Appendix D Biological Resources.pdf

Ten Year Operations and Maintenance Plan for the Glendale Narrows Reach of the Los Angeles River

Programmatic Environmental Assessment

Appendix D

Biological Resources (Surveys and USFWS Coordiantion)

In Reply Refer to:

23-0106672_S7-I_LA

July 26, 2023 Sent Electronically

Jodi L. Clifford Chief, Planning Division U.S. Army Corps of Engineers Los Angeles District 915 Wilshire Blvd.

Los Angeles, CA 90017

Subject: Informal Consultation for the Proposed Los Angeles River Reaches 2-6 Sediment and Vegetation Management Project, Los Angeles County, California

Dear Ms. Clifford:

This is in response to the U.S. Army Corps of Engineers’ (Corps) letter received June 8, 2023, requesting informal consultation on the proposed management of vegetation and sediment within the Glendale Narrows section (Reaches 2-6) of the Los Angeles River (LAR) channel, in and near the community of Glendale, California. Supporting documents including a revised proposed project description was received from the Corps on June 26, 2023. The Corps has requested the U.S. Fish and Wildlife Service’s (Service) concurrence with the Corps’ determination that the proposed action activities will not adversely affect the federally endangered least Bell’s vireo (Vireo bellii pusillus; “vireo”), in accordance with section 7 of the Endangered Species Act of 1973 (Act), as amended (16 U.S.C. 1531 et. seq.).

DESCRIPTION OF THE PROPOSED ACTION

The proposed Project action would implement sediment and vegetation removal activities through portions of LAR Reaches 2 through 6 (see Figure 1 below) with an overall purpose to increase diminished flood conveyance capacity of the channel through the proposed action area.

Increasing flood conveyance capacity would reduce the potential for breakout flood flows at bridge locations and facilitate inspection and maintenance access through the removal of shoaled sediment and vegetation atop engineered structures. The proposed Project is more fully described in the Corps document received by the Service on June 26, 2023 (Corps 2023).

The purposes of the proposed Project are to:

• Partially restore diminished flood conveyance capacity through reaches 2 through 6.

• Reduce potential for flood breakout flows at bridge locations.

Jodi Clifford (23-0106672_S7-I_LA) 2

• Remove shoaled sediment and vegetation atop engineered structures to facilitate inspection and restore maintenance access pursuant to guidance provided by Corps Engineering Pamphlet (EP) 1110-2-18.

• Establish and maintain a 15-foot-wide vegetation free zone (VFZ) in specified areas, also pursuant to EP 1110-2-18.

• Preserve and enhance native vegetation for incorporation into ecosystem restoration features in the upcoming Corps’ Los Angeles River Ecosystem Restoration Project (LARER) to the extent practicable.

Figure 1. Los Angeles River Reaches

Vegetation Management

The proposed action includes a vegetation management plan that seeks to protect areas of native riparian vegetation and systematically remove invasive exotic vegetation. Proposed vegetation management would be focused on a 15-foot-wide VFZ on top of grade control structures, and underneath bridges (ranging from 200 to 500 feet wide) within the action area. Methods would include a mix of cut-stump treatment with hand tools and heavy equipment activities to mechanically remove plants, as access permits. Vegetation in these project footprint areas is a mix of native and non-native vegetation and totals about 16 acres. Native vegetation (especially

Jodi Clifford (23-0106672_S7-I_LA) 3 woody native trees and shrubs) would be protected in-place in areas outside of these identified project footprints; this includes Verdugo Wash confluence, which has a concrete bottom.

Verdugo Wash currently functions from a flood risk management standpoint as a sand trap and has dense riparian vegetation growing on top. Only exotic vegetation removal would occur within this Verdugo Wash confluence area. In addition, because the proposed action area is co-located within the footprint of the Corps’ LARER, efforts would be made by the Project to preserve areas of native riparian vegetation to complement the goals of this ecosystem restoration project.

Targeted exotic plant management would occur on an additional 39 acres throughout Reaches 2-

6. Methods would include using a mix of cut-stump treatment with hand tools and heavy equipment activities to mechanically remove exotic plants, as access permits. Glyphosate would be used to treat exotic plants, such as the invasive giant reed (Arundo donax). Reach 6 includes the highest percentage of non-native exotic plant cover compared to the other Project reaches.

Additional follow-up treatments and control of exotics would continue throughout the Project area during the Project life and allow for passive recruitment of native riparian vegetation in those same areas.

Vegetation Free Zone

Corps EP 1110-2-18 guidance specifies a three-dimensional VFZ surrounding all levees, floodwalls, embankment dams, and critical appurtenant structures in all flood damage reduction systems. The primary purpose of the proposed Project VFZ is to provide a reliable corridor of access to and along levees, floodwalls, embankment dams, and appurtenant structures. In order to be consistent with the EP 1110-2-18 guidance, these areas must be free of obstructions to assure adequate access by personnel and equipment for surveillance, inspection, maintenance, monitoring, and flood risk management activities.

A VFZ consistent with EP 1110-2-18 must be both wide and tall enough to accommodate all likely access requirements. The minimum width of the VFZ corridor per the EP 1110-2-18 guidance must be the width of the levee, floodwall, or embankment dam, including all critical appurtenant structures, plus 15 feet on each side, measured from the outer edge of the outermost critical structure (e.g., toe of a levee). The purpose of this requirement is primarily intended to avoid and minimize potential damage to concrete structures from tree roots.

Sediment Removal

As proposed, sediment would be removed throughout Reaches 2 through 6. Sediment removal would be limited to only the areas where no vegetation is currently present as well as areas that are identified for vegetation management above. Heavy equipment such as excavators, loaders, and skid-steer loaders would remove sediment from the channel and load it into trucks to be hauled to an approved landfill or disposal area. Pickup trucks, grapple trucks, personal vehicles, street sweepers, and dump trucks would be utilized for on-road transportation of workers and sediment hauling.

Jodi Clifford (23-0106672_S7-I_LA) 4

Timing, Phasing, and Sequencing

The proposed Project work is expected to begin on September 16, 2023, and would be implemented over the course of 10-years using a phased approach. All work is planned to be conducted during weekdays and outside the typical migratory bird breeding season from September 16 to March 14. Table 1 indicates the proposed Project phasing and sequencing by reach of the LAR:

Table 1. Timing of Proposed Project Work Scheduled by Project Year Per LAR Reach

Years 1-2 Years 3-5 Years 5-10

Reach 2 X X

Reach 3 X

Reach 4 X X

Reach 5 X X X

Reach 6 X1 X2

In Project Years 1 and 2, work would be limited to Reaches 4, 5, and 6 and consist of vegetation and sediment removal. In Reach 6, the work in Project Years 1 and 2 would be limited to exotic vegetation removal only (i.e., Arundo, castor bean, and Mexican fan palm) along with associated sediment removal. The vegetation in the delineated VFZs (native vegetation) in Reach 6 would not be removed until at least 3 years after exotic vegetation management (that is, beginning in Year 5), to allow time for natural passive recruitment and establishment of native riparian plants within that same reach in nearby areas where exotic plants would have been controlled earlier.

Removing vegetation from the VFZs is anticipated to take about 2 years. In Project Years 3 through 10, the focus of the Project work would be in Reaches 2 through 5. Retreatment of exotic plants would continue throughout the duration of the 10-year Project life to ensure control of exotic plants and to assist in the passive recruitment of native vegetation in those same areas.

All work will be scheduled to occur outside of the breeding season to avoid potential direct effects to vireo and any migratory birds in the area.

Future Operations and Maintenance: The Proposed action is for 10 years of sediment and vegetation management of Reaches 2 through 6. Any future operation and maintenance beyond this 10-year program would likely include vegetation (non-native), sediment and trash management, and would be based on availability of funding and priority needs for flood risk

1 Project work in Reach 6 in Project Years 1 and 2 would be limited to exotic vegetation and sediment removal from soft-bottom areas only. No vegetation would be removed in the proposed Project VFZs. Starting in Project Year 5, removal of both native and non-native vegetation in the VFZs (along with sediment removal) would occur.

2 Project work in Reach 6 would be limited to VFZs only, starting in Project Year 5, with some sediment removal, and re-treatment of exotics in these areas. This work is anticipated to take 2 years.

Jodi Clifford (23-0106672_S7-I_LA) 5 management. Environmental compliance and approvals/concurrence for future operation and maintenance activities beyond the proposed 10-year program would be completed when plans for such activities are determined.

Conservation Measures

As part of the proposed action, the Corps has proposed the following conservation measures (CMs) to avoid impacts to the vireo and other migratory birds:

CM 1. All work within Project Reaches 2-4 will be scheduled to occur outside of the vireo breeding season; all Project work will be scheduled between September 16th through March 14th. In the event that unscheduled work must be conducted in Reaches 2-4 during the vireo breeding season, a Corps-approved biologist will survey for presence of vireo and any migratory birds within 500 feet of the Project footprint and surrounding areas at least 72 hours before any scheduled work is conducted. If vireos are not detected, including any information from recent survey and observation data, work will proceed with a Corps-approved biological monitor monitoring for vireos for the duration of the work activities during the breeding season. If vireos are detected, work will not occur, and the Corps will consult with the Service.

CM 2. All work within Project Reaches 5 and 6 will occur outside the breeding season for the vireo (between September 16 and March 14).

CM 3. Prior to construction activities, the Corps-approved biological monitor will conduct pre-construction environmental training for all construction crew members. The training will focus on required avoidance/minimization measures and conditions of regulatory agency permits and approvals, a summary of sensitive species and habitats potentially present within and adjacent to the proposed action area, and appropriate procedures/protocols of invasive species removal.

CM 4. Protocol level surveys for the vireo will be required every year prior to work in any suitable habitat areas within the Project footprint. Known vireo territories based on recent survey and observation data (2016, 2018, 2019, 2022, and 2023) along with proposed protocol level surveys will be mapped. In areas where vireos have been known to establish territories, vegetation management within these areas will be limited to non-native vegetation. No vegetation or sediment removal that results in removal of native vegetation will occur in these areas.

CM 5. A Corps-approved biological monitor will be on-site during all sediment and vegetation removal activities to ensure unintended impacts to biological resources including, but not limited to, vegetation and wildlife are avoided or minimized.

The monitor will also ensure that vegetation removal of native and non-native plant species only occurs in approved zones with minimal impact to native species to be retained.

Jodi Clifford (23-0106672_S7-I_LA) 6

CM 6. Sediment removal will be limited to no closer than 5 feet from tree canopy dripline (in adjacent native tree areas to be retained) to ensure survivorship of trees.

CM 7. If heavy machinery may impact the survival of native vegetation in enhancement areas, then hand tools will be used to remove exotics. This determination will be made by the Corps’ Project Biologists or Corps-approved qualified biologist in coordination with the Corps Operations Division and the contractor.

CM 8. An invasive species management plan will be prepared to describe methods and schedules used to treat exotic plants.

CM 9. Dust control measures will be implemented during the construction phase to reduce excessive dust emissions. Methods for reducing dust emissions may include wetting work areas by water truck on a regular basis such as dirt access roads and sediment stockpiles, as well as covering truck beds carrying material and stockpiles.

CM 10. Best Management Practices shall be implemented to reduce impacts to native habitats, including the following:

a. All equipment maintenance, staging, and dispending of fuel, oil, coolant, or any other toxic substances will occur in developed or designated non-sensitive upland areas. If a spill occurs outside of a designated area, the cleanup will be immediate and documented.

b. Fire suppression equipment including shovels, water, and extinguishers will be available onsite during the fire season (as determined by Los Angeles County Fire Department) and when activities may produce sparks. Emergency contacts must be established prior to work beginning.

c. To the extent feasible, the contractor will prevent exotic weeds from establishing within the work site during construction. Construction equipment will be cleaned of mud or other debris prior to mobilizing and before leaving the site to reduce the potential spread of invasive plants and/or seeds.

EFFECTS OF THE ACTION

Riparian scrub/woodland/forest are the primary vegetation communities used by vireos for breeding, feeding, and sheltering during the breeding season. Vireos are migratory birds that actively breed in southern California from mid-March to mid-September, including the region of the Project. The Project action area surrounds a 7.6-mile section of the LAR channel that is adjacent to Griffith Park and downtown Los Angeles. This portion of the LAR is segmented into six reaches (2-6). The upstream end of the action area is near Forest Lawn Memorial Park in the Hollywood Hills, and the downstream end is near Dodger Stadium.

Jodi Clifford (23-0106672_S7-I_LA) 7

Reach 6 of the action area has the highest potential to support vireo occupation of all the Project Reaches.

The proposed Project activities would be unlikely to occur within or near areas occupied by vireos during the breeding season. Almost all Project activities would occur outside of the breeding season, and potential breeding season Project activities would only occur well away from potential vireo occupation areas. This is due to the combination of seasonal and spatial Project conservation measures proposed, including ongoing directed surveys performed during the Project life. As such, no direct impacts to vireo would likely occur from the Project, nor would potential indirect effects occur to vireos from noise, nighttime lighting, dust, or adjacent human activities caused by the Project.

As proposed, the Project would not directly affect native vegetation or sediment within areas of current or recently occupied vireo territories (per surveys performed since 2016); these areas would be avoided by the Project. Project clearing of native vegetation in areas with potential to support vireos (but not occupied since 2016) would not be affected until Project Year 5, and this clearing would occur outside of the breeding season. This delay in clearing of unoccupied potential vireo habitat until Project Year 5 would provide at least 3 years of passive restoration of native riparian vegetation to have occurred within areas of exotic plant removal in other Project areas (occurring in Project Years 1 through 4). While only a modest portion of the exotic plant control/passive restoration areas would have subsequent potential to support the vireo, these Project riparian passive restoration areas are of a much larger acreage than the areas of native vegetation proposed for clearing in existing potential vireo habitat areas. As such, it is expected that no loss in vireo carrying capacity within the action area would occur in any Project year or in the decade following the Project as a result of Project activities. This is because areas that are currently exotic vegetation to be controlled and passively restored by the Project would likely support native riparian scrub and woodland areas of overall higher function for vireos (e.g., numbers of productive vireo pairs potentially supported) in each of Project Years 5 through 10, as compared to the potential vireo habitat areas that would be cleared of native vegetation in those years.

Overall, more acreage of non-native vegetation would be controlled and passively restored to native riparian vegetation within the action area than the acreage of existing potential vireo habitat that would be affected by project activities. For example, LAR Reach 6, the one portion of the action area where vireos have been detected in the LAR channel since 2016, also has the highest acreage of invasive plant cover compared to other river reaches within the action area. Within Reach 6, the total acreage of native vegetation/potential vireo habitat to be removed would be about 6 acres. This is in comparison to at least 21 acres of exotics control/riparian passive restoration that would also occur within Reach 6, and a total of about 39 acres of exotics control/riparian passive restoration that would occur within the whole action area.

Due to the Project measures causing no net loss of vireo habitat overall in the action area, the likely gain in vireo habitat carrying capacity in each year of the Project, the lack of direct impacts to the vireo, and the application of conservation measures that would avoid noise, dust, Jodi Clifford (23-0106672_S7-I_LA) 8 and other similar indirect impacts to vireos, we anticipate that it is unlikely for Project activities to adversely affect vireo.

CONCLUSION

Based on the information provided by the Corps during this consultation and the analysis provided above, we concur with your determination that the proposed Los Angeles River Reaches 2-6 Sediment and Vegetation Management Project on the LAR is not likely to adversely affect the vireo.

With this Corps determination and Service concurrence, the interagency consultation requirements of section 7 of the Act have been satisfied. This concurrence shall be reconsidered if

(1) new information reveals effects of the agency action that may affect listed species or critical habitat in a manner or to an extent not previously considered, (2) this action is subsequently modified in a manner that was not considered in this assessment, or (3) a new species is listed, or critical habitat designated that may be affected by the action.

We appreciate your coordination on this project. If you have any questions regarding this project, please contact Jon Avery3 at 760-431-9440, extension 309.

Sincerely, Jonathan D. Snyder Assistant Field Supervisor cc:

Tiffany.R.Bostwick@usace.army.mil Christopher.W.Solek@usace.army.mil

3 jon_avery@fws.gov

For mailto:jon_avery@fws.gov mailto:Tiffany.R.Bostwick@usace.army.mil mailto:Christopher.W.Solek@usace.army.mil mailto:Christopher.W.Solek@usace.army.mil

Jodi Clifford (23-0106672_S7-I_LA) 9

Citation:

[Corps] U.S. Army Corps of Engineers 2023. Los Angeles County Drainage Area (LACDA), Los Angeles River Reach 2-6 Sediment and Vegetation Management Project: Biological Assessment and Effects Determination. Los Angeles District, South Pacific Division.

June. Provided via e-mail by Kathlyn Osagie on June 26, 2023, with the filename: LAR Sediment Removal NLAA Determination_Updated_20230626.pdf i

USACE Los Angeles River Sediment and Vegetation Removal Project

Los Angeles County Drainage Area (LACDA)

Los Angeles River Reach 2-6 Sediment and Vegetation Management Project

Biological Assessment and Effects Determination

U.S. Army Corps of Engineers Los Angeles District South Pacific Division 915 Wilshire Blvd.

Los Angeles, CA 90017

June 2023 ii

Figures

Figure 1a. Los Angeles River sub-reaches 2-6.

Figure 2. Example profile of vegetation free zone.

Figure 3. Bridge or Freeway crossing over the LAR where vegetation will need to be removed.

Figure 4. Figure 4. Cemented bottom is illustrated in pink, while remaining areas are soft bottom.

Figure 5. Approximate eBird observation made by Dr. Dan Cooper of a nesting pair of LBVI in a pocket park next to the LAR. It was adjusted based on a phone conversation with Dan Cooper to confirm approximate location.

Figure 6. LBVI sightings during the 2018 and 2016 Protocol Level Survey. Northern yellow points represent one pair, and lower yellow point represents one individual male who was unsuccessful in establishing a territory.

Tables

Table 1. Sediment removal by reach.

Table 2. Timing of Work Scheduled Per Reach

Table 3. Federally Listed and Proposed Species in the Action Area.

Table 4 Vegetation Description Per Reach

Table 5. Tree Removal Associated with Structures

Table 6. Enhancement acreages versus vegetation free zone. This includes cemented and soft bottom areas.

Photos

Photo 1. Vegetation in Reach 2 taken in 2021.

Photo 2. Vegetation in Reach 2 taken in 2023.

Photo 3. Vegetation in Reach 3 taken in 2023.

Photo 4. Vegetation in Verdugo Wash confluence taken in 2021.

Photo 5. Vegetation in Verdugo Wash confluence taken in 2023.

Photo 6. Vegetation in Reach 4 taken in 2021.

Photo 7. Vegetation in Reach 4 taken in 2023.

iii

Photo 8. Vegetation in Reach 5 taken in 2021Photo

9. Vegetation in Reach 5 taken in 2023.

Photo 10. Vegetation in Reach 6 taken in 2021.

Photo 11. Vegetation in Reach 6c taken in 2021.

Photo 12. Vegetation in Reach 6 a&b taken in 2023.

Photo 13. Vegetation in Reach 6 taken in 2023.

Chapter 1. Introduction

1.1 Summary

Consistent with protecting the nation’s environment, pursuant to national environmental statutes, applicable executive orders, and other federal planning requirements, the U.S.

Army Corps of Engineers, Los Angeles District (Corps) proposes to begin implementation of a 10-year Programmatic Sediment and Vegetation Management

Project (Proposed Action) in the Glendale Narrows section (Reaches 2-6) of the Los

Angeles River, Los Angeles, California (Proposed Action Area). The Proposed Action would be implemented over a period of 10 years. This document presents the Corps’ biological evaluation and determination of effect on the least Bell’s vireo (Vireo bellii pusillus, LBVI) associated with the Proposed Action.

The Proposed Action will support the ability of the Corps and its responsibilities to operate and maintain the Los Angeles County Drainage Area (LACDA) to meet its goals for flood risk management and protection of human life-safety. Conservation measures

(CM) identified in this document would be implemented to avoid and minimize effects to federally listed least Bell’s vireo (LBVI) and other migratory birds:

CM-1: All work within Project Reaches 2-4 will be scheduled to occur outside of the LBVI breeding season (between September 16th through March 14th). In the event that work must be conducted in Reaches 2-4 during the LBVI breeding season, a Corps-approved biologist will survey for presence of LBVI and any migratory birds within 500 feet of the Project footprint and surrounding areas at least 72 hours before any scheduled work is conducted. If LBVI are not detected, and incorporating any information from recent survey and observation data, work would proceed with a Corps-approved biological monitor monitoring for LBVI for the duration of the work activities. If LBVI are detected, work will not occur and the Corps will consult with the USFWS.

CM-2: All work within Project Reaches 5 and 6 will occur outside the breeding season for LBVI (between September 16 and March 14).

CM-3 Prior to construction activities, the Corps-approved biological monitor will conduct pre-construction environmental training for all construction crew members. The training will focus on required avoidance/minimization measures and conditions of regulatory agency permits and approvals, a summary of sensitive species and habitats potentially present within and adjacent to the proposed action area, and appropriate procedures/protocols of invasive species removal.

CM-4 Protocol level surveys for LBVI will be required every year prior to work in any suitable habitat areas within the Project footprint. Known LBVI territories based on recent survey and observation data (2016, 2018, 2019, 2022, and

2023) along with proposed protocol level surveys will be mapped. In areas where

LBVI have and have known to establish territories, vegetation management within these areas will be limited to non-native vegetation management. No vegetation or sediment removal that results in removal of native vegetation would occur in these areas.

CM-5 A Corps-approved biological monitor would be on-site during all sediment and vegetation removal activities to ensure unintended impacts to biological resources including, but not limited to, vegetation and wildlife, are avoided or minimized. The monitor will also ensure that vegetation removal of native and non-native species only occurs in approved zones with minimal impact to native species.

CM-6 Sediment removal would be limited to no closer than five (5) feet from tree canopy dripline to ensure survivorship of trees.

CM-7 If heavy machinery may impact the survival of native vegetation in enhancement areas, then hand tools will be used to remove exotics.

Determination will be made by the Corps’ Project Biologists or Corps-approved qualified biologist in coordination with the Corps Operations Division and the

Contractor.

CM-8 An invasive species management plan will be prepared to describe methods and schedules used to treat exotic plants.

CM-9 Dust control measures will be implemented during the construction phase to reduce excessive dust emissions. Methods for reducing dust emissions may include wetting work areas by water truck on a regular basis such as dirt access roads and sediment stockpiles, as well as covering truck beds carrying material and stockpiles.

CM-10 Best Management Practices shall be implemented to reduce impacts to native habitats, including the following:

a. All equipment maintenance, staging, and dispending of fuel, oil, coolant, or any other toxic substances will occur in developed or designated non-sensitive upland areas. If a spill occurs outside of a designated area, the cleanup will be immediate and documented.

b. Fire suppression equipment including shovels, water, and extinguishers will be available onsite during the fire season (as determined by Los

Angeles County Fire Department) and when activities may produce sparks. Emergency contacts must be established prior to work beginning.

c. To the extent feasible, the contractor will prevent exotic weeds from establishing within the work site during construction. Construction equipment will be cleaned of mud or other debris prior to mobilizing and before leaving the site to reduce the potential spread of invasive plants and/or seeds.

1.2 Purpose and Focus of this Analysis

This analysis has been prepared by the Corps to evaluate the potential effects of the

Proposed Action on the federally listed least Bell’s vireo to determine whether such species or habitat are likely to be adversely affected by the Proposed Action.

1.3 Background

The Flood Control Act of 1936, as amended, included authorization for work on the Los

Angeles River (LAR) channel as approved by the Chief of Engineers, U.S. Army. The

LAR channel was authorized as a unit of the general comprehensive plan for flood risk management in the Los Angeles County Drainage Area (LACDA) authorized by the

Flood Control Act of 1941. The primary purpose of LACDA is to provide flood risk protection for residents of Los Angeles County.

Despite on-going efforts by the Corps to remove accumulated sediment and manage vegetation growing within the LAR channel, sediment and vegetation continue impede water flow conveyance capacity in the LAR and reduce the effectiveness of its flood risk reduction functions. In some reaches, the flood conveyance capacity is less than half of the original, intended design. The diminished conveyance capacity threatens critical infrastructure such as bridge crossings. Furthermore, accumulated sediment and vegetation can obscure engineered structures and inhibit visual inspections and maintenance access.

1.1.1. Proposed Action Area

The project area is a 7.58-mile section of the LAR channel that is adjacent to Griffith

Park and downtown Los Angeles. The Proposed Action Area is segmented into six reaches (2-6) and fifteen sub reaches: 2a-c, 3a-c, 4a-c, 5a-c, and 6a-c (Figure 1). The upstream terminus of the Proposed Action Area is near Forest Lawn Memorial Park in the Hollywood Hills and the downstream terminus is near Dodger Stadium. The Action

Area is adjacent to the cities of Glendale, Griffith Park, Los Feliz, Atwater Village, and Elysian Valley (Frogtown). Interstate 5 (I-5) and the Los Angeles River Bikeway parallel the LAR channel on its west side and the Amtrak/Metrolink rail line roughly parallels on the east side. The six reaches of the Action Area vary geo-morphically based on channel morphology, bank characteristics, soil exposure, existing habitat, and surrounding land uses. Specific geomorphic criteria that distinguish the reaches include:

(1) channel bed type (i.e., either soft bed with groundwater/surface water exchange or concrete), (2) side slope type (vertical or trapezoidal), and (3) adjacent land uses or open space.

Figure 1. Los Angeles River sub-reaches 2-6.

1.4 Proposed Action

The Proposed Action would implement sediment and vegetation removal activities through portions of LAR Reaches 2a through 6c with an overall purpose to increase diminished flood conveyance capacity of the channel through the proposed Action Area.

Increasing flood conveyance capacity would reduce the potential for breakout flows at bridge locations (Figure 3) and facilitate inspection and maintenance access through the removal shoaled sediment and vegetation atop engineered structures (EP 1110-2-18).

In summary the purpose of the proposed action is to:

• Partial restoration of diminished flood conveyance capacity through reaches 2a through 6c.

• Reduce potential for breakout flows at bridge locations (Figure 3).

• Remove shoaled sediment and vegetation atop engineered structures to facilitate inspection and restore maintenance access pursuant to EP 1110-2-18 (Figure 4).

• Establish and maintain at 15 ft. wide VFZ, also pursuant to EP 1110-2-18.

• Preserve and enhance native vegetation for incorporation into ecosystem restoration features in the upcoming LAR Ecosystem Restoration Project to the extent practicable.

Vegetation Management: The Proposed Action includes a vegetation management plan that seeks to protect areas of native habitat and systematically remove invasive vegetation.

Vegetation management would be focused with the 15-feet vegetation free zone (see discussion Vegetation Free Zone below), on top of grade control structures, and underneath bridges (ranging from 200-500’). Methods would include a mix of cut stump with hand tools and heavy equipment to mechanically remove plants, as access permits. Vegetation in these areas is a mix of native and non-native vegetation and totals approximately 16 acres (see Table 1). Native vegetation (especially rooted native trees and shrubs) will be protected in place in areas outside of these identified footprints and includes Verdugo Wash confluence, which is cemented bottom. Verdugo Wash is currently a sand trap and has dense riparian vegetation growing on top. Only exotic vegetation removal will occur within this area improving the habitat quality. In addition, because the proposed Action Area is co-located within the footprint of the Corps’ Los

Angeles River Ecosystem Restoration Project (LARER), efforts will be made to preserve areas of native riparian vegetation as to complement the goals of this ecosystem restoration project.

Targeted non-native exotic plant management would occur in an additional 39 acres throughout Reaches 2a-6c. Methods include using a mix of cut stump with hand tools and heavy equipment to mechanically remove exotic plants, as access permits.

Glyphosate will be used to treat exotics such as the invasive giant reed (Arundo donax).

Reach 6 includes the highest percentage of non-native exotic plant cover compared to other reaches (see Table 4). Additional follow-up treatments and control of exotics l1corkw9 Highlight l1corkw9 Highlight l1corkw9 Highlight l1corkw9 Highlight would continue throughout the project area and allow for passive recruitment of native vegetation. Project activities would result in enhanced quality of native habitat.

Vegetation Free Zone: Corps Engineer Pamphlet (EP) 1110-2-18 specifies a three-dimensional vegetation free zone (VFZ) surrounding all levees, floodwalls, embankment dams, and critical appurtenant structures in all flood damage reduction systems. The primary purpose of the VFZ is to provide a reliable corridor of access to, and along, levees, floodwalls, embankment dams, and appurtenant structures. This corridor must be free of obstructions to assure adequate access by personnel and equipment for surveillance, inspection, maintenance, monitoring, and flood-fighting.

The VFZ must be both wide and tall enough to accommodate all likely access requirements. The minimum width of the corridor must be the width of the levee, floodwall, or embankment dam, including all critical appurtenant structures, plus 15 ft on each side, measured from the outer edge of the outermost critical structure (e.g., toe of a levee). The purpose of this requirement is primarily intended to avoid and minimize damage to concrete structures from tree roots (Figure 2).

Figure 2. Example profile of vegetation free zone.

Sediment Removal: Sediment would be removed throughout Reaches 2a through 6c.

Sediment would be limited to areas where no vegetation is present as well as areas that are identified for vegetation management above. Table 1 identifies the estimated quantity of sediment that could be removed as part of the Proposed Action. Heavy equipment such as excavator, loaders, skid steer loaders would remove sediment from the channel and load into trucks to be hauled to an approved landfill or disposal area.

Pickup trucks, grapple trucks, personal vehicles, street sweepers, and dump trucks would be utilized for on-road transportation of workers and sediment hauling.

Table 1. Sediment removal by reach.

Reach 50% Cut

Volume (cy)

Average

Sediment

Volume Per

Year (cy)

6C 32,642

54,826 6B 41,721

6A 35,289

5C 10,879

7,401

5B 8,156

5A 7,645

4D 2,181

4C 5,224

4B 3,544

4A 4,747

3A+Verdugo 10,858

2A 5,976

Figure 3. Bridge or Freeway crossing over the LAR where vegetation will need to be removed.

Figure 4. Cemented bottom is illustrated in pink, while remaining areas are soft bottom.

1.1.2. Timing, Phasing, and Sequencing

The work is expected to begin on September 16, 2023 and be implemented over the course of 10-years using a phased approach. All work is planned to be conducted to occur during weekdays and outside the migratory bird breeding season from September

16 to March 14. Table 1 is the proposed phasing and sequencing by reach:

Table 2. Timing of Work Scheduled Per Reach

Year 1-2 Year 3-5 Year 5-10

Reach 2 X X

Reach 3 X

Reach 4 X X

Reach 5 X X X

Reach 6 X1 X2

1 work would be limited to exotic vegetation and sediment removal from soft-bottom areas ONLY. No vegetation would be removed in the vegetation free zones. At Year 5, removal of both native and non-native in the vegetation free zone (along with sediment removal) would occur.

2 work would be limited to vegetation free zones, some sediment removal, and re-treatment of exotics.

This work is anticipated to take 2 years.

In Years 1 and 2, work would focus on Reaches 4, 5 and 6 and consist of vegetation and sediment removal. In Reach 6, the first two (2) years will be limited to exotic vegetation removal only (i.e., arundo, castor bean, and Mexican fan palm) along with associated sediment removal. The vegetation free zones in Reach 6 will not be removed until at least three (3) years post exotic vegetation management (beginning in

Year 5) to allow natural recruitment and establishment of natives within that reach.

Removing vegetation from the vegetation free zone is anticipated to take about two (2) years. In years 3-10, the focus of the work would be in Reaches 2-5. It is anticipated that retreatment of exotic plants would continue throughout the duration of the 10-year period to ensure control of exotic plants and allow for passive recruitment of native vegetation. Project activities would result in enhanced quality of native habitat. All work will be scheduled to occur outside of the nesting season to avoid direct effects to

LBVI and any nesting migratory birds.

For Reaches 2-5, sediment and vegetation clearing would proceed from the edge to the middle of the channel per the following sequence: (1) remove from the levee toe and crossovers to establish access; (2) remove from the vegetation free zone; (3) remove around bridges.

1.1.3. Access and Haul Routes

Existing access ramps into the river will be the focal point of primary ingress/egress routes. All-access ramps are located on the left embankment of the LAR. These ramps and associated routes would be used to the extent practicable and are listed below.

Where use of existing ramps is not feasible, temporary access ramps would be constructed. A typical ramp would be approximately 120 ft. long by 22 ft. wide. The ramp would be constructed of approximately 200 cy of road base. Temporary ramps would be removed at the end of work within each reach.

• Reach 2A (Betty Davis Park Ramp): From the access ramp and access road adjacent to Betty Davis Park, haul trucks would proceed northwest and right turn onto Western Ave. and proceed to the Interstate 5 Freeway on-ramp.

• Reach 3A+Verdugo Wash (Verdugo Wash Ramp): From the access ramp at

Verdugo Wash, haul trucks would proceed northwest, right turn onto Fairmont

Ave., and proceed to the State Route 134 on-ramp.

• Reach 4A, 4B, & 4C (Colorado Street Ramp): From the access ramp on the left embankment, haul trucks would proceed onto Colorado Blvd. left turn onto the 5

Freeway on-ramp via Colorado St. Freeway Extension.

• Reach 4D, 5A, & 5B (Rigali Avenue Ramp): From the access ramp on the left embankment, haul trucks would proceed onto Rigali Ave., turn right on Brunswick

Ave., turn right on Los Feliz Blvd. and proceed onto the 5 Freeway on-ramp.

• Reach 5C & 6A (Fletcher Drive North Ramp): From the access ramp on the left embankment, haul trucks would proceed onto Fletcher Drive and proceed onto the 2 Freeway on-ramp.

• Reach 5C & 6A (Fletcher Drive South Ramp): From the access ramp, haul trucks would follow the access road within the Corps’ right-of-way towards Bowtie

Parcel. Once past Bowtie Parcel, haul trucks would proceed along an interior route between Taylor Yard and Rio de Los Angeles State Recreation Area.

Trucks would then proceed via an unnamed access road towards San Fernando

Road and onto the 2 Freeway.

• Reach 6A, 6B, & 6C (San Fernando Ramp): From the access ramp near the

State Route 110 bridge across the Los Angeles River, haul trucks would left-turn onto North San Fernando Road, transition to Riverside Drive via a round-about, left turn onto Duvall Street, cross underneath the I-5 Freeway and proceed onto the I-5 southbound on-ramp.

1.1.4. Staging Areas

The following areas are proposed for use as temporary staging areas.

• Reach 2A (Betty Davis Park Staging Area): This staging area encompasses a sliver of land within the Corps right-of-way between the levee and Betty Davis

Park.

• Reach 3A (Verdugo Wash Ramp Area): Verdugo Wash Ramp itself would serve as the staging area.

• Reach 4D (Rigali Ave. Ramp Staging Area): The staging area is an approximately 1-acre empty dirt lot owned by the City of Los Angeles. The lot is located immediately north of the Los Feliz Golf Course and is immediately adjacent to the access ramp. This lot has frequently been used as a staging area for past maintenance activities.

• Reach 4D (Los Feliz Golf Course Staging Area): This staging area encompasses a sliver of land within the Corps’ right-of-way between the levee and the golf course.

• Reach 5C (Fletcher Dr. Staging Area): This staging area is an approximately 1-acre sliver of land within the Corps’ right-of-way immediately adjacent to the levee.

• Reach 6C (San Fernando Ramp Area): This staging area is a sliver of paved and unpaved area between San Fernando Ramp and the Arroyo Seco Channel.

1.1.5. Future Operations and Maintenance (O&M)

The Proposed Action is for a 10-year programmatic sediment and vegetation management of Reaches 2a – 6c. Any future operation and maintenance beyond this

10-year program would likely include vegetation (non-native), sediment and trash management, and would be based on availability of funding and priority needs for flood risk management. Environmental compliance and approvals for future operation and maintenance activities beyond the proposed 10-year program would be completed when such activities are determined.

1.4 Threatened, Endangered, Proposed Threatened or Proposed

Endangered Species, Designated or Proposed Critical Habitat

Table 2 lists the federally-listed and proposed species, and the Corps’ assessment of whether the Proposed Action is likely to adversely affect such species or its habitat based on habitat suitability and best scientific and commercial data available.

Supporting analyses are provided in Chapter 3 of this analysis. There is no designated and proposed critical habitat for any species present in the Action Area, so this is not discussed further.

Table 3: Federally Listed and Proposed Species in the Action Area

Common Name Scientific Name Status Corps’ Determination

Least Bell’s vireo Vireo bellii pusillus E May Affect, Not Likely to

Adversely Affect

Coastal California gnatcatcher

Polioptila californica californica T

No Effect. No suitable habitat present within action area.

Monarch Butterfly Danaus plexippus C No Effect. No suitable habitat present within action area.

Nevin’s Barberry Berberis nevinii E

No Effect. Unlikely to occur within the action area. Has not been observed in recent surveys.

E = endangered, T = threatened, C=candidate for listing, D = designated

Chapter 2. Species Status & Environmental Baseline

2.1 Current Status of the Species

The least Bell’s vireo is the only listed species that may be affected by the Proposed

Action. The is no designated critical habitat for this or any other species within or adjacent to the Proposed Action Area.

2.1.1 Least Bell’s Vireo (LBVI)

The LBVI is a federal and state endangered songbird that regularly nests within the

Action Area. LBVI is one of four subspecies of Bell's vireo recognized by the American Ornithologist's Union (AOU 1957). It is the western-most subspecies, breeding entirely within California and northern Baja California. LBVI was listed as a federally endangered species in 1986 (51 FR 16474). Critical habitat for the species was designated in 1994 (59 FR 4845); however, none occurs within the Action Area.1

LBVI are migratory and are only present in southern California from approximately mid-

March through mid-September. The species breeds in dense, shrubby riparian vegetation in the vicinity of water or dry-river bottoms below 2,000 feet, often dominated by willows (Salix spp.), mulefat (Baccharis salicifolia) and California wild rose (Rosa californica), but may also utilize various shrubs, trees, and vines (Franzreb 1989). Nests are typically found in low-lying, dense vegetation located in the riparian zones, most frequently in 5- to 10-year-old stands. When LBVI nest in mature riparian woodlands, they nest in areas with a substantial, robust understory of willows as well as other plant species. LBVI generally prefer semi-complex riparian habitats that have understory scrub and ample vertical complexity; riparian areas with no understory are less likely to be used. In California, a dense shrub layer associated with riparian habitat was found to be the most critical structural component of occupied LBVI habitat (Kus 1998; Kus et al.

2010). In more xeric areas, this species will readily utilize unconventional habitats, including mesquites and tamarisk. In riverine habitats of Southern California, this species typically utilizes territory sizes of about two (2) acres on average (Kus et al.

1 Critical habitat, a term defined and used in the Endangered Species Act (ESA), is specific geographic areas that contain features (primary constituent elements or PCEs) essential to the conservation of an endangered or threatened species and that may require special management and protection. Critical habitat may also include areas that are not currently occupied by the species but will be needed for its recovery.

2010). LBVI are extremely site- tenacious and return to the same nesting habitat every year (Salata 1983).

2.1.1 Survey Methods and Analysis for LBVI

Surveys for LBVI were conducted in 2016, 2018, and 2019. Surveys for 2023 are ongoing. All surveys followed current USFWS standards for protocol level surveys. GPS locations of LBVI were recorded along with other observed wildlife such as cowbirds.

2.1.2 Survey Results for LBVI

The results of the LBVI surveys from 2016-2019 and the 2023 preliminary results, as well as observations made in 2022, are presented herein.

In 2016, protocol surveys detected two individual males in LAR Reach 6a and 6c. No other LBVI were observed in the remaining reaches during these surveys (RECON

2016). In 2018, mirroring the results of the 2016 surveys, protocol surveys detected a pair of LBVI in LAR Reach 6a and an individual male in reach 6c. The pair in Reach 6a was observed exhibited nesting behavior but no fledglings were observed. The individual male from Reach 6c was detected during two subsequent surveys

(Ultrasystems Environmental Inc. 2018). In 2019, protocol level surveys did not detect any LBVI within the project site (USGS 2019). In 2022, a LBVI nesting pair was observed by a professional birder in a “pocket” park next to LAR Reach 5 (eBird 2022).

This observation reports a female on a nest incubating eggs and a vocalizing male nearby (Figure 5). Foraging behavior by either individual was not reported within the proposed Action Area for this observation.

Figure 5. Approximate eBird observation made by Dr. Dan Cooper of a nesting pair of LBVI in a pocket park next to the LAR. It was adjusted based on a phone conversation with Dr. Cooper to confirm approximate location.

Figure 6. LBVI sightings during the 2016 and 2018 Protocol Level Survey. Northern yellow points represent one pair, and lower yellow point represents one individual male who was unsuccessful in establishing a territory.

Spring 2023 protocol level surveys for LBVI have thus far detected no LBVI. This may be attributable to the recent flood events and lack of understory vegetation throughout the project area that this species prefers.

In summary, LBVI have not been detected in Reaches 2-5 by any protocol level survey conducted since 2016. LBVI have been detected in Reach 6a and 6c in years 2016 and

2018. An LBVI nesting pair was observed in a pocket park adjacent to the LAR in 2022.

2.2 Environmental Baseline

Of the total length of the proposed Action Area (7.58 miles), 1.74 miles (24%) is concrete bottom and 5.64 miles (76%) is soft-bottom (Figure 4).

The consequences to listed species from ongoing agency activities or existing agency facilities that are not within the agency’s discretion to modify (like flood risk management operations) are part of the environmental baseline (50 C.F.R. 402.02).

Operations lands are those necessary to enable the Corps to operate and maintain the

LAR channel for its primary purpose of flood risk management. Operations lands occur within the LAR channel where access for operation and maintenance requirements is needed. Routine sediment and vegetation management needs to occur within the proposed Action Area.

2.3 Vegetation within the Action Area

In terms of current habitat condition, the vegetation of the Action Area is best classified as a “disturbed” community with a mosaic of vegetation types, including aquatic and mixed riparian habitats comprised of native and non-native species. Overall, native plant communities are highly fragmented, degraded, small, and frequently dominated by invasive species. Native species include various species of willows, including black willow (Salix goodingii), red willow (Salix laevigata), arroyo willow (Salix lasiolepis) and

Fremont cottonwood (Populus fremontii). Associated native understory species include mule fat (Baccharis salicifolia). Non-native species include giant reed and Shamel ash

(Fraxinus uhdei). Giant reed is the most prominent non-native species within the Action

Area. This species is extremely invasive and has been shown to reduce the functional value of riparian habitats for native riparian species.

Much of the in-channel vegetation is typically scoured out by seasonal, high flow events, as has most recently occurred in the winter of 2023. The habitat has been further degraded by the presence of a sizeable-unhoused population that utilizes the vegetated islands in the channel for domiciling.

Riparian areas in the Action Area are found within the LAR channel proper and are…