Attachment_0002_-_USFO_Riparian_Habitat_Restoration_EA_Final.pdf

United States Department of the Interior

Bureau of Land Management

Idaho Falls District

Upper Snake Field Office

Upper Snake Field Office

Aquatic and Riparian Habitat Restoration

Environmental Assessment

Prepared by:

Bureau of Land Management

Upper Snake Field Office

1405 Hollipark Dr.

Idaho Falls, ID 83401

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment i

Table of Contents

CHAPTER 1. INTRODUCTION

1.1 BACKGROUND

1.2 PURPOSE AND NEED FOR ACTION

1.3 DECISION TO BE MADE

1.4 CONFORMANCE WITH LAND USE PLAN

1.5 SCOPING AND ISSUE IDENTIFICATION

1.5.1 Resource Issues Identified for Analysis

CHAPTER 2. PROPOSED ACTION AND ALTERNATIVES

2.1 ALTERNATIVE A (NO ACTION)

2.2 ALTERNATIVE B (PROPOSED ACTION)

2.2.1 Project Area

2.2.2 Riparian Habitat Restoration

2.2.3 Aquatic Habitat Restoration

2.2.4 Implementation

2.2.5 Monitoring

CHAPTER 3. AFFECTED ENVIRONMENT AND ENVIRONMENTAL

CONSEQUENCES

3.1 INTRODUCTION

3.2 RIPARIAN AND WETLAND VEGETATION

3.2.1 Affected Environment

3.2.2 Environmental Consequences

3.3 FLOODPLAINS AND SOIL RESOURCES

3.3.1 Affected Environment

3.3.2 Environmental Consequences

3.4 WATER QUALITY

3.4.1 Affected Environment

3.4.2 Environmental Consequences

ii Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment

3.5 FISH AND AQUATIC SPECIES

3.5.1 Affected Environment

3.5.2 Environmental Consequences

3.6 WILDLIFE

3.6.1 Affected Environment

3.6.2 Environmental Consequences

CHAPTER 4. CONSULTATION AND COORDINATION

4.1 SUMMARY OF PUBLIC PARTICIPATION

APPENDIXES

APPENDIX A: CONFORMANCE WITH APPLICABLE LAND USE PLANS

APPENDIX B: RELATIONSHIP TO STATUTES AND REGULATIONS

APPENDIX C: RESOURCE ISSUES IDENTIFIED BUT ELIMINATED FROM DETAILED

ANALYSIS

APPENDIX D: RESOURCE PROTECTION MEASURES

APPENDIX E: PROJECT IMPLEMENTATION CHECKLIST

APPENDIX F: PROJECT AREA MAP

APPENDIX G: SPECIAL STATUS SPECIES LISTS

APPENDIX H: LITERATURE CITED

APPENDIX I: ACRONYMS

List of Tables

TABLE 2-1: PROJECT AREA ACREAGES BY WATER FEATURE TYPE

TABLE 3-1: ACRES OF PERCENT SLOPE INTERVALS IN THE PROJECT AREA

TABLE 3-2: ACRES OF EROSION HAZARD (OFF-ROAD, OFF-TRAIL) RATINGS IN THE PROJECT

AREA

TABLE 3-3: MILES OF 303(D)-LISTED STREAMS BY CATEGORY

TABLE 3-4: MILES OF BULL TROUT CRITICAL HABITAT IN THE PROJECT AREA

TABLE 3-5: MILES OF YCT STREAMS IN THE PROJECT AREA, 2018 POPULATION STATUS

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment iii

TABLE G-1: SPECIAL STATUS RIPARIAN AND WETLAND PLANT SPECIES KNOWN TO OCCUR

OR WITH THE POTENTIAL TO OCCUR IN THE USFO

TABLE G-2: FEDERALLY LISTED AND BLM-LISTED SENSITIVE FISH AND AQUATIC SPECIES

OCCURRING ON OR NEAR THE USFO

TABLE G-3: FEDERALLY THREATENED AND ENDANGERED TERRESTRIAL WILDLIFE SPECIES

OCCURRING IN OR NEAR THE USFO

TABLE G-4: BLM SENSITIVE SPECIES OCCURRING ON OR NEAR THE USFO

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 1

United States Department of the Interior

Bureau of Land Management

Upper Snake Field Office

1405 Hollipark Ave.

Idaho Falls, ID 83401

Upper Snake Field Office Aquatic and Riparian Habitat Restoration

Environmental Assessment

CHAPTER 1. INTRODUCTION

1.1 Background

The Bureau of Land Management (BLM) Upper Snake Field Office (USFO) is located within the

Upper Snake River Basin and adjacent mountain valleys of eastern Idaho. It contains approximately 1.8 million acres of BLM-administered lands. Most of these lands consist of semidesert plains and valley bottoms dominated by sagebrush-steppe vegetation communities.

These lands also contain foothills, buttes, canyons, and mountains with varying vegetation cover types, including mountain shrub communities, juniper woodlands, mixed-conifer forests, and stands of quaking aspen (Populus tremuloides). Within the USFO’s boundary, the BLM manages lands along approximately 470 miles of streams and rivers, 681 identified spring sources, and 70 acres of ponds and lakes (BLM 2009). The transitional area (ecotone) where these aquatic systems interact with the adjacent floodplain is considered the riparian zone (Gregory et al.

1991).

The interactions between these two ecosystem types vary widely, dependent on the landforms in which the aquatic system occurs; the amount of water (flow) in the system; the frequency, magnitude, and duration of floods; and the pattern of erosion (scour) and deposition. The physical and ecological processes associated with these interactions help to shape the landscape;

create a gradient of microclimate conditions; transfer nutrients, sediment, and organic matter between the two ecosystems; provide a foundation for the establishment and succession of vegetation communities; and form riparian habitats. The composition and extent of riparian habitats are largely dependent on the degree of interaction between the aquatic ecosystem and the floodplain and adjacent terrestrial uplands.

These interactions are much more dynamic and complex with lotic aquatic systems (flowing water systems such as streams and rivers) than they are for lentic systems (still water systems such as springs, wetlands, meadows, and lakes). Lotic ecosystems support approximately 9,500

2 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment acres of riparian habitat, and lentic sources support approximately 350 acres of riparian habitat on BLM-administered lands within the USFO’s boundary (BLM 2009). Combined, riparian habitats comprise less than 1 percent of the total acreage within the USFO’s boundary; however, the ecological importance of these riparian ecosystems greatly exceeds the minimal proportion of the landscape in which they occupy (Gregory et al. 1991).

Healthy riparian ecosystems can support productive native vegetation communities with diverse species’ compositions and complex structure. Microsite conditions vary widely within riparian zones, and vegetation communities often include species associated with hydric soils and species from the surrounding uplands. Vegetation growth forms can include grasses, forbs, rushes, sedges, shrubs, and trees. Dependent on the frequency and magnitude of disturbance events, riparian zones often include a mosaic of habitat patches in different successional stages.

These vegetation characteristics, and the availability of drinking water, provide crucial habitat components for a vast variety of wildlife species. Diverse vegetation species’ composition and growth forms provide abundant forage available for wildlife and their prey base. This diverse vegetation and the interactions with aquatic ecosystems allow riparian areas to support more insect assemblages than the adjacent upland communities. Compared with the surrounding semiarid uplands, riparian habitats support vegetation growth later into the growing season due to availability of water at or near the surface. This provides nutritional forage later into the year.

The complex structure associated with these vegetation communities provides hiding cover for wildlife. It also supports nesting habitat for more species of birds than any other habitat type in

Idaho (Ritter 1998). Variations in microclimate conditions throughout the riparian zone offer thermal refugia during different seasons of the year, particularly during hot weather. The linear pattern of lotic riparian ecosystems, as well as their location on the landscape, provides important movement corridors and migration routes. Riparian habitats also serve as crucial stopover sites for migratory bird species, including those that typically nest in other habitat types. The structure, composition, and availability of food and water make riparian ecosystems the most productive wildlife habitats within the USFO’s boundary. These habitats provide resources for a greater species richness of plants and animals than any other single habitat type.

Riparian zones have a strong influence on the formation of habitat structure and the availability of nutritional resources in aquatic ecosystems. Root networks and large woody debris (LWD) from riparian vegetation aid in the stabilization of stream banks and increase channel roughness.

This structure can influence channel morphology by increasing resistance to erosion, altering flow patterns, creating depositional areas, and increasing channel complexity (Gregory et al.

1991). Woody debris provides crucial substrate for assemblages of aquatic invertebrates and important cover for fish and other vertebrates (Hildebrand et al. 1998). By creating lateral obstructions to streamflow, rooted vegetation and accumulations of woody debris can contribute to increased channel complexity and the creation of important habitats, such as pools, side channels, and backwaters.

Foliar vegetation cover affects the amount of light energy that reaches the water surface and moderates water temperatures. Riparian vegetation and root systems also play a significant role

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 3 in the transfer and retention of nutrients, sediment, and organic material between aquatic and terrestrial ecosystems. Litter from trees, shrubs, and herbaceous vegetation provides aquatic systems with organic matter, which forms a major proportion of the food web base.

Aboveground vegetation within the floodplain aides in the retention and deposition of nutrient-rich sediment and organic matter during floods. Stems and root systems benefit the water quality by filtering sediment and pollutants from surface and subsurface water prior to entering the aquatic system. Accumulations of woody debris within the channel create depositional areas for materials in transport (Gregory et al. 1991). Although riparian zones and the aquatic systems they are associated with vary in size, structure, and composition, the interactions and influence between the two ecosystems are intricately linked.

The high demand for water in semiarid regions, such as the USFO, has led to a history of human activities and land-use practices that have compromised the ecological integrity and natural structure and function of many aquatic and riparian ecosystems (Hauer and Lorang 2004). Dams and diversions for hydropower, irrigation, and flood control have altered natural hydrologic regimes through intense flow regulation. Such developments have reduced the frequency, magnitude, and duration of downstream floods caused by seasonal pulses of high flows.

Channelization, diking of side channels, and removal of LWD to improve the efficiency of irrigation delivery have altered natural flow patterns and reduced habitat complexity.

As a result of these practices, several aquatic systems within the USFO’s boundary have reduced connectivity with adjacent floodplains; also, these practices have disrupted the balance between erosion and deposition. This has limited the natural interactions between aquatic and riparian ecosystems, reducing the ability for hydrologic and geomorphic processes to maintain habitat conditions and create new habitats.

Agricultural and urban development in or adjacent to riparian zones have caused habitat fragmentation, reduced habitat extent, limited or eliminated potential for habitat expansion, introduced nonnative invasive vegetation, and altered floodplain characteristics. Inappropriate grazing practices have altered the vegetation structure and composition by reducing understory herbaceous layers and limiting natural regeneration and recruitment of woody species. Bank erosion and soil compaction from heavy livestock or motorized use, or both, in certain areas have led to reduced vegetation cover, widened channels, increased sediment loading, and drying of soils. These land-use practices have led to the alteration of the natural structure, composition, and extent of some riparian habitats within the USFO’s boundary.

The USFO is preparing this programmatic environmental assessment (EA) to analyze a proposal for aquatic and riparian habitat enhancement and restoration efforts within the USFO’s boundary. This EA addresses a suite of different actions and treatment types. The analysis does not include site-specific project proposals; rather, it identifies potential actions to be implemented, establishes the scope and sideboards of those actions, and provides a programmatic analysis of the environmental consequences that would result from implementation of those actions, as required by the National Environmental Policy Act (NEPA) of 1969.

4 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment

A variety of past and present land-use practices across multiple jurisdictions and landownerships influences the inherent interconnectedness of aquatic habitats and watersheds. While the focus is primarily on BLM-administered lands, the USFO recognizes that opportunities for restoration or enhancement could benefit from working across ownership boundaries. Due to the interspersed ownership pattern of private, State, and federally managed lands, the USFO intends to work closely with partners to plan aquatic and riparian enhancement projects that benefit resources across ownership boundaries within the field office boundary. Such partnering could include funding or cost-sharing and/or contributions of expertise, workforce, materials, or equipment.

Partnering also could contribute to aquatic and riparian enhancement work occurring on non-

BLM-administered land that affects public land resources. This EA considers projects on BLM-administered lands and projects on partner lands where the BLM has a management connection, such as conservation easements.

The USFO prepared this EA to thoroughly examine the proposed action’s potential environmental impacts to support informed decision-making. This EA is consistent with NEPA’s purpose and goals; the requirements of the Council on Environmental Quality’s implementing

NEPA regulations at 40 Code of Federal Regulations (CFR) 1500–1508; long-standing federal judicial and regulatory interpretations; the Department of the Interior’s NEPA regulations (43

CFR 46); and the Biden administration’s priorities and policies, including Secretarial Order No.

3399 requiring bureaus and offices to use “the same application or level of NEPA that would have been applied to a proposed action before the 2020 Rule went into effect.”

1.2 Purpose and Need for Action

The proposed project’s overlying purpose is to maintain, restore, or enhance aquatic and riparian habitats within the USFO’s boundary. Healthy aquatic and riparian ecosystems provide invaluable habitat resources for more plant, fish, and wildlife species than any other ecosystem type in this semiarid landscape; this includes habitat for Endangered Species Act (ESA)-listed species and other special status species. These ecosystems are also essential to humans; this is because they provide clean renewable water supplies and generate economic value through sustainable uses. The influence and interactions between the two ecosystem types are dynamic and intricately linked, and they are essential in the maintenance of existing habitat conditions and the creation of new habitats.

A history of human activities and land-use practices has altered the structure and function of many aquatic and riparian ecosystems. This has led to the degradation of habitat quality, a reduction in the spatial extent of available habitat, and the interruption of natural processes and interactions between the two ecosystem types. Passive management actions have been routinely used across the project area, most often in the form of livestock exclusion fences or motorized access controls. However, riparian and aquatic habitat recovery can be naturally slow or inhibited by other factors. For many aquatic and riparian habitats in the project area, active management actions are needed to maintain, restore, or enhance the structure and function. These actions would advance aspects of the BLM’s sustainable multiple use mission; this is because they would contribute to the protection or improvement of water quality, support beneficial uses

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 5 of surface waters, and aid the conservation and recovery of ESA-listed species or other special status species and their habitats. The proposed action’s purpose would be to:

• Facilitate natural interactions and restore processes between aquatic and riparian ecosystems to improve floodplain connectivity and promote a dynamic equilibrium between sediment delivery and channel/floodplain form and function.

• Implement actions to maintain or improve water quality, reduce sources of degradation, and support beneficial uses.

• Improve aquatic habitat conditions by increasing the complexity and frequency of diverse habitat features, habitat patches, and ecosystem functions.

• Affect the duration and extent of water, sediment, nutrient, and organic matter retention to improve or maintain wetland and mesic habitat conditions.

• Improve or maintain native riparian vegetation species’ composition, structural complexity, and extent by promoting establishment, regeneration, recruitment, and varying successional stages and age classes.

• Improve habitat conditions for native plants, fish, and wildlife.

• Contribute to the conservation and recovery of habitat for ESA-listed species, proposed or designated critical habitat, and BLM sensitive species. Relative to aquatic and riparian habitat, priority species could include, but are not limited to:

o Ute ladies’-tresses (Spiranthes diluvialis), bull trout (Salvelinus confluentus), yellow-billed cuckoo (Coccyzus americanus), Yellowstone cutthroat trout (YCT)

(Oncorhynchus clarkii bouvieri), greater sage-grouse (Centrocercus urophasianus), northern leopard frog (Lithobates pipiens), and monarch butterfly

(Danaus plexippus)

• Protect aquatic and riparian habitat resources through the prevention of unauthorized uses.

• Improve water crossings (such as fords, culverts, and bridges) to facilitate the passage of aquatic organisms, minimize sediment input, and minimize adverse effects on hydrologic functions.

Furthermore, there has been an increased interest in aquatic and riparian restoration and enhancement projects in this region. Potential partnership opportunities and funding sources for such projects are available through both federal and state government agencies, nongovernmental entities, and various grants. Potential project partners and interested parties could include, but are not limited to, the United States Army Corps of Engineers, United States Fish and Wildlife

Service (USFWS), Idaho Department of Fish and Game (IDFG), Idaho Transportation

Department, Idaho Department of Water Resources (IDWR), Idaho Department of

Environmental Quality (IDEQ), Henry’s Fork Foundation, and Teton Regional Land Trust.

The USFO’s programmatic EA seeks to foster partnership developments, leverage funding opportunities, and facilitate project implementation by reducing the time and effort required to duplicate NEPA analyses and documentation for similar projects with similar effects. A programmatic approach would substantially improve the BLM’s timeliness and responsiveness to partners and others interested in implementing collaborative restoration projects. Completion

6 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment of the programmatic analysis would also benefit funding acquisition and project implementation as opportunities arise, regardless of the timing and location throughout the project area.

1.3 Decision to Be Made

The BLM Upper Snake field manager is the authorized officer responsible for decisions regarding the management of public lands within the project area. The EA will provide information for the authorized officer to make an informed decision of whether to select the proposed action, which includes programmatic aquatic and riparian habitat restoration activities, or the no action alternative. Based on the results of the NEPA analysis, the authorized officer will issue a determination of the significance of the environmental effects and whether an environmental impact statement will be required.

1.4 Conformance with Land Use Plan

The proposed action is in conformance with landscape-level objectives and management actions set forth in the Medicine Lodge Resource Management Plan (RMP) (BLM 1985), the Little Lost-

Birch Creek Management Framework Plan (MFP) (BLM 1981a), the Big Lost MFP (BLM

1982), and the Big Desert MFP (BLM 1981b); all of these have been amended by the Idaho and

Southwestern Montana Greater Sage-Grouse Approved Resource Management Plan Amendment

(ARMPA) (BLM 2015a). These plans and amendments direct the BLM to manage BLM-administered lands in a manner to protect, maintain, or improve aquatic and riparian resources to the greatest extent possible. Appendix A contains additional information relative to the proposed action’s conformance with these specific plans and amendments.

1.5 Scoping and Issue Identification

An interdisciplinary team (IDT) of BLM resource specialists conducted internal scoping meetings to discuss the purpose of and need for the project, develop a list of actions to propose, identify potential resource issues, and develop resource protection measures to minimize or eliminate effects on specific resources. The IDT documented their rationale for resources that would or would not be analyzed in detail in the EA. A summary of this internal scoping’s results and the resource issues identified are included in Section 1.5.1. Appendix C identifies the resource issues identified but eliminated from detailed analysis and the rationale for their elimination.

External scoping was initiated on August 30, 2021; the USFO sent a scoping package containing a draft of this EA’s Chapters 1 and 2 to interested agencies and organizations and potential project partners. This specific outreach was intended to inform these agencies and organizations of the proposal under consideration, solicit input on the identification of preliminary resource issues to be analyzed, and solicit comments or suggestions to the specific actions being proposed.

The USFO received comments from IDFG and the Henry's Fork Foundation, but no other agencies or organizations. Comments were favorable, and no specific resource issues were identified for analysis.

1.5.1 Resource Issues Identified for Analysis

The programmatic analysis is broad scale, encompassing a large geographical project area and including numerous proposed restoration actions and techniques. Individual projects that could

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 7 be implemented in the future would be narrow in scope, occurring at a much smaller scale and site-specific project area, and affecting specific resources. Considering the actions proposed, the potential locations of future projects, resource concerns, and management policy and objectives, the IDT determined that several resource issues must be analyzed in detail to inform decision-making and to determine the environmental effects’ potential significance. The following resource issues were identified during internal scoping and will be analyzed in detail in Chapter

3.

Issue 1: How would aquatic and riparian restoration activities affect floodplains and soils?

Issue 2: How would aquatic and riparian restoration activities affect wetland and riparian vegetation; threatened, endangered, and sensitive plants; and invasive, nonnative species?

Issue 3: How would aquatic and riparian habitat restoration activities affect water quality?

Issue 4: How would aquatic and riparian habitat restoration activities affect fisheries; threatened, endangered, and sensitive fish; and their habitat?

Issue 5: How would aquatic and riparian habitat restoration activities affect wildlife; threatened, endangered, and sensitive animals; migratory birds; and their habitat?

CHAPTER 2. PROPOSED ACTION AND ALTERNATIVES

This section describes two alternatives considered in detail. The alternatives analyzed include the required no action (Alternative A) and the proposed action (Alternative B).

2.1 Alternative A (No Action)

Under this alternative, the programmatic approach to aquatic and riparian habitat enhancement actions proposed in this analysis would not occur. The amount of time and effort required to conduct a NEPA analysis and documentation for similar projects would not be reduced. This is because no projects would be implemented unless separate, site-specific NEPA analyses were completed. The no action alternative would not improve the BLM’s ability to use available funding and facilitate project implementation in an efficient and timely manner.

Ultimately, fewer aquatic and riparian habitat enhancement projects would occur in the project area. The habitat structure and function would not be improved from their current condition beyond infrequent, smaller-scale restoration projects that could be implemented. Depending on staff resources, funding, and other workload priorities, the time required to develop a project, analyze impacts on a range of potentially affected resources, and prepare NEPA documentation could diminish partnerships. Also, the time required could be prohibitive relative to certain funding opportunities, project timing, or restoration partners’ needs.

2.2 Alternative B (Proposed Action)

The proposed action includes a suite of programmatic actions and treatments targeted at the restoration, enhancement, or maintenance of aquatic and riparian habitat conditions on BLM-administered lands within the USFO’s boundary. The proposed action does not include site-specific project proposals; rather, it identifies and describes potential actions to be implemented

8 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment throughout the project area. These actions are grouped into two main categories and are described below in Sections 2.2.2 (Riparian Habitat Restoration) and 2.2.3 (Aquatic Habitat

Restoration).

2.2.1 Project Area

The project area includes all riparian and aquatic habitats within the USFO’s boundary, totaling approximately 31,000 acres. Other than the Snake River (including Henry’s Fork, South Fork, and the main stem), identification and spatial recognition of riparian and aquatic habitats were originally derived from the National Hydrography Dataset, which was then verified on the ground and modified over several years of assessing riparian habitat conditions throughout the field office. Buffers, specific to the type of water feature identified, were then applied to each feature. These buffers include a 300-foot buffer on either side of a perennial stream, a 150-foot buffer on either side of intermittent and ephemeral streams, and a 150-foot buffer around lakes, reservoirs and ponds, playas, and springs. Table 2-1 describes the total acreages for each type of water feature within the project area.

Table 2-1: Project area acreages by water feature type

Feature Type Buffer Distance (feet) Acres1, 2

Ephemeral stream 150 110

Intermittent stream 150 600

Lake 150 120

Perennial stream 300 21,800

Playa 150 10

Reservoir/pond 150 40

Spring 150 830 1 Acres are rounded to the nearest 10. Acres do not total 31,000 acres due to overlapping buffers in some areas.

2 These buffer distances are generalized and assumed; the resulting acreage estimates may differ from actual wetland/riparian area inventory estimates.

Source: BLM GIS 2021.

Mapping the spatial extent of riparian habitat surrounding the Snake River, including the Henry’s

Fork, South Fork, and main steam, included using a combination of yellow-billed cuckoo critical habitat, available mapped FEMA floodplain data, and digitization based on aerial imagery, instead of a 300-foot buffer as applied to other perennial streams. This approach was intended to capture the full extent of riparian habitat near these waterways, which in many areas is greater than 300 feet wide.

Note that data sets could be incomplete, and features could exist outside of mapped areas due to mapping inaccuracies and map scale. While the project area acres described in this EA are generally applicable to BLM-administered lands, treatments could occur across ownership boundaries, as described in Section 1.1.

2.2.2 Riparian Habitat Restoration

Riparian habitat restoration projects would aim to improve the species composition, structural complexity, and extent of native riparian vegetation in the project area. Projects would focus on the establishment, recruitment, and natural regeneration of native vegetation to stabilize stream banks, increase structural diversity, improve species’ composition, and improve riparian

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 9 function. These actions would be implemented to restore and improve habitat conditions for

ESA-listed species, special status species, migratory birds, and big game species in the project area.

Because of the dynamic relationship between riparian vegetation and the associated aquatic ecosystems, many riparian habitat restoration projects would be coupled with additional restoration actions. However, riparian habitat restoration actions, independent of other actions, could be adequate for certain project locations, depending on the site-specific conditions and desired objectives.

2.2.2.1 Plantings

Native vegetation would be planted within riparian zones that have been altered or are lacking adequate amounts of one or more vegetation components expected for that site. Vegetation species to be planted, the types and sizes of plant material to be used, and the method of planting would vary between project locations and would be based on site-specific conditions and project objectives. Prior to the implementation of specific planting projects, intact riparian areas close to the proposed planting location could be used as a reference to help inform the site potential and which species would be planted at that location. Vegetation used for planting projects could represent several different growth forms, including trees, shrubs, forbs, grasses, rushes, and sedges.

Preferably, plant material used for planting projects would be locally sourced; however, commercial stock could be used in some situations, depending on the availability and timing.

Species that would commonly be used for planting projects include, but are not limited to:

• Narrowleaf cottonwood (Populus angustifolia)

• Black cottonwood (Populus balsamifera)

• Redosier dogwood (Cornus sericea)

• Coyote willow (Salix exigua)

• Booth’s willow (Salix boothii)

• Geyer willow (Salix geyeriana)

• Showy milkweed (Asclepias speciosa)

• Woods’ rose (Rosa woodsii)

• Water whorlgrass (Catabrosa aquatica)

• Beaked sedge (Carex rostrata)

• Nebraska sedge (Carex nebrascensis)

• Baltic rush (Juncus balticus)

Some soil disturbance would occur as a result of the planting process. The disturbance’s size would vary based on the type of plant material and the hole preparation method used. Plant materials used for these projects would depend on the site-specific conditions and desired objectives for planting locations. These materials could include:

• Containerized plants

• Balled-and-burlapped plants

• Bare-root plugs

• Cuttings, stakes, and poles

• Rhizomes

• Seed

• Sod mats

• Whole willow clumps

Container volumes would typically range from 10 cubic inches to 15 gallons for most projects;

however, certain projects could use larger plant material (such as whole willow clumps and

10 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment balled-and-burlapped plants), depending on the availability and desired objectives. Generally, planting projects would require 3-inch-diameter to 2-foot-diameter holes to be prepared for individual plants or small clusters. Projects using larger plant materials could require a 4-foot-diameter hole, or larger. A depth to wetted soil would be desired for most planting projects and would vary depending on the location within the riparian zone and other site characteristics.

Planting efforts would typically be conducted during the spring and/or fall dormancy months.

However, depending on the site-specific conditions, ability, and timing of other aspects of potential projects, planting efforts could be conducted during other times of the year.

Hand Planting

Hand planting efforts would be the preferred planting method in areas where the desired soil depth (that is, the depth to wetted soil) can be achieved with the use of hand tools. Hand tools that could be used for these planting efforts would include dibble bars, hoedads, digging bars, shovels, and handheld power augers. Typically, hand planting methods would be used when planting smaller plant materials, such as stem cuttings, bare-root plugs, rhizomes, and 5-gallon or smaller containerized plants. Sod mats would also typically be installed using hand tools, by rolling the mat to cover the desired area, and securing to the ground using live cuttings or wooden stakes. Hand plantings would also be conducted in locations where vehicle or equipment access is limited due to the topography, vegetation, or sensitive resource concerns. Vehicles could be used at some hand planting locations to facilitate the transport of plant materials and equipment, but travel would be minimized to reduce potential resource damage.

Mechanical Planting

The use of mechanized equipment could be required to achieve the necessary planting depth in areas where the soil substrate is too coarse for hand tools, or when large-diameter hole preparation is necessary. Mechanized equipment used for planting efforts could include, but would not be limited to, a skid steer, excavator, or backhoe equipped with an auger, bucket, expandable stinger, or hydraulic driver/pounder. Generally, mechanical planting methods would be used for larger plant materials, such as containerized plants exceeding 5 gallons, balled-and-burlapped plants, pole cuttings, and whole willow clumps.

Whole willow clumps, when used, could be harvested from within the specific project area or from outside the project area from locations that would not compromise slope or stream bank stability. Mechanized equipment would be used to excavate the root mass, transport the intact clump, and place it in a prepared hole. Excavated areas created by willow clump harvest would be contoured to blend with the surrounding terrain; also, these areas would be revegetated with seed, sod mats, or additional plantings.

Seeding

Seeding efforts could be conducted to stabilize soils, decrease the potential for noxious and invasive weed establishment or expansion, and improve native plant diversity and structure in riparian areas that contain degraded understory conditions, or where project implementation has resulted in localized areas of surface disturbance. In general, seeding efforts would focus on the establishment of native understory herbaceous vegetation, such as grasses and forbs, but could also include other native vegetation growth forms.

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 11

Hand broadcast seeding would be the preferred application method for most seeding efforts, particularly for small-scale projects less than 1 acre. Broadcast seeding by hand would include the use of handheld tools, such as crank broadcast spreaders or blower spreaders, followed by raking or harrowing of the soil to cover the seed and help ensure adequate seed-to-soil contact.

Larger seeding projects could require the use of broadcast seeding implements pulled behind a vehicle or mechanized equipment, followed by a cultipacker or roller. Hydroseeding, using a water-based slurry of seed and mulch, could also be considered as an alternative for some seeding projects, where site conditions allow. This technique would include transporting the slurry in a truck or trailer-mounted tank and applying the slurry to a prepared site with a high-pressured hose. The use of mechanized equipment for seeding efforts would only be conducted in areas where there is not an undue risk of damage to sensitive resources.

Supplemental Watering

Short-term supplemental watering of seeded disturbance and planted vegetation treatments would be conducted as needed. Following planting efforts using containerized trees and shrubs, harvested willow clumps, sod mats, or other planted vegetation, intermittent watering would be needed until at least seasonal plant dormancy occurs or as needed to ensure establishment.

Supplemental watering would most commonly employ hand-carried 5-gallon buckets filled from the project area and dispersed onto planted trees and shrubs. Where access to water in the project area is limited or planting zones occur off channel away from surface waters, vehicle-mounted water tanks could be used to implement supplemental watering.

Portable, gas-operated pumps could also be used to draft water from the project area’s surface waters to support supplemental watering using drip lines, sprinklers, or other means. If portable pumps or vehicle-mounted tanks are operated or filled from natural surface waters, a temporary water right would be obtained from the IDWR. During drafting or pumping from fish-bearing waterbodies, intake screens would be used to avoid entrainment of fish.

2.2.2.2 Plant Material Collection

Native plant materials could be collected for direct use in various projects, or for use in nursery propagation efforts for future projects. Typically, plant materials would be harvested from within the same drainage or watershed as the location where the materials are intended to be used.

However, the lack of adequate native plant materials could require harvest to occur from nearby drainages or watersheds. Plant materials that could be collected for project use would commonly include, but not be limited to, stem cuttings, seed, and wetland sod mats. Stem cuttings of willow, cottonwood, or dogwood would be harvested using hand tools (for example, loppers, pruning shears, and hand saws). Harvesting activities would be conducted in a manner to ensure the health and appearance of the source stand would not be impaired (see guidance provided in

NRCS 2007).

Wetland sod mats would typically include an intact section of wetland soil and vegetation, approximately 6 to 8 inches thick. Sod mats could be harvested by hand using shovels. They also could require the use of mechanized equipment equipped with a bucket, depending on the size and amount of sod needed for the specific project. Sod mat harvest locations would generally

12 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment include areas that are expected to be inundated or disturbed as a result of project implementation and are expected to recover relatively quickly (1 to 3 years) following harvest.

Root wads or whole trees could also be used in the implementation of some projects. However, the harvest of these products on BLM-administered lands is beyond the scope of this EA. A separate site-specific NEPA analysis would be conducted for harvest activities, when applicable.

Generally, root wads and whole trees would be harvested from forested areas being cleared for development, or selectively removed in conjunction with forest management projects. Root wads, whole trees, or logs could also be collected from areas where they have uprooted and fallen from natural causes, such as floods, blowdown, or avalanches.

Selective felling of individual trees from within the riparian zone could be conducted in some situations. These treatments would be conducted to mimic and/or accelerate channel recruitment of LWD, promote regeneration of desirable woody species and establishment of early successional habitats, or remove undesirable or nonnative species (such as saltcedar and Russian olive). Implementation would include cutting the tree using hand tools (for example, chainsaw, loppers, and hand saw) and letting the tree lay as it falls, placing the felled tree in the desired location, lopping and scattering it, or removing it from the project location. Selective felling would only be conducted in a manner to promote improved habitat (aquatic or riparian) composition and structural diversity. It would not be done in areas where it could compromise the stability of a slope or stream bank, or where it could cause habitat fragmentation or degradation.

2.2.2.3 Noxious and Invasive Vegetation

Chemical or mechanical treatments to control the spread of noxious and invasive vegetation would be conducted to improve the native riparian plant community’s composition throughout the project area. These treatments would be subject to standard operating procedures. The analysis of proposed noxious and invasive vegetation treatments to control targeted species is tiered to the Upper Snake-Pocatello Integrated Weeds Control Program Environmental

Assessment (Programmatic Weeds EA; BLM 2017).

2.2.2.4 Fencing

Fences could be constructed to protect riparian areas that contain sensitive resources, or to protect project investments such as plantings or bank stabilization efforts. Various types of fences could be installed (that is, metal t-posts and wire, post and cable, buck and pole, etc.) as either permanent or temporary exclosures or barriers, depending on site-specific conditions and fencing objectives. Some fence types would require fence posts to be installed in the ground, while others would have bucks or jacks that sit on the surface. Posts installed in the ground would either be pounded into the ground or placed in prepared holes and backfilled. Installation could include localized clearing or trampling of vegetation along the fence line, but clearing and trampling would be minimized to the extent practicable.

2.2.3 Aquatic Habitat Restoration

Most actions proposed in this category would apply to lotic aquatic ecosystems (streams and rivers); however, some concepts could also apply to lentic systems (springs, wetlands, meadows, Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 13 and lakes). For purposes of this EA, aquatic habitat includes both lotic and lentic systems.

Aquatic habitat restoration and enhancement projects aim to improve aquatic ecosystems’ structure and function and facilitate natural interactions between these systems and their associated riparian zones. Past human activities and land-use practices have degraded the aquatic habitat quality and interrupted natural processes and interactions between aquatic and riparian ecosystems. Objectives for aquatic restoration projects would typically be multifaceted; they intend to:

• Stabilize stream banks or shorelines

• Restore or improve hydrologic connectivity with the adjacent floodplain

• Promote the balance between typical rates of bed and bank scour and the transport, sorting, and deposition of alluvial materials

• Increase aquatic habitat structural diversity and complexity, and restore or enhance habitat features (for example, riffles, steps, pools, meanders, and point bars)

• Restore stream channels and improve stream road crossings for aquatic organism passage

(AOP) using stream simulation principles to restore fish habitat connectivity

2.2.3.1 Stream Bank Stabilization

Actions would be taken to restore unnaturally unstable stream banks and shorelines in areas where erosion is creating a chronic source of sediment input, where stream banks or shorelines do not support adequate riparian vegetation cover, or where existing or proposed infrastructure is threatened. One purpose of stream bank restoration efforts would be to enhance the shape and structural integrity of a bank or shoreline to restore the dynamic equilibrium between sediment delivery and channel/floodplain form and function. Natural stream bank stability would reduce the amount of sediment input to the aquatic system and allow for improved water quality. It also would prevent further erosion in areas where sensitive resources or infrastructure could be threatened. Another purpose would be to improve the bank or shoreline’s ability to support native riparian vegetation, restore ecological functions and riparian processes, and improve hydrologic connectivity with the adjacent floodplain.

Most actions proposed in this category would apply to banks along lotic systems; however, many of the concepts could also apply to shorelines along lentic systems. For purposes of this EA, stream bank stabilization in this document includes both lotic banks and lentic shorelines.

Bank stabilization would typically include shaping the bank and/or installing reinforcements to increase floodplain roughness and strengthen bank cohesion. Reinforcements could include plant materials, such as live plantings and LWD; natural biodegradable materials to provide temporary stabilization; and inert materials, such as rock and hard structures. Actions within this category have been divided into two subcategories, plant-based and rock-based bank stabilization. The type of actions to be used at a specific project site would be determined by the desired goals for that specific project, as well as site-specific conditions and potential threats to the infrastructure or sensitive resources.

14 Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment

Plant-Based Bank Stabilization

Plant-based bank stabilization treatments include a variety of actions that use live plant materials as the project design’s primary elements. These treatment methods would rely on live vegetation to reduce water velocity and stabilize the bank, while still allowing for bank dynamics (scour and deposition) to occur at a more natural rate. Plant-based bank stabilization treatments would typically be conducted in areas where the goal is to restore the dynamic equilibrium between bank scour and deposition, improve aquatic and riparian habitat structural diversity, increase the extent of riparian habitat, and improve floodplain connectivity to restore ecological functions and allow for natural riparian processes.

Treatments in this category could be used independently or in conjunction with other actions.

They would include planting live native vegetation, placement of large wood and other plant material, shaping and contouring banks, and installing soil reinforcements and erosion controls.

These treatment types would be the preferred method of bank stabilization efforts, where site conditions allow.

Many of the planting techniques that would be conducted, including stem cuttings and whole willow clumps, are further described under Section 2.2.1.1, Plantings. Additional plantings—or using plant material—could include bundles, brush layering, brush mattresses, and installation of root wads or other large wood.

Live Bundles

Live bundles consist of dormant stem cuttings (typically willow, cottonwood, or dogwood) bound together into linear cylindrical bundles, using natural-fiber twine or rope. Inert fascines consist of the same concept but use nonliving branch cuttings. Bundles would be used to increase channel and floodplain roughness, absorb flow velocity, reduce erosion and sedimentation, and promote deposition of sediment and nutrients suspended in flows. Once established, live bundles could increase the bank’s vegetation cover, and the root systems could provide further soil stabilization. Individual bundles used for bank stabilization efforts would typically range from 4 to 8 feet in length and 6 to 18 inches in diameter; however, they could be larger depending on site-specific project requirements.

Installation would typically be conducted with one of two methods, depending on site-specific project goals. One method would include excavating a trench along the bank face that is roughly the same depth and diameter as the bundle’s width, placing the bundle into the trench, and backfilling around the bundle’s sides and interior gaps. Wood stakes, live cuttings, or a combination of the two would then be driven through the bundles to secure them into the ground.

Trench excavation would typically be conducted using hand tools, and trench orientation could run either perpendicular or parallel to the bank slope, depending on project objectives. Another installation method would include staking the fascines directly into the bank, at or slightly below base flow levels, without using a trench. Installation of bundles could be conducted independently or in conjunction with other bank stabilization treatments.

Upper Snake Field Office Aquatic and Riparian Habitat Restoration Environmental Assessment 15

Fiber Logs

Coir logs consist of interwoven coconut fibers bound together with biodegradable netting to form long cylindrical rolls. These items, as well as other fiber logs or bales made from biodegradable organic fibers or coupled with wetland sod mats, could be used to increase roughness, reduce erosion, trap sediment and promote deposition, and provide a growth medium for vegetation. The length and diameter of individual fiber logs and bales would vary and depend on site-specific conditions.

There are two main potential applications for fiber logs associated with stream bank stabilization.

They could be used on the face of an eroding bank, or a recently rebuilt bank, to temporarily prevent excessive amounts of sediment from entering a stream while vegetation can become established. For this application, fiber logs would either be installed directly on the bank face’s surface and secured using wood stakes or live cuttings above and below fiber logs. Alternatively, they would be installed in a shallow trench similar to that described under bundle installation.

For either installation technique, the fiber rolls would be placed perpendicular to the bank’s slope or slightly angled.

Another application would include using fiber logs to secure the toe of a bank slope in low-velocity settings.