakos 1999). Impoundments would also reduce riparian vegetative cover 

along the channel, which would result in accelerated erosion and sedimentation (Poff et al. 1997). Dam failure 

would result in accelerated water erosion and sedimentation. Unlined water impoundments would change 

subsurface water flow regimes, which would alter natural soil formation processes, including nutrient cycling, 

mobilization (e.g., sulfate, selenium, arsenic, manganese, barium, chloride, and nitrate), and salt distribution 

(NAS 2010). Salts from the impoundment concentrated in soils would reduce infiltration and productivity, 

increase overland flow, accelerate erosion, or cause impacts toxic to biota (see the Soils Appendix for further 

discussion on salt-affected soils). Wet soils surrounding the impoundment would be susceptible to compaction 

from concentrated use.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-35

Trough and tank development in 

riparian and wetland areas would 

result in compaction from 

concentrated livestock use. 

Compacted soils would be at risk of 

increased surface salt accumulation, 

which would further reduce 

infiltration and productivity, 

increase overland flow, accelerate 

erosion, or cause impacts toxic to 

biota. 

Although allowing surfacedisturbing activities in areas of 

invasive vegetation species 

infestations would degrade soil 

resources already affected by the 

infestation, it would permit 

treatment strategies that maintained 

or enhanced soil resources. Treating 

invasive vegetation species on a 

case-by-case basis would promote 

natural soil systems in localized 

areas. However, basing priority 

treatment areas on sites either 

particularly susceptible to, or 

particularly affected by, weed 

invasions, would more effectively 

maintain or enhance the soil 

resource.

Wildlife requirements would 

potentially inhibit treatment 

strategies that improved soil 

resources. For example, 

revegetation would potentially be 

prohibited in the spring, which 

would result in accelerated erosion 

due to lack of vegetative cover.

The absence of sage-grouse habitat compensation requirements under this alternative would cause soil system 

fragmentation, which would alter soil structure and function. Soil system fragmentation would result in altered 

soil heterogeneity, microclimate, hydrology, nutrient cycling, biotic richness, and diversity (Perrow and Davy 

2003). Localized impacts would include microclimatic changes tens of meters into the patch (from the edge) but

altered biota and nutrient cycling would extend even further (Perrow and Davy 2003). Pre-existing 

disturbance regimes (e.g., fire) would be altered on a landscape scale, which would change natural rates of soil 

formation (Perrow and Davy 2003).

Although fuels reduction treatments would cause a surface disturbance in the short term, they would reduce the 

intensity and severity of wild and prescribed fire (Arno and Allison-Bunnell 2002; Perrow and Davy 2003). 

However, requiring pre-commercial or commercial fuels removal prior to prescribed fire actions would cause 

unnecessary degradation of the soil resource if other mitigation alternatives existed (Table 4-22). Allowing 

prescribed fire (up to approximately 7,500 acres annually) in B and C fire management sites and management of 

wildland fire to meet multiple objectives only within Fire Management Categories C and D sites would promote 

TABLE 4-20. 

BLM-ADMINISTERED SOIL RESOURCES CONSERVED 

UNDER ALTERNATIVE A

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

Greater 

than 

15% 

Acres 

of 

Slopes 

25% or 

Greater

Acres 

of 

Slopes 

30% or 

Greater

Soils

Mechanical 

treatment on steep 

slopes avoided 

(Big Dry only)

230,000 300,000 84,000 NA

Surface 

disturbance 

avoided (Big Dry) 

or oil and gas

controlled surface 

use (CSU) 

stipulation 

(Powder River) on 

steep slopes

79,000 NA NA 90,000

Mechanical 

treatments avoided 

on highly erodible 

soils (Big Dry 

only)

160,000 NA 4,800 NA

Fish and 

Wildlife

Wildlife, CSD1150 NA 20 NA

Travel Mgmt 

and OHV

Limited OHV Use 1,600,000 NA 150,000 NA

1CSD=Controlled Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-36

natural soil development within 

those areas and inhibit this 

development in areas in which 

prescribed fire or management of 

wildland fire to meet multiple 

objectives was prohibited. 

Although implementing terms and 

conditions in allotments that failed 

to meet Rangeland Health Standards

would encourage recovery of the 

soil system as the allotments 

progressed toward improvement, the 

compaction and accelerated erosion 

associated with further grazing

would slow the recovery of the 

compromised soil system. 

Allotments that failed to meet 

Rangeland Health Standards 

because of livestock grazing would 

contain soil in poor health, which 

would potentially include 

characteristics such as reduced 

ground cover, compaction, 

accelerated erosion, sedimentation, 

and decreased productivity, fertility, 

moisture, and organic matter (Evans 

and Ehleringer 1993; Bainbridge 

2007). Potential terms and 

conditions that supported soil system recovery would include exclosures around sensitive areas, optimization of 

herd distribution, reductions in animal unit months (AUMs), and alteration of grazing regimes. 

Deferring grazing for at least 1 growing season following fire within the Big Dry RMP area or temporarily 

closing grazing in the Powder River RMP area would encourage soil recovery from fire. However, 

reestablishing grazing before ground cover was reestablished would expose the soil resource to compaction and 

accelerated erosion by livestock. Reestablishment of vegetative cover following fire would typically occur over 

a minimum of 2 growing seasons (BLM 2007d). Prohibiting grazing until vegetation objectives were met would 

allow for climatic events (e.g., drought) that slowed 

the recovery of the system.

Basing carrying capacity on livestock species and age 

class would reduce the productivity of the soil 

resource because carrying capacity assessments 

would not include soil resource conditions, such as 

potential soil productivity. 

Areas of concentrated open OHV use would result in 

accelerated erosion and reduced ground cover, 

infiltration, nutrient cycling, and organic matter 

(BLM 2003m; Bainbridge 2007), particularly in areas 

of highly erodible soils. OHV use on slopes greater 

than 25 percent would have a severe risk of 

accelerated water erosion (NRCS 1998). Soils with 

biotic, physical, or chemical crusts in areas with low 

vegetative cover would be particularly susceptible to 

TABLE 4-21. 

BLM-ADMINISTERED SOIL RESOURCES MAINTAINED

UNDER ALTERNATIVE A

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Acres 

of 

Slopes 

40% or

Greater

Soils

Ground-based harvest and 

slash-treating equipment 

prohibited on steep slopes 

(Big Dry only)

12,000 NA 15,000

Water

Floodplain, NSO 30,000 220 NA

Waterbody, NSO 8,700 160 NA

Veg.

Riparian and wetland, oil and 

gas NSO 39,000 1,400 NA

Fish and 

Wildlife

Wildlife, oil and gas NSO 84,000 14,000 NA

Sage-grouse, oil and gas

NSO/NSD1 560,000 22,000 NA

Travel Mgmt

and OHV

Closed OHV 0 7 NA

1NSD=No Surface Disturbance

TABLE 4-22. 

BLM-ADMINISTERED SOIL RESOURCES AT 

RISK OF DEGRADATION 

UNDER ALTERNATIVE A

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes

25% or 

Greater

Fire 

Fuels in Condition Class 

3

21,000 4,000

Travel Mgmt 

and OHV

Open OHV Areas 2,000 69
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-37

destabilization from cross-country travel, which would result in accelerated erosion. Disturbance of areas 

dependent on biotic crusts for nutrient cycling would result in reduced fertility (Evans and Ehleringer 1993).

ALTERNATIVE B

Land uses proposed under Alternative B, such as vegetation or fuels treatments, range or habitat improvements,

mechanical invasive species (vegetation) control, oil and gas exploration and extraction, geophysical 

exploration, vehicle use, infrastructure, and ROW activities, would cause surface disturbance. Surface 

disturbances would result in reduced ground cover or soil mixing, compaction, or removal; exposure of the soil 

resource to accelerated wind and water erosion; and the irretrievable loss of topsoil and nutrients. Surface 

disturbances would potentially result in mass movement or sedimentation. Surface disturbances would also 

change soil structure, heterogeneity (variable characteristics), temperature regimes, nutrient cycling, biotic 

richness, and diversity. Mixed soils would have decreased bulk density and altered porosity, infiltration, airwater relationships, salt content, and pH (Perrow and Davy 2003; Bainbridge 2007). Soil compaction would 

result in increased bulk density and reduced porosity, infiltration, moisture, air, nutrient cycling, productivity, 

and biotic activity (Logan 2001; Perrow and Davy 2003; Bainbridge 2007). Altering such characteristics would 

reduce the soil system’s ability to adapt to climate change and withstand future disturbances.

Soils would take decades to hundreds of years to recover from the impacts of altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen

content (Perrow and Davy 2003). Mixed or removed soil horizons are perpetually altered by the disturbance; 

including texture class, rock fragment content, structure, and depth to bedrock. Soil recovery following 

disturbance would be accelerated by mitigation and reclamation to reduce natural recovery rates, typically 

hundreds of years, to within several decades (Perrow and Davy 2003). Within 2 to 5 years of reclamation, 

vegetative cover and rates of erosion would return to pre-disturbance conditions (BLM 2008g). Exceptions to 

this timeline would include sites poorly suited to reclamation (1.6 million acres, 57 percent of the planning 

area), which would require unconventional or site-specific reclamation measures.

Reserve, brine, and water disposal pits would contain material (e.g., drilling fluids, mud, cuttings, and salts) 

that altered soil chemistry and created soil toxic to biota if the material leaked out of the pit. Implementing 

closed-loop drilling or other pitless methods would avoid such impacts and reduce the total area of 

disturbance. Disposal of water with high salt content using land application or seepage ponds would result in 

reduced infiltration and productivity, increased overland flow, accelerated erosion, or cause impacts toxic to 

biota. Discharge of produced water would result in gullying, headcutting, and sedimentation (ALL 2001a; 

BLM 2008g). Spills or leaks of produced hydrocarbons, fuels, or produced water high in salt content would 

create soil toxic to biota (BLM 2008g). Early detection, containment, and cleanup would keep such impacts 

localized.

As slopes approach 30 percent, the risk of soil instability following disturbance increases, particularly if cover, 

structure, permeability, or bulk density has been altered (Monsen et al. 2004). Reclamation suitability is low for 

slopes greater than 20 percent (Monsen et al. 2004). However, surface disturbances would only impact soils on 

slopes less than 25 percent and soils well suited to reclamation. Allowing only management actions that 

benefited the functionality of soil resources would maintain or improve soil resources, including sensitive soils 

(1.6 million acres, 57 percent of the planning area) and soils on slopes greater than 25 percent (150,000 acres, 5 

percent of the planning area) (Table 4-23).

Management actions that prohibited surface-disturbing activities would maintain soil resources. Allowing only 

surface-disturbing activities that benefited the functionality of floodplains, waterbodies, and aquatic wildlife

habitat would enhance natural soil structure and function, particularly hydric soils. However, prohibiting such 

activities within designated riparian, wildlife habitat, cultural, and paleontological areas would inhibit treatment 

strategies that would improve soil resources. 

Management actions designed to maintain, conserve, or improve vegetation conditions (including timber

harvest or salvage for habitat improvement, haying, riparian and wetland areas, fuels management, 

approximating natural disturbance regimes, and supporting forest resilience) would promote natural soil 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-38

structure and function. Although some treatments would cause surface disturbance in the short term, such 

treatments would promote nutrient cycling, soil development, soil biodiversity, and site stability in the long 

term. 

Impoundments would accumulate 

sediment flows that would have 

been deposited naturally 

downstream in other areas, which 

would alter natural erosion and 

deposition rates at the 

impoundment and downstream 

(Zelt et al. 1999). Impoundments 

would also reduce riparian

vegetative cover along the 

channel, which would result in 

accelerated erosion and 

sedimentation (Poff et al. 1997). 

Dam failure would result in 

accelerated water erosion and 

sedimentation. Unlined water 

impoundments would change 

subsurface water flow regimes, 

which would alter natural soil 

formation processes, including 

nutrient cycling, mobilization 

(e.g., sulfate, selenium, arsenic, 

manganese, barium, chloride, and 

nitrate), and salt distribution (NAS

2010). Salts from the 

impoundment concentrated in 

soils would reduce infiltration and 

productivity, increase overland 

flow, accelerate erosion, or cause 

impacts toxic to biota (see the Soils Appendix for further discussion on salt-affected soils). Wet soils 

surrounding the impoundment would be susceptible to compaction from concentrated use. Requiring mitigation 

for such actions would encourage sustainable use of the soil resource.

Although prohibiting surface-disturbing activities in areas of invasive vegetation species infestations would 

maintain soils degraded by such infestations, it would inhibit treatment strategies that maintained or enhanced 

the soil resource. Basing priority treatment areas on Montana-designated invasive vegetation species would 

promote natural soil systems within areas particularly affected by such species. However, basing priority 

treatment areas on sites either particularly susceptible to, or particularly affected by, weed invasions, would 

more effectively maintain or enhance the soil resource.

Wildlife requirements would potentially inhibit treatment strategies that improved soil resources. For example, 

revegetation would potentially be prohibited in the spring, which would result in accelerated erosion due to lack 

of vegetative cover. 

Mitigating surface-disturbing activities to maintain habitat functionality within 2 miles of sharp-tailed grouse

nesting habitat and leks would encourage sustainable use of the soil resource within these areas (Table 4-24).

Requiring sage-grouse habitat compensation would encourage habitat connectivity, which would promote the 

soil system’s ability to adapt to climate change and resilience to future disturbances (Perrow and Davy 2003).

TABLE 4-23. 

BLM-ADMINISTERED SOIL RESOURCES MAINTAINED 

UNDER ALTERNATIVE B

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Soils

Sensitive soil, NSD11,600,000 140,000

Steep slope, NSD 140,000 150,000

Water

Floodplain, NSD 29,000 250

Waterbody, NSD 8,700 160

Veg.

Riparian and wetland, NSD 39,000 1,400

Riparian and wetland, livestock water 

developments prohibited 53,000 1,700

Fish and 

Wildlife

Wildlife, NSD 880,000 95,000

Travel Mgmt 

and OHV

Closed OHV Areas 18,000 2,900

1NSD=No Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-39

Although fuels reduction treatments would cause surface 

disturbance in the short term, they would reduce the intensity 

and severity of wild and prescribed fire (Arno and AllisonBunnell 2002; Perrow and Davy 2003). However, requiring 

pre-commercial or commercial fuels removal prior to 

prescribed fire actions would cause unnecessary degradation 

of the soil resource if other mitigation alternatives existed 

(Table 4-25). Prohibiting prescribed fire and management of 

wildland fire to meet multiple objectives would inhibit natural 

soil development.

Allotments that failed to meet Rangeland Health Standards as 

a result of livestock grazing would contain soil in poor health, 

which would potentially include characteristics such as 

reduced ground cover, compaction, accelerated erosion, 

sedimentation, and decreased productivity, fertility, moisture, 

and organic matter (Evans and Ehleringer 1993; Bainbridge 

2007). Prohibiting grazing in allotments that failed to meet 

Rangeland Health Standards would promote full recovery of 

the soil system. 

Requiring grazing restrictions for 2 growing seasons following fire would promote soil recovery. However, 

prohibiting grazing until vegetation objectives were met would allow for climatic events (e.g., drought) that 

slowed the recovery of the system. Reestablishment of vegetative cover following fire would typically occur 

over a minimum of 2 growing seasons (BLM 2007d).

Basing carrying capacity on soil resource conditions, such as potential soil productivity, would promote 

sustainable use of the soil resource.

ALTERNATIVE C

Land uses proposed under Alternative C, such as vegetation 

or fuels treatments, range or habitat improvements,

mechanical invasive species (vegetation) control, oil and 

gas exploration and extraction, geophysical exploration,

vehicle use, infrastructure development, and ROW

activities, would cause surface disturbance. Surface 

disturbances would result in reduced ground cover or soil 

mixing, compaction, or removal; exposure of the soil 

resource to accelerated wind and water erosion; and the 

irretrievable loss of topsoil and nutrients. Surface 

disturbances would potentially result in mass movement or 

sedimentation. Surface disturbances would also change soil 

structure, heterogeneity (variable characteristics), 

temperature regimes, nutrient cycling, biotic richness, and 

diversity. Mixed soils would have decreased bulk density 

and altered porosity, infiltration, air-water relationships, 

salt content, and pH (Perrow and Davy 2003; Bainbridge 

2007). Soil compaction would result in increased bulk 

density and reduced porosity, infiltration, moisture, air, 

nutrient cycling, productivity, and biotic activity (Logan 

2001; Perrow and Davy 2003; Bainbridge 2007). Altering such characteristics would reduce the soil system’s 

ability to adapt to climate change and withstand future disturbances.

TABLE 4-24. 

BLM-ADMINISTERED SOIL 

RESOURCES CONSERVED 

UNDER ALTERNATIVE B

Area or Resource

Acres of 

Sensitive 

Soils

Acres of 

Slopes 

25% or 

Greater

Fish and 

Wildlife

Wildlife, 

CSD1 760,000 86,000

Travel Mgmt 

and OHV

Limited 

OHV Use 1,600,000 150,000

1CSD=Controlled Surface Disturbance

TABLE 4-25. 

BLM-ADMINISTERED SOIL 

RESOURCES AT RISK OF 

DEGRADATION 

UNDER ALTERNATIVE B

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Fish and Wildlife

Sage-grouse

Habitat – General

Habitat Areas, 

aboveground 

power line

restriction

1,400,000 93,000

Fire 

Fuels in Condition 

Class 3 21,000 4,000
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-40

Soils would take decades to hundreds of years to recover from the impacts of altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen

content (Perrow and Davy 2003). Mixed or removed soil horizons are perpetually altered by the disturbance; 

including texture class, rock fragment content, structure, and depth to bedrock. Soil recovery following 

disturbance would be accelerated by mitigation and reclamation to reduce natural recovery rates, typically 

hundreds of years, to within several decades (Perrow and Davy 2003). Within 2 to 5 years of reclamation, 

vegetative cover and rates of erosion would return to pre-disturbance conditions (BLM 2008g). Exceptions to 

this timeline would include sites poorly suited to reclamation (1.6 million acres, 57 percent of the planning 

area), which would require unconventional or site-specific reclamation measures.

Reserve, brine, and water disposal pits would 

contain material (e.g., drilling fluids, mud, cuttings, 

and salts) that altered soil chemistry and created 

soil toxic to biota if the material leaked out of the 

pit. Implementing closed-loop drilling or other 

pitless methods would avoid such impacts and 

reduce the total area of disturbance. Disposal of 

water with high salt content using land application

or seepage ponds would result in reduced 

infiltration and productivity, increased overland 

flow, accelerated erosion, or cause impacts toxic to 

biota. Discharge of produced water would result in 

gullying, headcutting, and sedimentation (ALL 

2001a; BLM 2008g). Spills or leaks of produced 

hydrocarbons, fuels, or produced water high in salt 

content would create soil toxic to biota (BLM 

2008g). Early detection, containment, and cleanup 

would keep such impacts localized.

As slopes approached 30 percent, the risk of soil 

instability following disturbance would increase, 

particularly if cover, structure, permeability, or bulk 

density had been altered (Monsen et al. 2004). 

Reclamation suitability would be low for slopes 

greater than 20 percent (Monsen et al. 2004). 

Surface disturbance would impact soils on slopes 

less than 25 percent and soils well suited to 

reclamation; actions on slopes greater than 25 percent (150,000 acres, 5 percent of the planning area) and areas 

of sensitive soils (1.6 million acres, 57 percent of the planning area) would require mitigation to ensure 

sustainable use of the soil resource (Table 4-26).

Management actions that prohibited surface-disturbing activities would maintain soil resources (Table 4-27). 

However, prohibiting such activities within designated wildlife habitat, cultural, and paleontological areas 

would inhibit treatment strategies that improved soil resources. Allowing surface disturbances within 

floodplains, waterbodies, riparian areas, and along sport-fish reservoirs would impact natural soil structure and 

function, including hydric soils, which would result in compaction and accelerated water erosion and reduced 

productivity, infiltration, and water storage. Requiring mitigation for such actions would encourage sustainable 

use of the soil resource.

Management actions designed to maintain, conserve, or improve vegetation conditions (including timber

harvest or salvage for habitat improvement, managing for PFC, haying, fuels management, approximating 

natural disturbance regimes, and supporting forest resilience) would promote natural soil structure and function. 

Although some treatments would cause surface disturbance in the short term, such treatments would promote 

nutrient cycling, soil development, soil biodiversity, and site stability in the long term. 

TABLE 4-26. 

BLM-ADMINISTERED SOIL RESOURCES 

CONSERVED 

UNDER ALTERNATIVE C

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Soils

Sensitive soil, CSD11,600,000 140,000

Steep slope, CSD 140,000 150,000

Water

Floodplain, CSD 29,000 250

Waterbody, CSD 8,700 160

Veg.

Riparian and wetland, 

CSD 39,000 1,400

Fish and 

Wildlife

Wildlife, CSD 880,000 95,000

Travel Mgmt 

and OHV

Limited OHV Use 1,600,000 150,000

1CSD=Controlled Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-41

Impoundments would accumulate sediment flows that would have been deposited naturally downstream in 

other areas, which would alter natural erosion and deposition rates at the impoundment and downstream (Zelt et 

al. 1999). Impoundments would also reduce riparian vegetative cover along the channel, which would result in 

accelerated erosion and sedimentation (Poff et al. 1997). Dam failure would result in accelerated water erosion

and sedimentation. Unlined water impoundments would change subsurface water flow regimes, which would 

alter natural soil formation processes, including nutrient cycling, mobilization (e.g., sulfate, selenium, arsenic, 

manganese, barium, chloride, and nitrate), and salt distribution (NAS 2010).

Although allowing surface-disturbing activities in areas of invasive vegetation species infestations would 

degrade soil resources already affected by the infestation, it would permit treatment strategies that maintained 

or enhanced the soil resource. Basing priority treatment areas on sites either particularly susceptible to, or 

particularly affected by, weed invasions, would more effectively maintain or enhance the soil resource.

Wildlife requirements under this alternative would potentially inhibit treatment strategies that improved soil 

resources. For example, revegetation would potentially be prohibited in the spring, which would result in 

accelerated erosion due to lack of vegetative cover.

Mitigating surface-disturbing activities to maintain habitat functionality within 2 miles of sharp-tailed grouse

nesting habitat and leks would encourage sustainable use of the soil resource within these areas.

Requiring sage-grouse habitat compensation would encourage habitat connectivity, which would promote the 

soil system’s ability to adapt to climate change and resilience to future disturbances (Perrow and Davy 2003).

Although fuels reduction treatments would cause surface disturbance in the short-term, they would reduce the 

intensity and severity of wild and prescribed fire (Arno and Allison-Bunnell 2002; Perrow and Davy 2003). 

Allowing prescribed fire (up to approximately 7,500 acres annually) and management of wildland fire to meet 

multiple objectives would promote natural soil development. 

Allotments that failed to meet Rangeland Health Standards as a 

result of livestock grazing would contain soil in poor health, 

which would potentially include characteristics such as 

reduced ground cover, compaction, accelerated erosion, 

sedimentation, and decreased productivity, fertility, moisture, 

and organic matter (Evans and Ehleringer 1993; Bainbridge 

2007). Prohibiting grazing in allotments that failed to meet 

Rangeland Health Standards for 5 years would promote 

recovery of the soil system. However, the compaction and 

accelerated erosion associated with grazing over the course of 

the 5-year evaluation would slow the recovery of the 

compromised soil system. 

Requiring temporary grazing restrictions until the allotment 

reached vegetation objectives following fire would encourage 

soil recovery and allow for climatic events (e.g., drought) that 

slowed the recovery of the system. Reestablishment of 

vegetative cover following fire would typically occur over a 

minimum of 2 growing seasons (BLM 2007d).

Basing carrying capacity on soil resource conditions, such as 

potential soil productivity, would promote sustainable use of 

the soil resource.

TABLE 4-27. 

BLM-ADMINISTERED SOIL 

RESOURCES MAINTAINED 

UNDER ALTERNATIVE C

Area or Resource

Acres of 

Sensitive 

Soils

Acres of 

Slopes 

25% or 

Greater

Veg.

Riparian and 

wetland, 

livestock 

water 

developments 

prohibited

53,000 1,700

Fish and 

Wildlife

Wildlife, oil

and gas NSO 950 12

Wildlife, 

NSD1 21,000 770

Travel Mgmt 

and OHV

Closed OHV

Areas 49 0

1NSD=No Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-42

Areas of concentrated open OHV use would result in compaction, accelerated erosion, and reduced ground 

cover, infiltration, nutrient cycling, and organic matter (BLM 2003m; Bainbridge 2007), particularly in areas 

of highly erodible soils (Table 4-28). OHV use on slopes greater than 25 percent would have a severe risk of 

accelerated water erosion (NRCS 1998). Soils with biotic, physical, or chemical crusts in areas with low 

vegetative cover would be particularly susceptible to destabilization from cross-country travel, which would 

result in accelerated erosion. Disturbance of areas dependent on biotic crusts for nutrient cycling would result 

in reduced fertility (Evans and Ehleringer 1993).

Although soil compaction would occur in areas of 

concentrated use for big game retrieval, these 

impacts would be alleviated by annual freeze and 

thaw action, root penetration, or the shrink-swell 

action of clays.

ALTERNATIVE D

Land uses proposed under Alternative D, such as 

vegetation or fuels treatments, range or habitat 

improvements, mechanical invasive species 

(vegetation) control, oil and gas exploration and 

extraction, geophysical exploration, vehicle use,

infrastructure development, and ROW activities, 

would cause surface disturbances. Surface 

disturbances would result in reduced ground cover or 

soil mixing, compaction, or removal; exposure of the 

soil resource to accelerated wind and water erosion; 

and the irretrievable loss of topsoil and nutrients. 

Surface disturbances would potentially result in mass 

movement or sedimentation. Surface disturbances would also change soil structure, heterogeneity (variable 

characteristics), temperature regimes, nutrient cycling, biotic richness, and diversity. Mixed soils would have 

decreased bulk density and altered porosity, infiltration, air-water relationships, salt content, and pH (Perrow 

and Davy 2003; Bainbridge 2007). Soil compaction would result in increased bulk density and reduced 

porosity, infiltration, moisture, air, nutrient cycling, productivity, and biotic activity (Logan 2001; Perrow and 

Davy 2003; Bainbridge 2007). Altering such characteristics would reduce the soil system’s ability to adapt to 

climate change and withstand future disturbances.

Soils would take decades to hundreds of years to recover from the impacts of altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen

content (Perrow and Davy 2003). Mixed or removed soil horizons are perpetually altered by the disturbance; 

including texture class, rock fragment content, structure, and depth to bedrock. Soil recovery following 

disturbance would be accelerated by mitigation and reclamation to reduce natural recovery rates, typically 

hundreds of years, to within several decades (Perrow and Davy 2003). Within 2 to 5 years of reclamation, 

vegetative cover and rates of erosion would return to pre-disturbance conditions (BLM 2008g). Exceptions to 

this timeline would include sites poorly suited to reclamation (1.6 million acres, 57 percent of the planning 

area), which would require unconventional or site-specific reclamation measures.

Reserve, brine, and water disposal pits would contain material (e.g., drilling fluids, mud, cuttings, and salts) 

that altered soil chemistry and created soil toxic to biota if the material leaked out of the pit. Implementing 

closed-loop drilling or other pitless methods would avoid such impacts and reduce the total area of 

disturbance. Disposal of water with high salt content using land application or seepage ponds would result in 

reduced infiltration and productivity, increased overland flow, accelerated erosion, or cause impacts toxic to 

biota. Discharge of produced water would result in gullying, headcutting, and sedimentation (ALL 2001a; 

BLM 2008g). Spills or leaks of produced hydrocarbons, fuels, or produced water high in salt content would 

TABLE 4-28. 

BLM-ADMINISTERED SOIL RESOURCES AT 

RISK OF DEGRADATION 

UNDER ALTERNATIVE C

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Fish and 

Wildlife

Sage-grouse Habitat –

General Sage-grouse 

Areas, aboveground 

power line restriction

930,000 43,000

Travel Mgmt 

and OHV

Open OHV Areas 480 2
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-43

create soil toxic to biota (BLM 2008g). Early detection, containment, and cleanup would keep such impacts 

localized.

As slopes approached 30 percent, the risk of soil instability following disturbance would increase, particularly if 

cover, structure, permeability, or bulk density had been altered (Monsen et al. 2004). Reclamation suitability 

would be low for slopes greater than 20 percent (Monsen et al. 2004). Surface disturbance would impact soils 

on slopes less than 25 percent, soils well suited to reclamation, and slopes greater than 25 percent (150,000 

acres, 5 percent of the planning area). Areas of sensitive soils (1.6 million acres, 57 percent of the planning 

area) would require mitigation to ensure sustainable use of the soil resource (Table 4-29).

Management actions that prohibited surfacedisturbing activities would maintain soil 

resources. However, prohibiting such 

activities within designated cultural areas 

would inhibit treatment strategies that 

improved soil resources. Allowing surface 

disturbances within floodplains, 

waterbodies, riparian areas, and along sportfish reservoirs would impact natural soil 

structure and function, including hydric 

soils, and result in compaction, accelerated 

water erosion, and reduced productivity, 

infiltration, and water storage. Requiring 

mitigation for such actions would encourage 

sustainable use of the soil resource. 

Prohibiting livestock water developments in 

riparian and wetland areas would maintain 

53,000 BLM-administered acres of sensitive 

soils and 1,700 BLM-administered acres of 

slopes 25 percent or greater.

Management actions designed to maintain, 

conserve, or improve vegetation conditions 

(including timber harvest or salvage for 

habitat improvement, managing for PFC, 

fuels management, approximating natural 

disturbance regimes, and supporting forest

resilience) would promote natural soil 

structure and function. Although some 

treatments would cause surface disturbance 

in the short term, such treatments would 

promote nutrient cycling, soil development, soil biodiversity, and site stability in the long term.

Impoundments would accumulate sediment flows that would have been deposited naturally downstream in 

other areas, which would alter natural erosion and deposition rates at the impoundment and downstream (Zelt et 

al. 1999). Impoundments would also reduce riparian vegetative cover along the channel, which would result in 

accelerated erosion and sedimentation (Poff et al. 1997). Dam failure would result in accelerated water erosion 

and sedimentation. Unlined water impoundments would change subsurface water flow regimes, which would 

alter natural soil formation processes, including nutrient cycling, mobilization (e.g., sulfate, selenium, arsenic, 

manganese, barium, chloride, and nitrate), and salt distribution (NAS 2010). Requiring mitigation for such 

actions would encourage sustainable use of the soil resource.

TABLE 4-29. 

BLM-ADMINISTERED SOIL RESOURCES 

CONSERVED 

UNDER ALTERNATIVE D

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Soils

Sensitive soil, CSD11,600,000 140,000

Steep slope, CSD 140,000 150,000

Water

Floodplain, CSD 29,000 250

Waterbody, CSD 8,700 160

Veg.

Riparian and wetland, CSD 39,000 1,400

Fish and 

Wildlife

Wildlife, CSD 880,000 95,000

Travel Mgmt 

and OHV

Limited OHV Use 1,600,000 150,000

1CSD=Controlled Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-44

Although allowing surface-disturbing activities in areas of invasive vegetation species infestations would 

degrade soil resources already affected by the infestation, it would permit treatment strategies that maintained 

or enhanced the soil resource. Basing priority treatment areas on the area’s proximity to private lands with 

active weed management would conserve the soil resource in areas with particularly manageable weed 

infestations. However, basing priority treatment areas on sites either particularly susceptible to, or particularly 

affected by, weed invasions, would more effectively maintain or enhance the soil resource.

Mitigating surface-disturbing activities to maintain habitat functionality within 2 miles of sharp-tailed grouse

nesting habitat and leks would encourage sustainable use of the soil resource in these areas.

Requiring sage-grouse habitat compensation would encourage habitat connectivity, which would promote the 

soil system’s ability to adapt to climate change and resilience to future disturbances.

Although fuels reduction treatments would cause surface disturbance in the short-term, they would reduce the 

intensity and severity of wild and prescribed fire (Arno and Allison-Bunnell 2002; Perrow and Davy 2003). 

Allowing prescribed fire (up to approximately 7,500 acres annually) and management of wildland fire to meet 

multiple objectives would promote natural soil development. 

Allotments that failed to meet Rangeland Health Standards as a result of livestock grazing would contain soil in 

poor health, which would potentially include characteristics such as reduced ground cover; compaction; 

accelerated erosion; sedimentation; and decreased productivity, fertility, moisture, and organic matter. Although 

prohibiting grazing in allotments that failed to meet 

Rangeland Health Standards for 5 years would promote 

recovery of the soil system, the compaction and accelerated 

erosion associated with grazing over the course of the 5-

year evaluation would slow the recovery of the 

compromised soil system. 

Requiring grazing restrictions for 2 growing seasons 

following fire would promote soil recovery. However, 

prohibiting grazing until vegetation objectives were met 

would allow for climatic events (e.g., drought) that slowed 

the recovery of the system. Reestablishment of vegetative 

cover following fire would typically occur over a minimum 

of 2 growing seasons (BLM 2007d).

Areas of concentrated open OHV use would result in 

compaction, accelerated erosion, and reduced ground cover, 

infiltration, nutrient cycling, and organic matter (BLM 

2003m; Bainbridge 2007), particularly in areas of highly 

erodible soils (Table 4-30). Although soil compaction 

would occur in areas of concentrated use for big game

retrieval, these impacts would be alleviated by annual freeze 

and thaw.

ALTERNATIVE E (PREFERRED ALTERNATIVE)

Land uses proposed under Alternative E, such as vegetation or fuels treatments, range or habitat improvements,

mechanical invasive species (vegetation) control, oil and gas exploration and extraction, geophysical 

exploration, vehicle use, infrastructure development, and ROW activities, would cause surface disturbance. 

Surface disturbances would result in reduced ground cover or soil mixing, compaction, or removal; exposure of 

the soil resource to accelerated wind and water erosion; and the irretrievable loss of topsoil and nutrients. 

Surface disturbances would potentially result in mass movement or sedimentation. Surface disturbances would 

also change soil structure, heterogeneity (variable characteristics), temperature regimes, nutrient cycling, biotic 

richness, and diversity. Mixed soils would have decreased bulk density and altered porosity, infiltration, airTABLE 4-30. 

BLM-ADMINISTERED SOIL 

RESOURCES AT RISK OF

DEGRADATION 

UNDER ALTERNATIVE D 

Area or Resource

Acres of 

Sensitive 

Soils

Acres of 

Slopes 

25% or 

Greater

Fish and Wildlife

Sage-grouse

Habitat –

General Sagegrouse Areas, 

aboveground 

power line

restriction

560,000 22,000

Travel Mgmt and 

OHV

Open OHV

Areas 1,700 56
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-45

water relationships, salt content, and pH (Perrow and Davy 2003; Bainbridge 2007). Soil compaction would 

result in increased bulk density and reduced porosity, infiltration, moisture, air, nutrient cycling, productivity, 

and biotic activity (Logan 2001; Perrow and Davy 2003; Bainbridge 2007). Altering such characteristics would 

reduce the soil system’s ability to adapt to climate change and withstand future disturbances.

Soils would take decades to hundreds of years to recover from the impacts of altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen

content (Perrow and Davy 2003). Mixed or removed soil horizons are perpetually altered by the disturbance; 

including texture class, rock fragment content, structure, and depth to bedrock. Soil recovery following 

disturbance would be accelerated by mitigation and reclamation to reduce natural recovery rates, typically 

hundreds of years, to within several decades (Perrow and Davy 2003). Within 2 to 5 years of reclamation, 

vegetative cover and rates of erosion would return to pre-disturbance conditions (BLM 2008g). Exceptions to 

this timeline would include sites poorly suited to reclamation (1.6 million acres, 57 percent of the planning

area), which would require unconventional or site-specific reclamation measures.

Reserve, brine, and water disposal pits would contain material (e.g., drilling fluids, mud, cuttings, and salts) 

that altered soil chemistry and created soil toxic to biota if the material leaked out of the pit. Implementing 

closed-loop drilling or other pitless methods would avoid such impacts and reduce the total area of 

disturbance. Disposal of water with high salt content using land application or seepage ponds would result in 

reduced infiltration and productivity, increased overland flow, accelerated erosion, or cause impacts toxic to 

biota. Discharge of produced water would result in gullying, headcutting, and sedimentation (ALL 2001a; 

BLM 2008g). Spills or leaks of produced hydrocarbons, fuels, or produced water high in salt content would 

create soil toxic to biota (BLM 2008g). Early detection, containment, and cleanup would keep such impacts 

localized.

As slopes approached 30 percent, the risk of soil 

instability following disturbance would increase, 

particularly if cover, structure, permeability, or bulk 

density had been altered (Monsen et al. 2004). 

Reclamation suitability would be low for slopes 

greater than 20 percent (Monsen et al. 2004). Surface 

disturbance would impact soils on slopes less than 25 

percent and soils well suited to reclamation. Actions 

on slopes greater than 25 percent (150,000 acres, 5 

percent of the planning area) and areas of sensitive 

soils (1.6 million acres, 57 percent of the planning 

area) would require mitigation to ensure sustainable 

use of the soil resource (Table 4-31).

Allowing surface disturbance within floodplains, 

waterbodies, within 300 feet of waterbodies and 

streams, and along sport-fish reservoirs would impact 

natural soil structure and function, including hydric 

soils, which would result in compaction and 

accelerated water erosion and reduced productivity, 

infiltration, and water storage. Requiring mitigation 

for such actions would encourage sustainable use of 

the soil resource.

Management actions that were designed to maintain, 

conserve, or improve vegetation conditions (including 

timber harvest or salvage for habitat improvement, 

managing for PFC, haying, fuels management, 

approximating natural disturbance regimes, and 

supporting forest resilience) would promote natural 

TABLE 4-31. 

BLM-ADMINISTERED SOIL RESOURCES 

CONSERVED 

UNDER ALTERNATIVE E

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Soils

Sensitive soil, CSD11,600,000 140,000

Steep slope, CSD 140,000 150,000

Water

Floodplain, CSD 29,000 250

Waterbody (including 

300-foot buffer), CSD 8,700 160

Veg.

Riparian and wetland, 

CSD 46,000 1,400

Fish and 

Wildlife

Wildlife, CSD 880,000 95,000

Travel Mgmt 

and OHV

Limited OHV Use 1,600,000 150,000

1CSD=Controlled Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-46

soil structure and function. Although some treatments would cause surface disturbance in the short term, such 

treatments would promote nutrient cycling, soil development, soil biodiversity, and site stability in the long 

term.

Impoundments would accumulate sediment flows that 

would have been deposited naturally downstream in 

other areas, which would alter natural erosion and 

deposition rates at the impoundment and downstream 

(Zelt et al. 1999). Impoundments would also reduce 

riparian vegetative cover along the channel, which would 

result in accelerated erosion and sedimentation (Poff et 

al. 1997). Dam failure would result in accelerated water 

erosion and sedimentation. Unlined water impoundments 

would change subsurface water flow regimes, which 

would alter natural soil formation processes, including 

nutrient cycling, mobilization (e.g., sulfate, selenium, 

arsenic, manganese, barium, chloride, and nitrate), and 

salt distribution (NAS 2010). Wet soils surrounding the 

impoundment would be susceptible to compaction from 

concentrated use. Requiring mitigation for such actions 

would encourage sustainable use of the soil resource.

Trough and tank development in riparian and wetland

areas would result in compaction from concentrated 

livestock use. Compacted soils would be at risk of 

increased surface salt accumulation, which would further 

reduce infiltration and productivity, increase overland 

flow, accelerate erosion, or cause impacts toxic to biota. 

Requiring mitigation to maintain the integrity and 

functionality of the system would encourage sustainable 

use of the soil resource

Although allowing surface-disturbing activities in areas of invasive vegetation species infestations would 

degrade soil resources already affected by the infestation, it would permit treatment strategies that maintained 

or enhanced the soil resource (Table 4-32). Delineating priority treatment areas would enhance the soil 

resource in sites either particularly susceptible to, or particularly affected by, weed invasions.

Mitigating surface-disturbing activities to maintain habitat within 2 miles of sharp-tailed grouse nesting habitat 

and leks would encourage sustainable use of the soil resource in these areas.

The absence of sage-grouse habitat compensation requirements under this alternative would cause soil system 

fragmentation, which would alter soil structure and function. Soil system fragmentation would result in altered 

soil heterogeneity, microclimate, hydrology, nutrient cycling, biotic richness, and diversity (Perrow and Davy 

2003). Localized impacts would include microclimatic changes tens of meters into the patch (from the edge) but

altered biota and nutrient cycling would extend even further (Perrow and Davy 2003). Pre-existing disturbance 

regimes (e.g., fire) would be altered on a landscape scale, which would change natural rates of soil formation 

(Perrow and Davy 2003).

Although fuels reduction treatments would cause surface disturbance in the short-term, they would reduce the 

intensity and severity of wild and prescribed fire (Arno and Allison-Bunnell 2002; Perrow and Davy 2003). 

Allowing prescribed fire (up to approximately 7,500 acres annually) and management of wildland fire to meet 

multiple objectives would promote natural soil development. 

Allotments that failed to meet Rangeland Health Standards as a result of livestock grazing would contain soil in 

poor health, which would potentially include characteristics such as reduced ground cover, compaction, 

TABLE 4-32. 

BLM-ADMINISTERED SOIL RESOURCES 

MAINTAINED 

UNDER ALTERNATIVE E

Area or Resource

Acres of 

Sensitive 

Soils

Acres of 

Slopes 

25% or 

Greater

Water

Floodplain, oil and 

gas NSO 29,000 250

Waterbody, oil and 

gas NSO 39,000 1,400

Veg.

Riparian and 

wetland, oil and gas

NSO

39,000 1,400

Fish and 

Wildlife

Aquatics, sport-fish

reservoirs, oil and 

gas NSO

770 12

Travel Mgmt 

and OHV

Closed OHV Areas 1,100 96
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-47

accelerated erosion, sedimentation, and decreased productivity, fertility, moisture, and organic matter (Evans 

and Ehleringer 1993; Bainbridge 2007). Prohibiting grazing in allotments that failed to meet Rangeland Health 

Standards for 5 years would promote recovery of the soil system. However, the compaction and accelerated 

erosion associated with grazing over the course of the 5-year evaluation would slow the recovery of the 

compromised soil system. 

Requiring temporary grazing restrictions until the allotment reached resource objectives following fire would 

allow for climatic events (e.g., drought) that slowed the recovery of the soil system. Reestablishment of 

vegetative cover following fire would typically occur over a minimum of 2 growing seasons (BLM 2007d).

Basing carrying capacity on livestock species and age class would reduce the productivity of the soil resource, 

because carrying capacity assessments would not include soil resource conditions, such as potential soil 

productivity. 

Areas of concentrated open OHV use would result in 

compaction, accelerated erosion, and reduced ground cover, 

infiltration, nutrient cycling, and organic matter (BLM 2003m; 

Bainbridge 2007), particularly in areas of highly erodible soils 

(Table 4-33). OHV use on slopes greater than 25 percent would 

carry a severe risk of accelerated water erosion (NRCS 1998).

Soils with biotic, physical, or chemical crusts in areas with low 

vegetative cover would be particularly susceptible to 

destabilization from cross-country travel, which would result in 

accelerated erosion. Disturbance of areas dependent on biotic 

crusts for nutrient cycling would result in reduced fertility 

(Evans and Ehleringer 1993).

CUMULATIVE IMPACTS

Historical and ongoing activities adjacent to or within the 

planning area include mineral exploration and development, 

livestock grazing, on- and off-road vehicle use, recreation, 

infrastructure development, fire suppression, altered fire 

regimes, forestry, urbanization, invasive vegetation species 

infestations, pollution, and agriculture. The cumulative effects 

of such activities have contributed to compaction, increased 

overland flow, mass movement, and accelerated erosion by wind and water and resulted in sedimentation and 

the irretrievable loss of topsoil and nutrients. Long-term impacts have included altered pH and reduced soil 

stability, organic matter content, microbial mass, biotic richness and diversity, and phosphorus and nitrogen

content (Perrow and Davy 2003). Permanent impacts have included altered texture class, rock fragment content, 

structure, and depth to bedrock. Such activities have also caused habitat fragmentation, which has resulted in 

altered soil heterogeneity, microclimate, hydrology, nutrient cycling, biotic richness, and diversity (Perrow and 

Davy 2003). Pre-existing disturbance regimes (e.g., fire) have been altered, which also altered natural rates of 

soil formation (Perrow and Davy 2003). 

From the 1860s through the 1890s, the United States military brought great numbers of livestock (horses, 

mules, sheep, and cattle) to eastern Montana, replacing bison as the dominant large ungulate. Although the 

planning area evolved with large ungulate herbivory, uncontrolled grazing (first by the military and then by 

ranchers beginning in the late 19th century) has caused reduced ground cover, compaction, accelerated erosion, 

sedimentation, decreased productivity, fertility, moisture, and organic matter (Evans and Ehleringer 1993; 

Bainbridge 2007). Beginning in 1934, the Taylor Grazing Act and subsequent grazing management (e.g., proper 

stocking rates and season of use) improved range condition and soil conservation. 

Beginning in the late 1800s, commercial production of coal caused soil mixing, removal, compaction, 

accelerated erosion, and sedimentation. Starting in 1977, coal development became subject to the Surface 

TABLE 4-33. 

BLM-ADMINISTERED SOIL 

RESOURCES AT RISK OF 

DEGRADATION 

UNDER ALTERNATIVE E

Area or Resource

Acres of 

Sensitive 

Soils

Acres 

of 

Slopes 

25% or 

Greater

Fish and Wildlife

Sage-grouse

Habitat –

General Sagegrouse Areas, 

aboveground 

power line

restriction

560,000 22,000

Travel Mgmt 

and OHV

Open OHV

Areas 1,700 56
CHAPTER 4

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Soils

4-48

Mining Control and Reclamation Act (also known as SMCRA) (30 U.S.C. 1201 et seq.), which provided 

protection for soil resources. Such surface disturbances continue to this day, including oil and gas extraction 

(beginning in the 1950s), along with several other forms of minerals extraction such as bentonite, gravel, and 

scoria.

Homesteaders arriving in the early 20th century developed croplands, subjecting soils to surface-disturbing 

actions and irrigation, which resulted in accelerated erosion, nutrient depletion, soil salinity, and sodicity. Land 

application of water has resulted in saline seeps. Drought, in combination with cropland development in 1919 

and again in the 1930s, resulted in accelerated wind erosion of agricultural lands. The Soil Conservation and 

Domestic Allotment Act of 1935 (P.L. 74-46) encouraged farmers in eastern Montana to conserve the soil 

resource on croplands, which led to a decline in accelerated wind erosion. In 1985, the Conservation Reserve 

Program began promoting conservation of erodible soils by supporting cover crops, reduced surface-disturbing 

actions, and the conversion of marginal croplands to grassland.

Beginning early in the 20th century, fire suppression (in conjunction with grazing, development, and nonnative

vegetation) has altered natural fire regimes in eastern Montana (USFS and USDI 2007), resulting in altered soil 

development, nutrient cycling, and soil biodiversity. Recently, fuels treatments on lands adjacent to the planning 

area have reduced the intensity and severity of wild fire and resulted in the landscape trending toward a natural 

fire regime.

Although land management within watersheds contiguous to the planning area contributes to increased overland 

flow onto BLM-administered lands (leading to accelerated water erosion and sedimentation), soil conservation 

and improvement is a fundamental component of most management on lands adjacent to the planning area. 

Accelerated erosion from roads has been reduced with improved road construction and maintenance methods. 

Federal and state requirements for water quality have contributed to reductions in accelerated erosion and 

sedimentation. Federal and state air quality standards have contributed to fugitive dust control and reductions in 

atmospheric deposition of pollutants. Management for wildlife under the Endangered Species Act (ESA) and 

state sensitive species guidelines and regulations has contributed to soil conservation and restoration. Invasive 

weed control on adjacent lands continues to protect soils from many nonnative species. The Custer National 

Forest Plan provides for soil resource conservation (USFS 1986). Management actions that promoted organic 

soil carbon storage on adjacent lands would inherently reduce overland flow onto BLM-administered lands and 

would potentially alter water cycles and other ecosystem processes. Management of soil resources on lands 

adjacent to the planning area is expected to continue on the path of conservation and improvement, which 

would result in increased soil health and reduced accelerated erosion and sedimentation. Although surfacedisturbing actions on BLM-administered lands on up to approximately 50,000 acres in the short term and up to 

330,000 acres in the long term would potentially occur, all land uses under all alternatives would meet the 

Standards for Rangeland Health. Alternatives vary in the amount of localized site-level impacts.

Alternative A

The assessed resources, ecosystems, and human communities of concern are approaching conditions in which 

additional stresses associated with the proposed action and past, present, and future foreseeable actions would 

have cumulative effects. Alternative A would contribute to a decline in soil resource health and conservation. 

This alternative would maintain 17,000 acres of sensitive soils and 470 acres of slopes 25 percent or greater 

under surface-disturbing actions and require mitigation on 6,800 acres of sensitive soils and 590 acres of slopes 

greater than 25 percent. Historically, management actions proposed under Alternative A have led to allotments 

that failed to meet Rangeland Health Standards or that contained downward trend riparian or wetland areas, 

ecosystems with moderate to high departures from natural fire regimes, and disturbed lands with insufficient 

reclamation. 

Alternative B

The assessed resources, ecosystems, and human communities of concern are approaching conditions in which 

additional stresses associated with the proposed action and past, present, and future foreseeable actions would 

have cumulative effects. Alternative B would contribute to the continuing increase in soil resource health and 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Soils

4-49

conservation because many actions under Alternative B would not allow surface uses and ground-disturbing 

actions. This alternative would maintain 1.6 million acres of sensitive soils and 150,000 acres of slopes 25 

percent or greater under surface-disturbing actions and require mitigation on 6,400 acres of sensitive soils and 

470 acres of slopes greater than 25 percent. 

Alternative C

The assessed resources, ecosystems, and human communities of concern are approaching conditions in which 

additional stresses associated with the proposed action and past, present, and future foreseeable actions would 

have cumulative effects. Alternative C would contribute to the continuing increase in soil resource health and 

conservation because many actions within Alternative C would require controlled management of surface uses 

and ground-disturbing actions, including those aimed toward ecological improvement. Consequently, 

Alternative C would provide for conservation of the soil resources. This alternative would maintain 520,000

acres of sensitive soils and 34,000 acres of slopes 25 percent or greater under surface-disturbing actions and 

require mitigation on 1.1 million acres of sensitive soils and 20,000 acres of slopes greater than 25 percent.

Alternative D

The assessed resources, ecosystems, and human communities of concern are approaching conditions in which 

additional stresses associated with the proposed action and past, present, and future foreseeable actions would 

have cumulative effects. Alternative D would contribute to the continuing increase in soil resource health and 

conservation because many actions under Alternative D would require controlled management of surface uses 

and ground-disturbing actions, including those aimed toward ecological improvement. Consequently, 

Alternative D would provide for conservation of the soil resources. This alternative would maintain 

approximately 320,000 acres of sensitive soils and 17,000 acres of slopes 25 percent or greater under surfacedisturbing actions and require mitigation on 1.3 million acres of sensitive soils and 130,000 acres of slopes 

greater than 25 percent. 

Alternative E (Preferred Alternative)

The assessed resources, ecosystems, and human communities of concern are approaching conditions in which 

additional stresses associated with the proposed action and past, present, and future foreseeable actions would 

have cumulative effects. Alternative E would contribute to the continuing increase in soil resource health and 

conservation because many actions under Alternative E would require controlled management of surface uses 

and ground-disturbing actions, including those aimed toward ecological improvement. Consequently, 

Alternative E would provide for conservation of soil resources. This alternative would also provide for required 

mitigation in areas that buffered waterbodies and riparian areas. This alternative would maintain 480 acres of 

sensitive soils and 170 acres of slopes 25 percent or greater under surface-disturbing actions and require 

mitigation on 1.6 million acres of sensitive soils and 150,000 acres of slopes greater than 25 percent.

WATER RESOURCES

ASSUMPTIONS AND METHODOLOGY

There would be 1 to 10 watershed enhancement projects (with an emphasis on MDEQ water quality impaired or 

threatened streams) constructed each year, disturbing a total of 1 to 100 acres per year.

Surface water impoundments are human-constructed impoundments (e.g., pits, reservoirs, stock ponds) of 

surface water (e.g. overland flow, streamflow, springs) confined by a dam, dike, or other constructed barrier. 

This does not include impoundments of groundwater (unless the water were naturally discharged to the surface, 

as in a spring), water from wells, or produced water sources (e.g., water disposal pit). 

Waterbodies include all surface water (e.g., rivers, streams, creeks, coulees, springs, reservoirs, lakes, ponds, 

wetlands, and canals).
CHAPTER 4

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4-50

Acre figures and other numbers used in the analysis are approximate projections for comparison and analytical 

purposes only. The planning area is estimated to contain approximately:

 300,000 acres of waterbodies, of which 12,000 are BLM-administered surface acres and 41,000 are 

BLM-administered mineral estate acres;

 1.0 million acres of floodplains of major rivers, of which 35,000 acres are BLM-administered surface 

and 260,000 acres are BLM-administered mineral estate under Alternative A; and

 1.4 million acres of floodplains, of which 42,000 are BLM-administered surface acres and 330,000 are 

BLM-administered mineral estate acres under Alternatives B, C, and D.

The GIS estimation of waterbody acres is based on the 1:24,000-scale 2009 USGS National Hydrography 

Dataset flowlines (with an approximation of 12-foot wide perennial streams and 4-foot wide intermittent and 

ephemeral streams) in combination with waterbody and major stream polygons. 

The GIS estimation of floodplain acres are based on NRCS soil interpretation of a flood frequency classification 

of a rare to very frequent flooding class (a 1 percent or greater chance of flooding in any given year) in 

combination with the waterbodies and major stream polygons from the 1:24,000-scale 2009 USGS National 

Hydrography Dataset. The NRCS data are based on soil properties, evidence collected during soil survey 

fieldwork, and flood analyses, where available. Federal Emergency Management Agency data (of very limited 

extent in the planning area) were incorporated for classification of floodplains with very frequent flooding.

Because it is based on known acres, the estimate is low. Data would be incorporated as they were collected. 

Under Alternative A, floodplains of major streams were delineated based on floodplains within 250 feet of 

named streams. 

Impacts analysis and conclusions are based on interdisciplinary team knowledge of resources, reviews of 

existing literature, and information provided by other agencies and institutions.

Mitigation, specialized design features, and CSU stipulations for oil and gas leasing and development would not 

correlate directly to the reduction of BLM-administered oil and gas wells or acres of surface disturbance.

Acre figures in all tables, except where noted, may overlap, and adding these figures will not result in accurate 

total acreage values.

BLM-authorized activities would comply with state and federal regulations, Rangeland Health Standards, and 

BMPs to protect the chemical, physical, and biological integrity of the water and riparian habitat. 

Improving the condition of degraded uplands, riparian areas, and wetlands is a reasonable land, soil, and water 

conservation practice that reduces nonpoint source pollution from these source areas. Actions that increased the 

resiliency of ecosystems would reduce the vulnerability of the water resources to climate change impacts. A 

resilient ecosystem would be able to function properly during slow and moderate climate changes (CEICC 

2008).

MANAGEMENT COMMON TO ALL ALTERNATIVES

Management actions limiting surface disturbance would benefit water resources by reducing impacts to water 

resources. Water resources would be affected by surface disturbance in uplands, riparian areas, wetland areas, 

and waterbodies within the watershed (BLM-administered land and other ownerships). Surface-disturbing 

activities (including ROW actions; mineral and energy exploration [including renewable energy], leasing, and 

development; geophysical exploration; OHV and vehicle use; special designation and recreation area 

designations and use Table [4-34]; infrastructure development; vegetation and fuel treatments [including 

some habitat restoration projects]; cultural or paleontological excavation; establishment of wildfire fuel 

breaks; burial of power lines; and range improvements) would cause vegetation removal, soil compaction, 

and soil disturbance (Table 4-35). Impacts would include accelerated erosion, increased overland flow, 

decreased infiltration, and degradation of water quality through increased sedimentation, turbidity, nutrients, 

eutrophication, metals, and other pollutants in waterbodies. Erosion potential would be increased further 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-51

through soil compaction and low-permeability surfacing (e.g., roads and well pads), which would increase the 

energy and amount of overland flow, which would subsequently increase sedimentation and erosion and alter 

flow characteristics. The magnitude of these impacts would depend on the specific activity, season, proximity 

to waterbodies, location in the watershed, condition of upland and riparian vegetation, soils, watershed 

resilience, efficacy of mitigation (see the Best Management Practices Appendix), and the time elapsed until 

reclamation success (see the Reclamation Appendix). Although impacts from surface disturbance would 

typically be localized and short term, lasting until vegetation was reestablished, there would be the potential 

for severe and long-term effects to water quality and overall stream function (however the beneficial uses 

would be maintained). Impacts to water resources would increase as acres of surface disturbance increased 

within a watershed. Acquired lands that improved the continuity of BLM-administered lands within a 

particular watershed or increased BLM-administered land along streams would enable greater efficacy in 

altering water management and potentially prevent impacts of surface disturbance in these areas.

Management actions that 

limited emissions and 

enhanced or maintained air 

quality would benefit water 

resources by limiting 

reductions in water quality 

through atmospheric 

deposition and limiting wind 

erosion. Management 

actions that reduced 

contributions to climate 

change and accommodated 

or mitigated long-term 

changes in seasonal weather 

patterns would reduce 

impacts on water resources.

Management actions that 

limited soil erosion or 

compaction, such as 

requiring reclamation or 

limiting soil disturbances, 

would benefit water 

resources. Soil erodibility

would increase with 

increasing slope; 

subsequently, the magnitude 

of water quality degradation 

would increase with surface disturbance on steeper slopes. Eroded soil would introduce sediment, nutrients, 

metals, and chemicals to water. Because approximately 60 percent of water-eroded soil enters streams (Pimentel 

and Kounang 1998), reducing soil erosion would reduce impacts to water quality. Soil compaction would 

change watershed hydrology by reducing infiltration and increasing overland flow, which would subsequently 

accelerate erosion. Impacts to water quality would be reduced by the application of appropriate mitigation, 

relocation or denial of the activity, consideration of reclamation suitability, and use of reclamation plans (see 

the Reclamation Appendix).

Consulting with other agencies would facilitate water management on a watershed level across multiple agency 

boundaries. Meeting water quality standards and minimizing or controlling contributions of nonpoint source 

pollution would protect or improve water quality. However, water quality would vary considerably while 

meeting water quality standards. Filing for water rights would help to ensure that over-appropriation of water 

resources would not occur. Although leaks or spills from equipment would contaminate water, the potential for 

TABLE 4-34. 

WATER RESOURCES AFFECTED IN RECREATION OR 

SPECIAL DESIGNATION AREAS ON BLM-ADMINISTERED ACRES 

UNDER ALL ALTERNATIVES

Area or 

Resource

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Recreation

Powder River 

Depot Special 

Recreation

Management 

Area (SRMA)

3 0 7 4

Calypso

SRMA <1 0 50 0

Special Desig. Areas

Ash Creek 

Divide, Hell 

Creek, Sand 

Arroyo, and 

Bug Creek

ACECs1

130 170 34 490

Hoe 2 2 0 0

Jordan Bison

Kill 1 1 0 0

Finger Buttes 4 4 0 0

Piping Plover 0 0 3 0

Smoky Butte <1 <1 0 0

1

areas of critical environmental concern
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-52

this occurrence would be reduced by requiring that vehicle and equipment servicing and refueling activities take 

place away from wet areas and drainages. Appropriate well completion would reduce the potential for 

contamination from salts, drilling fluids, fluids and gases from other formations, detergents, solvents, 

hydrocarbons, metals, and nutrients.

Actions that maintained or improved vegetation conditions would generally maintain erosion rates and 

hydrologic cycles, which would maintain or enhance water resources in the long term. Actions that increased 

the resiliency of ecosystems would reduce the vulnerability of the water resources to climate change impacts 

(CEICC 2008). 

Vegetation manipulation treatments, forest health, or vegetation projects would have the potential to impact 

water resources. Most treatments would cause initial short-term impacts similar to those caused by surface 

disturbance described above. Changes in vegetation structure and composition would alter water flows, the 

quantity and quality of surface water and groundwater, and the rate of groundwater recharge (BLM 2007d). 

However, these impacts would be a 

natural result of healthier vegetation. 

Because evapotranspiration rates, rooting 

depth, and vegetative cover vary by 

species, a change would potentially impact 

water (e.g., changes in erosion and 

sedimentation rates, infiltration, amount of 

overland flow, evaporation, and turbidity). 

In the long term, treatments would 

promote watershed function and improve 

water quality. 

Herbicide treatments would have the 

potential to impact surface or groundwater

quality (or both). The use of paint-on 

chemicals would reduce the potential for 

surface water contamination in 

comparison to spraying. Generally, 

shallow groundwater aquifers would be at 

greater risk for contamination. Dicamba 

and diquat are known groundwater contaminants. Although diflufenzopyr is not known to contaminate 

groundwater, it would have a high potential to leach to groundwater. Except for fluridone, which has a high 

potential for surface water runoff, there is low potential for herbicide treatments to reach aquatic bodies in 

overland flow. These risks would be reduced by chemical choice and standard operating procedures designed to 

reduce potential, unintended impacts to water (BLM 2007d). In the long term, treatments would promote natural 

nutrient cycling patterns, erosion rates, stream morphology, evapotranspiration, infiltration (Hansen, Pfister, 

Boggs, Cook, Joy, and Hinckley 1995), and flow regimes associated with native vegetation. 

Actions that preserved or established vegetated riparian buffer zones, wetland function, PFC, and riparian 

enclosures would maintain or enhance water resources. Managing prairie streams for PFC would enhance 

riparian vegetation, water quality, and water quantity. Riparian and wetland areas would function as a buffer 

for waterbodies by reducing or eliminating nonpoint source pollution from upland areas (MDEQ 2007) and 

improve water quality, allow groundwater recharge, filter sediment, retain floodwater, and remove pollutants 

(Prichard et al. 1999). Maintaining PFC in riparian and wetland areas would preserve watershed resilience 

and facilitate rapid reclamation, which would reduce the impact of surface-disturbing activities on water 

resources. Erosion, turbidity, and sedimentation would be reduced and channel morphology and water quality 

maintained because healthy riparian vegetation would dissipate the energy of high water flows, filter 

sediment, stabilize streambanks, and allow for floodplain functionality. Actions that increased the resiliency 

of ecosystems would reduce the vulnerability of the water resources to climate change impacts (CEICC 

2008).

TABLE 4-35. 

WATER RESOURCES AT RISK OF DEGRADATION 

UNDER MANAGEMENT COMMON TO ALL 

ALTERNATIVES

Area or Resource Waterbodies 

(miles)

Floodplains

(acres)

Coal, high and moderate 

development areas 8,300 42,000

Coal, further study areas 6,100 35,000

Current oil and gas leases 5,700 20,000

High RFD, oil and gas

development 45,000 23,000

Moderate RFD, oil and gas

development 1,300 8,400

Low RFD, oil and gas

development 8,700 240,000
CHAPTER 4

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4-53

Habitat restoration projects would have the potential to impact water resources. Most treatments would cause 

initial short-term impacts similar to those caused by surface disturbance. Changes in vegetation structure and 

composition would alter water flows, the quantity and quality of surface water and groundwater, and the rate 

of groundwater recharge (BLM 2007d). However, these impacts would be a natural result of healthier 

vegetation. Because evapotranspiration rates, rooting depth, and vegetative cover vary by species, a change 

would potentially impact water (e.g., changes in erosion and sedimentation rates, infiltration, amount of 

overland flow, evaporation, and turbidity). Actions that conserved habitats would generally maintain erosion

rates and hydrologic cycles, which would maintain or enhance water resources in the long term.

Although 300-foot buffers would be applied under Wildland Fire Management actions in compliance with the 

Guidelines for Aerial Delivery of Retardant or Foam near Waterways (USFS, BLM, NPS, and USFWS 2000) 

and the Policy for Delivery of Wildland Fire Chemicals (Retardant and Foam) Near Waterways (USFS, BLM, 

NPS, and USFWS 2009), fire retardant would have the potential to enter waterbodies through wind or overland

flow, which would impair water quality (e.g., through the introduction of nitrogen, phosphorus, and boron) 

(Little and Calfee 2004) (see impacts from surface disturbance above).

Impacts to the watershed from fire would depend on fire size and severity, soils, watershed slope, vegetation, 

regrowth, precipitation, location in the watershed, and extent of watershed burned. Severe or highly intense 

fire would reduce watershed function and water quality by reducing infiltration, reducing vegetation cover, 

increasing erosion, and increasing overland flow. Soil erosion (0.42 tons per acre) for a single precipitation 

event in a wildfire burned watershed could be up to 90 percent of the estimated annual erosion (Elliot, Miller, 

and Audin 2010). Management of wildland fire to meet multiple objectives in riparian areas would cause 

erosion and sedimentation before revegetation occurred. Mechanical treatments would provide coarse woody 

debris that stabilized streambanks and dissipated energy. If applied in locations in which overland flow or soil 

erosion introduced fertilizer to water, fertilizer use would lead to short-term increases in nutrients and metals 

in surface water, which would subsequently lead to eutrophication and lower dissolved oxygen content. 

Short-term impacts of surface disturbance would occur during vegetation treatment and establishment. In the 

short to long term, watershed health and water quality would increase. 

Reduction of hazardous fuel loads would have the potential to impact water resources. Most treatments would 

cause initial short-term impacts similar to those caused by surface disturbance. Changes in vegetation 

structure and composition would alter water flows, the quantity and quality of surface water and groundwater, 

and the rate of groundwater recharge (BLM 2007d). However, these impacts would be a natural result of 

healthier vegetation. Because evapotranspiration rates, rooting depth, and vegetative cover vary by species, a 

change would potentially impact water (e.g., changes in erosion and sedimentation rates, infiltration, amount 

of overland flow, evaporation, and turbidity). Reducing hazardous fuel loads would reduce the vulnerability 

of the water resources to climate change impacts (CEICC 2008).

Cultural Resources management actions that required an NSO stipulation for oil and gas leasing, closed areas 

to leasing, and prohibited surface disturbance would maintain water quality. Allowing surface disturbances 

would decrease water quality in these areas (see impacts from surface disturbance above).

Forest management activities and harvest of dead or dying timber would have the potential to increase 

overland flow, erosion, and sedimentation, which would alter flow regimes and decrease water quality. Postfire salvage logging would delay or prevent natural watershed recovery, particularly in areas of high-severity 

fires, riparian areas, steep slopes, and erosion-prone soils (Karr et al. 2004). Salvage harvest of sawtimber

would remove vegetation in a watershed with an already reduced canopy cover, which would further 

accelerate erosion and add to the impacts caused by harvesting. 

Cottonwood (Populus sp.) harvest would occur in riparian areas, wetlands, floodplains, and near stream 

channels, which would cause short-term erosion, increased overland flow, decreased infiltration, and 

degradation of water quality associated with increasing sedimentation, turbidity, nutrients, eutrophication, 

metals, and other pollutants (MDEQ 2007). Riparian vegetation and large woody debris removal would 

reduce the system’s capacity to dissipate flood energy. Harvest of cottonwood species would have the 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-54

potential to change a riparian forest-type community to a shrub- or graminoid-dominated community 

(Hansen, Thompson, Massey, and Thompson 2008). 

Meeting Rangeland Health Standards would help to maintain water quality. Standard 1 requires stable soils, 

adequate ground cover, minimal accelerated erosion, and hydrologic function (the capacity of the site to 

capture, store, and release water). Standard 2 requires that riparian areas attain PFC. Standard 3 requires that the 

beneficial uses as defined by Montana Water Quality Standards are fully supported, which would reduce 

impacts to water quality (MDEQ 2007). Beneficial uses would not be supported when sources such as sediment, 

pollutants, stream modifications, riparian habitat degradation, and excessive water withdrawal caused 

impairment. Standard 4 requires compliance with air quality standards and limited emissions from nonpoint 

sources, which reduces the atmospheric deposition of pollutants such as nitrogen, phosphorus, mercury, and 

chemicals (MDEQ 2007). Standard 5 requires maintenance of upland watershed health through the 

improvement or maintenance of healthy, native plant populations. Standards 1 through 5 would maintain 

watershed functionality.

The magnitude of impacts from livestock grazing would vary based on utilization, location in the watershed, 

duration, and season of use. Livestock grazing would potentially alter the watershed hydrology by lowering 

the water table; compacting soils; decreasing low flows and infiltration rates; and increasing overland flow, 

volume of peak flows, and floodwater velocity (Belsky, Matzke, and Uselman 1999). Livestock grazing

would accelerate soil erosion, reduce riparian vegetation, increase water temperature, decrease dissolved 

oxygen, degrade the stream channel, and introduce pollutants such as sediment, salinity, bacteria, and 

nutrients to water (MDEQ 2007). Wide and shallow channels, high sediment yield, and high turbidity 

(Magilligan and McDowell 1997) would characterize grazing-disturbed streams. However, proper 

management (Mosley, Cook, Griffis, and O’Laughlin 1999; Saunders and Fausch 2007) and compliance with 

Rangeland Health Standards and Guidelines would minimize these impacts. 

Improved livestock management would reduce or reverse the impacts of livestock grazing, which would 

result in declines in erosion within 5 to 14 years and increased vegetation cover, riparian and wetland

functionality, and recruitment of desired riparian woody species; however, some channel and bank 

morphological properties would take longer (14 or more years) (Magilligan and McDowell 1997). Exclosures 

would allow stream systems the total rest from grazing required for full recovery of structure and function 

(Belsky et al. 1999) in the long term. Exclosures would allow for stream channel recovery (lower width-todepth ratio and increased pool area) in the long term and riparian vegetation recovery (increased percent 

cover, increased bank stability, reduced water temperature, and restored natural nutrient cycling) in the short 

to long term (Magilligan and McDowell 1997). AUM decreases, grazing plans and systems, and range 

improvements that reduced utilization in waterbodies and riparian areas would reduce impacts of grazing. 

Livestock grazing use adjustments (decreased use) due to drought, fire, flood, and insect infestations would 

decrease the compounded impacts of livestock grazing during watershed disturbance.

Coal Unsuitability Criterion 16 designates 100-year floodplains as unsuitable for coal leasing according to risks 

of substantial threat of loss of life or property, not resource values. As applied in the Powder River RMP, water 

resources on 3,215 acres along the Tongue River and 2,966 acres along the Powder River would be maintained. 

Floodplains of “lesser streams” would be affected by mining. Potential alluvial valley floors along 856 stream 

miles would be listed as unsuitable at the planning stage, which would maintain water resources (BLM 1985c). 

Monitoring by lessees in accordance with federal and state requirements would assure compliance and protect 

the quality and quantity of surface water and groundwater. Reclamation would reconstruct drainage with the 

approximate original contour and lower surface elevation, which would cause permanent changes in stream 

channels (BLM 1984).

Coal mining activities (e.g., surface disturbance, road construction, overburden removal, rerouting of stream 

systems, and the presence of sediment ponds) would disrupt surface water, reduce streamflow downstream, and 

reduce peak flows. During mining, sedimentation would be reduced by sedimentation ponds. Spoils would 

experience decreased infiltration following reclamation (for 10 to 15 years) and, as a result, overland flow and 

peak flows would increase by approximately 5 percent (BLM 1984). Discharge of produced water during 
CHAPTER 4

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operations and discharge of groundwater with leached salts following operations would impact surface water

quality and quantity.

Coal seams typically serve as groundwater aquifers. Drawdown from mining operations would be up to 75 feet 

and extend up to 5 miles from the site (BLM 2008g), which would take years to recover. Impounding or 

discharging produced water would increase evaporative losses of groundwater. Seepage from holding ponds 

would impact groundwater. As coal and overburden was removed, local groundwater quality and quantity 

would be affected permanently by replacement with a spoil aquifer (BLM 1984). After mining, for hundreds to 

thousands of years, groundwater discharged from the site would contain increased leached salts (increases of 

500 to 2,000 milligrams per liter total dissolved solids [TDS]). The degree of this increase would depend on the 

geology and the extent would be several miles downgradient (BLM 1984). Agricultural beneficial uses would 

not be supported in isolated areas in which groundwater was a major contributor to surface water (BLM 1984). 

Water quality and discharge impacts would be mitigated by compliance with state regulations. 

Produced water from conventional oil and gas, uranium recovery, and CBNG development would impact the 

quality of surface water and groundwater through impoundments, injection, and discharge. Permits from the

BLM, Montana Board of Oil and Gas Conservation (MBOGC), and MDEQ would mitigate these actions. 

Impounding or discharging produced water would increase evaporative losses of groundwater. Left untreated, 

produced water discharge and infiltration or leaking produced water disposal pits would be likely to reach 

stream channels via subsurface flow, which would decrease water quality. If aquifers were hydraulically 

connected to nearby streams and springs, the drawdown of groundwater would result in flow depletion. 

Typically, produced water from conventional oil and gas wells would originate from a depth below useable 

aquifers or coal seams. Underground injection control regulations would isolate injection zones from useable or 

potentially useable aquifers, which would limit the impacts. 

Bore crossing or horizontal directional drilling (HDD) would avoid contact with waterbodies. If staging areas 

were located in uplands with a sufficient vegetative buffer, there would be no direct impacts other than the 

possibility of an unexpected release of drilling fluids (commodity referred to as a “frac-out”).

Hydraulic fracturing would have the potential to reduce water quality through the introduction of fluids 

containing biocides, acids, diesel fuel, solvents, and alcohols (USEPA 2004). In the Powder River basin (PRB)

for CBNG, fracturing is used very infrequently because the coal seams are naturally highly permeable (NAS 

2010). Hydraulic fracturing would cause changes in vertical and horizontal aquifer permeability and potentially 

increase hydrologic communication with adjacent aquifers (USEPA 2004).

The contents of reserve pits would depend on the type of drilling system, formation, and chemicals added to the 

mud circulation system. Reserve pits would possibly contain drill cuttings, water, diesel oil, mineral oil, 

synthetic compounds (e.g., internal olefins, esters, linear alpha-olefins, poly alpha-olefins, or linear paraffins),

weighting agents (e.g., barium sulfate or barite), oil-based muds (including polynuclear aromatic hydrocarbons), 

polymers (partially hydrolyzed polyacrylamide, and polyanionic cellulose), glycols, chromium, zinc, 

polypropylene glycol, acrylamide copolymers, drilling detergents, bentonite, surfactants, hydrochloric acid, 

sodium carbonate (soda ash), lignosulfonates, and lignites (Ramirez 2009). Typically, water-based muds would 

have the lowest potential for impacts to water resources, followed by synthetic-based muds then oil-based 

muds. Reclamation of reserve pits would typically consist of fluid removal, followed by evaporation or 

solidification, then encapsulation and on-site burial. Other disposal methods would include off-site disposal, 

downhole injection, or treatment and reuse (Ramirez, Jr. 2009). 

The use of reserve pits and burial of reserve pits onsite would have the potential to contaminate groundwater

and surface water with metals and hydrocarbons if improperly managed or closed. Evaporation would 

concentrate water-soluble metals, salts, and other chemicals. Precipitation, fluctuation of shallow groundwater, 

and flooding would potentially mobilize these contaminants into groundwater. Liners “most often do not 

adequately seal the drilling wastes, especially if they are torn” (Ramirez, Jr. 2009, p. 8). Solidification would 

prevent mobilization of potential contaminants. Removal and off-site disposal of liquids would remove most of 

the water-soluble metals, salts, and chemicals from the drilling waste material. The use of pitless or closed-loop 

technology would potentially conserve water, recycle drilling fluids, reduce surface disturbance, and eliminate 
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the use of pits. If pits were not lined or buried onsite, drill cuttings would potentially leach metals and 

hydrocarbons to groundwater (Ramirez, Jr. 2009). Off-site disposal or treatment and reuse would reduce 

impacts to water.

Drawdown in coal seams after 20 years of CBNG development is expected to be 20 feet within 5 miles of 

development, which would impact groundwater wells completed in developed coal seams in these areas. 

These wells would have reduced yields but would not be expected to become dry because the aquifer would 

remain saturated. Within 3 to 4 years of the end of development, recovery would be expected be to within 20 

to 30 feet, with complete recovery within hundreds of years (BLM 2008g). “Little evidence exists to 

substantiate that surface water has been depleted by pumping water during CBM [CBNG] production at the 

large watershed scale” in the PRB (NAS 2010, p. 185).

Treated and untreated discharged produced water would have the potential to degrade water quality. The 

water produced by CBNG wells would be typically saline (electrical conductivity) and sodic (sodium 

adsorption ratio). Although surface water quality in some watersheds would be altered in combination with 

new and existing permits, beneficial uses would not be diminished. Surface water flow would moderately 

increase through the discharge of produced water, which would alter the natural hydrologic regimes (such as 

changes in the magnitude and timing of low and peak flows) and cause erosion, headcutting, and increased 

sedimentation (BLM 2008g). Produced water spilled or treated in infiltration, unlined, or leaking evaporation 

impoundments (water disposal pits) would impact shallow groundwater aquifers and contain the potential to 

reach and contaminate surface water through groundwater interface. The infiltration of produced water would 

potentially dissolve and mobilize sulfate, selenium, arsenic, manganese, barium, chloride, nitrate, and TDS 

from soils to water (NAS 2010). For a detailed analysis of CBNG impacts, refer to the BLM’s 2008 Final 

Supplement to the Montana Statewide Oil and Gas Environmental Impact Statement and Proposed 

Amendment to the Powder River and Billings Resource Management Plans (FSEIS).

Geothermal leasing has the potential to impact water quality and temperature through the discharge of hot 

water with concentrated metals and low or high pH values and the subsequent contamination of surface or 

groundwater. NSO stipulations for oil and gas leasing and development for waterbodies, riparian areas, 

wetlands, playas, 100-year floodplains, and slopes in excess of 40 percent or soils with high erosion potential 

and CSU stipulations within 500 feet of riparian or wetland vegetation and erosive soils and soils on slopes 

greater than 30 percent would mitigate these effects (BLM 2008h). However, no federal geothermal leasing 

would likely occur in either the short or long term. For a detailed analysis of impacts, refer to BLM and USFS 

2008 Final Programmatic Environmental Impact Statement for Geothermal Leasing in the Western United 

States.

Pit mining of locatable minerals and mineral materials would impact water resources through surface 

disturbance and removal and replacement of overburden. Drainage patterns would be affected during mining 

and, depending on the local geology salts, leach from spoils to surface water and groundwater.

Surface disturbance associated with locatable mineral activities on waterbodies and streams (300,000 acres) 

and on floodplains (320,000 acres) would cause destabilization of banks; sedimentation; altered channel 

morphology; decreased water quality; and increased erosion, turbidity, and water temperature (MDEQ 2007). 

Surface disturbance would reduce the capacity of these areas to dissipate the energy of high water events and 

cause changes in infiltration rates, water storage, and aquifer recharge. Any construction activity in flowing 

waterbodies would be likely to exceed Montana’s water quality criteria for turbidity and require a variance. 

The lack of vegetative buffers on waterbodies would further increase sedimentation and reduce water quality. 

The capability of floodplains to dissipate energy associated with high water events would be reduced and 

infiltration rates, water storage, and aquifer recharge would be altered. These impacts would be mitigated on a 

site-specific basis (see the Best Management Practices Appendix).

Bentonite mining would increase TDS and turbidity of surface water. Impacts to surface water and 

groundwater from in situ leach uranium recovery would be small to moderate (USNRC and WDEQ 2009). 

The process of in situ uranium mining would inject a solution that dissolved uranium minerals into 

groundwater, which would potentially migrate beyond the project area through equipment failures, aquifer 
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heterogeneity, fractures, or improper well completions. In addition to impacts from surface-disturbing 

activities, impacts would include the potential for contamination of aquifers at varying depths (including 

domestic water supplies and adjacent aquifers) by radionuclides or other constituents (e.g., selenium, metals, 

salinity, high or low pH) (Meredith 2010).

Transportation infrastructure is ranked second by the USEPA as a potential source of groundwater

contaminants to Montana’s public water supply (MDEQ 2007). The transportation system would cause 

erosion, nutrient loading, channel instability, changes in stream morphology, increased water temperature, 

and sedimentation. These impacts would be long term and accelerated by road construction or maintenance, 

stream channelization, vehicle fords, improper design and location, and inadequate maintenance. Vehicle use 

would introduce pollutants such as oil, grease, dust, and metals to water systems (MDEQ 2007). In addition 

to short-term impacts from construction, permanent impacts to streamflow and bank stability would include 

impacts from culverts and bridge column fill within waterbodies. Compaction of soil and impermeable road 

surfacing would reduce infiltration and increase overland flow, which would increase erosion and 

sedimentation; however, appropriate road surfacing would decrease wind and water erosion of the road 

surface. Impacts would be minimized by reducing the number and extent of road systems, avoiding riparian

areas and stream crossings, installing erosion control features, placing and designing culverts properly, 

designing roads properly, reclaiming closed roads, and complying with BMPs. Redesign, rerouting, closure, 

or decommissioning of existing roads, primitive roads, or trails would improve water quality and stream 

health. Watersheds with low to moderate numbers of stream crossings and properly located, designed, and 

maintained roads would have near background levels of sediment production (MDEQ 2007). 

Because OHV use is not evenly distributed across BLM-administered lands, impacts are localized in 

intensively used areas. OHV use is a source of nonpoint source pollution and associated vegetation loss 

would cause accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to 

sedimentation, soil compaction, increased overland flow, and decreased infiltration. Vehicle fords would 

cause localized erosion, sedimentation, and degradation of streambanks. Weed invasion would lead to 

accelerated erosion and changes in watershed hydrology. Sheet or rill erosion would be the most common on 

poorly designed or maintained (or both) roads and trails during periods of high moisture; these impacts would 

increase with increasing OHV use. Impacts would be reduced and localized in areas in which vehicles were 

limited to existing roads (e.g., Limited OHV areas). In general, these impacts are estimated to occur in less 

than 1 percent of a watershed (BLM and USFS 2001). Although the BLM’s 2003 Record of Decision, OffHighway Vehicle Environmental Impact Statement and Proposed Plan Amendment for Montana, North 

Dakota, and South Dakota would not restrict use in areas in which user-created roads and trails were 

established in riparian areas or areas of high soil erodibility (BLM 2003m), areas in which considerable 

impacts were occurring would be closed, in accordance with 36 CFR 295.5 and 43 CFR 8341.2 and 8364.1. 

Maintaining wilderness values of WSAs would maintain water quality and quantity in these watersheds, on 

490 miles of waterbodies on BLM-administered acres, and on 880 acres of floodplains on BLM-administered 

lands.

ALTERNATIVE A

Management actions that limited surface disturbance on approximately 1.0 million acres of mineral estate and 

960,000 acres of BLM-administered surface in the planning area would maintain water quality, watershed 

functionality, and potentially preserve a vegetative buffer to reduce impacts from upland areas (Table 4-36). 

Management actions limiting surface disturbance would benefit water resources by reducing impacts to water 

resources. Water resources would be affected by surface disturbance in uplands, riparian areas, wetland areas, 

and waterbodies within the watershed (BLM-administered land and other ownerships). Surface-disturbing 

activities (including ROW actions; mineral and energy exploration [including renewable energy], leasing, and 

development; geophysical exploration; OHV and vehicle use; special designation and recreation area 

designations and use [Table 4-37]; infrastructure development; vegetation and fuel treatments [including 

some habitat restoration projects]; cultural or paleontological excavation; establishment of wildfire fuel 

breaks; burial of power lines; and range improvements) would cause vegetation removal, soil compaction, 
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and soil disturbance. Impacts would include accelerated erosion, increased overland flow, decreased 

infiltration, and degradation of water quality through increased sedimentation, turbidity, nutrients, 

eutrophication, metals, and other pollutants in waterbodies. Erosion potential would be increased further 

through soil compaction and low-permeability surfacing (e.g., roads and well pads), which would increase the 

energy and amount of overland flow, which would subsequently increase sedimentation and erosion and alter 

flow characteristics. The magnitude of these impacts would depend on the specific activity, season, proximity 

to waterbodies, location in the watershed, condition of upland and riparian vegetation, soils, watershed 

resilience, efficacy of mitigation (see the Best Management Practices Appendix), and the time elapsed until 

reclamation success (see the Reclamation Appendix). Although impacts from surface disturbance would 

typically be localized and short term, lasting until vegetation was reestablished, there would be the potential 

for severe and long-term effects to water quality and overall stream function (however, the beneficial uses 

would be maintained). Impacts to water resources would increase as acres of surface disturbance increased 

within a watershed.

TABLE 4-36.

WATERBODIES MAINTAINED ON BLM-ADMINISTERED ACRES UNDER 

ALTERNATIVE A

Area or Resource

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Water

Floodplain, waterbody, and riparian, oil

and gas NSO 640 580 35,000 92,000

Waterbodies and streams, oil and gas

NSO 13,000 26,000 1,700 3,100

Veg.

Riparian and wetland, oil and gas NSO 1,700 4,000 10,000 30,000

Fish and Wildlife

Aquatics, reservoirs with fisheries, 

0.25-mile oil and gas NSO 27 26 60 187

Sharp-tailed Grouse, 0.25-mile oil and 

gas buffer 87 160 300 440

Colonial Waterbirds, NSD11 2 84 110

Bighorn Sheep Range, oil and gas NSO 330 490 770 1,500

Piping Plover and Interior Least Tern, 

oil and gas NSO 18 150 830 3,900

Prairie Falcon, oil and gas NSO 41 73 290 280

Special Status Species Raptors, oil and 

gas NSO 240 360 800 1,700

Sage-grouse, 0.25-mile oil and gas

buffer 110 190 370 750

Travel Mgmt 

and OHV

Limited OHV 13,000 NA 34,000 NA

Closed OHV 0 NA 0 NA

1NSD=No Surface Disturbance

Surface-disturbing activities that occurred on various slopes, sensitive soils, soils with poor reclamation 

potential, and highly erodible soils (particularly on 130,000 acres within 300 feet of waterbodies) under this 

alternative would cause soil erosion and sedimentation. Disturbance on soils with poor reclamation potential 

would cause permanent increases in erosion and sedimentation. 

Offering oil and gas leasing with an NSO stipulation on waterbodies and streams would prohibit surface 

disturbance associated with oil and gas activities on 41,000 acres of waterbodies on BLM-administered 
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mineral estate, which would maintain water quality. Other surface disturbance on 300,000 acres of 

waterbodies and streams would cause destabilization of banks; sedimentation; altered channel morphology; 

decreased water quality; and increased erosion, turbidity, and water temperature (MDEQ 2007). Surface 

disturbance would reduce the capacity of these areas to dissipate the energy of high water events and cause 

changes in infiltration rates, water storage, and aquifer recharge. The presence of aboveground facilities 

would create flood hazards. Any construction activity in flowing waterbodies would be likely to exceed 

Montana’s water quality criteria for turbidity and require a variance. The lack of vegetative buffers on 

waterbodies under this alternative would further increase sedimentation and reduce water quality.

Prohibiting permanent facilities 

and requiring an NSO stipulation 

for oil and gas leasing and 

development on 100-year 

floodplains of major rivers would 

prohibit oil- and gas-associated 

surface disturbance of floodplains 

on 260,000 acres (of 26,000 river 

miles) of BLM-administered 

mineral estate, which would 

maintain water quality. Allowing 

oil- and gas-associated surface 

disturbance on 65,000 acres of 

floodplains of non-major 

waterbodies (95,000 river miles) 

and all other surface disturbances 

on all floodplains (320,000 acres) 

would increase erosion, overland 

flow, sedimentation, and turbidity 

and degrade channel morphology 

and water quality. The capability 

of floodplains to dissipate energy 

associated with high water events 

would be reduced and infiltration rates, water storage, and aquifer recharge would be altered.

Surface water impoundments would reduce streamflow, dissolved oxygen, and floodplain size and extent 

downstream (Vörösmarty and Sahagian 2000); increase infiltration to groundwater, scour of the downstream 

streambed, and water temperature (Dodds, Gido, Whiles, Fritz, and Matthews 2004); substantially increase 

evaporative losses; degrade water quality; and change nutrient cycling, timing and magnitude of peak and low 

flows, sediment load, and riparian vegetation recruitment and succession. Under this action, there would also be 

the potential for permanent impacts including channel scour, erosion, and sedimentation downstream (if a dam 

broke). Water impoundments and developments in and near waterbodies, riparian areas, and wetlands would 

increase use in these areas, which would change morphology, increase water temperature, alter ecosystem 

processes, and decrease water quality by introducing sediment, salinity, bacteria, and nutrients. Expanded water 

use, withdrawals, and storage would exacerbate the impacts of climate change on water resources (IPCC 2007).

Use of groundwater for livestock water developments would drawdown groundwater and increase evaporative 

losses. New spring developments would reduce water flow locally and downstream, lower the local water table, 

and increase water temperatures, which would reduce riparian vegetation, change channel morphology, and 

increase sedimentation (Sada et al. 2001). Spring developments would not maintain the riparian community. 

Where used, flow-control devices would reduce water loss, soil erosion, riparian community losses, evaporative 

losses, and vulnerability of water resources to climate change. Impacts would not be minimized in areas in 

which flow-control devices were not installed on a case-by-case basis.

TABLE 4-37.

WATER RESOURCES AFFECTED IN RECREATION OR 

SPECIAL DESIGNATION 

AREAS ON BLM-ADMINISTERED ACRES UNDER 

ALTERNATIVE A

Area

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Glendive

OHV 4 12 200 200

Lewis and 

Clark Trail 

SRMA

78 110 3,700 7,700

Terry OHV

SRMA 1 1 0 0

Battle Butte 1 1 0 0

Powder 

River Depot

ACEC

7 6 13 21

Reynolds

Battlefield 1 1 4 126
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Depending on the fuel type, haying within 200 feet of waterbodies would increase sedimentation, cause soil 

compaction, reduce litter and vegetation cover, decrease infiltration, and increase erosion (Ellis 2008) but 

reduce the risk of high-intensity or severity fire in the long term, which would improve watershed functionality. 

Management actions that required NSO stipulations for oil and gas leasing and development in riparian areas 

would prohibit oil and gas surface disturbance on 41,000 acres of waterbodies, which would maintain water 

quality. Other surface disturbance in riparian areas would cause soil compaction, vegetation removal, and soil 

disturbance, which would increase overland flow, sedimentation, and turbidity. In these localized areas, riparian

areas would be incapable of dissipating flood energy or buffering waterbodies from upland nonpoint source 

pollution although the reach would remain in PFC. 

Allowing surface disturbance (including oil and gas disturbance) in wetlands would reduce the capacity of 

wetlands to improve water quality, allow groundwater recharge and discharge, filter sediment, retain 

floodwater, and remove pollutants from water (Prichard et al. 1999). Surface disturbance would increase soil 

compaction, overland flow, sedimentation, instability of stream channel and streambanks, and turbidity. 

Draining of wetlands would potentially increase the magnitude of large flooding events (Poff et al. 1997). 

Although many of these impacts would be short term with successful reclamation, success of reclamation 

activities would probably be low and impacts would be likely to persist. Following pipeline construction, the 

wetland restoration success rate (defined as at least 80 percent vegetative cover by native species and a plant 

diversity of the restored wetland that attains 50 percent of the pre-construction condition) was found to be 32 

percent in the arid western ecoregions (FERC 2004). There is the potential for changes to surface and 

subsurface drainage, which would result in permanent changes in wetland integrity and function if water 

retention were reduced or eliminated through the disturbance of impermeable layers. 

Although all methods would cause surface disturbance, the magnitude and duration of the impacts of surfacedisturbing activities such as linear underground facilities (including buried power lines) crossing perennial 

streams, intermittent streams, wetlands, and riparian areas would vary and depend on the method used to 

cross the waterbody. Because open-cut wet crossings (trenching) of flowing water would result in direct 

contact with water during all stages of construction and potential in-stream storage of spoil, these actions 

would increase sedimentation; destabilize streambanks; decrease streambed porosity; alter channel 

morphology; and cause short-term increases in total suspended solids (TSS), TDS, nutrients, metals, and total 

organic carbon (Lévesque and Dubé 2007). Additionally, riparian vegetation would be removed: "Excavation 

of streambeds composed primarily of clay or silt sized particles can generate persistent plumes of high 

suspended sediment concentration or turbidity" and "small particle diameters (e.g., clays) can, however, limit 

the ability of sediment control structures to reduce downstream sediment concentrations" (Reid, Ade, and 

Metikosh 2004, p. 6). Generally, if bank stabilization occurred, sediment entrainment would occur during 

construction (typically within 24 to 48 hours but potentially up to a few weeks) and the impacts would not be 

evident within 4 years (Reid et al. 2004). 

Isolated crossing methods (e.g., dam-and-pump and flume methods) would have, on average, peak TSS (i.e., 

turbidity) 3 to 20 times lower than open-cut wet methods (Reid et al. 2004) and more effectively mitigate 

sediment loading (Lévesque and Dubé 2007). Isolated methods would cause impacts with reduced severity 

and duration because the increases in turbidity and sedimentation would be limited to installation and removal 

of dam or flume structures (up to 10 hours) (Lévesque and Dubé 2007).

Unless the surface-disturbing activity established native vegetation, management actions that allowed surfacedisturbing activities in areas of invasive vegetation species infestations would increase damage to watersheds 

and reduce water quality and quantity (BLM 2007d). 

Management actions that required an NSO stipulation for oil and gas leasing and development within 0.25 

miles of designated reservoirs with fisheries would prohibit oil- and gas-associated surface disturbance on 

300,000 acres, which would maintain water quality on these acres. Other surface-disturbing activities and 

permanent facilities within 0.25 miles of designated reservoirs would reduce water quality. Because there 

would be no vegetative buffers, impacts (reducing sediment, nutrients, metals, and other pollutants) from 

surface-disturbing activities adjacent to water, riparian areas, and wetlands on 300,000 acres would not be 
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reduced or eliminated. Impacts would include sedimentation, erosion, soil compaction, decreased 

biodiversity, altered stream channel morphology, increased water temperature, reduced bank stability, 

reduced aquifer recharge, increased floodwater velocities and energy, altered nutrient input to aquatic 

habitats, and a lowered water table (which would decrease forage) (MDEQ 2007).

In the long term, management actions that required fish passage on a case-by-case basis would reduce 

sedimentation, streambed erosion, and streambank erosion. Existing and new culverts that impeded fish 

passage would result in sedimentation, streambed erosion, and streambank erosion.

Management actions that required an NSO stipulation for oil and gas leasing and development within 0.25 

miles of piping plover and interior least tern habitat would prohibit surface disturbance associated with oil 

and gas activities on 1,800 miles of streams, which would maintain water quality. Other surface disturbances 

would decrease water quality in these areas.

Management actions that required the burial of oil and gas low-voltage power lines would increase surface 

disturbance and decrease water quality. 

The absence of limits for cumulative, direct, and indirect disturbance within the sagebrush habitat in sagegrouse areas would result in an “extreme impact (which is defined in the Wyoming Department of Fish and 

Game’s (WDFG) March 2010 Recommendations for Development of Oil and Gas Resources Within 

Important Wildlife Habitats as more than 80 acres of disturbance per square mile)” from development on 

habitat function of aquatic and water resources (WDFG 2010a, p. 45).

Removal or treatment of pre-commercial or commercial material on 53,000 acres of Condition Class 3 sites 

would decrease water quality but reduce the intensity and severity of prescribed fire. High-intensity fire and 

fire suppression that resulted in fuel buildup would lead to increased erosion and sedimentation, which would 

impact water quality in both the short and long term. The impacts would be the same for low-intensity fire 

(including prescribed fire) except that the magnitude of impacts would be reduced and erosion rates would be 

similar to natural levels. Although typical timber harvest activities have been estimated to increase erosion 

rates to 0.05 to 0.25 tons per acre per year, intensive methods would potentially increase rates to 5 tons per 

acre per year (Elliot et al. 2010). Depending on the severity, fire in riparian areas would reduce water quality 

by reducing vegetation and riparian function. In the long term, although water quality would benefit from 

healthy uplands, road construction and use of heavy equipment would lead to increased soil compaction, 

erosion, and sedimentation, which would reduce water quality.

Paleontological Resources management actions that required an NSO stipulation for oil and gas leasing and 

prohibited surface disturbance would maintain water quality. 

Managing forestlands for resources would enhance water quality. Wood product sales would cause nonpoint 

source pollution, the magnitude of which would depend on the methods used. Vegetation removal, surface 

disturbance, road construction, and soil compaction would increase erosion, sedimentation, and overland 

flow. Streamside vegetation removal would increase water temperatures and reduce the ability of vegetative 

buffers to reduce nonpoint source pollution. However, forest management activities would use BMPs (e.g., 

Water Quality BMPs for Montana Forests [Logan 2001], see the Forestry and Woodland Products Appendix) 

and comply with the Streamside Management Zone Law, which would reduce these impacts. 

Because cottonwood harvest would occur near water, there would not be a sufficient vegetative buffer to reduce 

impacts of these activities.

Management actions that allowed livestock grazing on 2.7 million acres would reduce water quality and the 

ability of vegetative buffers to filter sediments and contaminants from upland areas. Excluding 200 acres 

from grazing would maintain water quality. 

Allotments in which livestock grazing has contributed to declines in riparian areas and water quality 

management would be managed to meet riparian and water quality standards.
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Allowing livestock grazing during or immediately after mining or development would accelerate impacts 

from multiple land use activities (e.g., mineral extraction and livestock grazing). Multiple land uses would 

compound land uses and cause impacts greater than impacts caused by livestock grazing, mining, or 

development alone. This action would increase erosion, sedimentation, and streambank instability and 

decrease water quality and riparian functionality.

Deferring livestock grazing for 1 growing season following fire activities would help minimize impacts to 

waterbodies from erosion during the first year. However, studies suggest that timing, use, and duration of 

grazing of burned rangelands are more important than a specific period of rest after fire (Bates, Rhodes, 

Davies, and Sharp 2009); therefore, during subsequent seasons (until vegetation recovered), livestock grazing 

would inhibit restoration of watershed function (Beschta et al. 2004), and the impacts of grazing and fire 

would be compounded. For areas with moderate to high fire intensity or severity (or both), severe erosion and 

sedimentation would occur. 

Management actions that ensured that Standards for Rangeland Health were met and maintained would 

maintain water resource conditions. Calculation of livestock carrying capacities exclusive of watershed and 

riparian objectives would not protect these areas from increased grazing.

Prohibiting coal exploration on 200,000 acres would maintain water quality and quantity.

CSU stipulations for oil and gas leasing and development would reduce impacts to water resources on 16,000 

miles of streams and 16,000 acres of floodplains. Management actions that allowed oil and gas leasing and 

surface disturbance with lease terms on 2.7 million acres would decrease water quality.

Mineral sales and permitting on 2.5 million acres would decrease water quality. 

Although closing 80 acres to OHV use would improve water quality and quantity, allowing Open OHV use on 

2,400 acres and Limited OHV use on 2.8 million acres would decrease water quality. 

Streams and floodplains would be affected in Recreation and Special Designation Areas under Alternative A.

ALTERNATIVE B

Actions that limited surface-disturbing activities on approximately 5.5 million acres of mineral estate and 2.5 

million acres of BLM-administered surface would maintain water quality, watershed functionality, and 

potentially preserve a vegetative buffer that reduced impacts from upland areas (Table 4-38). 

Management actions limiting surface disturbance would benefit water resources by reducing impacts to water 

resources. Water resources would be affected by surface disturbance in uplands, riparian areas, wetland areas, 

and waterbodies within the watershed (BLM-administered land and other ownerships). Surface-disturbing 

activities (including ROW actions; mineral and energy exploration [including renewable energy], leasing, and 

development; geophysical exploration; OHV and vehicle use; special designation and recreation area 

designations and use [Table 4-39]; infrastructure development; vegetation and fuel treatments [including 

some habitat restoration projects]; cultural or paleontological excavation; establishment of wildfire fuel 

breaks; burial of power lines; and range improvements) would cause vegetation removal, soil compaction, 

and soil disturbance. Impacts would include accelerated erosion, increased overland flow, decreased 

infiltration, and degradation of water quality through increased sedimentation, turbidity, nutrients, 

eutrophication, metals, and other pollutants in waterbodies. Erosion potential would be increased further 

through soil compaction and low-permeability surfacing (e.g., roads and well pads), which would increase the 

energy and amount of overland flow, which would subsequently increase sedimentation and erosion and alter 

flow characteristics. The magnitude of these impacts would depend on the specific activity, season, proximity 

to waterbodies, location in the watershed, condition of upland and riparian vegetation, soils, watershed 

resilience, efficacy of mitigation (see the Best Management Practices Appendix), and the time elapsed until 

reclamation success (see the Reclamation Appendix). Although impacts from surface disturbance would 
CHAPTER 4

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4-63

typically be localized and short term, lasting until vegetation was reestablished, there would be the potential 

for severe and long-term effects to water quality and overall stream function (however the beneficial uses 

would be maintained). Impacts to water resources would increase as acres of surface disturbance increased 

within a watershed. 

TABLE 4-38.

ESTIMATED WATERBODIES MAINTAINED ON BLM-ADMINISTERED ACRES 

UNDER ALTERNATIVE B

Area or Resource

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Soils

Steep, NSD18,900 8,500 35,000 89,000

Sensitive, NSD 270 700 250 640

Water

Floodplain, NSD 770 1,900 42,000 110,000

Waterbody, NSD 13,000 26,000 1,700 3,100

Veg.

Riparian and wetland, NSD 1,700 4,200 13,000 33,000

Fish and Wildlife

Aquatics, sport-fish reservoirs, 

0.5-mile buffer 57 64 230 510

Big Game Crucial Winter 

Range, NSO 7,500 15,000 29,000 75,000

Colonial Waterbirds 1 2 160 140

Bighorn Sheep Range, oil and 

gas NSO 330 490 780 1,500

Prairie Falcon, NSO 41 73 320 400

Special Status Species Raptors 240 360 900 0

Piping Plover and Interior Least 

Tern, 0.25-mile NSO buffer 18 150 1,300 5,800

Black-tailed prairie dog, NSD 650 1,300 3,000 6,400

Pallid Sturgeon, 0.5-mile, NSD 75 94 3,200 6,800

Sage-grouse Habitat –

Protection Priority ACEC, oil

and gas NSO

4,900 9,600 12,000 36,000

Travel 

Mgmt and 

OHV

Limited OHV 13,000 12,000 41,000 NA

Closed OHV 150 NA 570 NA

1NSD=No Surface Disturbance

Limiting surface-disturbing activities to slopes of 25 percent or less would decrease the magnitude of 

accelerated erosion, increased overland flow, decreased infiltration, and degradation of water quality. Slopes 25 

percent or greater within 300 feet of waterbodies (44,000 acres) would potentially act as vegetated buffers for 

nearby waterbodies. 

Sensitive soils (1.8 million acres) would contain greater potential for reduced vegetation cover, accelerated 

wind and water erosion, and occurrence near waterbodies (such as hydric soils, which occur on 110,000 acres in 

the planning area). Prohibiting surface disturbance and offering oil and gas leasing with an NSO stipulation in 

these areas would maintain water quality. Under this alternative, 630,000 acres of sensitive soils within 300 feet 

of waterbodies would potentially act as a vegetated buffer for nearby waterbodies.

Under this alternative, all waterbodies (300,000 acres or 120,000 river miles) and floodplains (330,000 acres) 

would be protected from surface-disturbing activities, which would maintain water quality. Offering oil and 

gas leasing with an NSO stipulation on waterbodies and streams would prohibit surface disturbance 
CHAPTER 4

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4-64

associated with oil and gas activities on 41,000 acres of waterbodies on BLM-administered mineral estate, 

which would maintain water quality. 

The impacts of constructing surface water impoundments (37 locations per year) would be reduced with 

mitigation or eliminated where new impoundments were prohibited. Surface water impoundments would reduce 

streamflow, dissolved oxygen, and floodplain size and extent downstream (Vörösmarty and Sahagian 2000); 

increase infiltration to groundwater, scour of the downstream streambed, and water temperature (Dodds et al. 

2004); substantially increase evaporative losses; degrade water quality; and change nutrient cycling, timing and 

magnitude of peak and low flows, sediment load, and riparian vegetation recruitment and succession. Under this 

action, there would also be the potential for permanent impacts, including channel scour, erosion, and 

sedimentation downstream (if a dam broke). Although impacts from existing impoundments would continue to 

occur, riparian vegetation, watershed functionality, and natural flow regimes would be maintained under this 

alternative (see the Reclamation Appendix). Expanded water use, withdrawals, and storage would exacerbate the 

impacts of climate change on water resources (IPCC 2007).

Installing flow-control 

devices on all water 

wells would reduce the 

impacts of all existing 

and new (10 wells per 

year) developments. 

Evaporative losses 

would be reduced, 

riparian vegetation 

would be maintained, 

and the vulnerability of 

water resources to 

climate change would 

be reduced.

Depending on the fuel 

type, haying within 200 

feet of waterbodies 

would increase 

sedimentation, cause 

soil compaction, 

reduce litter and 

vegetation cover, 

decrease infiltration, 

and increase erosion 

(Ellis 2008) but reduce the risk of high-intensity or severity fire in the long term, which would improve 

watershed functionality. 

Prohibiting surface-disturbing activities and oil and gas leasing within riparian and wetland areas would 

maintain water quality under this alternative. Wetlands would improve water quality, allow groundwater

recharge, filter sediment, retain floodwater, and remove pollutants from water (Prichard et al. 1999). 

Approximately 1.1 million acres of riparian and wetland areas would function as a buffer for streams by 

reducing or eliminating nonpoint source pollution from upland areas (MDEQ 2007). 

Locating new livestock water developments at least 0.25 miles from riparian and wetland areas and 

waterbodies would reduce impacts caused by grazing.

Prohibiting surface-disturbing activities in areas of invasive vegetation species infestations would reduce 

impacts to water resources by preventing activities that contributed to the spread of invasive species.

TABLE 4-39.

WATER RESOURCES AFFECTED IN RECREATION OR

SPECIAL DESIGNATION AREAS ON BLM-ADMINISTERED ACRES 

UNDER ALTERNATIVE B

Area

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Lewis and Clark Trail 

SRMA 72 100 3,500 8,800

Howrey Island 4 0 590 0

Matthews Recreation Area 0.5 0 11 0

Dean S. Reservoir 1 1 0 0

Pumpkin Creek Ranch and 

Recreation Area 100 40 630 9

Glendive OHV SRMA 2 11 200 200

Terry OHV SRMA 1 1 0 0

Strawberry Hill Recreation

Area 21 13 24 22

Moorhead <1 0 11 0

Powder River Depot ACEC 7 6 13 21

Battle Butte 1 1 0 0

Reynolds Battlefield ACEC 2 2 8 170

Walstein Area 11 11 5 33
CHAPTER 4

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Prohibiting surface-disturbing activities and requiring an NSO stipulation for oil and gas leasing and 

development within 0.5 miles of designated sport-fish reservoirs and pallid sturgeon habitat would maintain 

water quality and preserve a vegetative buffer that reduced or eliminated impacts (reduced sediment, 

nutrients, metals, and other pollutants) from surface-disturbing activities adjacent to 160 miles of streams. 

Buffers would reduce sedimentation, floodwater velocities and energy, erosion, and soil compaction; increase 

biodiversity; maintain stream channel shape, a higher water table (which would increase forage), late summer 

stream flows, and water temperature; stabilize streambanks; recharge aquifers; and facilitate nutrient input to 

aquatic habitats (MDEQ 2007). Because there would be no vegetative buffers, impacts (reduced sediment, 

nutrients, metals, and other pollutants) from surface-disturbing activities adjacent to 26,000 miles of streams, 

waterbodies, riparian areas, and wetlands would not be reduced or eliminated. 

Requirements for stream-crossing structures under this alternative would cause short-term surface disturbance 

and impacts (such as erosion and increased sediment load) but reduce the risk of erosion and damming in the 

long term.

Prohibiting surface-disturbing activities and requiring an NSO stipulation for oil and gas leasing and 

development within 0.25 miles of piping plover and interior least tern habitat would protect 1,300 miles of 

streams from surface disturbance, which would maintain water quality. This action would preserve a 24,000-

acre vegetative buffer for wetlands and streams to reduce impacts from upland areas.

Management actions that required the burial of power lines would increase surface disturbance and decrease 

water quality. Management actions that required the burial of low-voltage power lines would increase surface 

disturbance and decrease water quality. 

Limiting the cumulative, direct, and indirect disturbance to no more than 5 percent of the sagebrush habitat 

per section in Sage-grouse Habitat – General Habitat Areas, the Protection Priority ACEC, and Restoration

Areas would limit impacts to aquatic and water resources (WDFG 2010a). An NSO stipulation for oil and gas

leasing and development within the sagebrush habitat in the Sage-grouse Habitat – Protection Priority ACEC

would decrease impacts from surface disturbances. The resiliency of these ecosystems would increase, which 

would reduce the vulnerability of the water resources to climate change impacts (CEICC 2008).

Prohibiting prescribed fire on 2.5 million acres under this alternative would result in intense, stand-replacing 

wildfires, which would increase erosion and sedimentation and decrease water quality. Soil erosion (0.42 tons 

per acre) for a single precipitation event in a wildfire burned watershed would potentially be up to 90 percent 

of the estimated annual erosion (Elliot et al. 2010). Although requiring the removal or treatment of precommercial or commercial material on 53,000 acres of Condition Class 3 sites would decrease water quality 

in the short term, it would reduce the intensity and severity of fires, which would reduce erosion rates. 

Although typical timber harvest activities have been estimated to increase erosion rates to 0.05 to 0.25 tons 

per acre per year, intensive methods would potentially increase rates to 5 tons per acre per year (Elliot et al. 

2010).

Paleontological Resources management actions that required an NSO stipulation for oil and gas leasing and 

prohibited surface disturbance would maintain water quality. 

Not managing forestlands for forest products or sawtimber would enhance water quality. 

Because cottonwood harvest would occur near water, there would not be a sufficient vegetative buffer to reduce 

impacts of these activities.

Allowing cattle grazing on 2.4 million acres and sheep and goat grazing on 2.0 million acres would reduce 

water quality and the ability of vegetative buffers to filter sediments and contaminants from upland areas. 

Excluding 320,000 acres from grazing and closing 190,000 acres of allotments that fail to meet Rangeland 

Health Standards would substantially improve water quality and quantity. Closing allotments would decrease 

erosion, improve watershed function, and allow the total rest from grazing required for full recovery of 
CHAPTER 4

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4-66

structure and function of waterbodies (Belsky et al. 1999). In some areas, streams would have been degraded 

permanently, beyond recovery to a natural state, and adjust within the new potential.

Calculation of livestock carrying capacity based on watershed and riparian objectives would reduce the sitespecific impacts of grazing. Prioritizing allotments for monitoring and land health evaluations based on 

functionality of riparian areas would expedite the improvement of riparian health. Improved riparian health 

would decrease erosion; improve waterbody functionality, and increase water quality, infiltration, streambank 

stability, and the buffering capacity of riparian vegetation. Erosion and sedimentation from upland areas 

would be reduced. 

Excluding livestock within locatable mining areas, suspending AUMs based on acres of oil- and gasassociated surface disturbance, and suspending grazing during coal development would facilitate reclamation 

and reduce impacts to water resources. Multiple land uses would compound land uses and cause impacts 

greater than impacts caused by the individual land uses alone. 

Prohibiting coal exploration on 8.5 million acres would maintain water quality and quantity.

CSU stipulations for oil and gas leasing and development would reduce impacts to water resources on 16,000 

miles of streams and 16,000 acres of floodplains. Surface disturbance associated with offering oil and gas

with lease terms on 328,000 acres would decrease water quality. 

Mineral sales and permitting on 300,000 acres would decrease water quality.

Closing 35,000 acres to OHV use under this alternative would maintain water quality and quantity. Open 

OHV use on 2,900 acres would impact 200 acres of floodplains and Limited OHV use on 2.8 million acres 

would decrease water quality. 

Streams and floodplains would be affected in Recreation and Special Designation Areas under Alternative B.

ALTERNATIVE C

Management actions that prohibited surface-disturbing activities; required NSO stipulations for oil and gas

leasing and development; and removed BLM-administered mineral acreage from oil and gas leasing in 

uplands on approximately 2.1 million acres of mineral estate and 1.6 million acres of BLM-administered 

surface would maintain water quality, watershed functionality, and potentially preserve a vegetative buffer 

that reduced impacts from upland areas (Table 4-40). 

Management actions limiting surface disturbance would benefit water resources by reducing impacts to water 

resources. Water resources would be affected by surface disturbance in uplands, riparian areas, wetland areas, 

and waterbodies within the watershed (BLM-administered land and other ownerships). Surface-disturbing 

activities (including ROW actions; mineral and energy exploration [including renewable energy], leasing, and 

development; geophysical exploration; OHV and vehicle use; special designation and recreation area 

designations and use [Table 4-41]; infrastructure development; vegetation and fuel treatments [including 

some habitat restoration projects]; cultural or paleontological excavation; establishment of wildfire fuel 

breaks; burial of power lines; and range improvements) would cause vegetation removal, soil compaction, 

and soil disturbance. Impacts would include accelerated erosion, increased overland flow, decreased 

infiltration, and degradation of water quality through increased sedimentation, turbidity, nutrients, 

eutrophication, metals, and other pollutants in waterbodies. Erosion potential would be increased further 

through soil compaction and low-permeability surfacing (e.g., roads and well pads), which would increase the 

energy and amount of overland flow, which would subsequently increase sedimentation and erosion and alter 

flow characteristics. The magnitude of these impacts would depend on the specific activity, season, proximity 

to waterbodies, location in the watershed, condition of upland and riparian vegetation, soils, watershed 

resilience, efficacy of mitigation (see the Best Management Practices Appendix), and the time elapsed until 

reclamation success (see the Reclamation Appendix). Although impacts from surface disturbance would 

typically be localized and short term, lasting until vegetation was reestablished, there would be the potential 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-67

for severe and long-term effects to water quality and overall stream function (however the beneficial uses 

would be maintained). Impacts to water resources would increase as acres of surface disturbance increased 

within a watershed. 

TABLE 4-40. 

ESTIMATED WATERBODIES MAINTAINED ON BLM-ADMINISTERED ACRES 

UNDER ALTERNATIVE C

Area or Resource

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Fish and Wildlife

Aquatics, 

sport-fish

reservoir, 

0.25-mile 

NSO buffer

27 26 170 240

Black-tailed 

Prairie Dog, 

NSD1

270 490 1,500 2,900

Pallid 

Sturgeon, 0.5-

mile NSD

75 94 3,300 6,800

Travel 

Mgmt and 

OHV

Limited OHV 13,000 NA 41,000 NA

Closed OHV 1 NA 0 NA

1NSD=No Surface Disturbance

Avoiding or mitigating activities on slopes of 25 percent or greater (150,000 acres in the planning area) and 

sensitive soils would reduce impacts to water resources. Activities in these areas would cause accelerated 

erosion, increased overland flow, decreased infiltration, and degradation of water quality. Sensitive soils (1.8 

million acres) would contain greater potential for reduced vegetation cover, accelerated wind and water 

erosion, and occurrence near waterbodies (such as hydric soils, which occur on 110,000 acres in the planning 

area). Surface disturbances on slopes of 25 percent or greater or sensitive soils within 300 feet of waterbodies 

(44,000 acres and 630,000 acres) would inhibit the ability of vegetative buffers to reduce impacts from upland 

areas. 

Surface-disturbing activities in floodplains, streams, and waterbodies (when they could not be avoided) would 

reduce streambank stability; increase sedimentation, erosion, and turbidity; decrease water quality; remove 

riparian vegetation; increase flood severity; and alter channel morphology (MDEQ 2007) if they could not be 

avoided. Surface disturbance would reduce the capacity of these areas to dissipate the energy of high water 

events and cause changes in infiltration rates, water storage, and aquifer recharge. The presence of aboveground 

facilities would create flood hazards. Spills would potentially contaminate surface water and shallow 

groundwater. Construction activity in flowing waterbodies would be likely to exceed Montana water quality 

standards for turbidity and a variance would be required. The efficacy of mitigation measures would determine 

the severity of short- and long-term impacts caused by these management actions.
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Management actions 

that allowed surface 

water impoundments 

(37 locations per year) 

would reduce 

streamflow, dissolved 

oxygen, and 

floodplain size and 

extent downstream 

(Vörösmarty and 

Sahagian 2000); 

increase infiltration to 

groundwater, scour of 

the downstream 

streambed, and water 

temperature (Dodds et 

al. 2004); 

substantially increase 

evaporative losses; 

degrade water quality; 

and change nutrient 

cycling, timing and 

magnitude of peak 

and low flows, 

sediment load, and 

riparian vegetation 

recruitment and succession. Under this action, there would also be the potential for permanent impacts 

including channel scour, erosion, and sedimentation downstream (if a dam broke). Water impoundments and 

developments in and near waterbodies, riparian areas, and wetlands would increase use in these areas, which 

would change morphology, increase water temperature, alter ecosystem processes, and decrease water quality 

by introducing sediment, salinity, bacteria, and nutrients. Expanded water use, withdrawals, and storage would 

exacerbate the impacts of climate change on water resources; however, maintaining natural flow regime and 

watershed functionality would reduce these impacts (IPCC 2007). The efficacy of approved specialized design 

features in maintaining the natural flow regime and watershed functionality would determine the severity of 

long-term impacts caused by these management actions. Installing flow-control devices on new all water wells 

and spring developments would reduce the impacts of all new (10 wells and 2 springs per year) developments 

including water loss, soil erosion, riparian community losses, evaporation, and the vulnerability of water 

resources to climate change would be reduced. Riparian vegetation would be maintained at new sites. Current 

impacts (changes to the water table, soil erosion, loss of riparian communities, and evaporation) would 

continue. 

Depending on the fuel type, haying within 200 feet of waterbodies would increase sedimentation, cause soil 

compaction, reduce litter and vegetation cover, decrease infiltration, and increase erosion (Ellis 2008) but 

reduce the risk of high-intensity or severity fire in the long term, which would improve watershed functionality. 

Riparian and hydrologic function would be affected if surface-disturbing activities in riparian and wetlands

areas were not avoided. Although PFC would be maintained in the long term, surface disturbance in these 

areas would cause erosion, turbidity, and sedimentation in the short term. The functionality of riparian 

vegetation (such as the dissipation of the energy of high water flows, filtration of sediment, stabilization of 

streambanks, and enhancement of floodplain functionality) and wetlands (such as the improvement of water 

quality, facilitation of groundwater recharge, filtration of sediment, maintenance of floodwater, and removal 

of pollutants) would be reduced. Spills would potentially contaminate shallow groundwater and surface 

water. The severity of short-term and, potentially, long-term impacts would depend on the efficacy of the 

mitigation measures. 

TABLE 4-41.

WATER RESOURCES AFFECTED IN RECREATION OR 

SPECIAL DESIGNATION AREAS ON BLM-ADMINISTERED ACRES 

UNDER ALTERNATIVE C

Area

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Lewis and Clark Trail SRMA 72 100 3,500 8,800

Howrey Island 4 0 590 0

Matthews Recreation Area <1 0 11 0

Dean S. Reservoir 1 1 0 0

Pumpkin Creek Ranch and 

Recreation Area 100 40 630 9

Glendive OHV SRMA 2 11 200 200

Terry OHV SRMA 1 1 0 0

Strawberry Hill Recreation

Area 21 13 24 22

Moorhead <1 0 11 0

Powder River Depot ACEC 7 6 13 21

Powderville Paleontological 

Area 110 120 18 660

Battle Butte 1 1 0 0

Reynolds Battlefield ACEC 2 2 8 170

Walstein Area 11 11 5 33
CHAPTER 4

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Boring of streams, wetlands, or riparian areas would reduce surface disturbance and maintain water quality in 

these areas. Implementing linear underground facilities (including buried power lines) using open-cut wet or 

isolated crossing methods would reduce water quality. 

Although all methods would cause surface disturbance, the magnitude and duration of the impacts of surfacedisturbing activities such as linear underground facilities (including buried power lines) crossing perennial 

streams, intermittent streams, wetlands, and riparian areas would vary and depend on the method used to 

cross the waterbody. Because open-cut wet crossings (trenching) of flowing water would result in direct 

contact with water during all stages of construction and potential in-stream storage of spoil, these actions 

would increase sedimentation; destabilize streambanks; decrease streambed porosity; alter channel 

morphology; and cause short-term increases in total suspended solids (TSS), TDS, nutrients, metals, and total 

organic carbon (Lévesque and Dubé 2007). Additionally, riparian vegetation would be removed: "Excavation 

of streambeds composed primarily of clay or silt sized particles can generate persistent plumes of high 

suspended sediment concentration or turbidity" and "small particle diameters (e.g., clays) can, however, limit 

the ability of sediment control structures to reduce downstream sediment concentrations" (Reid, Ade, and 

Metikosh 2004, p. 6). Generally, if bank stabilization occurred, sediment entrainment would occur during 

construction (typically within 24 to 48 hours but potentially up to a few weeks) and the impacts would not be 

evident within 4 years (Reid et al. 2004). 

Isolated crossing methods (e.g., dam-and-pump and flume methods) would have, on average, peak TSS (i.e., 

turbidity) 3 to 20 times lower than open-cut wet methods (Reid et al. 2004) and more effectively mitigate 

sediment loading (Lévesque and Dubé 2007). Isolated methods would cause impacts with reduced severity 

and duration because the increases in turbidity and sedimentation would be limited to installation and removal 

of dam or flume structures (up to 10 hours) (Lévesque and Dubé 2007).

Not allowing new spring developments would maintain water flow locally and downstream, the local water 

table, water temperatures, riparian vegetation, and channel morphology (Sada et al. 2001). Locating water 

developments 0.25 miles from perennial and intermittent streams would reduce grazing impacts in these 

areas. Allowing new livestock water developments in and near ephemeral streams, springs, and riparian areas 

would lead to increased use in these areas, which would cause changes in morphology, increase water 

temperature, alter ecosystem processes, and decrease water quality by increasing sediment, salinity, bacteria, 

and nutrients. 

Unless the surface-disturbing activity established native vegetation, management actions that allowed surfacedisturbing activities in areas of invasive species infestations would increase damage to watersheds and reduce 

water quality and quantity (BLM 2007d). The magnitude of damage to surrounding watersheds would depend 

on the efficacy of mitigation.

Prohibiting surface-disturbing activities and requiring an NSO stipulation for oil and gas leasing and 

development within 0.5 miles of pallid sturgeon habitat and avoiding surface-disturbing activities and 

requiring an NSO stipulation for oil and gas leasing and development within 0.25 miles of designated sportfish reservoirs would maintain water quality and preserve a vegetative buffer that reduced or eliminated 

impacts (reduced sediment, nutrients, metals, and other pollutants) from surface-disturbing activities adjacent 

to 64 miles of streams. Buffers would reduce sedimentation, floodwater velocities and energy, erosion, and 

soil compaction; increase biodiversity; maintain stream channel shape, a higher water table (which would 

increase forage), late summer stream flows, and water temperature; stabilize streambanks; recharge aquifers; 

and facilitate nutrient input to aquatic habitats (MDEQ 2007). Because there would be no vegetative buffers, 

impacts (reduced sediment, nutrients, metals, and other pollutants) from surface-disturbing activities adjacent 

26,000 miles of streams, waterbodies, riparian areas, and wetlands would not be reduced or eliminated. 

Requirements for stream-crossing structures under this alternative would cause short-term surface disturbance 

and impacts (such as erosion and increased sediment load) but reduce the risk of erosion and damming in the 

long term.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-70

Allowing surface-disturbing activities within 0.25 miles of piping plover and interior least tern habitat would 

reduce water quality. 

Management actions that required the burial of low-voltage power lines would increase surface disturbance 

and decrease water quality. 

Limiting the cumulative, direct, and indirect disturbance to no more than 10 percent of the sagebrush habitat 

per 640 acres in Sage-grouse Habitat – Protection Priority Areas would limit impacts to aquatic and water 

resources (WDFG 2010a). 

High-intensity fire and fire suppression that resulted in fuel buildup would lead to increased erosion and 

sedimentation, which would impact water quality in both the short and long term. The impacts would be the 

same for low-intensity fire (including prescribed fire) except that the magnitude of impacts would be reduced 

and erosion rates would be similar to natural levels. Depending on the severity, fire in riparian areas would 

reduce water quality by reducing vegetation and riparian function. In the long term, although water quality 

would benefit from healthy uplands, road construction and use of heavy equipment would lead to increased 

soil compaction, erosion, and sedimentation, which would reduce water quality.

Although requiring the removal or treatment of pre-commercial or commercial material on 53,000 acres of 

Condition Class 3 sites would decrease water quality in the short term, it would reduce the intensity and 

severity of fires, which would reduce erosion rates. Although typical timber harvest activities have been 

estimated to increase erosion rates to 0.05 to 0.25 tons per acre per year, intensive methods would potentially 

increase rates to 5 tons per acre per year (Elliot et al. 2010). Forest product production and sawtimber harvest 

are a source of nonpoint source pollution, and the magnitude of impacts from these activities would depend 

on the methods used. Vegetation removal, surface disturbance, road construction, and soil compaction would 

result in an increase in erosion, sedimentation, and overland flow. The removal of streamside vegetation 

would change water temperature and reduce the ability of vegetative buffers to reduce nonpoint source 

pollution. Forest management activities that complied with the Streamside Management Zone Law, the Water 

Quality BMPs for Montana Forests (Logan 2001) (see the Forestry and Woodland Products Appendix), and 

other BMPs would reduce these impacts. Salvage harvest of sawtimber would remove vegetation in a 

watershed with a reduced canopy cover, which would further accelerate erosion. 

Paleontological Resources management actions that required an NSO stipulation for oil and gas leasing and 

prohibited surface disturbance would maintain water quality. 

Managing forestlands for a diversity of forest products would reduce water quality by increasing the acres of 

surface disturbance. Wood product sales and sawtimber harvest would cause nonpoint source pollution, the 

magnitude of which would depend on the methods used. Vegetation removal, surface disturbance, road 

construction, and soil compaction would increase erosion, sedimentation, and overland flow. Streamside 

vegetation removal would increase water temperatures and reduce the ability of vegetative buffers to reduce 

nonpoint source pollution. However, forest management activities would use BMPs (e.g., Water Quality 

BMPs for Montana Forests [Logan 2001], see the Forestry and Woodland Products Appendix) and comply 

with the Streamside Management Zone Law, which would reduce these impacts. 

Different methods of timber harvest would have various impacts (e.g., hand harvesting would cause localized 

disturbances but mechanized methods would disturb a greater area). Whole tree harvesting would generate 

skid trails, which would accelerate erosion. Leaving slash in place would reduce erosion, and BMPs and the 

Streamside Management Zone Law would reduce the magnitude of these impacts.

Forest health projects would have the potential to impact water resources. Most treatments would cause initial 

short-term impacts similar to those caused by surface disturbance. Changes in vegetation structure and 

composition would alter water flows, the quantity and quality of surface water and groundwater, and the rate 

of groundwater recharge (BLM 2007d). However, these impacts would be a natural result of healthier 

vegetation. Because evapotranspiration rates, rooting depth, and vegetative cover vary by species, a change 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-71

would potentially impact water (e.g., changes in erosion and sedimentation rates, infiltration, amount of 

overland flow, evaporation, and turbidity). 

Because cottonwood harvest would occur near water, there would not be a sufficient vegetative buffer to reduce 

the impacts of these activities; however, mitigation would reduce impacts of these activities. If this action 

resulted in healthier cottonwood stands, streambank stability and the system’s ability to dissipate flood energy 

would increase.

Livestock grazing on 2.7 million acres under this alternative would reduce water quality and the ability of 

vegetative buffers to filter sediments and contaminants from upland areas. Excluding 8,000 acres from 

livestock grazing, excluding sheep and goats from 64,000 acres, and closing allotments in which the 

Standards for Rangeland Health were not met (190,000 acres) would improve watershed function, water 

quality, and quantity. However, in the 5 years before allotments that failed to meet Standards for Rangeland 

Health were closed, sedimentation and erosion would continue to reduce water quality. In the long term, this 

management action would decrease erosion and sedimentation and allow the total rest from grazing required 

for full recovery of structure and function of waterbodies (Belsky et al. 1999). In some areas, streams would 

have been degraded permanently, beyond recovery to a natural state, and adjust within the new potential.

Because grazing would slow revegetation and reclamation, allowing livestock grazing immediately after 

locatable mineral and coal mining and during oil and gas development would cause persistent impacts (even 

if the Standards for Rangeland Health were met) and accelerate impacts from multiple land use activities. In 

areas in which associated surface disturbance would decrease forage, maintaining AUM numbers during oil 

and gas development would cause impacts from grazing to increase. Multiple land uses would compound 

land uses and cause impacts greater than impacts caused by livestock grazing, mining, or development alone. 

This action would increase erosion, sedimentation, and streambank instability and decrease water quality and 

riparian functionality.

Management actions that deferred livestock grazing until the area attained identified vegetative objectives 

following a wildfire, prescribed fire, or non-fire vegetative treatment would facilitate vegetative 

reestablishment and improve water quality. 

Water quality and riparian health monitoring would be prioritized on allotments in which grazing 

management contributed to the failure to meet Rangeland Health Standards. Management practices or levels 

of use would be adjusted to meet water quality or riparian health standards.

Prohibiting coal exploration on 200,000 acres would maintain water quality and quantity.

CSU stipulations for oil and gas leasing and development would reduce impacts to water resources on 16,000 

miles of streams and 16,000 acres of floodplains. Management actions that allowed oil and gas surface 

disturbance with lease terms on 737,000 acres would decrease water quality. Development of BLMadministered mineral estate would be predicted to cause surface disturbance on 1,000 to 4,000 acres under 

this alternative. 

Mineral sales and permitting on 1.1 million acres would decrease water quality.

Allowing big game retrieval would reduce water quality in areas in which vehicles crossed drainages, 

compacted soils, and accelerated erosion. 

Closing 550 acres to OHV use under this alternative would maintain water quality and quantity. Open OHV

use on 660 acres and Limited OHV use on 2.8 million acres would decrease water quality. 

Streams and floodplains would be affected in Recreation and Special Designation Areas under Alternative C.
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

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ALTERNATIVE D

Management actions that prohibited surface-disturbing activities and required NSO stipulations for oil and 

gas leasing and development in uplands on approximately 500,000 acres of mineral estate and 1.2 million 

acres of BLM-administered surface would maintain water quality, watershed functionality, and potentially 

preserve a vegetative buffer that reduced impacts from upland areas (Table 4-42). 

Management actions limiting surface disturbance would 

benefit water resources by reducing impacts to water 

resources. Water resources would be affected by surface 

disturbance in uplands, riparian areas, wetland areas, and 

waterbodies within the watershed (BLM-administered 

land and other ownerships). Surface-disturbing activities 

(including ROW actions; mineral and energy 

exploration [including renewable energy], leasing, and 

development; geophysical exploration; OHV and vehicle 

use; special designation and recreation area designations 

and use [Table 4-43]; infrastructure development; 

vegetation and fuel treatments [including some habitat 

restoration projects]; cultural or paleontological excavation; establishment of wildfire fuel breaks; burial of 

power lines; and range improvements) would cause vegetation removal, soil compaction, and soil 

disturbance. Impacts would include accelerated erosion, increased overland flow, decreased infiltration, and 

degradation of water quality through increased sedimentation, turbidity, nutrients, eutrophication, metals, and 

other pollutants in waterbodies. Erosion potential would be increased further through soil compaction and 

low-permeability surfacing (e.g., roads and well pads), which would increase the energy and amount of 

overland flow, which would subsequently increase sedimentation and erosion and alter flow characteristics. 

The magnitude of these impacts would depend on the specific activity, season, proximity to waterbodies, 

location in the watershed, condition of upland and riparian vegetation, soils, watershed resilience, efficacy of 

mitigation (see the Best Management Practices Appendix), and the time elapsed until reclamation success 

(see the Reclamation Appendix). Although impacts from surface disturbance would typically be localized and 

short term, lasting until vegetation was reestablished, there would be the potential for severe and long-term 

effects to water quality and overall stream function (however the beneficial uses would be maintained). 

Impacts to water resources would increase as acres of surface disturbance increased within a watershed. 

Prohibiting surface-disturbing activities and requiring NSO stipulations in uplands on approximately 500,000

acres of mineral estate and 1.2 million acres of BLM-administered surface would maintain water quality, 

watershed functionality, and potentially preserve a vegetative buffer that reduced impacts from upland areas. 

Avoiding or mitigating activities on slopes of 25 percent or greater (150,000 acres in the planning area) and 

sensitive soils would reduce impacts to water resources. Activities in these areas would cause accelerated 

erosion, increased overland flow, decreased infiltration, and degradation of water quality. Sensitive soils (1.8 

million acres) would contain greater potential for reduced vegetation cover, accelerated wind and water 

erosion, and occurrence near waterbodies (such as hydric soils, which occur on 110,000 acres in the planning 

area). Surface disturbances on slopes of 25 percent or greater or sensitive soils within 300 feet of waterbodies 

(44,000 acres and 630,000 acres) would inhibit the ability of vegetative buffers to reduce impacts from upland 

areas. 

Surface-disturbing activities in floodplains (330,000 acres) and waterbodies (300,000 acres) would reduce 

sedimentation, turbidity, and water temperature; decrease floodplain functionality, streambank stability, and 

water quality; cause riparian vegetation removal; and alter channel morphology in the short to long term when 

they could not be avoided. Because a sufficient vegetative buffer would not be preserved, nonpoint source 

pollution from uplands would not be reduced. Watershed resilience would be reduced, which would prolong the 

current and future periods until reclamation success. Construction activity in flowing waterbodies would be 

likely to exceed Montana water quality standards for turbidity and a variance would be required. The efficacy of 

mitigation measures would determine the severity of impacts caused by these management actions.

TABLE 4-42. 

ESTIMATED WATERBODIES 

MAINTAINED ON BLM-ADMINISTERED 

ACRES UNDER ALTERNATIVE D

Recreation

Area

Waterbodies

(acres)

Floodplains

(acres)

Limited 

OHV 132,000 41,000

Closed OHV 0 0
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-73

Management actions 

that allowed surface 

water impoundments 

(37 locations per 

year) would reduce 

streamflow, dissolved 

oxygen, and 

floodplain size and 

extent downstream 

(Vörösmarty and 

Sahagian 2000); 

increase infiltration to 

groundwater, scour of 

the downstream 

streambed, and water 

temperature (Dodds 

et al. 2004); 

substantially increase 

evaporative losses; 

degrade water 

quality; and change 

nutrient cycling, 

timing and magnitude 

of peak and low 

flows, sediment load, 

and riparian vegetation recruitment and succession. Under this action, there would also be the potential for 

permanent impacts including channel scour, erosion, and sedimentation downstream (if a dam broke). Water 

impoundments and developments in and near waterbodies, riparian areas, and wetlands would increase use in 

these areas, which would change morphology, increase water temperature, alter ecosystem processes, and 

decrease water quality by introducing sediment, salinity, bacteria, and nutrients. Expanded water use, 

withdrawals, and storage would exacerbate the impacts of climate change on water resources; however, 

maintaining natural flow regime and watershed functionality would reduce these impacts (IPCC 2007). The 

efficacy of approved specialized design features in maintaining the natural flow regime and watershed 

functionality would determine the severity of long-term impacts caused by these management actions.

Installing flow-control devices on all new water wells and spring developments would reduce the impacts of all 

new (10 wells and 2 springs per year) developments including water loss, soil erosion, riparian community 

losses, evaporation, and the vulnerability of water resources to climate change would be reduced. Riparian

vegetation would be maintained at new sites. Current impacts (changes to the water table, soil erosion, loss of 

riparian communities, and evaporation) would continue. 

Depending on the fuel type, haying within 200 feet of waterbodies would increase sedimentation, cause soil 

compaction, reduce litter and vegetation cover, decrease infiltration, and increase erosion (Ellis 2008) but 

reduce the risk of high-intensity or severity fire in the long term, which would improve watershed functionality. 

Although PFC would be maintained, surface-disturbing activities and surface disturbance associated with oil

and gas activities in riparian and wetland areas would reduce riparian and hydrologic function. In the short 

term, surface disturbance in riparian and wetland areas would result in erosion, turbidity, and sedimentation. 

The functionality of riparian vegetation (such as the dissipation of the energy of high water flows, filtration of 

sediment, stabilization of streambanks, and enhancement of floodplain functionality) and wetlands (such as 

the improvement of water quality, facilitation of groundwater recharge, filtration of sediment, maintenance of 

TABLE 4-43.

WATER RESOURCES AFFECTED IN RECREATION OR 

SPECIAL DESIGNATION AREAS ON BLM-ADMINISTERED ACRES 

UNDER ALTERNATIVE D

Area

Miles of 

streams 

(surface 

acres)

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Lewis and Clark Trail 

SRMA 72 100 3,500 8,800

Howrey Island 4 0 590 0

Matthews Recreation Area <1 0 11 0

Dean S. Reservoir 1 1 0 0

Pumpkin Creek Ranch and 

Recreation Area 100 40 630 9

Glendive OHV SRMA 2 11 200 200

Terry OHV SRMA 1 1 0 0

Strawberry Hill Recreation

Area 21 13 24 22

Moorhead <1 0 11 0

Powder River Depot ACEC 7 6 13 21

Powderville Paleontological 

Area 110 120 18 660

Battle Butte 1 1 0 0

Reynolds Battlefield ACEC 2 2 8 170

Walstein Area 11 11 5 33
CHAPTER 4

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Water

4-74

floodwater, and removal of pollutants) would be reduced. Spills would potentially contaminate shallow 

groundwater and surface water. Nonpoint source pollution from uplands would not be reduced under this 

alternative. Watershed resilience would be reduced, which would prolong the period until reclamation 

success. Spills, chemicals from drilling processes, and use of infiltration ponds in riparian and wetland areas 

would potentially contaminate shallow groundwater and surface water. The severity of short-term and, 

potentially, long-term impacts would depend on the efficacy of the mitigation measures.

Boring of streams, wetlands, or riparian areas would reduce surface disturbance and maintain water quality in 

these areas. Implementing linear underground facilities (including buried power lines) using open-cut wet or 

isolated crossing methods would reduce water quality. 

Unless the surface-disturbing activity established native vegetation, management actions that allowed surfacedisturbing activities in areas of invasive species infestations would increase damage to watersheds and reduce 

water quality and quantity (BLM 2007d). The magnitude of damage to surrounding watersheds would depend 

on the efficacy of mitigation.

Allowing surface-disturbing activities adjacent to sport-fish reservoirs would reduce water quality, reduce 

infiltration rates, increase erosion, and increase overland flow. A CSU stipulation for oil and gas leasing and 

development within 0.5 miles of pallid sturgeon habitat and prohibiting surface disturbances within 0.5 miles 

of pallid sturgeon habitat would reduce impacts to water resources. The magnitude of impacts would depend 

on the efficacy of mitigation. The lack of prescribed buffers on waterbodies would increase sedimentation and 

reduce water quality, and impacts (reducing sediment, nutrients, metals, and other pollutants) from surfacedisturbing activities adjacent to water, riparian areas, and wetlands would not be reduced or eliminated. 

Impacts would include sedimentation, erosion, soil compaction, decreased biodiversity, altered stream 

channel morphology, increased water temperature, reduced bank stability and aquifer recharge, increased 

floodwater velocities and energy, altered nutrient input to aquatic habitats, and lowered water table (which 

would decrease forage) (MDEQ 2007).

In the long term, management actions that required fish passage on a case-by-case basis would reduce 

sedimentation, streambed erosion, and streambank erosion. Existing and new culverts that impeded fish 

passage would result in sedimentation, streambed erosion, and streambank erosion.

Surface-disturbing activities within 0.25 miles of piping plover and interior least tern habitat would reduce 

water quality. 

Management actions that required the burial of low-voltage power lines would increase surface disturbance 

and decrease water quality. 

Limiting the cumulative, direct, and indirect disturbance to no more than 10 percent of the sagebrush habitat 

per 640 acres in Sage-grouse Habitat – Protection Priority Areas would limit impacts to aquatic and water 

resources (WDFG 2010a). 

High-intensity fire and fire suppression that resulted in fuel buildup would lead to increased erosion and 

sedimentation, which would impact water quality in both the short and long term. The impacts would be the 

same for low-intensity fire (including prescribed fire) except that the magnitude of impacts would be reduced 

and erosion rates would be similar to natural levels. Depending on the severity, fire in riparian areas would 

reduce water quality by reducing vegetation and riparian function. In the long term, although water quality 

would benefit from healthy uplands, road construction and use of heavy equipment would lead to increased 

soil compaction, erosion, and sedimentation, which would reduce water quality.

Although requiring the removal or treatment of pre-commercial or commercial material on 53,000 acres of 

Condition Class 3 sites would decrease water quality in the short term, it would reduce the intensity and 

severity of fires, which would reduce erosion rates. Although typical timber harvest activities have been 

estimated to increase erosion rates to 0.05 to 0.25 tons per acre per year, intensive methods would potentially 

increase rates to 5 tons per acre per year (Elliot et al. 2010). Forest product production and sawtimber harvest 
CHAPTER 4

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Water

4-75

are a source of nonpoint source pollution, and the magnitude of impacts from these activities would depend 

on the methods used. Vegetation removal, surface disturbance, road construction, and soil compaction would 

result in an increase in erosion, sedimentation, and overland flow. The removal of streamside vegetation 

would change water temperature and reduce the ability of vegetative buffers to reduce nonpoint source 

pollution. Forest management activities that complied with the Streamside Management Zone Law, the Water 

Quality BMPs for Montana Forests (Logan 2001) (see the Forestry and Woodland Products Appendix), and 

other BMPs would reduce these impacts.

Paleontological Resources management actions that required an NSO stipulation for oil and gas leasing and 

prohibited surface disturbance would maintain water quality. 

Managing forestlands for a diversity of forest products would reduce water quality by increasing the acres of 

surface disturbance. Wood product sales and sawtimber harvest would cause nonpoint source pollution, the 

magnitude of which would depend on the methods used. Vegetation removal, surface disturbance, road 

construction, and soil compaction would increase erosion, sedimentation, and overland flow. Streamside 

vegetation removal would increase water temperatures and reduce the ability of vegetative buffers to reduce 

nonpoint source pollution. However, forest management activities would use BMPs (e.g., Water Quality 

BMPs for Montana Forests [Logan 2001], see the Forestry and Woodland Products Appendix) and comply 

with the Streamside Management Zone Law, which would reduce these impacts. 

Different methods of timber harvest would have various impacts (e.g., hand harvesting would cause localized 

disturbances but mechanized methods would disturb a greater area). Whole tree harvesting would generate 

skid trails, which would accelerate erosion. Leaving slash in place would reduce erosion, and BMPs and the 

Streamside Management Zone Law would reduce the magnitude of these impacts.

Forest health projects would have the potential to impact water resources. Most treatments would cause initial 

short-term impacts similar to those caused by surface disturbance. Changes in vegetation structure and 

composition would alter water flows, the quantity and quality of surface water and groundwater, and the rate 

of groundwater recharge (BLM 2007d). However, these impacts would be a natural result of healthier 

vegetation. Because evapotranspiration rates, rooting depth, and vegetative cover vary by species, a change 

would potentially impact water (e.g., changes in erosion and sedimentation rates, infiltration, amount of 

overland flow, evaporation, and turbidity). 

Because cottonwood harvest would occur near water, there would not be a sufficient vegetative buffer to reduce 

impacts of these activities. If this action resulted in healthier cottonwood stands, streambank stability and the 

system’s ability to dissipate flood energy would increase.

Livestock grazing on 2.7 million acres under this alternative would reduce water quality and the ability of 

vegetative buffers to filter sediments and contaminants from upland areas. Excluding 8,000 acres from 

livestock grazing, excluding sheep and goats from 64,000 acres, and closing allotments in which the 

Standards for Rangeland Health were not met (190,000 acres) would improve watershed function, water 

quality, and quantity. However, in the 5 years before allotments that failed to meet Standards for Rangeland 

Health were closed, sedimentation and erosion would continue to reduce water quality. In the long term, this 

management action would decrease erosion and sedimentation and allow the total rest from grazing required 

for full recovery of structure and function of waterbodies (Belsky et al. 1999). In some areas, streams would 

have been degraded permanently, beyond recovery to a natural state, and adjust within the new potential.

Because grazing would slow revegetation and reclamation, allowing livestock grazing immediately after 

locatable mineral and coal mining and during oil and gas development would cause persistent impacts (even 

if the Standards for Rangeland Health were met) and accelerate impacts from multiple land use activities. In 

areas in which associated surface disturbance would decrease forage, maintaining AUM numbers during oil 

and gas development would cause impacts from grazing to increase. Multiple land uses would compound 

land uses and cause impacts greater than impacts caused by livestock grazing, mining, or development alone. 

This action would increase erosion, sedimentation, and streambank instability and decrease water quality and 

riparian functionality.
CHAPTER 4

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4-76

Management actions that allowed grazing the season following wildfire or prescribed fires would cause 

accelerated erosion, overland flow, and sedimentation, particularly if the wildfires were intense. Livestock 

grazing would inhibit restoration of aquatic ecosystem functionality (Beschta et al. 2004). Potentially 

(depending on site-specific fire situations, riparian areas, climatic conditions, and watershed conditions), a 1-

season resting period would not enable riparian and upland vegetative reestablishment sufficient to reduce the 

compounded impacts of grazing and fire. Multiple land uses would compound land uses and cause impacts 

greater than impacts caused by the individual land uses alone. Impacts from both activities would cause 

erosion, sedimentation, streambank instability, decreased water quality, and reduced riparian vigor. 

Water quality and riparian health monitoring would be prioritized on allotments in which grazing 

management contributed to the failure to meet Rangeland Health Standards. Management practices or levels 

of use would be adjusted to meet water quality or riparian health standards.

Prohibiting coal exploration on 1.8 million acres would maintain water quality and quantity.

Management actions that allowed surface disturbance associated with oil and gas activities under lease terms 

on 914,000 acres would decrease water quality on 2,000 to 6,000 acres of surface disturbance that occurred 

during development of BLM-administered mineral estate. 

CSU stipulations for oil and gas leasing and development would reduce impacts to water resources on 16,000 

miles of streams and 16,000 acres of floodplains. 

Mineral sales and permitting on 1.1 million acres would decrease water quality.

Allowing big game retrieval would reduce water quality in areas in which vehicles crossed drainages, 

compacted soils, and accelerated erosion. 

Management actions that allowed Open OHV use on 2,000 acres would impact 200 acres of floodplains, and 

Limited OHV use on 2.8 million acres would decrease water quality. 

Streams and floodplains would be affected in Recreation and Special Designation Areas under Alternative D.

ALTERNATIVE E (PREFERRED ALTERNATIVE)

Management actions that prohibited surface-disturbing activities; required NSO stipulations for oil and gas

leasing and development; and removed BLM-administered mineral acres from oil and gas leasing in uplands 

on approximately 1.0 million acres of mineral estate and 1.0 million acres of BLM-administered surface 

would maintain water quality, watershed functionality, and potentially preserve a vegetative buffer that 

reduced impacts from upland areas (Table 4-44). 

Management actions limiting surface disturbance would benefit water resources by reducing impacts to water 

resources. Water resources would be affected by surface disturbance in uplands, riparian areas, wetland areas, 

and waterbodies within the watershed (BLM-administered land and other ownerships). Surface-disturbing 

activities (including ROW actions; mineral and energy exploration [including renewable energy], leasing, and 

development; geophysical exploration; OHV and vehicle use; special designation and recreation area 

designations and use [Table 4-45]; infrastructure development; vegetation and fuel treatments [including 

some habitat restoration projects]; cultural or paleontological excavation; establishment of wildfire fuel 

breaks; burial of power lines; and range improvements) would cause vegetation removal, soil compaction, 

and soil disturbance. Impacts would include accelerated erosion, increased overland flow, decreased 

infiltration, and degradation of water quality through increased sedimentation, turbidity, nutrients, 

eutrophication, metals, and other pollutants in waterbodies. Erosion potential would be increased further 

through soil compaction and low-permeability surfacing (e.g., roads and well pads), which would increase the 

energy and amount of overland flow, which would subsequently increase sedimentation and erosion and alter 

flow characteristics. The magnitude of these impacts would depend on the specific activity, season, proximity 
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

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4-77

to waterbodies, location in the watershed, condition of upland and riparian vegetation, soils, watershed 

resilience, efficacy of mitigation (see the Best Management Practices Appendix), and the time elapsed until 

reclamation success (see the Reclamation Appendix). Although impacts from surface disturbance would 

typically be localized and short term, lasting until vegetation was reestablished, there would be the potential 

for severe and long-term effects to water quality and overall stream function (however the beneficial uses 

would be maintained). Impacts to water resources would increase as acres of surface disturbance increased 

within a watershed.

Avoiding or mitigating 

activities on slopes of 25 

percent or greater (150,000 

acres in the planning area) and 

sensitive soils would reduce 

impacts to water resources. 

Activities in these areas would 

cause accelerated erosion, 

increased overland flow, 

decreased infiltration, and 

degradation of water quality. 

Sensitive soils (1.8 million 

acres) would contain greater 

potential for reduced 

vegetation cover, accelerated 

wind and water erosion, and 

occurrence near waterbodies 

(such as hydric soils, which 

occur on 110,000 acres in the 

planning area). Surface 

disturbances on slopes of 25 

percent or greater or sensitive 

soils within 300 feet of 

waterbodies (44,000 acres and 

630,000 acres) would inhibit 

the ability of vegetative 

buffers to reduce impacts from 

upland areas. Although surface disturbances on slopes of 25 percent or greater or sensitive soils within 300 

feet of waterbodies (44,000 acres and 630,000 acres) would inhibit the ability of vegetative buffers to reduce 

impacts from upland areas, specialized design features would maintain water quality and fish and wildlife

habitat.

Avoiding surface-disturbing activities and requiring an NSO stipulation for oil and gas leasing and 

development in floodplains (330,000 acres), waterbodies, and streams (300,000 acres) would maintain water 

quality. Surface-disturbing activities in these areas would reduce streambank stability; increase 

sedimentation, erosion, and turbidity; decrease water quality; remove riparian vegetation; increase flood 

severity; and alter channel morphology (MDEQ 2007) when they could not be avoided. Surface disturbance 

would reduce the capacity of these areas to dissipate the energy of high water events and cause changes in 

infiltration rates, water storage, and aquifer recharge. The presence of aboveground facilities would create 

flood hazards. Spills would potentially contaminate surface water and shallow groundwater. Construction 

activity in flowing waterbodies would be likely to exceed Montana water quality standards for turbidity and a 

variance would be required. The efficacy of approved specialized design features to maintain the functionality 

of the floodplain, water quality, and fish and wildlife habitat would determine the severity of short- and longterm impacts caused by these management actions.

TABLE 4-44.

ESTIMATED WATERBODIES MAINTAINED ON BLMADMINISTERED ACRES UNDER ALTERNATIVE E

Area or Resource

Miles of 

streams 

(surface 

acres) 

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Water

Floodplain, 

NSD1 770 1,900 42,000 110,000

Waterbody, 

NSD 13,000 26,000 1,700 3,100

Veg.

Riparian and 

wetland, NSO 1,700 4,200 13,000 33,000

Fish and Wildlife

Aquatics, sportfish reservoirs, 

0.25-mile 

buffer

27 26 170 240

Pallid Sturgeon, 

0.5-mile buffer 75 94 3,300 6,800

Travel Mgmt and 

OHV

Limited OHV 13,000 NA 41,000 NA

Closed OHV 12 NA 65 NA

1NSD=No Surface Disturbance
CHAPTER 4

ENVIRONMENTAL CONSEQUENCES

Water

4-78

Avoiding surface-disturbing 

activities on perennial streams, 

intermittent streams, lakes, 

ponds, or reservoirs and 

requiring an NSO stipulation for 

oil and gas leasing and 

development in floodplains 

(330,000 acres), lakes, ponds, or 

reservoirs, and perennial and 

intermittent streams (41,000 

acres) would maintain water 

quality. Surface-disturbing 

activities in these areas and in 

ephemeral streams (259,000 

acres) would reduce streambank 

stability; increase sedimentation, 

erosion, and turbidity; decrease 

water quality; remove riparian

vegetation; increase flood 

severity; and alter channel 

morphology (MDEQ 2007) 

when they could not be avoided. 

Surface disturbance would 

reduce the capacity of these 

areas to dissipate the energy of 

high water events and cause 

changes in infiltration rates, 

water storage, and aquifer 

recharge. The presence of 

aboveground facilities would 

create flood hazards. Spills would potentially contaminate surface water and shallow groundwater. 

Construction activity in flowing waterbodies would be likely to exceed Montana water quality standards for 

turbidity and a variance would be required. Construction activity in ephemeral streams and within 300 feet of 

non-riparian waterbodies and streams would compromise the integrity of the vegetative buffer and inhibit the 

functionality of vegetative buffers and their role in reducing impacts from upland areas. The efficacy of 

approved specialized design features to maintain the functionality of the floodplain, water quality, and fish

and wildlife habitat would determine the severity of short- and long-term impacts caused by these 

management actions.

Avoiding surface-disturbing activities and requiring a CSU stipulation for oil and gas leasing and development 

within 300 feet of riparian areas and wetlands, would potentially preserve a vegetative buffer that reduced or 

eliminated impacts (reduced sediment, nutrients, metals, and other pollutants) from surface-disturbing activities 

immediately adjacent to riparian and wetlands. Buffers would reduce sedimentation, floodwater velocities and 

energy, erosion, and soil compaction; increase biodiversity; maintain stream channel shape, a higher water table 

(which would increase forage), late summer stream flows, and water temperature; stabilize streambanks; 

recharge aquifers; and facilitate nutrient input to aquatic habitats (MDEQ 2007). Surface-disturbing activities in 

these areas (when they could not be avoided) and livestock grazing would compromise the integrity of the 

vegetative buffer and reduce buffer efficacy. However, reduced water quality and sedimentation would occur in 

riparian areas and wetlands from a lack of buffers on ephemeral streams and non-riparian waterbodies upstream.

Management actions that allowed surface water impoundments (37 locations per year) would reduce 

streamflow, dissolved oxygen, and floodplain size and extent downstream (Vörösmarty and Sahagian 2000); 

increase infiltration to groundwater, scour of the downstream streambed, and water temperature (Dodds et al. 

2004); substantially increase evaporative losses; degrade water quality; and change nutrient cycling, timing 

and magnitude of peak and low flows, sediment load, and riparian vegetation recruitment and succession. 

TABLE 4-45.

WATER RESOURCES AFFECTED IN RECREATION OR 

SPECIAL DESIGNATION AREAS ON BLM-ADMINISTERED 

ACRES UNDER ALTERNATIVE E

Area

Miles of 

streams 

(surface 

acres)

Miles of 

streams 

(mineral)

Acres of 

floodplains

(surface)

Acres of 

floodplains

(mineral)

Lewis and Clark Trail 

SRMA 72 100 3,500 8,800

Howrey Island 4 0 590 0

Matthews Recreation

Area <1 0 11 0

Dean S. Reservoir 1 1 0 0

Pumpkin Creek

Ranch and Recreation

Area

100 31 630 9

Glendive OHV

SRMA 1 8 200 200

Terry OHV SRMA 1 1 0 0

Strawberry Hill

Recreation Area 21 13 24 22

Moorhead <1 0 11 0

Powder River Depot

ACEC 7 6 16 21

Powderville

Paleontological Area 38 38 3 71

Battle Butte 1 5 0 27

Reynolds Battlefield 

ACEC 2 4 13 190

Walstein Area 11 11 5 33
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4-79

Under this action, there would also be the potential for permanent impacts including channel scour, erosion, 

and sedimentation downstream (if a dam broke). Water impoundments and developments in and near 

waterbodies, riparian areas, and wetlands would increase use in these areas, which would change 

morphology, increase water temperature, alter ecosystem processes, and decrease water quality by 

introducing sediment, salinity, bacteria, and nutrients. Expanded water use, withdrawals, and storage would 

exacerbate the impacts of climate change on water resources however, maintaining natural flow regime and 

watershed functionality would reduce these impacts (IPCC 2007). The efficacy of approved specialized 

design features in maintaining the natural flow regime and watershed functionality would determine the 

severity of long-term impacts caused by these management actions.

Including design features to conserve water at the source of the water development would reduce the impacts of 

new (10 wells and 2 springs per year) developments and vulnerability of water resources to climate change. The 

integrity and functionality of the associated wetland, riparian area, stream, or creek would be maintained at new 

sites. Current impacts (changes to the water table, soil erosion, loss of riparian communities, and evaporation) 

would continue. 

Depending on the fuel type, haying within 200 feet of waterbodies would increase sedimentation, cause soil 

compaction, reduce litter and vegetation cover, decrease infiltration, and increase erosion (Ellis 2008) but 

reduce the risk of high-intensity or severity fire in the long term, which would improve watershed functionality. 

Although this action would inhibit the ability of vegetative buffers to reduce impacts from upland areas, 

specialized design features would maintain water quality and fish and wildlife habitat.

An NSO stipulation for oil and gas leasing and development and avoiding surface-disturbing activities in 

riparian and wetland areas would maintain water quality. However, riparian and hydrologic function would be 

affected where surface-disturbing activities in riparian and wetlands areas could not be avoided and from 

upstream sources where surface disturbance would be allowed within 300 feet of non-riparian areas and 

within ephemeral streams. Although PFC would be maintained in the long term, surface disturbance in these 

areas would cause erosion, turbidity, and sedimentation in the short term. The functionality of riparian 

vegetation (such as the dissipation of the energy of high water flows, filtration of sediment, stabilization of 

streambanks, and enhancement of floodplain functionality) and wetlands (such as the improvement of water 

quality, facilitation of groundwater recharge, filtration of sediment, maintenance of floodwater, and removal 

of pollutants) would be reduced. Spills would potentially contaminate shallow groundwater and surface 

water. The severity of short-term and, potentially, long-term impacts would depend on the efficacy of the 

mitigation measures. 

Avoiding surface-disturbing activities and requiring a CSU stipulation for oil and gas leasing and development 

within 300 feet of riparian areas and wetlands, would potentially preserve a vegetative buffer that reduced or 

eliminated impacts (reduced sediment, nutrients, metals, and other pollutants) from surface-disturbing activities 

immediately adjacent to riparian areas and wetlands. Buffers would reduce sedimentation, floodwater velocities 

and energy, erosion, and soil compaction; increase biodiversity; maintain stream channel shape, a higher water 

table (which would increase forage), late summer stream flows, and water temperature; stabilize streambanks; 

recharge aquifers; and facilitate nutrient input to aquatic habitats (MDEQ 2007). Surface-disturbing activities in 

these areas (when they could not be avoided) and livestock grazing would compromise the integrity of the 

vegetative buffer and reduce buffer efficacy. However, reduced water quality and sedimentation would occur in 

riparian areas and wetlands from a lack of buffers on ephemeral streams and non-riparian waterbodies upstream.

Boring of streams, wetlands, or riparian areas would reduce surface disturbance and maintain water quality in 

these areas. Implementing linear underground facilities (including buried power lines) using open-cut wet or 

isolated crossing methods would reduce water quality. 

New spring developments would maintain water flow locally and downstream, the local water table, water 

temperatures, riparian vegetation, and channel morphology (Sada et al. 2001). Locating water developments 

0.25 miles from perennial and intermittent streams would reduce grazing impacts in these areas. Allowing 

new livestock water developments in and near ephemeral streams, springs, and riparian areas would lead to 

increased use in these areas, which would change morphology, increase water temperature, alter ecosystem 
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processes, and decrease water quality by increasing sediment, salinity, bacteria, and nutrients. Locating and 

designing new livestock water developments (troughs or tanks) to maintain the integrity and functionality of 

wetlands, riparian areas, waterbodies, or creeks would reduce impacts caused by grazing.

Unless the surface-disturbing activity established native vegetation, management actions that allowed surfacedisturbing activities in areas of invasive species infestations would increase damage to watersheds and reduce 

water quality and quantity (BLM 2007d). The magnitude of damage to surrounding watersheds would depend 

on the efficacy of mitigation.

Avoiding surface-disturbing activities and requiring an NSO stipulation for oil and gas leasing and 

development within 0.25 miles of designated sport-fish reservoirs would maintain water quality. A CSU 

stipulation for oil and gas leasing and development within 0.5 miles of pallid sturgeon habitat and prohibiting 

surface-disturbing activities within 0.5 miles of pallid sturgeon habitat would reduce impacts to water 

resources. Surface-disturbing activities would cause reduced infiltration rates, increased erosion, and 

increased overland flow in these areas. Although the magnitude of the impacts would depend on the efficacy 

of mitigation, these actions would still cause short-term impacts to water resources, including increased 

erosion, sedimentation, and reduced water quality. 

Requirements for stream-crossing structures under this alternative would cause short-term surface disturbance 

and impacts (such as erosion and increased sediment load) but reduce the risk of erosion and damming in the 

long term.

Avoiding surface-disturbing activities within piping plover and interior least tern habitat would maintain 

water quality. 

Management actions that required the burial of low-voltage power lines would increase surface disturbance 

and decrease water quality. 

The absence of limits for cumulative, direct, and indirect disturbance in sage-grouse habitat in Sage-grouse 

Habitat – General Habitat and Restoration Areas would result in an “extreme impact (which is defined in the 

WDFG’s March 2010 Recommendations for Development of Oil and Gas Resources Within Important 

Wildlife Habitats as more than 80 acres of disturbance per square mile)” from development on habitat 

function of aquatic and water resources (WDFG 2010a, p. 45). The resiliency of these ecosystems would be 

reduced, which would increase the vulnerability of the water resources to climate change impacts (CEICC 

2008).

High-intensity fire and fire suppression that resulted in fuel buildup would lead to increased erosion and 

sedimentation, which would impact water quality in both the short and long term. The impacts would be the 

same for low-intensity fire (including prescribed fire) except that the magnitude of impacts would be reduced 

and erosion rates would be similar to natural levels. Depending on the severity, fire in riparian areas would 

reduce water quality by reducing vegetation and riparian function. In the long term, although water quality 

would benefit from healthy uplands, road construction and use of heavy equipment would lead to increased 

soil compaction, erosion, and sedimentation, which would reduce water quality.

Although requiring the removal or treatment of pre-commercial or commercial material on 53,000 acres of 

Condition Class 3 sites would decrease water quality in the short term, it would reduce the intensity and 

severity of fires, which would reduce erosion rates. Although typical timber harvest activities have been 

estimated to increase erosion rates to 0.05 to 0.25 tons per acre per year, intensive methods would potentially 

increase rates to 5 tons per acre per year (Elliot et al. 2010). Forest product production and sawtimber harvest 

are a source of nonpoint source pollution, and the magnitude of impacts from these activities would depend 

on the methods used. Vegetation removal, surface disturbance, road construction, and soil compaction would 

result in an increase in erosion, sedimentation, and overland flow. The removal of streamside vegetation 

would change water temperature and reduce the ability of vegetative buffers to reduce nonpoint source 

pollution. Forest management activities that complied with the Streamside Management Zone Law, the Water 

Quality BMPs for Montana Forests (Logan 2001) (see the Forestry and Woodland Products Appendix), and 
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other BMPs would reduce these impacts. Salvage harvest of sawtimber would remove vegetation in a 

watershed with a reduced canopy cover, which would further accelerate erosion. 

Managing forestlands for a diversity of forest products would reduce water quality by increasing the acres of 

surface disturbance. Wood product sales and sawtimber harvest would cause nonpoint source pollution, the 

magnitude of which would depend on the methods used. Vegetation removal, surface disturbance, road 

construction, and soil compaction would increase erosion, sedimentation, and overland flow. Streamside 

vegetation removal would increase water temperatures and reduce the ability of vegetative buffers to reduce 

nonpoint source pollution. However, forest management activities would use BMPs (e.g., Water Quality 

BMPs for Montana Forests [Logan 2001], see the Forestry and Woodland Products Appendix) and comply 

with the Streamside Management Zone Law, which would reduce these impacts. 

Different methods of timber harvest would have various impacts (e.g., hand harvesting would cause localized 

disturbances but mechanized methods would disturb a greater area). Whole tree harvesting would generate 

skid trails, which would accelerate erosion. Leaving slash in place would reduce erosion, and BMPs and the 

Streamside Management Zone Law would reduce the magnitude of these impacts.

Forest health projects would have the potential to impact water resources. Most treatments would cause initial 

short-term impacts similar to those caused by surface disturbance. Changes in vegetation structure and

composition would alter water flows, the quantity and quality of surface water and groundwater, and the rate 

of groundwater recharge (BLM 2007d). However, these impacts would be a natural result of healthier 

vegetation. Because evapotranspiration rates, rooting depth, and vegetative cover vary by species, a change 

would potentially impact water (e.g., changes in erosion and sedimentation rates, infiltration, amount of 

overland flow, evaporation, and turbidity). 

The use of mitigation and a riparian buffer would reduce impacts of cottonwood harvest. If this action resulted 

in healthier cottonwood stands, streambank stability and the system’s ability to dissipate flood energy would 

increase.

Livestock grazing on 16 million acres under this alternative would reduce water quality and the ability of 

vegetative buffers to filter sediments and contaminants from upland areas. Excluding acres from livestock 

grazing, excluding sheep and goats from acres, and closing allotments in which the Standards for Rangeland 

Health were not met (190,000 acres) would improve watershed function, water quality, and quantity. 

However, in the 5 years before allotments that failed to meet Standards for Rangeland Health were closed, 

sedimentation and erosion would continue to reduce water quality. In the long term, this management action 

would decrease erosion and sedimentation and allow the total rest from grazing required for full recovery of 

structure and function of waterbodies (Belsky et al. 1999). In some areas, streams would have been degraded 

permanently, beyond recovery to a natural state, and adjust within the new potential.

Because grazing would slow revegetation and reclamation, allowing livestock grazing immediately after 

locatable mineral and coal mining and during oil and gas development would cause persistent impacts (even 

if the Standards for Rangeland Health were met) and accelerate impacts from multiple land use activities. In 

areas in which associated surface disturbance would decrease forage, maintaining AUM numbers during oil 

and gas development would cause impacts from grazing to increase. Multiple land uses would compound 

land uses and cause impacts greater than impacts caused by livestock grazing, mining, or development alone. 

This action would increase erosion, sedimentation, and streambank instability and decrease water quality and 

riparian functionality.

Management actions that deferred livestock grazing until the area attained identified vegetative objectives 

following a wildfire, prescribed fire, or non-fire vegetative treatment would facilitate vegetative 

reestablishment and improve water quality. 

Water quality and riparian health monitoring would be prioritized on allotments in which grazing 

management contributed to the failure to meet Rangeland Health Standards. Management practices or levels 

of use would be adjusted to meet water quality or riparian health standards.
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CSU stipulations for oil and gas leasing and development would reduce impacts to water resources on 13, 000 

miles of streams and 110,000 acres of floodplains. Management actions that allowed oil and gas surface 

disturbance on 910,000 acres with lease terms would decrease water quality. 

Mineral sales and permitting on 2.5 million acres would decrease water quality. 

Closing 2,800 acres to OHV use under this alternative would maintain water quality and quantity on 12 miles 

of streams and 65 acres of floodplains. Open OHV use on 2,000 acres and Limited OHV use on 2.8 million 

acres would decrease water quality. 

Streams and floodplains would be affected in Recreation and Special Designation Areas under Alternative E.

CUMULATIVE IMPACTS

Past and present land use, dams, natural events, changes in local and global climatic patterns, and 

management actions impact water resources. Impacts would increase as human populations increased and 

expanded. Management of water resources is complicated by scattered land ownership because water is 

connected throughout a watershed (longitudinally from headwaters downstream; laterally through interactions 

with floodplains, riparian areas, and uplands; vertically through interactions with the substrate and 

subsurface; and temporally).These interactions compound the impacts of all land management and land use 

throughout an entire watershed.

Erosive soils and arid climate across the planning area form hydrologic systems prone to erosion, channel 

degradation, downcutting, accelerated lateral cutting, and sedimentation. These systems have high levels of 

natural instability and rapid degradation can occur from human disturbance (Elmore and Kauffman 1994). 

Within uplands, the amount of vegetation and natural erosion control is limited by the climate. Prior to 

European settlement, integral factors in watershed health in the form of disturbances such as fire, beaver 

activity, occasional or patchy large ungulate herbivory, and flooding were common across the landscape. 

Beaver (Castor canadensis) influenced nutrient cycling, water temperature, residence time of water, aquatic 

habitat, vegetation dispersal, and riparian community structure. The extirpation of beaver through trapping 

influenced the composition, structure, and function of stream systems by decreasing surface water

availability, reducing channel diversity, and converting wetland communities to xeric plant communities 

(Elmore and Kauffman 1994). Prior to their near extinction during the mid-1800s, bison (Bison bison) roamed 

the area in large herds, consuming vegetation in the uplands and riparian and wetland areas. Although local 

increases in soil bulk density at bison stream crossings decreased water infiltration and accelerated fluvial 

erosion, disturbance of streams was spatially and temporally minimized because bison distribution patterns 

were unaffected by slope or proximity to water (Fritz, Dodds, and Pontius 1999; Fleischner 1994), they 

grazed in patches, ranged over large areas, and typically crossed creeks at specific locations (Fritz et al. 

1999). 

An influx of livestock to eastern Montana beginning in the 1860s has altered stream and river ecosystems. 

Livestock grazing has degraded about 80 percent of stream and riparian ecosystems in the arid western United 

States. Livestock grazing alters watershed hydrology by increasing overland flow, the volume of peak flows, 

and floodwater velocity; lowering the water table; and decreasing low flows and infiltration rates (Belsky et 

al. 1999). Livestock grazing accelerates soil erosion, reduces riparian vegetation, increases water temperature, 

decreases dissolved oxygen, degrades the stream channel, and introduces pollutants such as sediment, 

salinity, bacteria, and nutrients (MDEQ 2007). Wide and shallow channels, high sediment yield, and high 

turbidity characterize grazing-disturbed streams (Magilligan and McDowell 1997). Because livestock spend a 

disproportionate amount of time in riparian areas for forage, shade, and water (Belsky et al. 1999; Saunders 

and Fausch 2007), heavy use, particularly in riparian areas, leads to major changes in stream morphology, 

water quality, and water availability. Grazing practices, particularly year-long grazing, have resulted in 

increased sedimentation, declines in woody species and deep-rooted vegetation, soil compaction, increased 

overland flow, accelerated erosion, decreased water quality, and extreme instability of stream channels. 

During high flows, channel instability created over-widened or incised channels, eventually lowering the 
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water table. The Taylor Grazing Act of 1934 addressed overgrazing of federal lands by attempting to reduce 

livestock numbers (Elmore and Kauffman 1994).

Beginning in the late 19th and early 20th century, surface disturbances such as homesteading, mining, OHV

use, infrastructure development, community development, agriculture, and the introduction of invasive

species has affected channel morphology and resulted in soil compaction, increased overland flow and 

sedimentation, accelerated erosion, and decreased water quality. Soil compaction and the presence of 

impervious surfaces have reduced infiltration and increased overland flow, which results in increased channel 

degradation, sedimentation, and reduced water quality and quantity. 

Farming and grazing drastically changed native vegetation. Cropland development and drought in 1919 and 

the 1930s resulted in accelerated wind erosion of agricultural lands. Since the 1930s, flood control, irrigation 

development, and wetland conversion have modified stream channels through in-stream structures, 

channelization, bank modification, and placement of riprap (Elmore and Kauffman 1994). OHV use, 

particularly during wet conditions, has caused rutting, erosion, stream channel degradation, and established 

roads and trails. Many of these surface disturbances continue to degrade water quality. 

Since the late 19th century, federal and state regulations have improved water quality. The Rivers and Harbors 

Act of 1899 (33 U.S.C. 403 10) preserved water quality by requiring permits for refuse discharge and channel 

alteration of navigable waters and their tributaries. Water quality has been improved through the 

establishment of water quality standards through the Water Pollution Control Act of 1948, Federal Water 

Pollution Control Act in 1956, and the Water Quality Act of 1965. The Clean Air Act of 1970 and Clean Air 

Act Amendments of 1990 have reduced atmospheric deposition of pollutants. In 1972, the Clean Water Act 

created regulations for reducing point source and nonpoint source pollution. The Water Quality Act of 1987 

established numeric criteria for toxic pollutants to reduce impairment of beneficial uses.

Scattered land ownership and the absence of watershed-wide management strategies have complicated efforts 

for ongoing conservation and restoration. Water resources are influenced by land use throughout an entire 

watershed. Multiple land uses would compound land uses and cause impacts greater than impacts caused by 

the individual land uses alone. Land use within watersheds of the planning area is approximately 65 percent 

rangeland, 26 percent agriculture, 7 percent forest, less than 1 percent mines or quarries, and less than 1 

percent urban or developed (MNRIS 2010). 

The BLM’s ability to influence future conditions in watersheds is limited by scattered and minority land 

ownership in many watersheds. Activity that occurs adjacent to BLM-administered lands would impact water 

resources on BLM-administered land. Activities occurring on BLM-administered lands or adjacent to BLMadministered lands (including livestock grazing, agriculture, urbanization, fire suppression, mineral 

exploration and development, weed infestation, OHV use, and pollution, decrease watershed health and water 

quality), cause accelerated erosion, increased overland flow, decreased infiltration, channel degradation, 

atmospheric deposition of pollutants, and degradation of water quality through increased sedimentation, 

turbidity, nutrients, eutrophication, metals, and other pollutants in waterbodies. These activities have resulted 

in 14 percent of the assessed stream miles becoming listed as impaired or threatened (see the Water 

Appendix). Crop and livestock production compose the largest percentage of nonpoint source pollution in 

Montana (MDEQ 2007) and is the most common anthropogenic contributor to stream impairment in the 

planning area (MDEQ 2010b). Fire suppression has increased fire severity and intensity, leading to increased 

overland flow, erosion, and sedimentation. 

Overgrazing in riparian areas; historical impacts to stream morphology and groundwater; and the construction 

of numerous impoundments, spring developments, and stream crossings contribute to disconnection within 

the watershed. Connectivity is essential for the cycling of water, nutrients, and sediment throughout the 

watershed. Continued degradation of stream channels and riparian areas would result in accelerated loss of 

water resources and hydrologic function. The cumulative impacts of grazing; local geology; soils; agricultural 

practices; and surface-disturbing activities within uplands, riparian areas, and stream channels have 

contributed to accelerated erosion and increased sedimentation. Sedimentation from activities in the upper 

watershed is compounded as these drainages combine and flow into larger streams and rivers.
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Produced water from oil, gas, CBNG, and coal development in Wyoming and Montana impacts the quality and 

quantity of surface water and groundwater through impoundments, injection, and discharge; impacts caused by 

these activities would be mitigated by permits. The combination of these activities increases the potential for 

degradation of water quality. The total amount of water produced by CBNG wells within the PRB in Wyoming 

and Montana during 2007 was approximately 85,000 acre-feet from approximately 5,500 wells (Wheaton, 

Reddish-Kuzara, Meredith, and Donato 2008). Although surface water quality in some watersheds would be 

altered in combination with new and existing permits and developments in Wyoming and Montana, beneficial 

uses would not be diminished. Surface water flow would moderately increase alteration of the natural 

hydrologic regimes (such as changes in the magnitude and timing of low and peak flows) and cause erosion and 

increased sedimentation (BLM 2008g). Discharge of sodic and saline water from CBNG development and the 

use of seepage ponds to dispose of this water cause cumulative impacts to water quality. 

Hydrologic resources would be vulnerable to the impacts of climate change and mitigation or a reduction of 

these effects would reduce the impacts on water resources (see Chapter 3, Water for more information). 

Conversely, activities that exacerbated the effects of climate change would increase the vulnerability of water 

resources to impacts. Water conservation measures (including limiting the number of impoundments, limiting 

surface and groundwater withdrawal, and increasing irrigation efficiency) would reduce the vulnerability of 

water resources to climate change. Conversely, expanded water use, withdrawals, and storage would exacerbate 

the impacts of climate change on water resources (IPCC 2007).

Alternative A

Alternative A would contribute to a decline in water quality and quantity; however, water quality standards 

would be met and beneficial uses maintained. Buffers would not be established to reduce nonpoint source 

pollution and non-oil and gas surface disturbance would be allowed in waterbodies, floodplains, wetlands, 

and riparian areas. Surface disturbance associated with oil and gas activities would be allowed in wetlands, 

floodplains of non-major rivers, and 80 percent of the federal mineral estate in the planning area without 

stipulations. Surface disturbance in areas of sensitive soils, soils with poor reclamation potential, and highly 

erodible soils would reduce water quality and result in long-term to permanent increases in sedimentation. 

Surface disturbance would be allowed on 1.7 million acres under this alternative. Closures and NSO 

stipulations for oil and gas leasing and development would protect approximately 2,000 miles of waterbodies, 

20 miles of impaired streams, and 260,000 acres of floodplains (Table 4-46). Oil, gas, and CBNG activities 

would cause surface disturbance on 16,000 to 46,000 acres, with 28 percent occurring through activities on 

BLM-administered mineral estate.

Alternative A would continue to accelerate erosion, increase 

sedimentation, reduce connectivity within watersheds, increase 

channel degradation, increase overland flow, and impair water 

quality. Under Alternative A, some waterbodies and their associated 

riparian areas would decline, some areas beyond recovery to 

historical potential.

Alternative B

Under this alternative, water quality, water quantity, and watershed 

health would be maintained or improved through reduced livestock 

grazing, restricted OHV use, use of buffers to reduce nonpoint source 

pollution, and restricted or prohibited surface disturbance, 

particularly in and near waterbodies, floodplains, wetlands, and 

riparian areas. These actions would increase riparian vigor and decrease impacts from surface disturbance in 

upland areas. The physical and biological connections between the riparian areas and streams would be 

maintained, which would improve water quality by decreasing sedimentation and pollution. 

TABLE 4-46. 

ESTIMATED WATERBODIES 

MAINTAINED ON BLMADMINISTERED ACRES BY 

CUMULATIVE RESTRICTIONS

NSOs Streams

(miles)

Floodplains

(acres)

A 26,000 92,000

B 26,000 110,000

C 2,000 18,000

D 0 0

E 26,000 110,000
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Surface disturbance would be allowed on 180,000 acres under this alternative. Closures and NSO stipulations 

for oil and gas leasing and development would protect approximately 3,000 miles of waterbodies, 40 miles of 

impaired streams, and 330,000 acres of floodplains (Table 4-46). Oil, gas, and CBNG activities would cause 

surface disturbance on 12,000 to 33,000 acres, with none occurring through activities on BLM-administered 

mineral estate. The elimination of several future oil, gas, and CBNG field development projects (because 

sufficient BLM-administered mineral estate would not be available) under this alternative would maintain 

water quality. 

Alternative C

Surface disturbance would be allowed under this alternative (if they could not be avoided) in and near 

waterbodies, wetlands, riparian areas, and floodplains. Alternative C would contribute to declines in water 

quality and quantity. Alternative C would require minimal restrictions for construction of livestock water 

developments in ephemeral and intermittent streams and surface water impoundments. The long-term 

cumulative impacts from these actions would include the loss of hydrologic connectivity within the 

watershed, altered channel morphology and hydrologic flow regime, increased sedimentation, and reduced 

water quality.

Water quality and riparian health monitoring would be prioritized on allotments in which grazing 

management contributed to the failure to meet Rangeland Health Standards. Management practices or levels 

of use would be adjusted to meet water quality or riparian health standards.

Surface disturbance would be allowed on 1.1 million acres under this alternative. Closures and NSO 

stipulations for oil and gas leasing and development would protect approximately 2,000 miles of waterbodies, 

3 miles of impaired streams, and 18,000 acres of floodplains (Table 4-46). Oil, gas, and CBNG activities 

would cause surface disturbance on 13,000 to 36,000 acres, with 11 percent occurring through activities on 

BLM-administered mineral estate. 

Alternative C would continue to accelerate erosion, increase sedimentation, reduce connectivity within 

watersheds, increase channel degradation, increase overland flow, and impair water quality. 

Alternative D

Alternative D would cause a decline in water quality, water quantity, and overall watershed health. Buffers 

would not be established to reduce impacts from upland surface disturbance and surface disturbances would be 

allowed in waterbodies, floodplains, wetlands, and riparian areas. Livestock water developments and surface 

water impoundments would be built with minimal restrictions. The long-term cumulative impacts from these 

actions would include the loss of hydrologic connectivity within the watershed, altered channel morphology and 

hydrologic flow regime, increased sedimentation, and reduced water quality. 

Surface disturbance would be allowed on 1.7 million acres under this alternative. Closures and NSO stipulations 

for oil and gas leasing and development would not protect any waterbodies, impaired streams, or floodplains

under this alternative (Table 4-46). Oil, gas, and CBNG activities would cause surface disturbance on 14,000 to 

40,000 acres, with 15 percent occurring through activities on BLM-administered mineral estate.

Alternative D would accelerate erosion, alter stream morphology, decrease connectivity within watersheds, 

decrease streambank stability, increase overland flow, decrease infiltration, and degrade water quality through 

increased sedimentation, turbidity, nutrients, eutrophication, metals, and other pollutants. Under Alternative D, 

many waterbodies and their associated riparian areas would decline, some beyond recovery to historical 

potential.
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Alternative E (Preferred Alternative)

Alternative E would maintain water quality and quantity through restricted OHV use, use of buffers to reduce 

nonpoint source pollution, and restricted or prohibited surface disturbance, particularly in and near streams, 

waterbodies, floodplains, wetlands, and riparian areas. Alternative E would require the maintenance of 

watershed and riparian functionality during water developments. 

Water quality and riparian health monitoring would be prioritized on allotments in which grazing 

management contributed to the failure to meet Rangeland Health Standards. Management practices or levels 

of use would be adjusted to meet water quality or riparian health standards. Allotments still contributing to 

the failure to meet riparian health standards within 5 years would be closed to grazing.

Closures and NSO stipulations for oil and gas leasing and development would protect approximately 120,000 

miles of streams and 16,000 acres of floodplains (Table 4-46). 

VEGETATION

ASSUMPTIONS AND METHODOLOGY

Approximately 17,500 acres would be burned with prescribed fire in the short term and approximately 70,000 in 

the long term. Treatments such as prescribed fire and mechanical treatments are used to meet resource 

objectives (e.g., vegetation, wildlife, or other objectives).

Approximately 220,000 acres would be treated biologically in the short term and approximately 500,000 in the 

long term. Biological control for vegetation management involves the use of insects or domestic livestock to 

manipulate vegetation. Target-specific insect pests are used to weaken invasive plant populations and reduce 

their ability to spread by damaging plant parts (e.g., roots, stems, or flowers).

Approximately 5,000 acres would be treated chemically in the short term and approximately 50,000 in the long 

term. Pesticides (primarily herbicides) would be used to manipulate vegetation to meet resource objectives (e.g., 

using herbicides to reduce big sagebrush density and create a mosaic of shrubs and herbaceous vegetation).

Approximately 12,000 acres would be treated mechanically in the short term and approximately 80,000 in the 

long term. Mechanical treatment includes commercial thinning and pre-commercial thinning for logging as well 

as all mastication treatments (Hydro-axe, brush hog, and chainsaw). 

Approximately 1,500 acres would be seeded in the short term and approximately 50,000 in the long term.

Seeded acres include those required under reclamation plans, as contract stipulations, or included for projects 

such as oil and gas development.

Emergency stabilization and rehabilitation vegetation treatments are addressed in Wildland Fire Management 

and Ecology.

Vegetation treatment acres proposed under an emergency stabilization and rehabilitation plan are not included 

under other restoration proposals. For example, a plan to restore a Wyoming big sagebrush and prairie grassland

association might call for 10,000 acres of seeding desirable species. An emergency stabilization and 

rehabilitation plan written for a large wildfire might propose 10,000 acres of seeding native species. Acres 

treated for vegetation restoration and analyzed in this RMP do not include those that would be proposed under 

an emergency stabilization and rehabilitation plan. 

Implementing NSO stipulations for oil, gas, and geothermal leasing and development and removing federal 

acreage from leasing would correlate directly to the reduction of federal oil and gas wells, as predicted in the 

RFD (see the Minerals Appendix) and result in fewer acres of surface disturbance in the planning area. For 

example, if NSO stipulations for oil, gas, and geothermal leasing and development or no-leasing decisions 
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affected 10 percent of the federal mineral estate under an alternative, there would be a corresponding 10-

percent reduction in the number of BLM-administered oil and gas wells predicted under the RFD. 

Conversely, mitigation, specialized design features, and CSU stipulations for oil, gas, and geothermal leasing 

and development would not correlate directly to the reduction of federal oil and gas wells or acres of surface 

disturbance. 

Special status plant species are known to or may occur in the planning area. Designation of critical habitat or 

special considerations for the management of these plant species (known populations or discovered) could 

impact plant communities. Management for plant and wildlife species designated as threatened or endangered 

under the ESA or designated as special status species by the BLM can affect resource uses in areas in which 

these special status species occurred. Specifically, restrictions on the type, location, or period in which

consumptive use activities were allowed to occur could limit management options on lands containing special 

status species and, in turn, could affect vegetative communities; for example, surface use restrictions could 

affect development or placement of range improvement projects.

MANAGEMENT COMMON TO ALL ALTERNATIVES

Actions that limited surface disturbance would benefit vegetation resources. Surface-disturbing activities 

would cause vegetation removal, soil compaction, and soil disturbance. Surface-disturbing activities under all 

alternatives would include mineral and energy exploration, leasing, and development (including renewable 

energy and geophysical exploration); OHV and vehicle use; ROWs; land use; infrastructure development; 

vegetation or fuel treatment (including the sale or harvest of hay, timber, wood, or seed); establishment of 

wildfire fuel breaks; and implementation of range improvements. Impacts from surface disturbance would 

typically be localized and short term. Impacts to vegetation resources would increase as acres of surface 

disturbance increased within an area. These impacts (the magnitude of which would depend on the condition 

of upland and riparian vegetation, the efficacy of mitigation, the specific activity and season, and the length of 

the period preceding reclamation success) would include accelerated erosion, increased overland flow, and 

increased invasion of weedy or invasive species.

Vegetation treatments would cause short-term disturbance and result in long-term impacts to grassland and 

shrubland communities. Vegetation treatments that successfully achieved vegetative objectives would increase 

plant and seral stage diversity, control invasive species, improve wildlife habitat and livestock forage, and 

create or maintain the desired mosaic. Natural recovery of hardwood draws would be emphasized. A presettlement successional pathway would include a disturbance factor (typically fire, insects, or disease) that 

would reinitiate natural succession of these hardwood ecosystems. Vegetation succession and the health of these 

hardwood draw communities would be heavily influenced by large ungulates. 

Treatments to approximate natural disturbance regimes would sustain complexity, diversity, resiliency, and 

productivity in hardwood draws. 

Livestock grazing would impact the health and productivity of vegetative communities. Livestock 

congregation areas, which would include areas containing water, shade, or more palatable forage, would be 

the most likely to impact rangeland health; subsequently, management would often be geared toward 

improving the overall distribution of livestock within an allotment. This distribution would be accomplished 

through the implementation of BMPs, such as developing allotment management plans (AMPs), altering 

grazing systems, and implementing range improvement projects (e.g., fencing, water developments, or salt 

and mineral licks). 

Livestock transport of invasive species seed would increase the spread of these species when moving 

livestock from an allotment infested with invasive species (and the seeds are attached to the hair of the animal 

or in contained internally in the digestive tract).

Maintaining adaptive ecosystems of the Northern Great Plains would benefit rangeland health by improving 

plant vigor, increasing vegetative cover, and reducing invasive species infestations. Hoof action would remove 

vegetation that inhibited new growth, increased cover and vigor of native vegetation, decreased soil erosion, and 
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broke soil crust that would restrict infiltration and inhibit seedling establishment. Healthier plant communities 

would resist the spread of invasive species and other undesirable plant species. Targeted grazing in areas 

containing invasive species at crucial points in the species’ lifecycle would decrease the spread of invasive

species by decreasing seed production or limiting vegetative propagation. 

Wildfire and prescribed fires impact grassland and shrubland communities. In the short term, fire would 

potentially cause habitat loss and promote the spread of invasive species. In the long term, because of fire’s 

historic role in these communities, fire would increase vegetative diversity across the landscape, rejuvenate 

decadent plants, and improve the overall health of these communities. In shrubland communities, fire 

impacts, which are typically more long term than in other communities, depend on the scale and severity of 

the disturbance. The potential for reestablishment of sagebrush shrublands would depend on the sum of the 

acreage burned, the distance to seed sources, and the spread of invasive species. Invasive vegetation species, 

such as cheatgrass, would increase fire frequency, which would prevent shrub establishment. Limiting fire in 

some cases would reduce direct loss of grassland and shrubland communities and reduce the potential for the 

spread of invasive species in the short term. In the long term, the lack of fire would decrease the overall 

health of these fire-adapted communities. Fire would enhance age structure, restore vigor, and restore 

community types through regeneration. 

Although fire suppression activities would limit short- and long-term fire damage to vegetation, they would 

cause mechanical and chemical damage to vegetation and increase the likelihood of the introduction or spread 

of invasive species. Wildland fire and suppression tactics would cause short- and long-term impacts to 

grassland and shrubland communities. Using full suppression or limited tactics would damage vegetation and 

potentially spread invasive species. If invasive species were already present, the potential for spread would 

increase regardless of the type of suppression used. Generally, the natural role of fire (if left unchecked by 

human intervention) would trend toward a natural range of variability of vegetation characteristics and fuel 

composition. However, with human intervention (fire suppression) the majority of the planning area is 

currently in a condition class of 2, which is a moderate departure from the natural (historical) regime of 

vegetation characteristics and fuel composition. The fire regime itself is currently at a 1, typically described 

by the 0 to 35-year fire frequency and low to mixed fire severity. It would appear that global climate change 

is having an influence on the duration and severity of the average fire season within the region. If this recent 

trend continues over the long term, the fire regime may increase to a 2, which indicates higher severity fires, 

although the frequency would likely remain the same at 0 to 35 years.

ALTERNATIVE A

Allowing surface-disturbing activities would impact the relative abundance, distribution, and occurrence of 

seral stages. Although these actions would not result in the complete elimination of a plant species, plant 

community, or seral stage, they would allow an opening for invasive species infestations. This alternative would 

allow disturbance on 2.8 million acres of BLM-administered land in the planning area.

NSO stipulations for oil and gas leasing and development would protect vegetation and prevent soil 

compaction and vegetation removal.

Treating invasive species on a case-by-case basis would be an inefficient and ineffective method for weed 

control on a field office level. Small, isolated treatments would not produce the same results as large-scale 

watershed treatments. 

Allowing prescribed fire in Category B and C Fire Management Categories, which make up the entire planning 

area, would impact vegetation through disturbance. Usually, invasive species appear in the short term following 

fire. Until vegetation was reestablished, road construction and heavy equipment use associated with prescribed

fire would impact soil health and vegetative buffers in the short term. Favorable conditions would allow 

prescribed fire to accelerate nutrient cycling, sprouting, and forage availability. Very intense burning would 

decrease sprouting and forage growth and increase the occurrence of invasive species. 
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Allowing harvest of cottonwood on public lands only when human safety was a factor or disease or insect 

infestations were threatening cottonwood stands would improve the health, resiliency, ecological function, and 

sustainability of cottonwood stands and provide an incidental amount of forest products (e.g., firewood).

Because livestock grazing would impact the vigor and reproduction of palatable species, livestock 

management actions that enhanced associated characteristics of key plant species would benefit these species.

OHV use on BLM-administered lands would result in short- and long-term impacts to vegetation in grassland

and shrubland communities. Depending on soil conditions, slope, and ground cover, light OHV use would 

disturb the soil surface and cause physical damage to vegetation by breaking stems and branches. However, 

plants and disturbed areas would recover from light disturbance. With increased use, new trails would be 

established, which would result in soil erosion, invasive seed introduction into grassland and shrubland

habitats, and long-term vegetation losses.

ALTERNATIVE B

Minimizing surface-disturbing activities would limit the impacts to the relative abundance, distribution, and 

occurrence of seral stages. These actions would not result in the complete elimination of a plant species, plant 

community, or seral stage and would decrease the opportunity for invasive species infestations. This alternative 

would not allow surface disturbance on 89 percent of the BLM-administered surface (2.5 million acres) in the 

planning area.

Management of wildland fire to meet multiple objectives would have a long-term impact on vegetation by 

accelerating nutrient cycling, sprouting, and forage availability. 

Because livestock grazing would impact the vigor and reproduction of palatable species, livestock 

management actions that enhanced associated characteristics of key plant species would benefit these species.

Targeted grazing of invasive species using sheep would support desirable plant species. Restricting this 

activity would allow invasive species to spread and impact native plant communities.

Allowing harvest of cottonwood on public lands only when human safety was a factor or disease or insect 

infestations were threatening cottonwood stands would improve the health, resiliency, ecological function, and 

sustainability of cottonwood stands and provide an incidental amount of forest products (e.g., firewood).

Depending on soil conditions, slope, and ground cover, light OHV use would disturb the soil surface and 

cause physical damage to vegetation by breaking stems and branches. However, plants and disturbed areas 

would recover from light disturbance. With increased use, new trails would be established, which would 

result in soil erosion, invasive seed introduction into grassland and shrubland habitats, and long-term 

vegetation losses.

ALTERNATIVE C

Although avoiding or restricting surface-disturbing and disruptive activities or requiring burial of power lines

would not result in the complete elimination of a plant species, plant community, or seral stage, these 

activities would impact the relative abundance, distribution, and occurrence of seral stages. Burying power 

lines would create desirable conditions for invasive species infestations. Surface-disturbing activities would 

not be allowed on 2 percent or 63,000 acres of BLM-administered lands in the planning area. All other 

activities would require specialized design features.

Allowing surface-disturbing activities in areas of invasive species infestations would increase the potential for 

weed infestations and expansion and decrease the vigor of desirable vegetative species.

Using Early Detection Rapid Response for controlling invasive species in publicly accessible areas, riparian

areas, and special status species habitat areas would assist in recovering vegetation to its native state. 
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Prioritizing these areas of treatment would reduce the degree of spread by invasive species in these areas (and 

other areas) by eliminating or significantly decreasing weed infestations, which would decrease the possibility 

of invasive species seed dispersal on other lands. 

Management of wildland fire to meet multiple objectives would have a long-term impact on vegetation by 

accelerating nutrient cycling, sprouting, and forage availability. 

Allowing prescribed fire throughout the entire planning area would impact vegetation through disturbance. 

Usually, invasive species appear in the short term following prescribed fire. Until vegetation was reestablished, 

road construction and heavy equipment use associated with prescribed fire would impact soil health and 

vegetative buffers in the short term. Favorable conditions would allow prescribed fire to accelerate nutrient 

cycling, sprouting, and forage availability. Very intense burning would decrease sprouting and forage growth 

and increase the occurrence of invasive species. 

Allowing limited harvest of cottonwood only to restore the health and resiliency of cottonwood stands or 

remove hazard trees would ensure that cottonwood trees were protected from further decline.

Because livestock grazing would impact the vigor and reproduction of palatable species, livestock 

management actions that enhanced associated characteristics of key plant species would benefit these species.

OHV use on BLM-administered lands would result in short- and long-term impacts to vegetation in grassland

and shrubland communities. Depending on soil conditions, slope, and ground cover, light OHV use would 

disturb the soil surface and cause physical damage to vegetation by breaking stems and branches. However, 

plants and disturbed areas would recover from light disturbance. With increased use, new trails would be 

established, which would result in soil erosion, invasive seed introduction into grassland and shrubland

habitats, and long-term vegetation losses.

ALTERNATIVE D

Allowing surface-disturbing and disruptive activities or requiring burial of power lines would not result in the 

complete elimination of a plant species, plant community, or seral stage, these activities would impact the 

relative abundance, distribution, and occurrence of seral stages. Burying power lines would create desirable 

conditions for invasive species infestations. This alternative would allow surface-disturbing activities on 

project sites on 99 percent of all BLM-administered lands (2.7 million acres) within the planning area.

Allowing surface-disturbing activities in areas of invasive species infestations only with approved measures 

would increase the potential for weed infestations and expansion and decrease the vigor of desirable 

vegetative species.

Allowing prescribed fire throughout the entire planning area would impact vegetation through disturbance. 

Usually, invasive species appear in the short term following prescribed fire. Until vegetation was reestablished, 

road construction and heavy equipment use associated with prescribed fire would impact soil health and 

vegetative buffers in the short term. Favorable conditions would allow prescribed fire to accelerate nutrient 

cycling, sprouting, and forage availability. Very intense burning would decrease sprouting and forage growth 

and increase the occurrence of invasive species. 

Management of wildland fire to meet multiple objectives would have a long-term impact on vegetation by 

accelerating nutrient cycling, sprouting, and forage availability. 

Allowing limited harvest of cottonwood only to restore the health and resiliency of cottonwood stands or 

remove hazard trees would ensure that cottonwood trees were protected from further decline.

Because livestock grazing would impact the vigor and reproduction of palatable species, livestock

management actions that enhanced associated characteristics of key plant species would benefit these species.
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OHV use on BLM-administered lands would result in short- and long-term impacts to vegetation in grassland

and shrubland communities. Depending on soil conditions, slope, and ground cover, light OHV use would 

disturb the soil surface and cause physical damage to vegetation by breaking stems and branches. However, 

plants and disturbed areas would recover from light disturbance. With increased use, new trails would be 

established, which would result in soil erosion, invasive seed introduction into grassland and shrubland

habitats, and long-term vegetation losses.

ALTERNATIVE E (PREFERRED ALTERNATIVE)

Allowing surface-disturbing and disruptive activities or requiring burial of power lines would not result in the 

complete elimination of a plant species, plant community, or seral stage, these activities would impact the 

relative abundance, distribution, and occurrence of seral stages in the specific project areas. Burying power 

lines would create desirable conditions for invasive species infestations. Surface-disturbing and disruptive 

activities would be allowed on approximately 2.8 million acres of BLM-administered lands in the planning 

area. Specialized design features would be used to mitigate possible negative impacts.

Allowing surface-disturbing activities in areas of invasive species infestations would increase the potential for 

weed infestations and expansion and decrease the vigor of desirable vegetative species.

Using Early Detection Rapid Response for controlling invasive species in publicly accessible areas, riparian

areas, and special status species habitat areas would assist in recovering vegetation to its native state. 

Prioritizing these areas of treatment would reduce the degree of spread by invasive species in these areas (and 

other areas) by eliminating or significantly decreasing weed infestations, which would decrease the possibility 

of invasive species seed dispersal on other lands. 

Allowing prescribed fire throughout the entire planning area would impact vegetation through disturbance. 

Usually, invasive species appear in the short term following prescribed fire. Until vegetation was reestablished, 

road construction and heavy equipment use associated with prescribed fire would impact soil health and 

vegetative buffers in the short term. Favorable conditions would allow prescribed fire to accelerate nutrient 

cycling, sprouting, and forage availability. Very intense burning would decrease sprouting and forage growth 

and increase the occurrence of invasive species. 

Management of wildland fire to meet multiple objectives would have a long-term impact on vegetation by 

accelerating nutrient cycling, sprouting, and forage availability. 

Allowing limited harvest of cottonwood only to restore the health and resiliency of cottonwood stands or 

remove hazard trees would ensure that cottonwood trees were protected from further decline.

Because livestock grazing would impact vigor and reproduction of palatable species, livestock management 

actions that enhanced these characteristics of key plant species would benefit these species.

Although closing livestock grazing in allotments that failed Standards for Rangeland Health and made no 

progress toward meeting those goals within 5 years would improve vegetation in the short term, vegetation 

would be dominated by older plants, contain a high litter cover, and experience reduced recruitment over the 

long term.

OHV use on BLM-administered lands would result in short- and long-term impacts to vegetation in grassland

and shrubland communities. Depending on soil conditions, slope, and ground cover, light OHV use would 

disturb the soil surface and cause physical damage to vegetation by breaking stems and branches. However, 

plants and disturbed areas would recover from light disturbance. With increased use, new trails would be 

established, which would result in soil erosion, invasive seed introduction into grassland and shrubland

habitats, and long-term vegetation losses.
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CUMULATIVE IMPACTS

Historical and ongoing activities within the planning area that have affected, or are currently affecting, soils 

include energy and mineral development, livestock grazing, on- and off-highway vehicle use, recreation, 

infrastructure development, fire suppression, fuels management, forestry, urbanization, invasive weed 

infestations, pollutants, and agriculture; these impacts are expected to continue into the future. The cumulative 

effects of such activities have directly or indirectly contributed to increased compaction, increased overland 

waterflow, mass movement, and accelerated wind and water erosion. Currently, the BLM is not aware of any 

other reasonably foreseeable future actions, other than those discussed above. 

The BLM’s current and future goals for soil management are aimed at maintaining and improving soil health 

and productivity, minimizing soil erosion and compaction, and maintaining soil water infiltration rates. Under 

all alternatives, the standards for rangeland health would be used to assess compaction and soil erosion. 

Current and future activities have the potential to cumulatively impact soil resources within the planning area as 

demand for resources continues to grow; however, the land pattern in the planning area would prevent anything 

more than minor impacts from BLM-authorized activities. Vegetation treatments, roads management, and 

energy and mineral resource activities would have the greatest potential to contribute to cumulative impacts to 

soils on BLM-administered lands. 

In general, Alternative B would restrict the greatest number of surface use authorizations, subsequently 

protecting more soil resources than all other alternatives, and Alternative C would restrict the fewest surface use 

authorizations and protect the fewest soil resources of all alternatives. Alternatives A and D would also restrict

surface use authorizations. Typically, there would be fewer restrictions under Alternatives A and D than under 

Alternative B, but more than those under Alternative C. Alternative D would generally be more restrictive than

Alternative A.

Implementation of project stipulations and mitigation measures by the BLM would result in minor cumulative 

impacts to special status plant populations. Impacts would be caused by ground disturbances created by new 

road and trail construction; fuels management; energy and mineral activities; forestry activities; livestock 

grazing; OHVs; and utility, transportation, and communications projects.

Alternative A 

Management actions on grasslands and shrublands (e.g., prescribed fire, weed treatments, livestock grazing, 

mechanical treatments, and reseeding) throughout the planning area would impact vegetation composition and 

structure. Although proposed vegetation treatments in the planning area would vary, impacts at the planning 

area scale would be minor for Alternative A.

Alternative B 

Proposed treatments would have the potential to affect plant communities by changing the relative abundance of 

species within plant communities, the relative distribution of plant communities, and the relative occurrence of 

seral stages of those communities. Cumulative impacts would include those caused by livestock grazing, habitat 

manipulation, and invasive species. Changing levels of livestock use on BLM-administered lands would 

potentially cause changes in grazing practices on private land. A reduction of the grazing periods or quantity of 

livestock permitted on BLM-administered lands would potentially lead to increased or longer durations of use 

on private lands, which would potentially cause a decline in the ecological condition of these lands and reduce 

the wildlife habitat quality.

Alternative C 

Although avoiding or restricting surface-disturbing and disruptive activities would not result in the complete 

elimination of a plant species, plant community, or seral stage, these activities would impact the relative 

abundance, distribution, and occurrence of seral stages. 
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Alternative D 

Although avoiding or restricting surface-disturbing and disruptive activities would not result in the complete 

elimination of a plant species, plant community, or seral stage, these activities would impact the relative 

abundance, distribution, and occurrence of seral stages. 

Alternative E (Preferred Alternative)

Although avoiding or restricting surface-disturbing and disruptive activities would not result in the complete 

elimination of a plant species, plant community, or seral stage, these activities would impact the relative 

abundance, distribution, and occurrence of seral stages. 

RIPARIAN AND WETLAND AREAS

ASSUMPTIONS AND METHODOLOGY

There would be 2 to 10 riparian and wetland projects constructed for the benefit of riparian and wetland 

resources each year, disturbing a total of 10 to 100 acres per year. It is assumed there are between 800,000 and 

1.3 million acres of riparian and wetland areas in the planning area with a 50-foot corridor. Riparian and 

wetland areas were calculated using the best available data from the Montana Gap Analysis Program and the 

2009 National Hydrography Dataset area waterbodies data. When data are collected on all the potential riparian 

and wetland areas, it is assumed that 5 percent of the total streams assessed for riparian and wetland areas would 

be rated functional-at risk with downward trend, and 3 percent of the total streams assessed for riparian and 

wetland areas would be rated nonfunctional (approximately 833 miles of the potential 15,166 streams have been 

assessed). 

In the planning area, there are approximately 1.6 million surface acres of total riparian and wetland areas, 

including waterbodies and streams, with a 0.5-mile corridor (using the best available data from the known 

riparian and wetland areas from the MCFO riparian database and the 2009 National Hydrography Dataset area 

waterbodies data). These acres include both ephemeral and intermittent streams. It is assumed that 35 percent of 

these acres would be rated non-riparian when new data are collected.

MANAGEMENT COMMON TO ALL ALTERNATIVES

Actions to limit surface disturbance would benefit riparian and wetland areas. Surface-disturbing activities 

would remove vegetation and compact soils. Although impacts from surface disturbance typically would be 

localized and short term and last until reestablishment of vegetation, impacts of surface disturbances would 

increase as disturbed acres increased within a watershed.

Evaluating the activity and, if necessary, relocating the activity to a more suitable soil type or denying the 

authorization would minimize disturbance in riparian and wetland areas. Proper reclamation of surfacedisturbing activities would decrease erosion and excess sedimentation. 

Management actions that preserved or enhanced water quality would also maintain or improve riparian and 

wetland area functionality. 

Meeting Rangeland Health Standards would ensure healthy sustainable rangelands, including healthy riparian

and wetland areas. Properly functioning riparian and wetland areas would contain adequate vegetation and 

woody debris to dissipate the stream energy associated with high flow events, which would subsequently reduce 

erosion and improve water quality. Meeting all five standards would ensure riparian and wetland vegetation was 

in balance with upland vegetation and assist in erosion control, bank stabilization, and sediment filtration. 

Because timing, intensity, frequency, grazing duration, livestock behavior, and foraging preferences would 

potentially alter impacts to the vegetative component of riparian and wetland areas, adjusting livestock grazing

use would promote sufficient vegetation within riparian and wetland buffers.
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Treatments of woody and non-woody vegetation through mechanical thinning, biomass removal, and chemical 

and biological treatments would threaten native vegetation in riparian and wetland areas in the short term, 

accelerate erosion of streambanks, and increase sedimentation. Reducing hazardous fuels through woody and 

non-woody vegetation treatments would alter the balance of water in streams and subsurface flow for native 

species within riparian and wetland areas, which would subsequently impact water quality, soil health, and 

wildlife habitat. Over time, this reduction would be managed to ensure riparian and wetland areas continued to 

meet the standards to maintain functionality or maintain improving trends. 

Use of fertilizer to accomplish natural vegetation community restoration would improve riparian and wetland

areas rated lower than PFC. Fertilizer use in riparian and wetland areas rated at PFC would maintain functioning 

condition. If desired riparian and wetland native vegetation was established to stabilize soil or increase plant 

cover in buffers, restoration of natural vegetation communities would improve water quality. If applied where 

overland flow or soil erosion introduced fertilizer into water, fertilizer use would increase nutrients and metals 

in surface water in the short term, which would lead to short-term eutrophication and lower dissolved oxygen 

levels. 

If herbivory were temporarily excluded or livestock grazing patterns changed to allow for desired vegetation 

heights, emphasizing the recovery of hardwood draws would increase seedlings, saplings, and woody species. 

Although limiting livestock herbivory would eliminate a treatment option, it would allow for the introduction of 

disturbances needed to maintain hardwood draws dominated by woody species. Because established hardwood 

draws decrease erosion from disturbances and increase bank stabilization for riparian and wetland areas, 

allowing large numbers of seedlings and saplings to reach their desired heights before authorizing livestock and 

wildlife to graze would improve riparian and wetland areas. Allowing the establishment of multi-aged stands of 

hardwood draws before introducing treatments or livestock grazing would increase bank stabilization, filter 

sediments, and allow nutrient cycling, which would improve riparian and wetland areas. This action would 

increase woody species in hardwood draws and ensure that these areas would not pass the transitional threshold 

into grass-dominated draws. However, hardwood draws are not necessarily riparian or wetlands, so improving 

these areas would potentially not impact riparian conditions.

Reducing use on riparian and wetland areas rated lower than PFC would increase desired vegetation and 

decrease erosion and sedimentation. However, the majority of the riparian and wetland areas within the 

planning area are rated at PFC. Reduced upland or riparian use would ensure that sufficient vegetation was 

present during high flow events to protect streambanks, dissipate energy, and trap sediments.

Healthy and diverse riparian and wetland areas would be important for watershed functionality. Under all 

alternatives, temporary or permanent enclosures would be built around riparian and wetland areas that required 

increased species diversity, recruitment, and functionality. Enclosures would also be built for any riparian and 

wetland system needing additional management and attention to meet site-specific goals and objectives for the 

system.

Herbicide treatments would potentially impact drainages within a watershed by altering riparian and wetland

vegetative components. In the long term, treatments would reduce impacts from nonnative species, which 

would include alteration of natural nutrient cycling patterns, erosion rates, stream morphology, 

evapotranspiration, infiltration (Hansen et al. 1995), and flow regimes.

Managing prairie streams to provide quality aquatic wildlife habitat and meet the riparian standard for 

rangeland health would maintain or improve riparian and wetland areas and increase the likelihood that water 

quality was maintained. Riparian and wetland vegetative buffers would protect associated streams from 

excessive erosion or sedimentation. Riparian area vegetation would also buffer waterbodies by reducing or 

eliminating nonpoint source pollution from upland areas (MDEQ 2007). 

Although 300-foot buffers would be applied under Wildland Fire Management actions in compliance with the 

Guidelines for Aerial Delivery of Retardant or Foam near Waterways (USFS et al. 2000) and the Policy for 

Delivery of Wildland Fire Chemicals (Retardant and Foam) Near Waterways(USFS et al. 2009), it would be 
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possible for fire retardant to enter waterbodies and riparian and wetland areas via wind or overland flow, which 

would impair water quality (Little and Calfee 2004). This action would also introduce ammonium 

polyphosphate and sulfate ions, iron oxide, clay, or bentonite to riparian and wetland areas (USFS 2007).

Compliance with the Streamside Management Zone Law and the Water Quality BMPs for Montana Forests

(Logan 2001) (see the Forestry and Woodland Products Appendix) would reduce impacts to riparian and 

wetland areas from forest management activities by minimizing soil erosion and sedimentation. The Streamside 

Management Zone Law prescribes specific buffers for forest activities near streams or waterbodies to maintain 

riparian and wetland area functionality and decrease pollutants. Minimizing disturbances from forest activities 

may be required where necessary to increase the width of the zone to ensure consistency with the riparian and 

wetland standard. 

The magnitude of impacts from livestock grazing would vary based on utilization, location in the watershed, 

duration, and season of use. Excessive livestock grazing would accelerate soil erosion, reduce the riparian

vegetation, increase water temperature, degrade the stream channel, and introduce pollutants such as sediment, 

salinity, bacteria, and nutrients to riparian and wetland areas and water (MDEQ 2007). Wide and shallow 

channels, high sediment yield, and high turbidity would characterize grazing-disturbed streams (Magilligan and 

McDowell 1997). Livestock grazing within riparian and wetland areas would allow browsing of species 

important for dissipating energy during high flow events. Proper management (Mosley et al. 1999; Saunders 

and Fausch 2007) and compliance with, or progress toward, meeting Standards for Rangeland Health would 

minimize these impacts. 

Coal mining activities (e.g., surface disturbance, road construction, overburden removal, rerouting of stream 

systems, and the presence of sediment ponds) would disrupt surface water, which would impact vegetation 

along riparian and wetland areas. During mining, sedimentation would be reduced by sedimentation ponds. 

Spoils would experience decreased infiltration following reclamation (for 10 to 15 years) and, as a result, 

overland flow and peak flows would increase by approximately 5 percent (BLM 1984). Because adequate 

vegetation cover would be necessary to dissipate energies during high flow events, operations discharging 

groundwater with leached salts would alter the vegetative components of riparian and wetland areas. 

Carrying forward coal leasing from the Big Dry and Powder River RMPs using current suitability and 

unsuitability criteria on 1.6 million acres within the planning area would impact and alter riparian and wetland

areas. Soil-stabilizing vegetation would be reduced, which would cause severe erosion that affected the ability 

of riparian areas to dissipate energy during high flow events. Considering potential alluvial valley floors along 

860 stream miles to be unsuitable at the planning stage would protect native vegetation within those riparian 

and wetland buffers (BLM 1984). 

Surface-disturbing activities and oil and gas development within riparian and wetland areas would remove 

riparian vegetation and increase erosion and sedimentation, which would alter streambanks.

Impacts to vegetation within riparian and wetland areas would increase as mineral extraction activity and well, 

road, and facility density increased. Increased road construction and stream crossings would increase erosion 

and sedimentation, which would impact stream channel morphology and alter riparian and wetland area 

vegetation. Discharged product water must meet water quality standards, which would ensure that activities 

would not impair water quality or riparian and wetland areas. 

Impacts to riparian and wetland area vegetation from in situ leach uranium recovery would be small to 

moderate. In addition to impacts from surface-disturbing activities, contamination of aquifers at varying depths, 

shallow groundwater aquifers, and adjacent aquifers with radionuclides or other constituents (e.g., selenium, 

metals) would potentially occur. The resulting changes to soil properties or hydrology would alter riparian and 

wetland species diversity and composition.

Ground disturbance associated with transportation routes would increase bank erosion, which would degrade 

valuable riparian habitat and tree cover and lead to higher water temperatures and sedimentation. These longterm impacts would be accelerated by the construction or maintenance of roads, stream channelization, vehicle 
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fords, improper design and location, and inadequate maintenance. In addition to any short-term impacts caused 

by construction, the placement of culverts would potentially cause long-term impacts to the waterway. 

Compaction of soil and impermeable road surfacing would reduce infiltration and increase overland flow, 

which would increase erosion and sedimentation. Impacts would be minimized by using appropriate road 

surfacing (which would decrease wind and water erosion on the road surface), reducing the number and extent 

of road systems, avoiding riparian areas and stream crossings, installing erosion control features, using proper 

culvert placement and design, reclaiming closed roads, and following BMPs.

OHV use that loosened soil would be a source of nonpoint source pollution and cause vegetation losses and 

accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to sedimentation, soil 

compaction, increased overland flow, and decreased infiltration. Vehicle fords would cause localized erosion, 

sedimentation, and degradation of streambanks. Increased potential for weed invasion would also lead to 

accelerated erosion. 

Acquired lands that improved the continuity of BLM-administered lands within a particular watershed or 

increased ownership along streams would increase the ecological viability of managing riparian and wetland

areas.

ALTERNATIVE A

Avoiding activities on sensitive soils on slopes or highly erodible soils on slopes would decrease potential 

impacts to adjacent riparian and wetland areas from soil erosion and sedimentation, which would cause siltation 

of wetlands, degradation of water quality, and alteration of drainage patterns. 

NSO stipulations for oil and gas leasing and development would protect vegetative buffers and prevent soil 

compaction and vegetation removal, which would protect riparian and wetland areas from erosion and 

sedimentation and maintain overall watershed health. These actions would protect 62,000 acres of riparian and 

wetland areas from additional disturbances. Limiting the number and restricting the size of permanent facilities 

would also contribute to this protection.

The magnitude and duration of the impacts of surface-disturbing activities such as linear underground facilities 

that crossed perennial streams, intermittent streams, wetlands, and riparian areas would vary depending on the 

method used to cross the waterbody. All methods would cause either short- or long-term surface disturbance, as 

described below. 

 Trenching would have direct contact with riparian vegetation during all stages of construction. 

Impacts to stream morphology from the resulting erosion and sedimentation would impact the ability 

of riparian buffers to withstand high flow events until the buffer was reestablished. 

 Isolated crossing methods (e.g., dam-and-pump and flume methods) would cause impacts similar to 

those caused by trenching, but with less severity and duration. The increases in turbidity and 

sedimentation would be limited to the installation and removal of dam or flume structures (up to 10 

hours) (Lévesque 2007). Vegetation removal would be short term, and vegetation would have a 

greater chance to recover with reduced impacts of erosion and sedimentation to riparian areas.

 Bore crossing or HDD avoids contact with the waterbody and would avoid a large portion of the 

riparian area buffer. This method would protect the native riparian vegetation, decreasing vegetation 

removal and allowing the area to continue to dissipate energy during high flow events, with 

decreasing erosion and sedimentation. Slight impacts to riparian vegetation from heavy equipment 

activity on the outer edge of riparian buffers would occur in the short term.

Springs would provide additional moisture and runoff for riparian and wetland vegetation, and installing flowcontrol devices on troughs would limit excess water diverted from the source. Limiting this diversion would 

reduce soil moisture in overflow areas and increase flows from the source into the natural drainage, which 

would enhance the vigor and type of riparian vegetation. However, without fencing the source, trampling 

caused by congregating livestock would increase. Fencing springs would protect the vegetative buffer at the 

source and increase species vigor and composition.
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Avoiding the placement of troughs and tanks in areas containing important riparian and wetland vegetation 

would increase species vigor and composition by limiting impacts caused by livestock trampling and 

congregating.

Because riparian and wetland areas are susceptible to invasive species (vegetation) invasion and often invaded 

by multiple species, allowing surface-disturbing activities in areas infested by invasive species (vegetation) 

would expand infestations in riparian and wetland areas. Invasive species infestations located outside of riparian 

and wetland areas would potentially invade and degrade adjacent native riparian vegetative communities. 

Surface disturbances in areas of invasive species would potentially disrupt existing weed infestations and allow 

seeds to blow or drain into riparian areas, which would reduce the ability of native riparian vegetation to 

stabilize streambanks. 

NSO stipulations for oil and gas leasing and development within 0.25 miles of designated reservoirs with 

fisheries would protect riparian and wetland vegetation around the reservoir. Wetland vegetation would provide 

habitat for aquatic species and decrease bank erosion and instability, excess sedimentation, and habitat 

fragmentation.

Burying power lines would increase surface disturbance and remove vegetation within riparian and wetland

areas. Depending on the crossing methods, the magnitude of the impacts to riparian and wetland vegetation 

would vary.

An NSO stipulation for oil and gas leasing and development within 0.25 miles of wetlands identified as piping 

plover or interior least tern habitat would protect 1,700 acres of riparian and wetland areas from erosion and 

sedimentation. Prohibiting surface occupancy would decrease the removal of vegetation and soil compaction 

and protect vegetative buffers important to piping plovers and interior least terns.

Allowing prescribed fire in Fire Management Categories B and C, which compose the entire planning area, 

would increase native riparian and wetland vegetation in watersheds. Road construction and heavy equipment 

use associated with prescribed fire would impact water quality, soil health, and vegetative buffers in the short 

term until vegetation was reestablished. Favorable conditions would allow prescribed fire to accelerate nutrient 

cycling, sprouting, and forage availability. Very intense burning would decrease sprouting and forage growth. 

Riparian and wetland areas within cultural and paleontological sites would be protected when lease terms were 

applied, so vegetative buffers would prevent soil compaction and vegetation removal, which would decrease 

erosion and sedimentation and maintain overall riparian health.

Allowing surface-disturbing activities (other than oil and gas activities with NSO stipulations) would increase 

erosion and sedimentation. Surface-disturbing activities outside of riparian and wetland areas would impact 

vegetative buffers by decreasing native plant composition and increasing erosion. Changes in vegetation 

composition would increase runoff and sedimentation, alter streambank and channel structure, and cause 

nutrient losses. 

Allowing cottonwood harvest on public lands only when human safety was a factor or disease or insect 

infestations were threatening cottonwood stands would cause impacts similar to those caused by 

surface-disturbing activities. Because cottonwoods stands typically occur within riparian areas, harvesting 

would increase erosion and sedimentation and decrease infiltration. Harvesting cottonwoods would reduce 

vegetation within buffers, which would accelerate erosion and reduce the stream’s ability to dissipate energy 

during high flow events.

Under this alternative, 440 acres of riparian and wetland areas would be closed to livestock grazing, and 1.6 

million acres would be open to livestock grazing (99 percent of total riparian and wetland acres within the 

planning area). Improper livestock grazing and hoof disturbance would increase bank erosion and 

sedimentation, alter riparian vegetation, and introduce pollutants. Because behavior and feeding preferences 

differ between livestock species, overuse and trampling would impact the composition of native riparian and 
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wetland vegetation species or eliminate some species important to the system. Differing grazing intensities 

would alter the impacts to riparian and wetland vegetation. Congregating livestock would impact riparian and 

wetland vegetation, erosion, and sedimentation. Livestock grazing would potentially be compatible in riparian 

and wetland areas when managed in harmony with land management objectives such as meeting Standards for 

Rangeland Health. Managing livestock based on resource use and land health standard assessments would 

ensure riparian and wetland areas continue to meet standards. Those areas failing to meet standards would be 

adjusted to generate improving riparian and wetland conditions and trends. 

If Standards for Rangeland Health were not met and livestock grazing was a causal factor for this failure, the 

management of riparian and wetland areas would change to ensure that allotments were moving toward PFC. 

(Standard 2 requires that riparian and wetland areas attain and maintain PFC.) Ensuring that riparian, wetland, 

and upland vegetation was properly functioning would help control erosion, stabilize banks, and filter sediment. 

Grazing management and activities would be adjusted to allow riparian and wetland areas to improve toward 

PFC.

Allowing livestock grazing during or immediately after mining or development would impact riparian and 

wetland areas by increasing erosion and sedimentation along streambanks caused by localized livestock 

congregating or trampling.

Permits would be renewed on a case-by-case basis when monitoring demonstrated that riparian and wetland

area objectives were met on I allotments and maintained on M and C allotments. Meeting these resource 

objectives would maintain or improve PFC in riparian and wetland areas.

Geophysical exploration would temporarily disturb soil and vegetation. Prohibiting geophysical exploration 

would protect 72,000 acres of riparian wetland areas from this activity. 

OHV use that loosened soil would be a source of nonpoint source pollution and cause vegetation losses and 

accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to sedimentation, soil 

compaction, increased overland flow, and decreased infiltration. Vehicle fords would cause localized erosion, 

sedimentation, and degradation of streambanks. Increased potential for weed invasion would also lead to 

accelerated erosion. 

ALTERNATIVE B

Prohibiting mineral leasing and permitting within riparian and wetland areas and prohibiting surface-disturbing 

activities on sensitive soils or slopes 25 percent or greater would decrease potential soil erosion and 

sedimentation in riparian and wetland areas. These actions would help riparian and wetland areas to maintain or 

improve PFC and protect vegetative buffers. 

Prohibiting surface-disturbing and disruptive activities or mineral development would decrease streambank 

erosion, sedimentation, and vegetation removal and protect riparian and wetland areas. Riparian and wetland 

areas rated at PFC would be subject to disturbance if the activity maintained or improved riparian and wetland 

areas. Oil and gas leasing with an NSO stipulation would for riparian and wetland areas would protect 59,000 

acres of riparian and wetland areas from erosion and sedimentation. Even when disturbances occurred in the 

uplands, short-term disturbances occurring outside of riparian and wetland areas would impact adjacent riparian 

vegetative buffers.

Prohibiting mineral leasing and permitting within riparian and wetland areas and for water resources and 

prohibiting surface-disturbing activities would decrease potential soil erosion and sedimentation in riparian and 

wetland areas. These actions would help riparian and wetland areas to maintain or improve PFC and protect 

vegetative buffers. 

Springs would provide additional moisture and runoff for riparian and wetland vegetation, and installing flowcontrol devices on troughs would limit excess water diverted from the source. Limiting this diversion would 

reduce soil moisture in overflow areas and increase flows from the source into the natural drainage, which 
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would enhance the vigor and type of riparian vegetation. However, without fencing the source, trampling 

caused by congregating livestock would increase. Fencing springs would protect the vegetative buffer at the 

source and increase species vigor and composition. Designing spring developments to ensure riparian 

communities were maintained or improved would benefit overall watershed health.

Prohibiting surface-disturbing activities, disruptive activities, and permanent facilities within 0.5 miles of 

designated sport-fish reservoirs (unless the activity or facility would benefit aquatic wildlife habitat) would 

protect riparian and wetland vegetative buffers. Protecting vegetative buffers from surface-disturbing activities 

would decrease streambank erosion and sedimentation, which would improve riparian and wetland areas rated 

lower than PFC.

Because riparian and wetland areas are susceptible to invasive species (vegetation) invasion and often invaded 

by multiple species, prohibiting surface-disturbing activities in areas infested by invasive species (vegetation) 

would protect riparian and wetland areas. Surface disturbances in areas of invasive species would potentially 

disrupt existing weed infestations and allow seeds to blow or drain into riparian areas, which would reduce the 

ability of native riparian vegetation to stabilize streambanks. 

Prohibiting invasive species control within riparian and wetland areas would include 14.3 miles of the 

designated Bighorn Sheep Range, which would allow invasive species to outcompete desired species on 

valuable riparian wildlife habitat such as point bars and side channels. 

An NSO stipulation for oil and gas leasing and development within 0.25 miles of wetlands identified as piping 

plover or interior least tern habitat would protect 1,700 acres of riparian and wetland areas from erosion and 

sedimentation. Prohibiting surface occupancy would decrease the removal of vegetation and soil compaction 

and protect vegetative buffers important to piping plovers and interior least terns.

Burying low-voltage oil and gas power lines within 4 miles of a lek and within sage-grouse winter 

concentration areas would increase surface disturbance within riparian and wetland areas, which would increase 

erosion and sediment loads in the short term. 

High-intensity fire would potentially impact vegetation composition and slow reestablishment of vegetation. 

However, fires would help to minimize some woody invasive species within a watershed, which would allow 

for the reestablishment of desired native species.

Short-term impacts following a prescribed fire would impact riparian and wetland health by decreasing water 

quality, affecting soil health, and altering vegetative riparian and wetland buffers.

Management actions that required buffers around upland cultural and paleontological sites would facilitate the 

functionality of riparian and wetland vegetative buffers, which would decrease erosion and sedimentation and 

maintain or improve riparian and wetland conditions. 

Allowing cottonwood harvest on public lands only when human safety was a factor or disease or insect 

infestations were threatening cottonwood stands would cause impacts similar to those caused by 

surface-disturbing activities. Because cottonwoods stands typically occur within riparian areas, harvesting 

would increase erosion and sedimentation and decrease infiltration. Harvesting cottonwoods would reduce 

vegetation within buffers, which would accelerate erosion and reduce the stream’s ability to dissipate energy 

during high flow events.

Under this alternative, 1,500 acres of riparian and wetland areas would be closed to livestock grazing, and 1.6 

million acres would be open to livestock grazing (99 percent of total riparian and wetland acres within the 

planning area). Ensuring that riparian and wetland vegetation was in balance with upland vegetation and met the 

Standards for Rangeland Health would help control erosion, stabilize banks, and filter sediment. Differing 

grazing intensities would alter the impacts to riparian and wetland vegetation. Congregating livestock would 

impact riparian and wetland vegetation, erosion, and sedimentation. Monitoring and evaluating priority 

allotments that contained specific nonfunctional or functional-at risk with downward trend riparian areas and 
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adjusting management of priority areas would help these areas to improve toward PFC. Livestock grazing

would potentially be compatible in riparian and wetland areas when managed in harmony with land 

management objectives such as meeting Standards for Rangeland Health.

Management of riparian and wetland areas would be changed to ensure that allotments maintained or improved 

PFC in areas in which the Standards for Rangeland Health were not met and livestock grazing was a causal 

factor for the failure to meet these standards. (Standard 2 requires that riparian and wetland areas are rated 

PFC.) Ensuring that riparian and wetland vegetation was in balance with upland vegetation and met the 

Standards for Rangeland Health would help control erosion, stabilize banks, and filter sediment for a properly 

functioning riparian and wetland area. Closing allotments to livestock grazing would speed fulfillment of 

riparian objectives. 

Locating new livestock water developments at least 0.25 miles from riparian and wetland areas would protect 

2.5 million acres from livestock trampling or congregating. Locating water developments near riparian and 

wetland areas would allow riparian and wetland areas to maintain or progress toward PFC. Ensuring riparian 

and wetland vegetation was in balance with upland vegetation and met the Standards for Rangeland Health

would help control erosion, stabilize banks, and filter sediment for a properly functioning riparian and wetland 

area.

Temporarily closing BLM-administered lands to grazing for at least 2 growing seasons after prescribed fire or 

non-fire vegetation treatments would promote the regrowth of desired native vegetation in riparian and wetland

areas (with normal precipitation). Consecutive drought years following a prescribed fire would degrade riparian 

and wetland areas by slowing the reestablishment of native species’ vigor and diversity. Allowing native species 

to sprout and regenerate would maintain or improve riparian and wetland conditions.

Suspending livestock grazing to ensure that adequate fine fuels were present to carry a prescribed fire would 

enable attainment of long-term objectives for riparian and wetland vegetation. Suspending livestock use during 

this period would increase herbaceous biomass, which would decrease potential erosion and sedimentation 

along streambanks. 

Transferring or renewing grazing permits for C grazing allotments under this alternative would maintain or 

improve PFC in riparian and wetland areas. 

Priority allotments under this alternative would increase management review to ensure criteria were met for 

permit renewals. 

Restricting geophysical exploration would protect 71,000 acres of riparian and wetland areas from potential 

erosion and sedimentation. Limiting use to existing roads and trails would ensure that no new disturbances 

occurred outside of or along riparian and wetland areas, which would minimize degradation to these areas. 

Management actions that allowed mineral materials sales and permitting on 1.2 million acres would increase 

potential erosion and sediment loads to riparian and wetland areas. 

OHV use that loosened soil would be a source of nonpoint source pollution and cause vegetation losses and 

accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to sedimentation, soil 

compaction, increased overland flow, and decreased infiltration. Vehicle fords would cause localized erosion, 

sedimentation, and degradation of streambanks. Increased potential for weed invasion would also lead to 

accelerated erosion. 

ALTERNATIVE C

Avoiding surface-disturbing activities on slopes 25 percent or greater (71,000 acres of riparian and wetland

areas) or on sensitive soils would decrease soil erosion potential and sedimentation within riparian and wetland 

areas. Soil disturbance on slopes 25 percent or greater would accelerate potential erosion from human-caused 
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activity, which would increase sediment loads to riparian and wetland areas and potentially alter vegetation and 

stream morphology. 

Restricting or prohibiting surface-disturbing or disruptive activities or mineral leasing or development would 

protect riparian and wetland areas from additional erosion and sedimentation that would impact riparian and 

wetland vegetative buffers and their functioning condition. A CSU stipulation for oil and gas leasing and 

development in riparian and wetland areas would protect 11,000 acres of riparian and wetland areas from the 

erosion and sedimentation associated with surface disturbances. These stipulations would prevent vegetation 

removal and soil compaction, protect vegetative buffers important to some species, and maintain overall 

watershed health. Unless mitigation ensured the activity maintained or improved riparian and wetland 

conditions, allowing mineral exploration and development would cause opposite impacts.

Springs would provide additional moisture and runoff for riparian and wetland vegetation, and installing flowcontrol devices on troughs would limit excess water diverted from the source. Not authorizing spring 

developments would ensure that the riparian and wetland areas around springs would continue to maintain 

species’ vigor and composition without disturbances. Limiting this diversion would reduce soil moisture in 

overflow areas and increase flows from the source into the natural drainage, which would enhance the vigor and 

type of riparian vegetation. However, without fencing the source, trampling caused by congregating livestock 

would increase. Fencing springs would protect the vegetative buffer at the source and increase species vigor and 

composition. Designing spring developments to ensure riparian communities were maintained or improved 

would benefit overall watershed health.

Locating new livestock water developments at least 0.25 miles from riparian and wetland areas would protect 

2.5 million acres from livestock trampling or congregating. Locating water developments near riparian and 

wetland areas would allow riparian and wetland areas to maintain or progress toward PFC. Ensuring riparian 

and wetland vegetation was in balance with upland vegetation and met the Standards for Rangeland Health

would help control erosion, stabilize banks, and filter sediment for a properly functioning riparian and wetland 

area.

Because riparian and wetland areas are susceptible to invasive species (vegetation) invasion and often invaded 

by multiple species, allowing surface-disturbing activities in areas infested by invasive species (vegetation) 

would expand infestations in riparian and wetland areas. Invasive species infestations located outside of riparian 

and wetland areas would potentially invade and degrade adjacent native riparian vegetative communities. 

Surface disturbances in areas of invasive species would potentially disrupt existing weed infestations and allow 

seeds to blow or drain into riparian areas, which would reduce the ability of native riparian vegetation to 

stabilize streambanks. 

Avoiding surface-disturbing activities within 0.25 miles of designated sport-fish reservoirs would prevent 

excess soil erosion, streambank erosion, and sedimentation. Approved mitigation under this alternative would 

ensure riparian and wetland areas would maintain or improve PFC in compliance with guidance found in the 

Reclamation Appendix.

Prohibiting domestic sheep and goat grazing for invasive species control on 11,000 acres of riparian and 

wetland areas within 14.3 miles of the Bighorn Sheep Range would allow invasive species (vegetation) to 

outcompete desired vegetative species. Invasive vegetation species would increase on point bars and side 

channels, which are valuable areas for wildlife habitat. Appropriate control of invasive species with targeted 

grazing would ensure riparian and wetland areas were maintained or progressing toward PFC. 

Prohibiting surface-disturbing activities within 0.25 miles of wetlands identified as piping plover or interior 

least tern habitat would protect 1,700 acres of riparian and wetland areas from erosion, sedimentation, and 

vegetation removal. Activities occurring adjacent to the 0.25-mile buffer for wetlands would potentially 

increase erosion and sedimentation. Mitigation would ensure wetlands continued to be maintained or improved 

and functioning habitat was maintained for piping plovers and interior least tern.
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Short-term disturbances associated with the burial of power lines within 3.1 miles of a lek and in sage-grouse

winter concentration areas would occur in areas in which vegetation was removed in association with these 

activities. In the long term, recovery of vegetation in these areas would decrease erosion and sedimentation.

Allowing prescribed fire throughout the planning area would provide the most opportunities to meet objectives 

for native vegetation in riparian and wetland areas, particularly if environmental conditions allowed for proper 

regrowth.

Management actions that required buffers around upland cultural and paleontological sites would facilitate the 

functionality of riparian and wetland vegetative buffers, which would decrease erosion and sedimentation and 

maintain or improve riparian and wetland conditions. Riparian and wetland areas would assist in nonpoint 

source pollution by holding and using nutrients and reducing sediments in waterbodies. Decreased surface 

disturbance would improve riparian and wetland conditions. 

Harvesting cottonwood to restore the health and resiliency of cottonwood stands or hazard tree removal would 

increase erosion and sedimentation and decrease infiltration in the short term. Harvesting cottonwoods would 

reduce vegetation within buffers, which would accelerate erosion. Over the long term, this action would 

maintain or improve the integrity and functionality of riparian and wetland areas by maintaining cottonwood 

health and providing vegetation resiliency that helped dissipated energy during high flow events.

Under this alternative, 1,400 acres of riparian and wetland areas would be closed to livestock grazing, and 1.6 

million acres would be open to livestock grazing (99 percent of total riparian and wetland acres in the planning 

area). Ensuring that riparian and wetland vegetation was in balance with upland vegetation and met the 

Standards for Rangeland Health would help control erosion, stabilize banks, and filter sediment. Differing 

grazing intensities would alter the impacts to riparian and wetland vegetation. Congregating livestock would 

impact riparian and wetland vegetation, erosion, and sedimentation. In the Dean S. Reservoir SRMA, excess 

livestock grazing would degrade wetland vegetative components, which would decrease composition and 

increase erosion along banks. In the Pumpkin Creek Ranch and Recreation SRMA, excess livestock grazing 

would cause trampling and soil compaction to 410 acres of riparian and wetland areas. Livestock grazing would 

potentially be compatible in riparian and wetland areas when managed in harmony with land management 

objectives such as meeting Standards for Rangeland Health.

If conditions were favorable, prescribed fire would accelerate nutrient cycles, sprouting, and forage availability; 

however, very intense burns would potentially decrease sprouting and forage growth. Closing BLMadministered lands to livestock grazing until the area attained identified vegetative objectives after wildfire, 

prescribed fire, or non-fire vegetative treatments would allow the shortest regrowth period for desired native 

riparian and wetland vegetation. Allowing species to sprout and regenerate would allow the shortest recovery 

period toward PFC. Intense burns would delay reestablishment of desired riparian and wetland vegetative 

communities, particularly if a healthy plant community were absent prior to burning. Delayed reestablishment 

would increase the risk of erosion and sedimentation. This alternative would protect riparian and wetland 

resources by expediting the recovery of plant communities.

Closing allotments that did not show progress toward meeting Standards for Rangeland Health within 5 years 

due to grazing would protect riparian and wetland areas from increased erosion caused by livestock trampling 

and congregating along streambanks. This action would allow riparian and wetland areas to improve to PFC. 

Impacts of erosion and increased sedimentation from livestock grazing in riparian and wetland areas would 

occur until allotments were closed.

Transferring or renewing grazing permits for C grazing allotments under this alternative would maintain or 

improve PFC in riparian and wetland areas. 

Priority allotments under this alternative would increase management review to ensure criteria were met for 

permit renewals. 
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Allowing livestock grazing during or immediately after mining or development if Standards for Rangeland 

Health were met would increase erosion and sedimentation along streambanks through excess livestock 

congregating or trampling in riparian and wetland areas. Preventing vegetative recovery from mining before 

authorizing grazing would delay or prevent native vegetative reestablishment in riparian and wetland areas. 

Restricting geophysical exploration would protect 4,300 acres of riparian and wetland areas. The remainder of 

the planning area would be open to geophysical exploration on existing roads or trails (which would include 10 

acres of riparian and wetland areas in the Dean S. Reservoir SRMA, 30 acres in the Pumpkin Creek Ranch and 

Recreation SRMA, and 4 acres in the Strawberry Hill Recreation SRMA). Geophysical exploration in areas 

outside of riparian and wetland areas would increase erosion and sedimentation from uplands, which would 

impact adjacent riparian and wetland vegetative buffers. 

OHV use that loosened soil would be a source of nonpoint source pollution and cause vegetation losses and 

accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to sedimentation, soil 

compaction, increased overland flow, and decreased infiltration. Vehicle fords would cause localized erosion, 

sedimentation, and degradation of streambanks. Increased potential for weed invasion would also lead to 

accelerated erosion. 

ALTERNATIVE D

Avoiding surface-disturbing activities on slopes 25 percent or greater (71,000 acres of riparian and wetland

areas) or on sensitive soils would decrease soil erosion potential and sedimentation within riparian and wetland 

areas. Soil disturbance on slopes 25 percent or greater would accelerate potential erosion from human-caused 

activity, which would increase sediment loads to riparian and wetland areas and potentially alter vegetation and 

stream morphology. 

Restricting or prohibiting surface-disturbing and disruptive activities or mineral leasing or development would 

protect riparian and wetland areas from additional erosion and sedimentation that would impact riparian and 

wetland vegetative buffers and their functioning condition. A CSU stipulation for oil and gas leasing and 

development in riparian and wetland areas would protect 11,000 acres of riparian and wetland areas from the 

erosion and sedimentation associated with surface disturbances. These stipulations would prevent vegetation 

removal and soil compaction, protect vegetative buffers important to some species, and maintain overall 

watershed health. Surface-disturbing activities would be mitigated to decrease erosion and sedimentation and 

maintain or improve riparian and wetland conditions. Unless mitigation ensured the activity maintained or 

improved riparian and wetland conditions, allowing mineral exploration and development would cause opposite 

impacts.

Mitigation that minimized the impacts of surface-disturbing and disruptive activities would protect riparian and 

wetland vegetative buffers, assist in erosion control, provide wildlife habitat and flood storage, decrease 

sedimentation, and promote progress toward PFC. 

Springs would provide additional moisture and runoff for riparian and wetland vegetation, and installing flowcontrol devices on troughs would limit excess water diverted from the source. Limiting this diversion would 

reduce soil moisture in overflow areas and increase flows from the source into the natural drainage, which 

would enhance the vigor and type of riparian vegetation. However, without fencing the source, trampling

caused by congregating livestock would increase. Fencing springs would protect the vegetative buffer at the 

source and increase species vigor and composition. Designing spring developments to ensure riparian 

communities were maintained or improved would benefit overall watershed health.

Locating new livestock water developments at least 0.25 miles from riparian and wetland areas would protect 

2.5 million acres from livestock trampling or congregating. Locating water developments near riparian and 

wetland areas would allow riparian and wetland areas to maintain or progress toward PFC. Ensuring riparian 

and wetland vegetation was in balance with upland vegetation and met the Standards for Rangeland Health

would help control erosion, stabilize banks, and filter sediment for a properly functioning riparian and wetland 

area.
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Because riparian and wetland areas are susceptible to invasive species (vegetation) invasion and often invaded 

by multiple species, allowing surface-disturbing activities in areas infested by invasive species (vegetation) 

would expand infestations in riparian and wetland areas. Invasive species infestations located outside of riparian 

and wetland areas would potentially invade and degrade adjacent native riparian vegetative communities. 

Surface disturbances in areas of invasive species would potentially disrupt existing weed infestations and allow 

seeds to blow or drain into riparian areas, which would reduce the ability of native riparian vegetation to 

stabilize streambanks. 

Mitigation to minimize impacts of oil and gas leasing and development and geophysical exploration near 

designated sport-fish reservoirs would reduce the potential of streambank erosion and instability, excess 

sedimentation, and impacts to riparian and wetland vegetation components. 

Prohibiting domestic sheep and goat grazing for invasive species control on 11,000 acres of riparian and 

wetland areas within 14.3 miles of the Bighorn Sheep Range would allow invasive species (vegetation) to 

outcompete desired vegetative species. Invasive vegetation species would increase on point bars and side 

channels, which are valuable areas for wildlife habitat. Appropriate control of invasive species with targeted 

grazing would ensure riparian and wetland areas were maintained or progressing toward PFC. 

Prohibiting surface-disturbing activities within 0.25 miles of wetlands identified as piping plover or interior 

least tern habitat would protect 1,700 acres of riparian and wetland areas from erosion, sedimentation, and 

vegetation removal. Activities occurring adjacent to the 0.25-mile buffer for wetlands would potentially 

increase erosion and sedimentation. Mitigation would ensure wetlands continued to be maintained or improved 

and functioning habitat was maintained for piping plovers and interior least tern.

Burying power lines to maintain habitat functionality within 2 miles of a lek and within sage-grouse winter 

concentration areas would decrease vegetation alteration in riparian and wetland areas. Short-term disturbances 

would occur in areas in which vegetation was removed in association with these activities. In the long term, 

recovery of vegetation in these areas would decrease erosion and sedimentation.

Allowing prescribed fire throughout the planning area would provide the most opportunities to meet objectives 

for native vegetation in riparian and wetland areas, particularly if environmental conditions allowed for proper 

regrowth. In the short term, water quality, soil health, and vegetative buffers would be affected by fire or other 

disturbances until vegetation was reestablished. If conditions were favorable, prescribed fire would accelerate 

nutrient cycling and vegetative sprouting and forage availability; however, very intense burns would potentially 

decrease sprouting and forage growth. 

Management actions that required buffers around upland cultural and paleontological sites would facilitate the 

functionality of riparian and wetland vegetative buffers, which would decrease erosion and sedimentation and 

maintain or improve riparian and wetland conditions. Riparian and wetland areas would assist in nonpoint 

source pollution by holding and using nutrients and reducing sediments in waterbodies. Decreased surface 

disturbance would improve riparian and wetland conditions. 

Harvesting cottonwood to restore the health and resiliency of cottonwood stands or hazard tree removal would 

increase erosion and sedimentation and decrease infiltration in the short term. Harvesting cottonwoods would 

reduce vegetation within buffers, which would accelerate erosion. Over the long term, this action would 

maintain or improve the integrity and functionality of riparian and wetland areas by maintaining cottonwood 

health and providing vegetation resiliency that helped dissipated energy during high flow events.

Under this alternative, 60 acres of riparian and wetland areas would be closed to livestock grazing, and 1.6 

million acres would be open to livestock grazing. Livestock grazing would potentially be compatible in riparian 

and wetland areas when managed in harmony with land management objectives such as meeting Standards for 

Rangeland Health.
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Closing allotments that did not show progress toward meeting Standards for Rangeland Health within 5 years 

due to grazing would protect riparian and wetland areas from increased erosion caused by livestock trampling

and congregating along streambanks. This action would allow riparian and wetland areas to improve to PFC. 

Impacts of erosion and increased sedimentation from livestock grazing in riparian and wetland areas would 

occur until allotments were closed.

Even if Standards for Rangeland Health were met, allowing livestock grazing during or immediately after 

mining or development would impact riparian and wetland vegetation by increasing erosion. Impacts from 

grazing would occur when livestock congregated in riparian and wetland areas and trampled vegetation. This 

action would increase sedimentation, decrease the stability of streambanks, and reduce riparian vigor. 

Deferring livestock grazing on BLM-administered lands until seed matured on perennial herbaceous vegetation 

in the growing season following wildfire, prescribed fire, or non-fire vegetative treatments would protect 

riparian and wetland vegetative buffers by promoting the regrowth of desired native vegetation (during a year 

with normal precipitation). However, during drought years, vegetation would potentially fail to reestablish 

sufficiently to protect riparian and wetland health.

Prioritizing monitoring and evaluations on allotments that failed to meet Standards for Rangeland Health would 

ensure that these allotments met resource objectives, which would include attainment of properly functioning 

riparian and wetland areas. 

Prohibiting geophysical exploration on BLM-administered surface acres would protect 70,000 acres of riparian

wetland areas. Geophysical exploration in the remaining areas (outside of riparian and wetland areas) would 

increase upland erosion and sedimentation adjacent to riparian and wetland vegetative buffers.

OHV use that loosened soil would be a source of nonpoint source pollution and cause vegetation losses and 

accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to sedimentation, soil 

compaction, increased overland flow, and decreased infiltration. Vehicle fords would cause localized erosion, 

sedimentation, and degradation of streambanks. Increased potential for weed invasion would also lead to 

accelerated erosion. 

ALTERNATIVE E (PREFERRED ALTERNATIVE)

Avoiding surface-disturbing activities on slopes 25 percent or greater (71,000 acres of riparian and wetland

areas) or on sensitive soils would decrease soil erosion potential and sedimentation within riparian and wetland 

areas. Soil disturbance on slopes 25 percent or greater would accelerate potential erosion from human-caused 

activity, which would increase sediment loads to riparian and wetland areas and potentially alter vegetation and 

stream morphology. 

NSO stipulations for oil and gas leasing and development would protect vegetative buffers and prevent soil 

compaction and vegetation removal on 62,000 acres of riparian and wetlands areas, which would protect these 

areas from erosion and sedimentation and maintain overall watershed health. Limiting the number and 

restricting the size of permanent facilities would contribute to this protection.

Avoiding surface-disturbing activities within 300 feet of riparian and wetland areas would protect most 

vegetative components of the riparian and wetland areas along waterbodies and streams. Vegetated buffers 

would be the most effective way of reducing or eliminating impacts by reducing sediments, nutrients, metals 

and other pollutants from surface-disturbing activities adjacent to water. The use of a buffer would maintain 

PFC in riparian and wetland areas. A 300-foot buffer would reduce sedimentation and erosion and soil 

compaction, increase streambank stabilization, maintain late summer stream flows, recharge aquifers, and 

maintain a higher water table (which would increase forage). The buffer area would allow for stream channel 

migration over time and protect most riparian and wetland areas by improving integrity and functionality.

Requiring spring developments designed to conserve water at the source would limit diversion, reduce soil 

moisture in overflow areas, and increase flows from the source into the natural drainage, which would enhance 
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the vigor and type of riparian vegetation. Springs would provide riparian and wetland areas with additional 

moisture and runoff for riparian and wetland vegetation. However, without fencing the source, trampling caused 

by congregating livestock would increase. Fencing springs would protect the vegetative buffer at the source and 

increase species vigor and composition. Designing spring developments to ensure riparian communities were 

maintained or improved would benefit overall watershed health.

Locating and designing new livestock water developments to maintain the integrity and functionality of riparian

and wetland areas would protect these areas from excess trampling or congregating by livestock. Water 

developments near riparian and wetland areas would be designed to maintain riparian and wetland areas or 

ensure they progressed toward PFC. Ensuring riparian and wetland vegetation was in balance with upland 

vegetation would help control erosion, stabilize banks, and filter sediment for a properly functioning riparian 

and wetland area.

Because riparian and wetland areas are susceptible to invasive species (vegetation) invasion and often invaded 

by multiple species, allowing surface-disturbing activities in areas infested by invasive species (vegetation) 

would expand infestations in riparian and wetland areas. Invasive species infestations located outside of riparian 

and wetland areas would potentially invade and degrade adjacent native riparian vegetative communities. 

Surface disturbances in areas of invasive species would potentially disrupt existing weed infestations and allow 

seeds to blow or drain into riparian areas, which would reduce the ability of native riparian vegetation to 

stabilize streambanks. 

Avoiding surface-disturbing activities within 0.25 miles of designated sport-fish reservoirs would avoid the 

impacts of surface-disturbing activities, such as excess soil erosion, streambank erosion, and sedimentation. 

Approved mitigation under this alternative would ensure riparian and wetland areas maintained or improved 

PFC in compliance with guidance found in the Reclamation Appendix.

Prohibiting domestic sheep and goat grazing for invasive species control on 11,000 acres of riparian and 

wetland areas within 14.3 miles of the Bighorn Sheep Range would allow invasive species (vegetation) to 

outcompete desired vegetative species. Invasive vegetation species would increase on point bars and side 

channels, which are valuable areas for wildlife habitat. Appropriate control of invasive species with targeted 

grazing would ensure riparian and wetland areas were maintained or progressing toward PFC. 

Prohibiting surface-disturbing activities in wetlands identified as piping plover or interior least tern habitat 

(unless the habitat was maintained) would protect 1,700 acres of riparian and wetland areas from erosion, 

sedimentation, and vegetation removal. Activities adjacent to wetlands would potentially increase erosion and 

sedimentation. Mitigation would ensure wetlands continued to be maintained or improved and functioning 

habitat was maintained for piping plovers and interior least terns.

Short-term disturbances associated with the burial of low-voltage power lines within 2 miles of leks would 

occur in areas in which vegetation was removed in association with these activities. In the long term, recovery 

of vegetation in these areas would decrease erosion and sedimentation. If burial of low-voltage power lines was 

not feasible, impacts to riparian and wetlands areas would be the same as impacts from surface-disturbing 

activities.

Allowing prescribed fire throughout the planning area would provide the most opportunities to meet objectives 

for native vegetation in riparian and wetland areas, particularly if environmental conditions allowed for proper 

regrowth.

Prohibiting surface-disturbing activities in cultural and paleontological sites would facilitate the functionality of 

riparian and wetland vegetative buffers, which would decrease erosion and sedimentation. Riparian and wetland 

areas would assist in nonpoint source pollution by holding and using nutrients and reducing sediments in 

waterbodies. Decreased surface disturbance would improve riparian and wetland conditions.

Harvesting cottonwood to restore the health and resiliency of cottonwood stands or hazard tree removal would 

increase erosion and sedimentation and decrease infiltration in the short term. Harvesting cottonwoods would 
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reduce vegetation within buffers, which would accelerate erosion. Over the long term, this action would 

maintain or improve the integrity and functionality of riparian and wetland areas by maintaining cottonwood 

health and providing vegetation resiliency that helped dissipated energy during high flow events.

Under this alternative, 1,400 acres of riparian and wetland areas would be closed to livestock grazing, and 1.6 

million acres would be open to livestock grazing (99 percent of total riparian and wetland acres in the planning 

area). Ensuring that riparian and wetland vegetation was in balance with upland vegetation and met the 

Standards for Rangeland Health would help control erosion, stabilize banks, and filter sediment. Differing 

grazing intensities would alter the impacts to riparian and wetland vegetation. Congregating livestock would 

impact riparian and wetland vegetation, erosion, and sedimentation. In the Dean S. Reservoir SRMA, excess 

livestock grazing would degrade wetland vegetative components, which would decrease composition and 

increase erosion along banks. In the Pumpkin Creek Ranch and Recreation SRMA, excess livestock grazing 

would cause trampling and soil compaction to 410 acres of riparian and wetland areas. Livestock grazing would 

potentially be compatible in riparian and wetland areas when managed in harmony with land management 

objectives such as meeting Standards for Rangeland Health.

If conditions were favorable, prescribed fire would accelerate nutrient cycles, sprouting, and forage availability; 

however, very intense burns would potentially decrease sprouting and forage growth. Closing BLMadministered lands to livestock grazing until the area attained identified vegetative objectives after wildfire, 

prescribed fire, or non-fire vegetative treatments would allow the shortest regrowth period for desired native 

riparian and wetland vegetation. Allowing species to sprout and regenerate would allow the shortest recovery 

period toward PFC. Intense burns would delay reestablishment of desired riparian and wetland vegetative 

communities, particularly if a healthy plant community were absent prior to burning. Delayed reestablishment 

would increase the risk of erosion and sedimentation. This alternative would protect riparian and wetland 

resources by expediting the recovery of plant communities.

Closing allotments that did not show progress toward meeting Standards for Rangeland Health within 5 years 

due to grazing would protect riparian and wetland areas from increased erosion caused by livestock trampling 

and congregating along streambanks. This action would allow riparian and wetland areas to improve to PFC. 

Impacts of erosion and increased sedimentation from livestock grazing in riparian and wetland areas would 

occur until allotments were closed.

If allotments near riparian and wetland areas met the Standards for Rangeland Health, livestock grazing would 

not directly affect these areas.

Priority allotments under this alternative would increase management review on specific allotments to ensure 

the allotments demonstrated progress toward meeting the Standards for Rangeland Health. Condition of riparian

and wetland areas are one of the five standards identified when determining status of the allotments. 

Renewing grazing permits and leases in areas in which the Standards for Rangeland Health were met would 

allow for proper management of the allotments.

Allowing livestock grazing during or immediately after mining or development if Standards for Rangeland 

Health were met would increase erosion and sedimentation along streambanks through excess livestock 

congregating or trampling in riparian and wetland areas. Preventing vegetative recovery from mining before 

authorizing grazing would delay or prevent native vegetative reestablishment in riparian and wetland areas. 

Restricting geophysical exploration would protect 4,300 acres of riparian and wetland areas. The remainder of 

the planning area would be open to geophysical exploration on existing roads or trails (which would include 30 

acres of riparian and wetland areas in the Pumpkin Creek Ranch and Recreation SRMA and 4 acres in the 

Strawberry Hill Recreation SRMA). Geophysical exploration in areas outside of riparian and wetland areas 

would increase erosion and sedimentation from uplands, which would impact adjacent riparian and wetland 

vegetative buffers. 
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OHV use that loosened soil would be a source of nonpoint source pollution and cause vegetation losses and 

accelerated erosion. Repeated crossings, particularly in riparian areas, would lead to sedimentation, soil 

compaction, increased overland flow, and decreased infiltration. Vehicle fords would cause localized erosion, 

sedimentation, and degradation of streambanks. Increased potential for weed invasion would also lead to 

accelerated erosion. 

CUMULATIVE IMPACTS

From the 1860s to the 1890s, the military brought large numbers of domesticated animals (such as horses, 

mules, sheep, and cattle) to eastern Montana. This introduction contributed to heavy vegetation use, which 

affected riparian and wetland areas with accelerated erosion and sedimentation. As homesteaders settled during 

the late 19th century and early 20th century, additional surface disturbances (such as mining, agriculture, and 

introductions of invasive species) resulted in compaction, accelerated erosion, sedimentation, and altered 

vegetation competition in riparian and wetland areas. Although homesteaders were required to farm a portion of 

the land, it was not always suited to intensive agricultural use, and this practice, combined with uncontrolled 

grazing, took its toll on the native vegetation. To this day, many of the same surface disturbances continue to 

accelerate erosion and sedimentation and continue to impact riparian and wetland vegetative buffers, 

streambanks, and channels. 

Prior to the homesteading days, bison roamed the area in large herds and consumed vegetation in the uplands 

and riparian and wetland areas, affecting vegetative buffers and trampled streambanks. Without vegetative 

cover, winds removed topsoil and floods and runoff removed soil, causing erosion and sedimentation within 

riparian and wetland areas. 

Droughts in the early 20th century, in combination with cropland development, worsened wind erosion of 

agricultural lands. At this time, under the authority of the Bankhead-Jones Act, the federal government 

purchased areas of abandoned homesteads and rangelands that were sub-marginal in size and condition and 

operated these lands under conservation practices and management. Crested wheatgrass was planted in most of 

these areas while others returned the plowed ground to native vegetation. 

Invasive vegetation species and altered upland vegetation became a problem in areas of disturbed soils. Invasive 

vegetation species changed the vegetative component of riparian and wetland areas throughout the 20th century 

and remain a problem today. Invasive vegetation species (particularly leafy spurge) outcompete desired riparian 

and wetland vegetation, decreasing soil moisture and increasing erosion and sedimentation. The Conservation 

Reserve Program, which began in 1985, was another effort to turn marginal, privately owned cropland back into 

grassland. Most lands enrolled in the Conservation Reserve Program were planted with crested wheatgrass or 

other introduced grasses, further altering riparian and wetland vegetation types. 

OHV use and road and interstate development in the 20th century contributed to vegetation removal, increasing 

compaction, erosion, and sedimentation in riparian and wetland areas across the planning area. Increased 

vehicle use on unimproved roads (particularly during wet conditions) has caused rutting, erosive channeling, 

and braided or parallel roads and trails. Fire suppression and the introduction of nonnative vegetation has 

altered natural fire regimes and created hazardous fuels. Vegetation recovery takes several years and depends on 

many environmental conditions, including soil type and precipitation. Compaction and excessive vegetation 

removal impact the hydrology of a watershed by significantly reducing infiltration and increasing surface 

runoff. Faster runoff rates and increased runoff amounts result in the rapid delivery of water to stream channels, 

causing increased channel degradation and sedimentation. 

Ongoing disturbance activities would impact riparian and wetland areas and associated vegetation buffers by 

increasing erosion and sedimentation. Such activities would potentially include fire suppression, excessive 

livestock grazing, vegetation removal, weed invasions, mineral exploration and development, OHV use, and 

nearby agriculture. However, activities that affected riparian and wetland areas would meet land health 

standards and would not cause effects to lower ratings and trends on individual reaches. Activities occurring 

adjacent to BLM-administered lands would potentially contribute to the functioning condition of riparian and 

wetland areas and enable the improvement of nonfunctional and functional-at risk with downward trend areas 
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toward PFC. Erosion from roads and trails has been reduced with improved road construction and maintenance 

methods. Continued improvement in conservation and control methods for riparian and wetland vegetation 

buffers in the planning area would increase the functionality of riparian and wetland areas and control 

accelerated erosion, compaction, and sedimentation. Grazing management and monitoring has improved or 

maintained properly functioning riparian and wetland areas.

INVASIVE SPECIES

ASSUMPTIONS AND METHODOLOGY

Assumptions for invasive species are described below.

 Constant seed sources from wildlife movement, rivers, recreationists, and general public land use 

would prevent eradication of invasive species over the life of the RMP. Domestic animals, wildlife, 

recreationists, clothing, pets, and hay contribute to the spread of invasive species as do many other 

activities in daily life (such as water, air, and vehicle travel and animal transportation). 

 Invasive vegetation species not known to occur in the planning area would occur. 

 Increases in invasive vegetation species would reduce habitat quality and quantity. 

 The demand for control of weeds is expected to increase as general public knowledge of the 

detrimental impacts of invasive species increases. 

 Control of invasive vegetation species would continue to be a combination of mechanical, chemical, 

biological, or manual methods. 

 The BLM would manage invasive species designated noxious by the State of Montana and prioritize

treatments.

MANAGEMENT COMMON TO ALL ALTERNATIVES

Reclamation plans for approved surface-disturbing activities would reduce invasive species seed spread with 

weed-seed-free seed mixtures. 

Vegetation management that met Rangeland Health Standards and supported endangered species, wildlife, 

water quality, and fisheries would support native vegetation and enhance its ability to outcompete invasive

species infestations. These actions would reduce invasive species development and the spread of invasive

species.

Maintaining consistency for vegetative manipulation (or prescriptive) treatments (including chemical, fire, 

biological, manual, and mechanical methods) with the guidelines stated in specific plans under Vegetation, 

Invasive Species actions would support minimal invasive species spread and move toward invasive species 

treatment using an Integrated Weed Management approach.

Establishing riparian buffer zones to trap silt from surface runoff and prevent it from entering and affecting 

the riparian wetland system would prevent the spread of weed seeds that may be dispersed with the silt.

Using temporary or permanent enclosures (i.e., in woody draw or riparian areas) to promote species diversity, 

recruitment, and functionality would allow for stronger species competition and decrease the potential for 

invasive species infestations.

Allowing woody and non-woody vegetation mechanical thinning, biomass removal, and chemical and 

biological treatments to reduce hazardous fuels would also aid in invasive species treatments by removing 

dense vegetation and permitting access to these areas.

Allowing the removal of woody and non-woody biomass products, commercial or personal use in forest and 

woodlands, or the salvage of dead and dying timber would spread invasive species seed during the removal 

process. An invasive species prevention plan would need to be in place prior to these activities.
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Limited OHV use would reduce the spread of invasive species in these areas.

Implementing new travel management areas would increase the probability of spreading invasive species 

through vehicle use (weed seeds falling from vehicles that passed through infestations in other areas).

Climate change is likely to combine with other human-induced stress to further increase the vulnerability of 

ecosystems to other pests, invasive species, and loss of native species. 

ALTERNATIVE A

Treating invasive species infestations on a case-by-case basis, which is not the most cost-efficient method,

would not allow for an overall holistic approach in managing the program. Treating invasive species in the 

northern part of the planning area and then treating invasive species in the southern part of the planning area 

the next day would increase the overall cost of treatment per acre.

Allowing surface-disturbing activities in areas of invasive species infestations would increase the potential of 

weed-seed spread. An operation plan for washing equipment would need to be in place. 

Allowing prescribed fire in Category B and C Fire Management Categories (the entire planning area), would 

impact vegetation through disturbance. Commonly, invasive species appear in the short term following 

prescribed fire. Road construction and heavy equipment use associated with prescribed fire would impact soil 

health and vegetative buffers in the short term until reestablishment of vegetation. Favorable conditions 

would allow prescribed fire to accelerate nutrient cycling, sprouting, and forage availability. Very intense 

burning would decrease sprouting and forage growth and increase the possibility of invasive species.

ALTERNATIVE B

Prioritizing treatment areas in which Montana-designated invasive species were present would not allow for 

project-level treatments. This action would be inefficient and economically ineffective.

Prohibiting surface-disturbing activities in areas of invasive species infestations would limit the spread of 

weed seeds, which would assist in meeting BLM goals.

Restricting grazing of domestic sheep or goats for invasive species control in or near the Bighorn Sheep 

Range would prevent use of the most cost-effective method of invasive species control along the Powder 

River.

Closing livestock grazing allotments that failed to meet Standard for Rangeland Health 5 and in which the 

BLM administered 51 percent or more of the lands in a pasture would limit grazing and Integrated Weed 

Management (which is the best and most cost-effective tool for combating invasive species). Domestic sheep

grazing for invasive species control would not be allowed under this alternative.

ALTERNATIVE C

Under this alternative, invasive species treatments would not be allowed across the entire planning area.

Allowing surface-disturbing activities within areas of invasive species infestations only with approved 

mitigation measures would limit the possibility of seed spread through timing stipulations or equipment 

washing.

Using Early Detection Rapid Response to designate priority treatment areas would emphasize the newest, 

most efficient technological system for invasive species treatments. Because the majority of invasive species 

are spread in publicly accessible areas, primary invasive species control in these areas would minimize 

impacts.
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Allowing disruptive activities within 2 miles of sharp-tailed grouse leks with specialized design features, 

which would most likely consist of timing stipulations, would allow invasive vegetation species (weed) 

treatments in these areas and improve the habitat. 

Closing livestock grazing allotments that failed to meet Standard for Rangeland Health 5 and in which the 

BLM administered 51 percent or more of the lands in a pasture would limit grazing and Integrated Weed 

Management (which is the best and most cost-effective tool for combating invasive species). 

Domestic sheep grazing for invasive species control would be allowed within 14.3 miles of the Bighorn 

Sheep Range under this alternative with specialized design features (such as an on-site, round-the-clock 

sheepherder). Domestic sheep grazing is an important tool for controlling invasive species and the most costeffective, integrated approach.

Allowing prescribed fire throughout the planning area would increase the spread of invasive species through 

vegetation disturbance.

Closing allotments to cattle grazing if Standards for Rangeland Health were not improved after 5 years would 

potentially cause a short-term increase in invasive species but should decrease invasive species over the long 

term. 

Allowing big game retrieval would promote invasive species seed spread onto BLM-administered lands via 

vehicles.

ALTERNATIVE D

Although allowing surface-disturbing activities would not result in the complete elimination of a plant 

species, plant community, or seral stage, these activities would affect the relative abundance, distribution, and 

occurrence of seral stages. Surface-disturbing activities would create desirable conditions for invasive species 

infestations.

Allowing surface-disturbing activities within areas of invasive species infestations only with approved 

mitigation measures would limit the possibility of seed spread through timing stipulations or equipment 

washing.

Treating invasive weed species only in areas in which landowners were actively controlling invasive species 

would not represent a holistic approach. Although cooperating with landowners is beneficial, it is not cost 

effective or the most efficient method when treating invasive species with a landscape approach. 

Domestic sheep grazing for invasive species control would be allowed under this alternative with specialized 

design features (such as an on-site, round-the-clock sheepherder). Domestic sheep grazing is an important 

tool for controlling invasive species and the most cost-effective, integrated approach.

Allowing prescribed fire throughout the planning area would increase the spread of invasive species through 

vegetation disturbance.

Allowing big game retrieval would promote invasive species seed spread onto BLM-administered lands 

through vehicle traffic.

ALTERNATIVE E (PREFERRED ALTERNATIVE)\

Although allowing surface-disturbing activities would not result in the complete elimination of a plant 

species, plant community, or seral stage, these activities would affect the relative abundance, distribution, and 

occurrence of seral stages. Surface-disturbing activities would create desirable conditions for invasive species 

infestations.
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Using Early Detection Rapid Response to designate priority treatment areas would emphasize the newest, 

most efficient technological system for invasive species treatments. Because the majority of invasive species 

are spread in publicly accessible areas, primary invasive species control in these areas would minimize 

impacts.

Domestic sheep grazing for invasive species control would be allowed under this alternative with specialized 

design features (such as an on-site, round-the-clock sheepherder). Domestic sheep grazing is an important 

tool for controlling invasive species and the most cost-effective, integrated approach.

Allowing prescribed fire throughout the planning area would increase the spread of invasive species through 

vegetation disturbance.

Limiting OHV use to existing roads in the camping and boating ramp area and closing OHV use on the east 

side of the walking trail through the island in the Howrey Island ACEC would assist in controlling the spread 

of invasive species. 

CUMULATIVE IMPACTS

Management of invasive species would not reduce the total number of invasive-species-infested acres within the 

planning area because treatments would not exceed the rate of expansion under any alternative. Natural 

expansion of previous biological releases without treatments would occur at a rate of approximately 14 percent 

per year (BLM 1996). Alternative prescriptions would affect the locations and quantity of invasive species 

(vegetation) treatments, and invasive species populations would decline in vigor and extent on treated sites. 

Coordination of invasive species management with federal, state, county, and private landowners and 

organizations would result in more effective and cost-efficient invasive species control because treatments 

would address the natural boundaries of the infestations and management resources could be shared between 

partners, which would protect more acres from new infestations and control more acres of existing weed 

infestations. Using Integrated Weed Management would also assist with invasive species (vegetation) control 

by focusing the multiple methods of invasive species management on the conditions that affect invasive species

population size and outbreak of new infestations.

Increases in invasive species (vegetation) acreage within the planning area would result primarily from 

expansion of existing invasive species infestations supplemented by new infestations. Invasive species 

(vegetation) population size is dependent on three conditions: the relative amount of invasive species seed or 

root sources for reproduction, the availability of safe sites for germination or propagation, and access to the 

necessary resources for plant growth, which are sunlight, water, and nutrients. 

Management actions that reduced these conditions would decrease or control invasive species population size 

while actions that produced these conditions would usually increase invasive species population size. Promoting 

healthy desired vegetation is the most common and long-term reducer of invasive species populations because 

the desired plants continually compete with weeds in producing seeds, occupying germination sites, and 

acquiring resources for growth. Vegetation restoration and fire rehabilitation activities, including revegetation 

and protection of post-fire plantings, would be effective methods for improving desired vegetation populations,

although vegetation treatments would potentially initially cause weeds to increase through associated ground 

disturbance. Vegetation treatments that restore grasslands, shrublands, and riparian areas would be particularly 

effective in reducing potential invasive species spread because most invasive species occur in these habitats. 

Using weed-seed-free forage and cleaning vehicles and equipment would decrease invasive species seed and 

root sources; thereby reducing the number of new infestations. Education and outreach would reduce invasive 

species establishment and spread because people often act once informed about the impacts of invasive species 

on ecosystem health and economics. Education about methods for invasive species management would also 

assist.

Ground-disturbing activities would be the biggest increase of both new and existing weed infestations because 

they often bring in seeds on equipment and vehicles, create bare spots for seed germination, and reduce 
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competition for resources by removing desired vegetation. Fire retardant and burning of natural fuels release 

compounds useful for plant growth, thereby benefiting colonizing plants, particularly invasive species, by 

providing a surplus of nutrients. Therefore, forest management designed to reduce unnaturally large and severe 

wildfires would reduce the potential for increased invasive species populations. Motorized public travel and 

camping within 300 feet of existing roads, acquisition of easements and exchanges to improve access to public 

lands, and use of SRMAs could potentially increase human use through hiking, camping, hunting, horseback 

riding, and driving for pleasure; thereby increasing both disturbance and the risk of igniting wildfires, which 

could lead to expansions in invasive species populations. Other management activities that caused surface 

disturbances would also increase the potential for new invasive species infestations, although most activities 

incorporate methods to reduce introduction and expansion of invasive species infestations like minimizing new 

road construction in invasive-species infested areas, reseeding disturbed and exposed soils where necessary, and 

locating new utility facilities in existing ROWs. 

The degree to which invasive species populations impact their environments depends on the cumulative effect 

of infestations on the resiliency and sustainability of the desired plant community. Infestations that are a nondominant part of a diverse, otherwise healthy desired plant community that controls the size and density of the 

infestations would cause reduced impacts. Infestations would have a high impact when they dominate the plant 

community and are substantially reducing its sustainability and resiliency by negatively affecting the water 

cycle, erosion potential, nutrient cycling, and forage availability for wildlife and livestock. Infestations that 

affect some or all of these things but do not yet substantially reduce the community’s sustainability or resiliency 

would have a medium, or moderate, impact.

Alternative A

The spread of invasive species caused by equipment movement under Alternative A would potentially impact 

the ecological status of vegetation in the planning area. With 4,500 public acres infested by leafy spurge alone 

and limited funding for weed control, invasive species would continue to spread under this alternative. 

Scattered patches of knapweed, which has a high potential to spread, have been found in the planning area. 

Tamarisk or salt-cedar, an introduced ornamental, has had devastating impacts in the southwest, has 

outcompeted native riparian plants, and completely eradicated some riparian areas because it requires large 

volumes of water. Tamarisk has been observed along isolated waterbodies; the Fort Peck Reservoir; and the 

Yellowstone, Tongue, and Powder rivers and their tributaries. 

Under this alternative, the spread of invasive plant species, including invasive species, would be controlled in 

some areas but spread more rapidly in others. Factors affecting the spread or control of invasive species would 

include the frequency and amount of motorized traffic and recreational use on public lands in the planning area, 

development occurring on private lands adjacent to BLM-administered lands, and the type of actions occurring 

on federal, state, and private lands. Any actions that limited the treatment of invasive species on public lands 

would potentially limit the efficacy of treatments on lands with other ownership or administration. The 

cumulative impacts of reducing the efficacy of control on invasive species and invasive species would 

potentially decrease the amount and availability of native forage for livestock and wildlife and contribute to soil 

erosion and increased sediment loads in streams. 

Alternative B

The spread of invasive species caused by restrictions to sheep grazing under Alternative B would potentially 

impact the ecological status of vegetation in the planning area. With 4,500 public acres infested by leafy spurge

alone and limited funding for weed control, invasive species would continue to spread. Leafy spurge has been 

observed along isolated waterbodies and the Yellowstone, Tongue, and Powder rivers and their tributaries. 

Sheep grazing would be the best method for controlling leafy spurge along waterways.
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Alternative C

Allowing sheep grazing with specialized design features under Alternative C would reduce the impacts to the 

ecological status of vegetation in the planning area. With 4,500 public acres infested by leafy spurge alone and 

limited funding for weed control, invasive species would continue to spread. Leafy spurge has been observed 

along isolated waterbodies and the Yellowstone, Tongue, and Powder rivers and their tributaries. Sheep grazing 

would be the best method for controlling leafy spurge along waterways.

Alternative D

The spread of invasive species caused by equipment movement under Alternative D would potentially impact 

the ecological status of vegetation in the planning area. With 4,500 public acres infested by leafy spurge alone 

and limited funding for weed control, invasive species would continue to spread. 

Scattered patches of spotted and Russian knapweed have been found in the planning area. Tamarisk or saltcedar, an introduced ornamental, has had devastating impacts in the southwest, outcompeted native riparian

plants, and completely eradicated some riparian areas because with its need for large volumes of water. 

Tamarisk and spotted knapweed have been observed along isolated waterbodies and the Yellowstone, Tongue, 

and Powder rivers and their tributaries. 

Alternative E (Preferred Alternative)

Allowing sheep grazing with specialized design features under Alternative C would reduce impacts to the 

ecological status of vegetation in the planning area. With 4,500 public acres infested by leafy spurge alone and 

limited funding for weed control, invasive species would continue to spread. Leafy spurge has been observed 

along isolated waterbodies and the Yellowstone, Tongue, and Powder rivers and their tributaries. Sheep grazing 

would be the best method for controlling leafy spurge along waterways.

Scattered patches of spotted and Russian knapweed have been found in the planning area. Tamarisk or saltcedar, an introduced ornamental, has had devastating impacts in the southwest, outcompeted native riparian

plants, and completely eradicated some riparian areas with its need for large volumes of water. Tamarisk and 

spotted knapweed have been observed along isolated waterbodies and the Yellowstone, Tongue, and Powder

rivers and their tributaries.

FISH AND WILDLIFE, AQUATICS (INCLUDING SPECIAL STATUS SPECIES)

ASSUMPTIONS AND METHODOLOGY

Restoration projects in prairie streams would focus on restoring the riparian area and in-stream attributes that 

promote quality native fish and aquatic wildlife habitat and communities.

In sport-fish reservoirs, a 0.25-mile buffer would include 3,834 acres of sport-fish habitat.

There would be 1 to 5 aquatic wildlife projects constructed each year, disturbing a total of 10 to 100 acres per 

year.

There would be changes in listed and special status species in the future.

MANAGEMENT COMMON TO ALL ALTERNATIVES

Actions that minimized the potential impacts of climate change would have the potential to maintain or enhance 

aquatic wildlife habitat.
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Potential changes in climate that would increase surface water temperature, dramatically alter precipitation and 

runoff patterns, and alter growth of riparian vegetation would have deleterious effects to aquatic wildlife 

habitat.

Surface-disturbing activities associated with soils management actions would have the potential to cause 

increased soil erosion in both uplands and riparian areas, which would reduce aquatic wildlife habitat and cause 

accelerated erosion, increased overland flow, decreased infiltration, and degradation of water quality associated 

with increased sedimentation, turbidity, eutrophication, metals, and other pollutants in waterbodies. Ultimately, 

all of these chemical-physical impacts would degrade or reduce aquatic wildlife habitat, instigate toxicological 

impacts, isolate populations, and disrupt or destroy nutrient cycling and the aquatic food web. Because there is 

an intrinsic connection between uplands and riparian areas and aquatic wildlife habitat, following the 

Reclamation Appendix for Soils management actions would minimize impacts to aquatic wildlife by decreasing 

the amount of soil erosion degrading habitat for aquatic wildlife. 

Following the Watershed Protection and Flood Control Act and Clean Water Act and minimizing nonpoint 

source pollution would maintain water quality and maintain or improve aquatic wildlife habitat. Meeting or 

exceeding water quality standards would maintain or enhance aquatic wildlife habitat.

Emphasizing native plant reestablishment under vegetation management actions would improve aquatic 

resources by helping stabilize soils and stream-banks. Additionally, replacing nonnative plant communities 

would minimize unwanted impacts (e.g., excessive transpiration by salt-cedar and Russian olive) to aquatic 

resources. 

Approximating a natural disturbance regime in hardwood draws would benefit aquatic resources in the long 

term. Hardwood draws are typically arranged in ephemeral or headwater reaches of watersheds, and, because 

physical, chemical, and biological attributes and processes of rivers and streams constantly occur on a 

longitudinal scale, moving downstream from headwaters to large rivers (Vannote, Minshall, Cummins, Sedell, 

and Cushing 1980; Ward and Stanford 1995; Dodds et al. 2004), the ephemeral portions of streams are 

connected to aquatic wildlife habitat. 

Protection and mitigation of special status plants would maintain or improve aquatic wildlife habitat, 

particularly in riparian areas.

Because riparian, wetland, and aquatic resources are inherently connected, actions that maintained or enhanced 

riparian and wetland areas have the potential to benefit aquatic resources. Vegetated riparian buffer zones would 

provide shade to streams, enhance thermal cover, provide food substrate (e.g., habitat for invertebrates) and 

food sources to aquatic wildlife (Saunders and Fausch 2007), and trap sediment that would otherwise alter or 

eliminate habitat for aquatic wildlife. Improving riparian areas to meet PFC standards would not, necessarily, 

improve aquatic wildlife habitat. 

Enclosures around riparian areas would improve aquatic wildlife habitat. However, it could take many years (on 

the order of 5 to 20 or more years) and active restoration efforts (riparian plantings, bank stabilization, etc.) to 

realize an improvement to the riparian area and aquatic wildlife habitat.

Although PFC is a minimum ecological threshold for riparian areas, this concept has not been empirically 

demonstrated to have an influence on aquatic wildlife habitat. Managing riparian areas to meet PFC will not 

universally improve aquatic wildlife habitat.

Controlling and decreasing the spread of invasive species, particularly in riparian areas, would improve habitat 

for aquatic wildlife. 

Proactive management of threatened and endangered species would improve habitat conditions for threatened 

and endangered aquatic wildlife in those habitats where threatened and endangered aquatic species thrive. 

Improved habitat for threatened and endangered species would also provide improved habitat for a suite of other 

aquatic wildlife species. 
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Managing prairie streams to meet PFC standards would maintain a minimum ecological threshold for riparian 

areas but not necessarily improve aquatic wildlife habitat. Prairie streams already exist in a precarious balance 

between flooding and drying, and a legacy of various land use impacts has rendered them a resource “living on 

the edge” (Dodds et al. 2004). As a result, additional surface disturbance across the prairie landscape of the 

planning area would impact stream channel morphology, which would lead to gullying or sloughing that would 

compromise aquatic wildlife habitat. Finally, this additional surface disturbance would lead to a decrease in 

abundance and diversity of fish and other aquatic organisms. Many intermittent and ephemeral streams are not 

recognized as important components of viable aquatic wildlife habitat. Recent evidence (Franssen et al. 2006; 

Ostovar 2007; Scheurer, Fausch, and Bestgen 2003) demonstrates that the dynamic nature of prairie streams and 

the large spatial scale over which some native prairie fish species carry out their life cycle requires conservation 

and management at the landscape or river-scape scale (an ecosystem or watershed perspective), beyond the 

local habitat scale (Fausch, Torgersen, Baxter, and Li 2002). 

Actions that improved habitat for terrestrial wildlife, particularly in riparian areas, would generally maintain or 

enhance aquatic wildlife habitat. 

Participating in and developing recovery plans, management plans, and conservation strategies, particularly 

from an ecosystem form and function theory, for special status species would indirectly maintain or enhance 

aquatic wildlife habitat. 

Reducing fuel or woody debris within riparian zones would reduce habitat for aquatic resources. There is not 

conclusive empirical evidence that thinning in riparian areas is necessary for resource health, particularly in the 

Northern Great Plains Ecoregion of the planning area.

Although the Policy for Aerial Delivery of Wildland Fire Chemicals near Waterways (USFS et al. 2000) 

suggests 300-foot buffers on all waterways, recent evidence demonstrates that fire retardant that does end up in 

waterways through overland flow (or other methods) would cause toxic impacts to aquatic wildlife (Little and 

Calfee 2004). Subsequently, the use of fire retardant chemicals near all streams and rivers would have the 

potential to impact aquatic systems.

Intense fires in uplands would have the potential to increase erosion and sediment loads to streams, which 

would degrade aquatic wildlife habitat. Climate change is increasing wildfire frequency and intensity. Heavy 

equipment use and road construction for fire suppression activities would cause erosion and subsequent 

increased sediment to streams, which would alter habitat for aquatic resources. However, following fire 

management protocol to mitigate for these impacts would typically alleviate impacts from wildland fire 

suppression. 

Prescribed fire would not generally cause deleterious impacts to aquatic wildlife habitat, provided infrastructure 

(roads and other structures) and equipment used to accomplish the tasks were used in a manner that did not 

contribute to excessive long term sedimentation and accidental spills that compromised water quality were 

avoided.

Reducing live or dead trees within riparian zones would reduce habitat for aquatic resources. There is not 

conclusive empirical evidence that thinning or harvest in riparian areas is necessary for resource health, 

particularly in the Northern Great Plains Ecoregion of the planning area.

Forestry and woodland products practices would not generally cause deleterious impacts to aquatic wildlife 

habitat, provided infrastructure (roads and other structures) and equipment used to accomplish the tasks were 

used in a manner that did not contribute to excessive long-term sedimentation and accidental spills that 

compromised water quality were avoided.

Although grazing management that meets Standards for Rangeland Health and guidelines would reduce the sum 

and extent of impacts to uplands, the same reduction would not necessarily occur in riparian areas and aquatic 

wildlife habitat. Grazing in riparian areas and streams would cause impacts different from those caused by 
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grazing in uplands. Additionally, managing riparian areas to meet PFC requires only a minimum ecological 

threshold for riparian areas and does not specifically address water quality, water quantity, food-web dynamics, 

and other important factors for aquatic wildlife habitat. Riparian areas and uplands have vastly different 

physical characteristics, and livestock often spend a disproportionate amount of time in riparian areas. In a 

literature review of grazing in riparian areas and streams, Belsky et al. (1999) stated that grazing activities had 

no ecological benefits for aquatic wildlife, riparian areas, or stream ecosystems in general. Belsky et al. (1999) 

also found that degradation of aquatic wildlife habitat in streams and rivers caused by livestock continues to the 

present day. The magnitude of the impacts from livestock grazing would vary based on utilization, location in 

the watershed, duration, season of use, history of land use for that allotment and watershed, and physicalchemical characteristics of the particular watershed or riparian ecosystem (Green and Kauffman 1995; Henley 

et al. 2000). Alternate grazing schedules (other than season long grazing) or buffers are a proven tool to prevent 

impacts to the riparian areas, river and stream habitat, and aquatic wildlife (Magilligan and McDowell 1997; 

Henley et al. 2000; Saunders and Fausch 2007).

Coal mining activities (e.g., surface disturbance, road construction, overburden removal, rerouting of stream 

systems, and the presence of sediment ponds) would disrupt surface water and reduce streamflow and habitatforming peak flows. During mining, sedimentation would be reduced by sedimentation ponds. Discharge of 

produced water during operations and discharge of groundwater with leached salts or metals (or both) following 

operations would cause toxic impacts to aquatic wildlife. 

In general, impacts to streams and aquatic wildlife would increase as mineral extraction activity and well, road, 

and facility density increased. The increase in roads and construction would cause a parallel increase in erosion, 

which would impact stream channel morphology and habitat quality and ultimately decrease aquatic wildlife

populations. An increase in stream crossings would cause habitat fragmentation, which would lead to isolation 

of populations and block dispersal and migration. Following BMPs, following guidance in the Reclamation

Appendix, and installing fish-passable culverts would minimize these impacts.

Recreation management actions would not directly impact aquatic resources. However, various recreation 

actions associated with particular locations would impact aquatic wildlife habitat if a particular recreation use 

contributed to erosion into streams or destruction of riparian vegetation. For example, OHV areas would impact 

aquatic wildlife habitat through erosion and sedimentation of habitat. Livestock grazing in particular recreation 

areas would cause the impacts described in the grazing and aquatics discussions of this section. Road 

construction would cause increased sedimentation in aquatic wildlife habitat. Following BMPs, following 

guidance in the Reclamation Appendix, and installing fish-passable culverts would minimize these impacts.

Exploration for renewable energy, installation of renewable energy facilities, and the subsequent increase in 

road and facility density would increase erosion, which would impact stream channel morphology, habitat 

quality, and, ultimately, aquatic wildlife habitat and populations. Following BMPs, following guidance in the

Reclamation Appendix, and installing fish-passable culverts would minimize these impacts.

Roads would cause impacts similar to those caused by surface-disturbing activities; however, installing fishpassable culverts and following guidance found in the Reclamation Appendix during road construction would 

minimize these impacts. The redesign, rerouting, closure, or decommissioning of roads already causing impacts 

to resources would improve aquatic wildlife habitat. 

Aquatic wildlife habitat adjacent to or downstream of OHV areas would be affected by erosion and 

sedimentation of habitat. Although stream crossings would be immediately affected in the localized crossing 

area, downstream areas would also be affected by erosion and sedimentation of aquatic wildlife habitat. 

Following BMPs, following guidance in the Reclamation Appendix, and installing fish-passable culverts would 

minimize these impacts.

Acquired lands that improved continuity of BLM-administered lands within a particular watershed or increased 

ownership along streams would make management of aquatic wildlife more ecologically viable.
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Extensive Recreation Management Areas (ERMAs), SRMAs, and ACECs with aquatic wildlife habitat would 

include Powder River Depot, Calypso, Howrey Island, Matthews Recreation Area, Dean S. Reservoir, and 

Pumpkin Creek Ranch and Recreation Area. Additionally, Powder River Depot, Calypso, Howrey Island, and 

Matthews Recreation Area are adjacent to the Yellowstone River, which is habitat for the endangered pallid 

sturgeon and other fish species of special concern.

Maintaining wilderness values of WSAs would maintain water quality, and, consequently, aquatic wildlife

habitat, in these watersheds.

ALTERNATIVE A

Sedimentation is one of the most frequently occurring physical and chemical pollutants in aquatic wildlife

habitat (Wenger 1999). Aquatic wildlife habitat in areas in which surface disturbance would be allowed would 

be degraded by sediment input to streams. 

An NSO stipulation for 100-year floodplains of major rivers would maintain floodplains of major rivers and not 

necessarily aquatic wildlife habitat. Although NSO stipulations for oil and gas leasing would be designated for 

waterbodies and streams, no specific aquatic wildlife habitat would be closed to surface-disturbing and 

disruptive activities under this alternative, and aquatic wildlife habitat would be subjected to impacts of surfacedisturbing activities, which would include erosion and sedimentation of habitat, physical and chemical pollution 

of water by sedimentation and pollutants, habitat fragmentation resulting from road and facility development 

(and other activities), alteration of the normative flow regime through increased product water, and 

displacement or extirpation of aquatic wildlife. Aquatic wildlife habitat does not occur only where water occurs; 

this habitat is intrinsically connected to riparian area and even uplands via physical, biological, and chemical 

associations. Subsequently, buffers are the best way to protect aquatic wildlife habitat in relationship to water 

resources. 

Water impoundments on any stream (ephemeral, intermittent, or perennial) would compromise or decrease 

aquatic wildlife habitat by increasing erosion and sediment transport and altering the connectivity of hydrologic 

flows, nutrient cycling and food web dynamics, and riparian vegetation recruitment and succession. 

Impoundments would disrupt or disconnect both the linear landscape of streams and organisms within the 

streams (Dodds et al. 2004). The open water of a reservoir would lead to altered thermal regimes and large-scale 

evaporation, which would further impact the hydrologic cycle by decreasing overall water quantity. Some 

reservoirs contain habitat for nonnative fishes or other predators, which would impact sensitive native fish and 

other aquatic wildlife populations in prairie streams. Impoundments constructed on streams would limit 

dispersal and migration between habitats, which are key life history strategies for prairie fishes and other 

aquatic wildlife. 

An NSO stipulation for oil- and gas-associated surface-disturbing activities in riparian areas and wetlands

would provide protection of key aquatic wildlife attributes. However, discretionary buffers would ensure 

protection of aquatic wildlife habitat. Ongoing inventory efforts to determine the extent and condition of 

riparian areas in the planning area would elucidate critical information for this action. Riparian areas provide 

stability; thermal and protective cover; food resources and key food web items and connections; thermal 

buffering; habitat components and structure (e.g., wood); and key ecosystem physical, chemical, and biological 

processes important to aquatic wildlife habitat. 

Allowing livestock tanks or troughs in riparian areas would lead to trampling of riparian soils and plants. These 

actions would impact aquatic wildlife habitat by causing excessive sedimentation (Belsky et al. 1999); thermal 

and protective cover losses; food resource losses; and alteration or disruption of key physical, chemical, or 

biological ecosystem processes.

Fencing spring developments would minimize impacts to aquatic wildlife but complete fencing of riparian areas 

near the water development would help decrease impacts.
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Allowing livestock tanks or troughs in riparian areas would lead to trampling of riparian soils and plants. These 

actions would impact aquatic wildlife habitat by causing excessive sedimentation (Belsky et al. 1999); thermal 

and protective cover losses; food resource losses; and alteration or disruption of key physical, chemical, or 

biological ecosystem processes.

Although this alternative would require a 0.25-mile buffer with an NSO stipulation for oil- and gas-associated 

surface-disturbing and disruptive activities for leasing in sport-fish reservoirs, sport-fish reservoirs would not be 

protected from other surface-disturbing activities under this alternative. Many of these reservoirs are already 

constrained by low water due to current climate conditions and trampling of banks by livestock; collectively, 

these two conditions have decreased riparian and aquatic vegetation near shores, increased erosion, reduced 

shade for thermal buffering and cover habitat, decreased water quality, and reduced food resources for fish and 

the aquatic food web. 

Stream-crossing structures that restricted fish passage would cause habitat fragmentation, isolation of 

populations, and contribute to disrupted life cycles patterns of fish and other aquatic wildlife. Although many 

prairie streams in the planning area are intermittent, aquatic wildlife historically thrived in these intermittent 

pools and depended on periods of high flow to redistribute; subsequently, fish-passable, stream-crossing 

structures would be important in the many prairie streams throughout the planning area. Additionally, fishpassable structures, by design, would contribute less to erosion than other stream-crossing structures.

Pallid sturgeon habitat under this alternative would be exposed to excessive sedimentation through surfacedisturbing activities. Floodplain and riparian habitat important to pallid sturgeon (e.g. large cottonwood trees 

and snags) would have the potential to be eliminated. Water quality would be degraded, and the potential for 

toxic impacts and impairment of the food web would increase.

Infrequent cottonwood harvest would cause minimal impacts to aquatic wildlife habitat. However, because 

cottonwood decline is a rampant problem throughout the Great Plains (Rood and Mahoney 1990; Lytle and 

Merritt 2004), harvesting of cottonwoods would contribute to the decline of this important riparian species. 

Cottonwood stands are important physical modifiers of aquatic wildlife habitat and provide thermal protection, 

cover, and food resources in the form of leaves and organic matter; subsequently, a loss of these attributes 

through cottonwood harvest would degrade aquatic wildlife habitat.

Where grazing allotments failed to meet Standards for Rangeland Health and grazing was a causal factor, 

impairment of riparian areas and aquatic wildlife habitat would occur through continued permitted grazing. 

Because recovery of riparian zones and streams from livestock grazing would require total rest from grazing 

(Belsky et al. 1999; Henley et al. 2000), allowing grazing without resting these allotments would continue to 

degrade aquatic wildlife habitat and degrade some areas beyond recovery to historical potential. In a review of 

grazing and stream ecosystems, Belsky et al. (1999) found that the impacts from livestock trampling soils and 

vegetation included poor water quality, decreased seasonal water quantity, unstable stream channel morphology 

(e.g., eroding banks), altered hydrology, unstable riparian soils and vegetation, and decreased aquatic wildlife

populations. Although Rangeland Health Standards and PFC guidelines address riparian areas qualitatively, 

they do not specifically address aquatic wildlife habitat, which is strongly linked to riparian health and vigor. 

Current Rangeland Health Standards do not specifically address the grazing, the history of land use, and the 

cumulative impacts on streams and aquatic wildlife habitat from an ecosystem perspective. The specific impacts 

of grazing would depend on the particular environmental location, history of land use, and aquatic wildlife

communities present. 

Allowing livestock grazing during or immediately after locatable mining would impact aquatic wildlife habitat. 

Collective impacts from successive multiple erosive land use activities would cause extreme sedimentation in 

streams and aquatic wildlife habitat, instability and mass wasting of streambanks, decreased water quality, 

decreased riparian vigor, and, accordingly, degraded aquatic habitat, food webs, and ecosystem processes.

Allowing livestock grazing during or immediately after oil and gas development would degrade aquatic wildlife

habitat, particularly in light of the widespread oil and gas development already in progress and the potential for 

increased activities. Collectively, impacts from both activities have the potential to cause extreme sedimentation 
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in streams and aquatic wildlife habitat, instability and mass wasting of streambanks, decreases in water quality 

and riparian vigor, and, accordingly, degraded aquatic habitat, food webs, and ecosystem processes.

Deferring livestock grazing for 1 growing season following a wildfire or prescribed fire would help facilitate 

vegetative reestablishment and minimize impacts to aquatic wildlife habitat from soil erosion common after 

wildfires. However, if wildfires were intense, trampling of soils and plants and herbivory in upland and riparian

areas 1 season after a wildfire would cause erosion and excessive sedimentation in aquatic wildlife habitat. In a 

review of post-fire activities in the western United States, Beschta et al. (2004) found several activities, 

including livestock grazing, would generally inhibit restoration of ecosystem functions. As a result, exclusion of 

livestock for 1 season post-fire would not allow sufficient time to prevent severe erosion in some cases. Specific 

climatic conditions and each fire situation, riparian area, and local history of land use in the watershed would 

best determine the resting period that would allow riparian vegetative reestablishment and subsequently protect 

aquatic wildlife habitat. 

ALTERNATIVE B

Not allowing surface-disturbing activities that did not benefit the functionality of the soil resource on sensitive 

soils and slopes 25 percent or greater would decrease the amount of sediments that entered streams, which 

would help maintain aquatic wildlife habitat. 

For Alternative B, surface-disturbing activities that did not benefit floodplain functionality would not be 

allowed and an NSO stipulation for oil and gas leasing would be required within 100-year floodplains. 

Similarly, under this alternative, surface-disturbing activities that did not benefit floodplain functionality would 

not be allowed and an NSO stipulation for oil and gas leasing would be required in waterbodies and streams. 

However, buffers would better protect aquatic wildlife habitat in prairie streams because there is an intrinsic 

connection between adjacent uplands, riparian areas, streams, and aquatic wildlife habitat because and defining 

floodplain boundaries and aquatic wildlife habitat of intermittent prairie streams in the planning area is 

complex. The lack of buffers on most prairie streams would impact aquatic wildlife. Sedimentation, which is 

one of the most frequently occurring chemical and physical pollutants in many streams and rivers, would occur 

(Wenger 1999) if buffers were not implemented; subsequently, stream buffers should be applied to all streams, 

including intermittent and ephemeral streams. Impacts would include erosion and excessive sedimentation in 

aquatic wildlife habitat, bank instability, habitat fragmentation, and, ultimately, displacement or extirpation of 

aquatic wildlife. 

Impacts caused by surface water impoundments under this alternative would be similar to impacts caused by 

impoundments under Alternative A. Water impoundments on any stream (ephemeral, intermittent, or perennial) 

would impact aquatic wildlife habitat by altering connectivity of hydrologic flows, nutrient cycling and food 

web dynamics, and riparian vegetation recruitment and succession and by increasing erosion and sediment 

transport, all of which would compromise or decrease aquatic wildlife habitat. Impoundments would disrupt or 

disconnect both the linear landscape of streams and the organisms within the streams (Dodds et al. 2004). The 

open water of a reservoir would lead to altered thermal regimes and large-scale evaporation, which would 

further impact the hydrologic cycle by decreasing overall water quantity. Some reservoirs contain habitat for 

nonnative fishes or other predators, which would impact sensitive native fish and other aquatic wildlife

populations in prairie streams. Impoundments constructed on streams would limit dispersal and migration

between habitats, which are key life history strategies for prairie fishes and other aquatic wildlife. 

Prohibiting surface-disturbing and disruptive activities in riparian areas and wetlands would provide protection 

of key aquatic wildlife attributes. However, mandatory buffers would ensure protection of aquatic wildlife

habitat. Riparian areas provide stability; thermal and protective cover; food resources and key food web items 

and connections; thermal buffering; habitat components and structure (e.g., wood); and key ecosystem physical, 

chemical, and biological processes important to aquatic wildlife habitat. 

Prohibiting spring development in riparian and wetland areas would benefit aquatic wildlife habitat.

Locating livestock wells and troughs at least 0.25 miles from riparian and wetland areas would protect, restore, 

and maintain the riparian area and aquatic wildlife habitat. This action would protect aquatic wildlife habitat 
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from excessive sedimentation (Belsky et al. 1999); cover and food resource losses; and alteration or disruption 

of key physical, chemical, and biological ecosystem processes.

Under Alternative B 10,000 acres of sport-fish reservoirs would be closed to surface-disturbing and disruptive 

activities. These actions would protect these sport-fish reservoir acres from the impacts of surface-disturbing 

and disruptive activities, including erosion and sedimentation of habitat, physical and chemical pollution of 

water by sedimentation and pollutants, habitat fragmentation from road and facility development, and 

displacement or extirpation of aquatic wildlife. 

Management actions that required fish-passable culverts would be economically responsible and ensure that 

aquatic wildlife habitats remained intact. In Oregon and Washington, the Government Accountability Office 

(2001) found 2,600 culverts (and estimated that up to 5,500) were impeding fish passage on USFS and BLMadministered lands. The cost of replacing these structures was estimated at over $375 million. Given the 

dynamic patterns of drying and flooding and the colonization and emigration patterns of prairie fish and aquatic 

wildlife, constructing fish passable structures would alleviate future resource and economic problems associated 

with stream-crossing structures impassable by fish. Designing new structures so that they would not contribute 

to erosion would protect and enhance aquatic wildlife habitat (see the Reclamation Appendix). 

This alternative would protect pallid sturgeon habitat through the implementation of a non-discretionary buffer. 

Because pallid sturgeon habitat occurs in large river systems and because interaction of river-floodplain and 

riparian area-adjacent uplands occurs on a landscape scale, impacts to pallid sturgeon would potentially occur 

from a variety of factors. A 0.5-mile buffer would ensure that an accidental oil spill from a well, for example, 

would have less probability of harming this species that is already on the brink of extinction. 

Infrequent cottonwood harvest would cause minimal impacts to aquatic wildlife habitat. However, because 

cottonwood decline is a rampant problem throughout the Great Plains (Rood and Mahoney 1990; Lytle and 

Merritt 2004), harvesting of cottonwoods would contribute to the decline of this important riparian species. 

Cottonwood stands are important physical modifiers of aquatic wildlife habitat and provide thermal protection, 

cover, and food resources in the form of leaves and organic matter; subsequently, a loss of these attributes 

through cottonwood harvest would degrade aquatic wildlife habitat.

Closing grazing allotments in which Standards for Rangeland Health were not met and grazing was a causal 

factor would improve riparian areas and aquatic wildlife habitat. 

Suspending livestock grazing during locatable mining, coal mining, and oil and gas development would reduce 

the potential for compounded impacts on aquatic wildlife habitat from multiple resource uses, which would 

include extensive sedimentation and degradation beyond recovery to historical potential.

Deferring livestock grazing for 2 growing seasons following a wildfire, prescribed fire, or non-fire vegetative 

treatment would facilitate vegetative reestablishment and subsequently minimize impacts to aquatic wildlife

habitat caused by soil erosion, trampling of upland and riparian areas, and livestock herbivory. Specific climatic 

conditions and each fire situation, riparian area, and local history of land use in the watershed would best 

determine the resting period that would allow riparian vegetative reestablishment and protect aquatic wildlife

habitat. 

ALTERNATIVE C

Avoiding surface-disturbing activities on slopes 25 percent or greater and sensitive soils would decrease the 

amount of soil that entered streams and affected aquatic wildlife habitat. However, if these activities were 

allowed with mitigation (and depending on the activity’s proximity to streams), there would be at least an initial 

period in which sedimentation in streams and impacts to aquatic wildlife habitat occurred.

For Alternative C, surface-disturbing activities that did not benefit floodplain functionality would be avoided 

unless no other practicable alternative existed, and an NSO stipulation for oil and gas leasing would be required 

within 100-year floodplains. Similarly, under this alternative, surface-disturbing activities that did not benefit
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functionality of streams and waterbodies would be avoided unless no other practicable alternative existed, and a 

CSU stipulation for oil and gas leasing would be required. Allowing surface-disturbing activities in these areas 

when no other practicable alternative existed would be subject to multiple interpretations and would provide 

very little protection to the water resource. Additionally, buffers would better protect aquatic wildlife habitat in 

prairie streams because there is an intrinsic connection between adjacent uplands, riparian areas, streams, and 

aquatic wildlife habitat. The lack of buffers on most prairie streams would impact aquatic wildlife. 

Sedimentation, which is one of the most frequently occurring chemical and physical pollutants in many streams 

and rivers, would occur (Wenger 1999) if buffers were not implemented; subsequently, stream buffers should 

be applied to all streams, including intermittent and ephemeral streams. Impacts would include erosion and 

excessive sedimentation in aquatic wildlife habitat, bank instability, habitat fragmentation, and, ultimately, 

displacement or extirpation of aquatic wildlife.

Allowing surface water impoundments with design features that maintained the natural flow regime and 

watershed functionality, and, in particular, flows that allowed the maintenance and formation of pool habitats 

would minimize impacts to aquatic wildlife habitat. Avoiding habitat fragmentation and ensuring fish passage 

would maintain habitat for aquatic wildlife by maintaining the natural flow regime and watershed functionality. 

Management actions that allowed surface-disturbing or disruptive activities in riparian and wetland areas 

subject to PFC and approved specialized design features would potentially minimize aquatic wildlife habitat in 

perennial and intermittent streams. 

Not allowing spring development in riparian and wetland areas would benefit aquatic wildlife habitat.

Management actions that allowed livestock tanks or troughs in ephemeral portions of streams would impact 

aquatic wildlife habitat in downstream intermittent and perennial reaches. Headwaters, which include ephemeral 

channels in the planning area, are key components of physical, chemical, and biological processes of watersheds 

and interact in a longitudinal manner, upstream to downstream (Vannote et al. 1980; Belsky et al. 1999; Fausch 

et al. 2002), to influence aquatic wildlife habitat. Allowing tanks or troughs on sport-fish reservoirs without a 

buffer would cause erosion and trampling of the banks, which would degrade aquatic wildlife habitat.

The NSO stipulation for oil and gas leasing and development for sport-fish reservoirs would protect habitat and 

water quality. A 0.25-mile buffer would protect approximately 3,800 acres of sport-fish reservoir habitat. In this 

situation, the 0.25-mile buffer would help to eventually reestablish the littoral zone (shallow shoreline area), 

decrease erosion, lower evaporation rates, provide shade, decrease water temperature, and provide additional 

food resources for fish and the aquatic food web within these reservoirs. Many of these reservoirs are already 

constrained by low water due to current climate conditions and livestock trampling of banks. 

Management actions that required fish-passable culverts would be economically responsible and ensure that 

aquatic wildlife habitats remained intact. In Oregon and Washington, the Government Accountability Office 

(2001) found 2,600 culverts (and estimated that up to 5,500) were impeding fish passage on USFS and BLMadministered lands. The cost of replacing these structures was estimated at over $375 million. Given the 

dynamic patterns of drying and flooding and the colonization and emigration patterns of prairie fish and aquatic 

wildlife, constructing fish passable structures would alleviate future resource and economic problems associated 

with stream-crossing structures impassable by fish. Designing new structures so that they would not contribute 

to erosion would protect and enhance aquatic wildlife habitat (see the Reclamation Appendix). Installing fish 

screens on all diversions would ensure fishes and aquatic wildlife were not stranded in irrigation ditches or 

deposited on agricultural fields.

This alternative would protect pallid sturgeon habitat through the implementation of a non-discretionary buffer. 

Because pallid sturgeon habitat occurs in large river systems and because interaction of river-floodplain and 

riparian area-adjacent uplands occurs on a landscape scale, impacts to pallid sturgeon would potentially occur 

from a variety of factors. A 0.5-mile buffer would ensure that an accidental oil spill from a well, for example, 

would have less probability of harming this species that is already on the brink of extinction. 
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Management actions that allowed cottonwood harvest would impact aquatic wildlife habitat. Cottonwood stands 

are important physical modifiers of aquatic wildlife habitat and provide thermal protection, cover, and food 

resources in the form of leaves and organic matter; subsequently, a loss of these attributes through cottonwood 

harvest would degrade aquatic wildlife habitat. Large cottonwood trees would also provide seed sources for 

future cohorts of cottonwood trees. Various cohorts of cottonwoods and other riparian woody species provide a 

physical template within which streams and rivers interact to form various habitat patches upon which aquatic 

wildlife depend. Additionally, cottonwoods provide an important habitat component to the endangered pallid 

sturgeon in the Missouri and Yellowstone rivers. Furthermore, there have been numerous cases in which 

cottonwoods have declined throughout the Great Plains because of mature tree mortality without adequate 

regeneration (Rood and Mahoney 1990; Lytle and Merritt 2004). Although this occurrence is due primarily to 

hydrologic alterations, harvesting mature cottonwoods would exacerbate these impacts and alter the important 

patchy habitat mosaic (Pringle et al. 1988; Stanford, Lorang, and Hauer 2005) in riparian areas and aquatic 

wildlife habitat. Finally, there is no empirical evidence that harvesting of cottonwoods is necessary for resource 

health.

Where grazing allotments failed to meet Standards for Rangeland Health and grazing was a causal factor, 

impairment of riparian areas and aquatic wildlife habitat would occur through continued permitted grazing. 

However, if impairment continued and the allotment closed after 5 years of non-compliance, recovery would 

then begin. That additional 5 years, if impairment continued, would cause severe impacts to the upland, riparian

areas, and consequently aquatic wildlife habitat. Recovery of riparian zones and streams from livestock grazing

would require total rest from grazing (Belsky et al. 1999; Henley et al. 2000), and allowing grazing without 

resting these allotments would continue to degrade aquatic wildlife habitat and degrade some areas beyond 

recovery to historical potential. 

Suspending livestock grazing in areas of active locatable mining and coal development, and resuming after 

reclamation would decrease potential for effects such as sedimentation from compounding multiple land-use 

activities.

Allowing livestock grazing during or immediately after oil and gas development would degrade aquatic wildlife

habitat, particularly in light of the widespread oil and gas development already in progress and the potential for 

increased activities. Collectively, impacts from both activities have the potential to cause extreme sedimentation 

in streams and aquatic wildlife habitat, instability and mass wasting of streambanks, decreases in water quality 

and riparian vigor, and, accordingly, degraded aquatic habitat, food webs, and ecosystem processes.

Deferring livestock grazing until identified vegetative conditions are met following a wildfire or prescribed fire 

would help facilitate vegetative reestablishment and minimize impacts to aquatic wildlife habitat from soil 

erosion common after wildfires. However, if wildfires were intense, trampling of soils and plants and herbivory 

in upland and riparian areas would cause erosion and excessive sedimentation in aquatic wildlife habitat. In a 

review of post-fire activities in the western United States, Beschta et al. (2004) found several activities, 

including livestock grazing, would generally inhibit restoration of ecosystem functions. Post-fire exclusion of 

livestock would need to incorporate climatic conditions and each fire situation, riparian area, and local history 

of land use in the watershed to understand and ensure there were no impacts to aquatic wildlife habitat.

ALTERNATIVE D

Avoiding surface-disturbing activities on slopes 25 percent or greater and sensitive soils would decrease the 

amount of soil that entered streams and affected aquatic wildlife habitat. However, if these activities were 

allowed with mitigation (and depending on the activity’s proximity to streams), there would be at least an initial 

period in which sedimentation in streams and impacts to aquatic wildlife habitat occurred.

For Alternative D, surface-disturbing activities that did not benefit floodplain functionality would be avoided 

unless no other practicable alternative existed, and an NSO stipulation for oil and gas leasing would be required 

within 100-year floodplains. Similarly, under this alternative, surface-disturbing activities that did not benefit

functionality of streams and waterbodies would be avoided unless no other practicable alternative existed, and a 

CSU stipulation for oil and gas leasing would be required. Allowing surface-disturbing activities in these areas 
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when no other practicable alternative existed would be subject to multiple interpretations and would provide 

very little protection to the water resource. Additionally, buffers would better protect aquatic wildlife habitat in 

prairie streams because there is an intrinsic connection between adjacent uplands, riparian areas, streams, and 

aquatic wildlife habitat. The lack of buffers on most prairie streams would impact aquatic wildlife. 

Sedimentation, which is one of the most frequently occurring chemical and physical pollutants in many streams 

and rivers, would occur (Wenger 1999) if buffers were not implemented; subsequently, stream buffers should 

be applied to all streams, including intermittent and ephemeral streams. Impacts would include erosion and 

excessive sedimentation in aquatic wildlife habitat, bank instability, habitat fragmentation, and, ultimately, 

displacement or extirpation of aquatic wildlife.

Allowing surface water impoundments with design features that maintained the natural flow regime and 

watershed functionality, and, in particular, flows that allowed the maintenance and formation of pool habitats 

would minimize impacts to aquatic wildlife habitat. Avoiding habitat fragmentation and ensuring fish passage 

would maintain habitat for aquatic wildlife by maintaining the natural flow regime and watershed functionality.

Management actions that allowed surface-disturbing or disruptive activities in riparian and wetland areas 

subject to PFC and approved specialized design features would potentially minimize aquatic wildlife habitat in 

perennial and intermittent streams. 

Not allowing spring development in riparian and wetland areas would benefit aquatic wildlife habitat.

Management actions that allowed livestock tanks or troughs in ephemeral portions of streams would impact 

aquatic wildlife habitat in downstream intermittent and perennial reaches. Headwaters, which include ephemeral 

channels in the planning area, are key components of physical, chemical, and biological processes of watersheds 

and interact in a longitudinal manner, upstream to downstream (Vannote et al. 1980; Belsky et al. 1999; Fausch 

et al. 2002), to influence aquatic wildlife habitat. Allowing tanks or troughs on sport-fish reservoirs without a 

buffer would cause erosion and trampling of the banks, which would degrade aquatic wildlife habitat.

Allowing surface-disturbing and disruptive activities adjacent to sport-fish reservoirs would cause 

sedimentation, decreasing the overall life of the sport-fish reservoir. Excessive sedimentation on reservoirs in 

this region would fill in the reservoir more quickly than without surface disturbance adjacent to the reservoir.

Stream-crossing structures that restricted fish passage would cause habitat fragmentation, isolation of 

populations, and contribute to disrupted life cycles patterns of fish and other aquatic wildlife. Although many 

prairie streams in the planning area are intermittent, aquatic wildlife historically thrived in these intermittent 

pools and depended on periods of high flow to redistribute; subsequently, fish-passable, stream-crossing 

structures would be important in the many prairie streams throughout the planning area. Additionally, fishpassable structures, by design, would contribute less to erosion than other stream-crossing structures.

This alternative would protect pallid sturgeon habitat through the implementation of a non-discretionary buffer. 

Because pallid sturgeon habitat occurs in large river systems and because interaction of river-floodplain and 

riparian area-adjacent uplands occurs on a landscape scale, impacts to pallid sturgeon would potentially occur 

from a variety of factors. A 0.5-mile buffer subject to habitat functionality would ensure that an accidental oil

spill from a well, for example, would have less probability of harming this species that is already on the brink of 

extinction. 

Management actions that allowed cottonwood harvest would impact aquatic wildlife habitat. Cottonwood stands 

are important physical modifiers of aquatic wildlife habitat and provide thermal protection, cover, and food 

resources in the form of leaves and organic matter; subsequently, a loss of these attributes through cottonwood 

harvest would degrade aquatic wildlife habitat. Large cottonwood trees would also provide seed sources for 

future cohorts of cottonwood trees. Various cohorts of cottonwoods and other riparian woody species provide a 

physical template within which streams and rivers interact to form various habitat patches upon which aquatic 

wildlife depend. Additionally, cottonwoods provide an important habitat component to the endangered pallid 

sturgeon in the Missouri and Yellowstone rivers. Furthermore, there have been numerous cases in which 

cottonwoods have declined throughout the Great Plains because of mature tree mortality without adequate 
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regeneration (Rood and Mahoney 1990; Lytle and Merritt 2004). Although this occurrence is due primarily to 

hydrologic alterations, harvesting mature cottonwoods would exacerbate these impacts and alter the important 

patchy habitat mosaic (Pringle et al. 1988; Stanford, Lorang, and Hauer 2005) in riparian areas and aquatic 

wildlife habitat. Finally, there is no empirical evidence that harvesting of cottonwoods is necessary for resource 

health.

Where grazing allotments failed to meet Standards for Rangeland Health and grazing was a causal factor, 

impairment of riparian areas and aquatic wildlife habitat would occur due to continuing to allow grazing. 

However, if impairment continued and it was closed after 5 years of non-compliance, recovery would then 

begin. That additional 5 years, if impairment continued, would cause severe impacts to the upland, riparian 

areas, and consequently aquatic wildlife habitat. Recovery of riparian zones and streams from livestock grazing

would require total rest from grazing (Belsky et al. 1999; Henley et al. 2000), allowing grazing without resting 

these allotments would continue to degrade aquatic wildlife habitat and degrade some areas beyond recovery to 

historical potential. 

Suspending livestock grazing in areas of active locatable mining and coal development, and resuming after 

reclamation would decrease potential for localized effects such as sedimentation from compounding multiple 

land-use activities.

Allowing livestock grazing during or immediately after oil and gas development would degrade aquatic wildlife

habitat, particularly in light of the widespread oil and gas development already in progress and the potential for 

increased activities. Collectively, impacts from both activities have the potential to cause extreme sedimentation 

in streams and aquatic wildlife habitat, instability and mass wasting of streambanks, decreases in water quality 

and riparian vigor, and, accordingly, degraded aquatic habitat, food webs, and ecosystem processes.

Deferring livestock grazing until the seed set the following season would not protect aquatic wildlife. In a 

review of post-fire activities in the western United States, Beschta et al. (2004) found several activities, 

including livestock grazing, would generally inhibit restoration of ecosystem functions. Post-fire exclusion of 

livestock would need to incorporate climatic conditions and each fire situation, riparian area, and local history 

of land use in the watershed to understand and ensure there were no impacts to aquatic wildlife habitat.

ALTERNATIVE E (PREFERRED ALTERNATIVE)

Avoiding surface-disturbing activities on slopes 25 percent or greater and sensitive soils would decrease the 

amount of soil that entered streams and affected aquatic wildlife habitat. However, if these activities were 

allowed with mitigation (and depending on the activity’s proximity to streams), there would be at least an initial 

period in which sedimentation in streams and impacts to aquatic wildlife habitat occurred.

For Alternative E, specialized design features to maintain functionality and resiliency of the floodplain would 

maintain aquatic wildlife habitat provided water quality was not affected, flows were not altered, the ability of 

the river or stream to interact with the floodplain and riparian area was not altered, sedimentation did not 

increase substantially, and exotic species were not unintentionally introduced. 

For Alternative E, impacts to stream and waterbodies would be similar to Alternative A. A loss of protection to 

ephemeral drainages would have substantial, degrading impacts to aquatic wildlife habitat. Water moves 

downstream from ephemeral or headwater areas, causing impacts downstream to intermittent and perennial 

portions of watersheds. If water quality was degraded in ephemeral portions of a stream, associated impacts 

would potentially occur downstream. Additionally, buffers would better protect aquatic wildlife habitat because 

there is an intrinsic connection between adjacent uplands, riparian areas, streams, and aquatic wildlife habitat. 

The lack of buffers on most prairie streams would impact aquatic wildlife. Sedimentation, which is one of the 

most frequently occurring chemical and physical pollutants in many streams and rivers, would occur (Wenger 

1999) if buffers were not implemented; subsequently, stream buffers should be applied to all streams, including 

intermittent and ephemeral streams. Impacts would include erosion and excessive sedimentation in aquatic 

wildlife habitat, bank instability, habitat fragmentation, and ultimately, displacement or extirpation of aquatic 

wildlife.
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Similarly, under this alternative, surface-disturbing activities that did not benefit functionality of streams and 

waterbodies would be avoided unless no other practicable alternative existed, and a CSU stipulation for oil and 

gas leasing would be required. Allowing surface-disturbing activities in these areas when no other practicable 

alternative existed would be subject to multiple interpretations and would provide very little protection to the 

water resource. 

Allowing surface water impoundments with design features that maintained the natural flow regime, water 

quality, and watershed or riparian functionality would minimize impacts to aquatic wildlife habitat if the 

activities succeeded in maintaining flows that allowed for natural scouring events, which maintain pool habitat 

and encourage groundwater-surface water interactions. Avoiding habitat fragmentation and ensuring fish 

passage would maintain habitat for aquatic wildlife.

Management actions that allowed surface-disturbing or disruptive activities with approved specialized design 

features in riparian and wetland areas would still potentially impact aquatic wildlife and their habitat. A 300-

foot buffer from riparian areas and wetlands would help ensure that impacts to riparian area and wetlands, (and 

consequently aquatic wildlife and their habitat) were minimal.

Management actions that allowed spring developments and livestock water developments in riparian areas and 

wetlands would impact aquatic wildlife habitat even if they were designed to maintain functionality of wetlands, 

riparian areas, waterbodies, or creeks. Complete fencing of riparian areas near the water development would 

help decrease impacts. Water developments or livestock water access on sport-fish reservoirs without a buffer 

would cause erosion and trampling of the banks, which would degrade aquatic wildlife habitat.

Alternative E would provide some protection for sport-fish reservoirs. In this situation, the 0.25-mile buffer 

would help to eventually reestablish the littoral zone (shallow shoreline area), decrease erosion, lower 

evaporation rates, provide shade, decrease water temperature, and provide additional food resources for fish and 

the aquatic food web within these reservoirs. Many of these reservoirs may be constrained by low water due to 

current climate conditions and also experience livestock trampling of banks. 

Management actions that required fish-passable culverts would be economically responsible and ensure that 

aquatic wildlife habitats remained intact. In Oregon and Washington, the Government Accountability Office 

(2001) found 2,600 culverts (and estimated that up to 5,500) were impeding fish passage on USFS and BLMadministered lands. The cost of replacing these structures was estimated at over $375 million. Given the 

dynamic patterns of drying and flooding and the colonization and emigration patterns of prairie fish and aquatic 

wildlife, constructing fish passable structures would alleviate future resource and economic problems associated 

with stream-crossing structures impassable by fish. Designing new structures so that they would not contribute 

to erosion would protect and enhance aquatic wildlife habitat (see the Reclamation Appendix). Installing fish 

screens on all diversions would ensure fishes and aquatic wildlife were not stranded in irrigation ditches or 

deposited on agricultural fields.

This alternative would protect pallid sturgeon habitat through the implementation of a non-discretionary buffer. 

Because pallid sturgeon habitat occurs in large river systems and because interaction of river-floodplain and 

riparian area-adjacent uplands occurs on a landscape scale, impacts to pallid sturgeon would potentially occur 

from a variety of factors. A 0.5-mile buffer subject to the requirements under this alternative would ensure that 

an accidental oil spill from a well, for example, would have less probability of harming this species that is 

already on the brink of extinction. 

Management actions that allowed cottonwood harvest would impact aquatic wildlife habitat. Cottonwood stands 

are important physical modifiers of aquatic wildlife habitat and provide thermal protection, cover, and food 

resources in the form of leaves and organic matter; subsequently, a loss of these attributes through cottonwood 

harvest would degrade aquatic wildlife habitat. Large cottonwood trees would also provide seed sources for 

future cohorts of cottonwood trees. Various cohorts of cottonwoods and other riparian woody species provide a 

physical template within which streams and rivers interact to form various habitat patches upon which aquatic 

wildlife depend. Additionally, cottonwoods provide an important habitat component to the endangered pallid 
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sturgeon in the Missouri and Yellowstone rivers. Furthermore, there have been numerous cases in which 

cottonwoods have declined throughout the Great Plains because of mature tree mortality without adequate 

regeneration (Rood and Mahoney 1990; Lytle and Merritt 2004). Although this occurrence is due primarily to 

hydrologic alterations, harvesting mature cottonwoods would exacerbate these impacts and alter the important 

patchy habitat mosaic (Pringle et al. 1988; Stanford, Lorang, and Hauer 2005) in riparian areas and aquatic 

wildlife habitat. Finally, there is no empirical evidence that harvesting of cottonwoods is necessary for resource 

health.

Where grazing allotments failed to meet Standards for Rangeland Health and grazing was a causal factor, 

impairment of riparian areas and aquatic wildlife habitat would occur through continued permitted grazing. 

However, if impairment continued and the allotment closed after 5 years of non-compliance, recovery would 

then begin. That additional 5 years, if impairment continued, would cause severe impacts to the upland, riparian 

areas, and consequently aquatic wildlife habitat. Recovery of riparian zones and streams from livestock grazing

would require total rest from grazing (Belsky et al. 1999; Henley et al. 2000), and allowing grazing without 

resting these allotments would continue to degrade aquatic wildlife habitat and degrade some areas beyond 

recovery to historical potential. 

Suspending livestock grazing in areas of active locatable mining, and resuming after reclamation would 

decrease potential for localized effects such as sedimentation from compounding multiple land-use activities.

Allowing livestock grazing during or immediately after oil and gas development would degrade aquatic wildlife

habitat, particularly in light of the widespread oil and gas development already in progress and the potential for 

increased activities. Collectively, impacts from both activities have the potential to cause extreme sedimentation 

in streams and aquatic wildlife habitat, instability and mass wasting of streambanks, decreases in water quality 

and riparian vigor, and, accordingly, degraded aquatic habitat, food webs, and ecosystem processes.

Deferring livestock grazing until the area attained treatment or rehabilitation plan resource objectives following 

a wildfire or prescribed fire would help facilitate vegetative reestablishment and minimize impacts to aquatic 

wildlife habitat from soil erosion common after wildfires. However, if wildfires were intense, trampling of soils 

and plants and herbivory in upland and riparian areas would cause erosion and excessive sedimentation in 

aquatic wildlife habitat. In a review of post-fire activities in the western United States, Beschta et al. (2004) 

found several activities, including livestock grazing, would generally inhibit restoration of ecosystem functions. 

Post-fire exclusion of livestock would need to incorporate climatic conditions and each fire situation, riparian 

area, and local history of land use in the watershed to understand and ensure there were no impacts to aquatic 

wildlife habitat.

CUMULATIVE IMPACTS

River and stream aquatic wildlife habitat has been affected by past land use, dams and reservoirs, natural events, 

changes in local and global climatic patterns, and current management actions and land uses. Historically, 

prairie streams, in which species thrived in perennial pools of intermittent streams with intact riparian zones, 

contained warm-water fish and other aquatic wildlife species adapted to a flow regime that straddled a delicate 

balance of drying and flooding. Aquatic wildlife in the larger perennial streams and rivers were generally 

adapted to free-flowing river systems in which some species, such as the endangered pallid sturgeon and the 

paddlefish, required unimpeded access to hundreds of miles of river habitat to complete their life cycles. 

Prior to European settlement, disturbances caused by fire, occasional or patchy bison and large ungulate grazing 

(McNaughton 1984; Knapp et al. 1999), and flooding were common across the landscape. These disturbances 

were an integral part of the ecology of prairie ecosystems and established a diverse habitat template that created 

niches for a biodiverse flora and fauna. Although bison grazing was prevalent, these animals were nomadic, 

unconfined by fences or other measures, and likely did not cause dramatic impacts to streams and aquatic 

wildlife on a landscape scale. Conversely, livestock grazing from the late 1800s through the mid-1900s 

dramatically damaged stream and river ecosystems (Armour, Duff, and Elmore 1991; Armour, Duff, and 

Elmore 1994; Belsky et al. 1999; Magilligan and McDowell 1999). 
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Bison typically spend more time in uplands or open landscapes in which they specifically target grasses instead 

of forbs and woody species, while cattle often pass longer periods in areas with moist soils such as swales and 

riparian areas (Knapp et al. 1999; Peden, Van Dyne, Rice, and Hansen 1974; Steuter and Hidinger 1999). 

Knapp et al. (1999) suggested that bison might have used moist sites or riparian areas in late summer when 

uplands became very dry, causing localized and seasonal impacts. Fritz et al. (1999) found that bison crossed 

creeks at specific locations (crossings) of less than 2 meters of stream length and that impacts to aquatic 

macroinvertebrates at bison creek crossings was minimal and localized, which indicates that bison crossings 

created a small spatial and temporal disturbance in which recovery from the disturbance occurred quickly. This 

pattern is in accordance with the nature of patchy habitat types important to the enhancement of habitat 

diversity and biodiversity. 

Similarly, McNaughton (1984) and Fritz et al. (1999) discussed the historical maintenance of “grazing lawns” 

in prairie uplands, in which large ungulates (including bison) grazed upland patches while adjacent areas were 

left untouched as these animals moved, encouraged by predators to travel great distances across the landscape. 

In contrast, because livestock spend a disproportionate amount of time in riparian areas, livestock grazing

directly impacts riparian areas and aquatic wildlife (Belsky et al. 1999; Henley et al. 2000). The result has been 

widespread loss of riparian cover and subsequent dramatic changes, including streambank erosion, loss of 

streambank stability, and alteration of in-stream habitat and food webs. McEldowney, Flenniken, Frasier, 

Trlica, and Leininger (2002) found decreased stem density and aboveground biomass in grazed riparian areas 

retarded the ability of riparian areas to filter and trap sediments. Similarly, Saunders and Fausch (2007) 

demonstrated that the aboveground riparian biomass and terrestrial invertebrate input to streams was 2 to 3 

times higher and fish biomass was more than twice as high in high-intensity, short duration (14 days) 

treatments, in comparison to seasonal treatments.

Aquatic wildlife in prairie streams are adapted to harsh conditions, including warm to hot summers and nearfreezing winter water temperatures. These species are also adapted to turbid conditions because the Northern 

Great Plains Ecoregion, which includes a large portion of the planning area, is naturally erosive. However, 

cumulative impacts from land use activities have dramatically increased erosion, altered thermal and hydrologic 

regimes, decreased riparian vigor and riparian connections with streams, and increased the numbers and impacts 

of exotic species, subsequently pushing some prairie aquatic wildlife to the edge of tolerance or even to 

localized extinctions. Although improved livestock grazing management has resulted in better habitat 

conditions in some stream systems, unless innovative (Green and Kauffman 1995; Saunders and Fausch 2007), 

but mostly unpracticed, grazing management strategies are employed, there is potential for widespread 

deleterious impacts to riparian areas and aquatic wildlife. Although the Clean Water Act of 1972, the ESA of 

1973, and better grazing management have improved conditions in some stream and river systems, oil and gas

development, road construction, urban expansion, the spread of introduced species, drought and climate change, 

continued reservoir development, and obstruction of aquatic wildlife migration patterns have compounded the 

impacts of already constrained prairie stream and river ecosystems in the planning area. Although prairie 

streams are already considered an endangered resource (Dodds et al. 2004), they receive much less political and 

social attention than streams and rivers since the latter conservation focus is driven by sport-fishing demands. 

Streams are complex systems connected physically, chemically, and biologically where they interact with their 

respective watershed. They operate in four-dimensional scales: 

 longitudinally, from headwaters (or ephemeral streams) to the large rivers to oceans; 

 laterally, through interactions with riparian areas and uplands; 

 vertically, through interactions with the substrate and groundwater or hyporheic water; and 

 temporally. 

Although scattered land ownership and the absence of an ecosystem or watershed discipline have made 

management at an appropriate (watershed) scale difficult, aquatic resources in the planning area would benefit 

from this holistic or ecosystem-level perspective.
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Alternative A

Alternative A would contribute to a general declining trend in habitat conditions of prairie streams and rivers. 

This alternative would decrease riparian vigor, continue erosion and sedimentation of aquatic wildlife habitat, 

and fail to protect aquatic wildlife passage and migration patterns at road and trail crossings. This alternative 

would lead to increased designations of state and federally listed sensitive aquatic wildlife species and ESA 

species in the future. 

Alternative B

Alternative B would enable habitat conditions of prairie stream and rivers in the planning area to plateau or 

even improve through the implementation of buffers and NSO stipulations for oil and gas leasing and 

development in riparian areas and aquatic wildlife habitat. This alternative would decrease excessive erosion 

and sedimentation or physical pollution of aquatic wildlife habitat; repair and protect aquatic wildlife passage 

and migration patterns at stream-road crossings (where feasible); and increase riparian vigor, which would 

restore physical and biological connections between the riparian zone and stream. This alternative would also 

help to protect endangered (pallid sturgeon) and sensitive fish (seven species), amphibian (three), and reptile

(four) species in the planning area.

Alternative C

Alternative C would enable habitat conditions of prairie stream and rivers in the planning area to plateau, rather 

than continue to decline, through the use of buffers and NSO stipulations for oil and gas leasing and 

development in riparian areas and aquatic wildlife habitat. This alternative would increase riparian vigor, 

decrease excessive erosion and sedimentation or physical pollution of aquatic wildlife habitat, and repair and 

protect aquatic wildlife passage and migration patterns at stream-road crossings, where feasible.

Alternative D

Alternative D would contribute to a general declining trend in habitat conditions of prairie streams and rivers. 

This alternative would decrease riparian vigor, continue erosion and sedimentation of aquatic wildlife habitat, 

and fail to protect aquatic wildlife passage and migration patterns at road and trail crossings. This alternative 

would lead to increased designations of state and federally listed sensitive aquatic wildlife species and ESA 

species in the future.

Alternative E (Preferred Alternative)

Alternative E would slowly enable habitat conditions of some prairie streams and rivers in the planning area to 

plateau, rather than continue to decline, through the use of buffers and NSO stipulations for oil and gas leasing 

and development in streams, waterbodies, riparian areas, and wetlands. This would occur, if and only if, the 

NSO stipulations for oil and gas leasing and development were actively applied. However, livestock grazing

would continue to degrade habitat conditions for aquatic wildlife in some streams. In some areas, this 

alternative would lead to decreased habitat fragmentation and increased migratory ability of aquatic wildlife by 

requiring fish passage on all newly constructed and replacement culverts and stream-crossing structures.
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