FWS-WRIV-08B0408-18F1350_ALCOA_Dike.pdf

United States Department of the Interior

FISH AND WILDLIFE SERVICE

Ecological Services

Palm Springs Fish and Wildlife Office

777 East Tahquitz Canyon Way, Suite 208

Palm Springs, California 92262 In Reply Refer To:

FWS-WRIV-08B0408-18F1350

August 23, 2018

Sent by email

Colonel Aaron Barta

Commander and District Engineer

U. S. Army Corps of Engineers, Los Angeles District

915 Wilshire Boulevard, Suite 930

Los Angeles, California 90017-3409

Attention: Naeem A. Siddiqui, Project Biologist

Subject: Reinitiation of Formal Section 7 Consultation on the Santa Ana River Mainstem Flood

Control Project at the Alcoa Dike, Corona, Riverside County, California

Dear Colonel Barta:

This letter is in response to your staff’s correspondence dated April 6, 2018 and received via email

April 10, 2018, requesting reinitiation of consultation to address changes to the project description and subsequent potential impacts to the federally endangered least Bell’s vireo (Vireo bellii pusillus;

vireo) and its designated critical habitat, and the federally threatened coastal California gnatcatcher

(Polioptila californica californica; gnatcatcher) at the Alcoa Dike project feature of the Santa Ana

River Mainstem Flood Control Project (SARP). You have also identified potential impacts to proposed critical habitat for the federally threatened (western distinct population segment of the) yellow-billed cuckoo (Coccyzus americanus; cuckoo); therefore, the discussion provided herein regarding cuckoo critical habitat is a conference opinion. The Alcoa Dike feature was originally evaluated in two amendments of the original SARP biological opinion dated June 22, 1989 (1-6-88-

F-6) and December 5, 2001 (FWS-SB-909.6).

This reinitiation of the SARP biological opinion does not consider or cover potential identified effects of operations of Seven Oaks Dam and Prado Dam that were not discussed in the original biological opinion or subsequent amendments. New analyses that are currently being conducted by the Corps would consider holistic effects from flood control and water conservation operations, as well as ongoing management requirements for flood control facilities located within the 100-year floodplain. Per 50 CFR § 402.16, reinitiation of formal consultation is required and shall be requested by the Federal agency or by the Service, where discretionary Federal involvement or control over the action has been retained or is authorized by law and new information reveals effects of the action that may affect listed species or critical habitat in a manner or to an extent not previously considered. As such, we recommend that you, the U.S. Army Corps of Engineers (Corps) develop an analysis of these effects on listed species and critical habitat, identify appropriate conservation measures, and then request reinitiation of formal consultation on any effects of operations under the SARP not previously addressed by the SARP biological opinion or its amendments.

Col. Aaron Barta (FWS-WRIV-08B0408-15F0592-R001)

This amendment also does not address the federally endangered southwestern willow flycatcher

(Empidonax traillii extimus; flycatcher) or its designated critical habitat. In its biological assessment of the Alcoa Dike project, the Corps determined that the proposed action will not affect flycatcher or its designated critical habitat. While flycatcher territories were documented in 2003, 2005, 2006, and

2007 within 200 feet of the northern edge of the project footprint, adjacent to the haul route, no flycatcher territories have been documented in this area since 2007 despite yearly monitoring efforts.

The project is expected to temporarily impact 1.79 acres of flycatcher designated critical habitat on the edge of Prado Basin at Temescal Creek. This is only a very small fraction of the designated critical habitat in the Santa Ana Management Unit. As the Corps has agreed to restore each acre of riparian vegetation that is temporarily disturbed (conservation measure 9), we do not anticipate negative effects to flycatcher or its designated critical habitat.

The analysis and conclusions provided in this amendment to the biological opinion are based on information provided in your letter requesting reinitiation of consultation, the Biological Assessment for the Alcoa Dike Project, the Draft Supplemental Environmental Assessment/Environmental

Impact Report (DSEA/EIR) Addendum for the Alcoa Dike feature of the Santa Ana River Mainstem

Project, and email correspondence between the Corps and the U.S. Fish and Wildlife Service

(Service) between February 6, 2017 and August 7, 2018. The information and other references cited in this amendment to the biological opinion constitute the best available scientific information on the status and biology of the species considered. The complete project file for this consultation is maintained at the Carlsbad Fish and Wildlife Office (CFWO).

CONSULTATION HISTORY

The Service has issued a series of biological opinions (i.e., Service 1980, 1989, 2001, 2004, 2005, 2012, 2013, 2015, 2017) addressing the effects of constructing, operating, and maintaining the SARP on federally listed species and their designated critical habitat. In the 1989 opinion (1-6-88-F-6) we discussed the effects of six features of the SARP: 1) raising the existing Prado Dam from elevation

566 feet to 594 feet; 2) construction of a new intake structure and outlet conduits; 3) raising the spillway sidewalls from 566 feet to 596 feet with containment dikes on each side of the spillway entrance; 4) construction of a dike along the Santa Fe Railway from the existing spillway to Pomona

Rincon Road; 5) raising a portion of the existing Highway 71 to an elevation of 594 feet; and 6) construction of ring dikes around the Corona Sewage Treatment Plant, Alcoa Aluminum Plant, Corona National Housing Tract, and the California Institute for Women. To date, all of these projects have been completed except for raising the spillway sidewalls and the construction of the Alcoa

Dike. Impacts due to a modified Alcoa Dike design were last considered in the biological opinion on the Prado Mainstem and Santa Ana River Reach 9 Flood Control Projects and Norco Bluffs

Stabilization Project (FWS-SB-909.6), dated December 5, 2001. Conservation measures for the

SARP were described in this biological opinion, as well as the Final Supplemental Environmental

Impact Statement/Environmental Impact Report for Prado Basin and Vicinity, Including Reach 9 and

Stabilization of the Bluff Toe at Norco Bluffs (2001 SEIS/EIR; Corps 2001). These conservation measures were subsequently updated in an amendment to the SARP dated March 28, 2012 (FWS-

SB/WRIV/OR-08B0408-11F0551).

On April 10, 2018, we received a request to initiate formal consultation on the effects of the Alcoa

Dike project, as revised. The request was submitted with the biological assessment and DSEA/EIR

Addendum. On April 27, we asked several follow-up questions via email and received responses to all by April 30. On June 5, 2018 we submitted comments on the DSEA/EIR Addendum via email, which included a more formalized list of questions and items that needed clarification before we could complete our analysis, and we received responses to these items on July 2, 2018. On June 26, 2018 we received preliminary results of spring 2018 surveys documenting the presence and approximate locations of gnatcatchers within the project footprint, from the Santa Ana Watershed

Association (SAWA). Between July 3 and August 7, 2018 we asked additional questions and received responses from the Corps via email. We were provided with a slightly modified project footprint, from what was provided in the biological assessment and DSEA/EIR Addendum, via email on August 1, 2018.

BIOLOGICAL OPINION

DESCRIPTION OF THE PROPOSED ACTION

The Alcoa Dike project feature of the SARP is located within the drainage basin of Temescal Creek, approximately 2.5 miles east of the Prado Dam embankment, on the southeastern perimeter of the

Prado Basin reservoir, in the City of Corona, Riverside County, California. The project involves constructing an embankment to provide flood risk reduction to public and private property in the area, as the reservoir capacity has been increased to hold water up to a maximum elevation of 566 feet since the dam has been raised. The Alcoa Dike project design has been modified since originally proposed to conform to current engineering requirements that provide adequate flood protection to the public. The local sponsor for this feature of the SARP is the Orange County Flood Control

District.

The dike will be located on Federal, City and County land, and will be adjacent to Smith Avenue and

Rincon Street. The project area is bounded by residential areas to the north, Butterfield Park and industrial areas to the south, residential and industrial areas to the east, and the Prado Basin and

Corona Municipal Airport to the west. The alignment of the dike was selected to minimize impacts on existing facilities such as streets, utilities, percolation ponds, and other industrial and commercial development. The dike will cross over Rincon Street, Butterfield Drive, and Auburndale Street, therefore Rincon Street will be raised to match the grade of the dike, Butterfield Drive will be realigned, and a horizontal single swing floodgate will be constructed at Auburndale Street. These interrelated actions will occur post- or during dike construction but their anticipated impacts based on current design information have been taken into account under this opinion. As the road modification designs are finalized, if effects to listed species differ from the analyses presented in this document, the Corps will coordinate further with the Service to determine if re-consultation is required prior to road construction. Temporary detours will be provided as necessary during construction.

The dike will be approximately 7,530 feet in length, and its top will vary in elevation between 566.0 and 569.8 feet in accordance with the freeboard design. The dike will have a top width of 15 feet, and a maximum height of 30 feet above the existing ground surface with an average height of approximately 20 feet. Permanent steel wire fencing with sufficient spacing for wildlife movement will be installed on top of the dike along its entire length on both sides. The reservoir side slopes will be protected with 15 inches of stone over 12 inches of bedding. Four ponding areas with a total storage volume of 82 acre-feet will be constructed behind the dike. Two 36-inch drainage structures extending through the main dike embankment, two culverts extending through roadway embankments, a concrete v-ditch, and 36-inch drainage pipe to Temescal Creek will be provided for interior drainage behind the dike. Approximately 7,553 feet of stone protection (approximately

40,630 tons of riprap) will be required for the construction of the embankment. Riprap will be imported from a local quarry. Approximately 231,558 cubic yards of onsite excavation and approximately 709,103 cubic yards of fill will be required. Therefore, approximately 477,545 cubic yards of fill will be imported from the borrow site located approximately 1.5 miles west of the proposed project site.

The staging area will be located at the northwest corner of the intersection of Rincon Street and

Lincoln Avenue, and will be approximately 4.5 acres in size. Additional staging, stockpile and equipment storage locations may be identified within the proposed construction footprint during construction. Haul routes will be used to bring equipment, stone, fill material, and other construction materials from the borrow site, commercial quarries or from the staging area(s). The primary haul route to the proposed project site begins at the proposed borrow area located approximately 1.5 miles west of the proposed project site. The route moves from west to east and will utilize existing roadways. Construction vehicles will access the site from Butterfield Drive, Rincon Street, Auburndale Street, Smith Avenue, and Lincoln Avenue. Two 15-foot permanent maintenance access roads will be constructed (one along each side of the toe of the embankment), which will be utilized throughout the construction period. Construction equipment will likely include a combination of concrete pumpers, water trucks, waste trucks, haul trucks, scrapers, loaders, dozers, cranes, soil compactors, rollers, graders, vegetation chippers, and excavators.

The original mapping and description of vegetation communities has been updated to reflect the current conditions (based on 2017 surveys). Construction of the Alcoa Dike, and associated road work, is expected to result in the permanent loss of approximately 5.4 acres of native riparian vegetation and 61.0 acres of non-native upland habitat (non-native grassland and non-native woodland). The project will also result in the temporary loss of approximately 29.7 acres of native riparian vegetation, 12.8 acres of native upland/mixed coastal sage scrub, and 124.4 acres of non-native upland habitat (non-native grassland and non-native woodland). The native and non-native upland habitats that will temporarily be affected are located primarily at the borrow site.

Topsoil containing organic material retrieved by construction activities may be stockpiled and spread on embankment slopes or borrow areas as a part of site restoration. Other organic materials, such as trees, shrubs, and abandoned timber structures, will be disposed of by hauling them to a local commercial site. Disposal of these materials by burning or burying at the proposed project site will not be permitted. Inorganic materials will be taken to a commercial landfill.

Construction is scheduled to begin in September 2018 and last approximately 24 months. The project may be built in stages, with multiple start dates and construction periods for various sections of the project depending on land acquisition and utility relocations schedule, environmental windows and weather delays. Construction phasing may result in an extension of the overall project duration beyond winter 2020. Proposed construction hours would be 7:00 a.m. to 6:00 p.m., Monday through

Friday, however occasional overtime may be required to maintain the construction schedule.

Routine maintenance inspections and minor repairs will be required after construction is completed.

These activities may include inspection and patrol with pickup trucks and sport utility vehicles weekly to daily during the flood season, and weekly to monthly during the non-flood season;

utilizing dump trucks and hydraulic excavators to haul and place stones along eroded areas of the embankment to protect and reinforce the dike as necessary; periodic weeding, patching stone, and asphalt maintenance of road pavement; periodic clearing of debris around drainage structures; and periodic mending of fencing and painting metal gates.

Conservation Measures

General and species-specific conservation measures pertaining to the Alcoa Dike project feature of the SAPR are listed below, which are designed to avoid, minimize and offset impacts to federally listed species and their designated critical habitats. All of the conservation measures from the 2001

SEIS/EIR and SEA/EIR Addendums, as listed in our 2001 biological opinion and revised 2012 amendment, if not listed here, remain in effect.

CM 1: Prior to construction activities, a Corps qualified biologist (or the environmental monitor) will conduct pre-construction environmental training for all construction crew members. The training will focus on required mitigation measures and conditions of regulatory agency permits and approvals (if required). The training will also include a summary of sensitive species and habitats potentially present within and adjacent to the project site.

CM 2: Upon development of final construction plans and prior to site disturbance, the Corps will clearly delineate the limits of construction on project plans. All construction, site disturbance, and vegetation removal will be located within the delineated construction boundaries. The storage of equipment and materials, and temporary stockpiling of soil will be located within designated areas only, and outside of natural habitat areas and/or drainage features. The limits of construction will be delineated in the field with temporary orange construction fencing, staking, or flagging, and construction activities will be monitored by the Corps to assure that vegetation is removed only in the designated areas.

CM 3: The construction contractor will clear vegetation associated with project construction only during periods when vireo and gnatcatcher are not nesting (16 August through 14

February). (Note: This environmental window will be used for all vegetation clearing to avoid direct effects to other nesting birds.)

CM 4: The construction contractor will install a noise barrier prior to February 28 along the access road east and southeast of the dam along the southwestern border of the Basin

(along the haul road/borrow areas) to shield nesting vireos (and other riparian birds) from excessive noise generated by construction vehicles and equipment. Sound walls along the northern boundary of the borrow site will include occasional openings to allow for wildlife movement.

CM 5: The construction contractor will be required to monitor noise when activities approach within 500 feet of riparian habitat during the nesting season. Ambient noise levels will be recorded prior to the nesting season, or prior to construction during that period. If construction noise levels exceed authorized limits (per the 2001 and 2012 BO or as otherwise agreed to by the Service), the Contractor will construct or modify sound barriers, equipment, or procedures (including construction schedules) as necessary to meet these conditions to ensure that: 1) noise does not exceed 60 dBA, or otherwise agreed upon limit with the Service, within occupied vireo habitat; or, (2) noise does not exceed 5 dBA above ambient conditions if said levels are above 60 dBA, or another agreed upon limit. If construction noise levels within riparian habitat areas outside of the project footprint cannot be reduced below 60 dBA or another agreed upon and documented limit, during the period of February 28 through August 15 of any year, the Corps will offset impacts at a 1:1 ratio per breeding season affected by such noise levels. This 1:1 ratio will be based on the acreage of riparian habitat outside the project footprint subject to noise levels over 60 dBA, or 5 dBA above ambient, or other agreed upon limit, during the noted period, per the number of breeding seasons affected (e.g., 1 acre of riparian, habitat affected by noise in two breeding seasons will result in 2 acres of restoration). The area affected will be determined by the periodic project noise monitoring, and the effort will be doubled at the dike construction site itself, as compared to the other project footprint areas. The offsetting measure will consist of riparian habitat restoration (non-native invasive vegetation control) for 5 years, from the upper Santa Ana River watershed and/or action area.

CM 6: Prior to utilizing the borrow site, the construction contractor will place dirt berms between the borrow site and the riparian forest (or otherwise ensure that existing sound walls between the borrow site and adjacent habitat are in good condition and positioned correctly) to shield nesting vireos and other sensitive species from excessive noise generated by heavy equipment.

CM 7: Prior to any ground-disturbing activities (e.g. mechanized clearing or rough grading) for all project related construction activities, a Corps qualified biologist (or environmental monitor) will conduct pre-construction surveys of the project site for terrestrial special-status, including Western Riverside Multiple-Species Habitat

Conservation Plan (MSHCP)-covered, wildlife species. During these surveys the biologist will:

a. Inspect the project area for any sensitive wildlife species;

b. Ensure that potential habitats within the construction zone are not occupied by sensitive species (e.g., potential burrows/nests are inspected); and

c. In the event of the discovery of a non-listed, special-status ground-dwelling animal, recover and relocate the animal to adjacent suitable habitat within the project site at least 200 feet from the limits of construction activities.

CM 8: The Corps biologist (or the environmental monitor) will monitor construction activities to ensure compliance with environmental commitments.

CM 9: The Corps will successfully restore each acre of riparian vegetation that is temporarily disturbed [on-site] during construction-related activities and will keep all temporarily disturbed areas free of exotic plants until riparian vegetation is re-established. If the site(s) have not begun to recover within five years (i.e., 50 percent of the disturbed areas are not vegetated with young riparian vegetation), then the site(s) will be replanted with cuttings from native riparian species.

CM 10: The Corps will maintain non-riparian areas that are temporarily disturbed free of exotic plants for eight years.

CM 11: The Corps will remove one acre of Arundo donax (arundo) from the upper Santa Ana

River watershed off-site for each acre of riparian/wetland vegetation that is temporarily disturbed during construction-related activities; actively monitor and manage this acreage for a period of one year; and then arrange for the local sponsors

(i.e., the Orange County Flood Control District) and/or another approved entity such as SAWA to maintain this acreage arundo-free for the life of the project. This option would result in the removal of 29.7 acres of arundo removal due to an expected 29.7 acres of temporary riparian impacts. OR Remove three acres of arundo for each acre of temporary impact and maintain this acreage arundo-free for a minimum of five years. This option would result in the removal of 89.1 acres of arundo removal.

CM 12: The Corps will successfully create three acres of riparian vegetation within the action area for each acre of riparian vegetation that is permanently destroyed or isolated from the floodplain during construction-related activities. This option would create 16.0 acres of riparian habitat, due to an expected 5.4 acres of permanent riparian impacts.OR Remove five acres of arundo and other non-native species from the upper

Santa Ana River watershed off-site for each acre of riparian vegetation that is permanently destroyed during construction-related activities; actively monitor and manage this acreage for a period of 5 years; and then arrange for the local sponsors and/or another approved entity such as SAWA to maintain this acreage arundo-free for the life of the project; and conduct cowbird removal trapping in the vicinity of the restored habitat for the life of the project. This option would result in the removal of

26.8 acres of arundo and other non-native species removal.

Note: A combination of these alternatives can be used to fulfill the requirements of this conservation measure.

CM 13: Restoration activities will be initiated immediately following the completion of project activities within the restoration area. Creation and restoration activities will occur during the non-breeding season for vireos (if adjacent to occupied vireo habitat).

CM 14: Creation and restoration of riparian habitat will be considered successful when the following target/threshold objectives are met: 1) a minimum of 30 percent absolute ground cover of native plant species; 2) less than 10 percent absolute ground cover of exotic plant species (including 0 percent arundo); 3) the absolute ground cover of native species must be represented by, at least, five dominant or co-dominant plant species; 4) the recruitment of native plant seedlings must be documented to occur within the replanted areas; 5) a positive trend in the diversity and absolute ground cover of native plant species must be observed based on appropriate statistical analyses that account for natural, year to year variations; and 6) the structure and composition of the revegetated area is statistically similar (i.e., not significantly different) to habitat occupied by vireos in the vicinity. Alternatively, riparian revegetation efforts can be considered successful if the habitat is occupied by a breeding pair of vireos, flycatchers, and/or yellow-breasted chats (Icteria virens). In addition, habitat must sustain itself for 2 consecutive years without supplemental water.

CM 15: For restoration options that include management for the life of the project, the Corps should continue exotic species removal (e.g., arundo) and cowbird control until such time as the Service receives written documentation that the local sponsors and/or another approved entity [such as SAWA] have accepted responsibility for management of the restored area(s). Written documentation should include an estimate of costs associated with management responsibilities and a description of the funding mechanism(s) that will be used to ensure management will continue for the life of the project. If SAWA or another non-public entity accepts management responsibility and then becomes unwilling or unable to continue, then responsibility for continued management will revert to the local sponsors. Any advance mitigation that exceeds the requirements of the project (i.e., if actual project impacts are less than what was anticipated when the mitigation was initiated), may be credited as compensation for the effects of future projects.

CM 16: When construction is completed in a given area, the construction contractor will hydroseed the completed dikes and all temporarily disturbed upland areas, including the borrow site, with local native shrubs and groundcover to return it to its pre-project condition. The mix of native species in the hydroseed will be approved in advance by the Environmental Resources Branch of the Corps, Los Angeles District.

(Hydroseeding of dikes will be limited to native grasses in compliance with Corps

Dam and Levee Safety Regulations; other areas greater than 15 feet from the structures will be seeded/planted with a more diverse mix of native species.)

CM 17: The Corps will also offset impacts for the temporary loss of 12.8 acres of coastal sage scrub gnatcatcher foraging vegetation by restoring this same amount of habitat within an area adjacent to the borrow site, outside of the project limits. This acreage will be managed for eight (8) years post-construction while the borrow site is being restored.

CM 18: The Corps’ construction contractor will prepare a Spill Prevention and Contingency

Plan. The Plan will be implemented prior to and during site disturbance and construction activities. The plan will include measures to prevent or avoid an incidental leak or spill, including identification of materials necessary for containment and clean-up and contact information for management and agency staff. The plan and necessary containment and clean-up materials will be kept within the construction area during all construction activities. Workers will be educated on measures included in the plan at the pre-construction meeting or prior to beginning work on the project.

CM 19: The construction contractor will not allow water containing mud, silt or other pollutants from grading, aggregate washing, or other activities to enter channel stream or be placed in locations that may be subjected to high storm flows.

CM 20: To the maximum extent practicable, equipment, haul routes and staging areas will be located outside of the active channel/wash.

CM 21: The construction contractor must avoid all impacts to the low-flow channel of

Temescal Creek and restrict all construction-related access to outside of the channel whenever water is present.

CM 22: The project construction contractor will increase dust control watering when wind speeds exceed 15 miles per hour for a sustained period of greater than 10 minutes, as measured by an anemometer. The amount of additional watering would depend upon soil moisture content at the time; but no airborne dust should be visible.

Action Area

According to 50 CFR § 402.02 pursuant to section 7 of the Act, the “action area” means all areas to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action. Subsequent analyses of the environmental baseline, effects of the action, and levels of incidental take are based upon the action area. The action area for the Alcoa Dike Project includes the southeastern portion of Prado Basin extending to the 566 feet elevation contour between

Temescal Creek and the Prado Dam Spillway. This area includes lands proposed for offsetting impacts to both riparian vegetation (i.e. vireo) and coastal sage scrub vegetation (i.e. gnatcatcher).

Also included within the action area are the approximately 125-acre borrow pit (based on GIS files provided by the Corps), Butterfield Drive, Rincon Street, Auburndale Street, Smith Avenue, and

Lincoln Avenue. These lands include the project area where we anticipate project-related effects such as increased noise, light, dust levels and human activity during construction of the project. The action area also encompasses the affected range of the vireo within Prado Basin where temporary changes in the distribution of the species may occur in association with the project.

STATUS OF THE SPECIES

Least Bell’s Vireo and its Critical Habitat

The vireo was listed as endangered on May 2, 1986 (51 FR 16474). We designated critical habitat for vireo on February 2, 1994 (FR 59 4845). A draft recovery plan was published in March 1998

(Service 1998), though a final plan has not been issued. We completed a 5-year review for vireo in

September 2006 (Service 2006). Please refer to the above documents for detailed information on the habitat affinities, life history requirements, status and distribution, threats, and conservation needs of the vireo. These documents can be found at:

http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=B067

In our 5-year review we recommended that the vireo be downlisted from endangered status to threatened status because of a ten-fold increase in population size since its listing in 1986, expansion of locations with breeding vireo throughout southern California, and conservation and management of suitable breeding habitat throughout its range (Service 2006). When the Alcoa Dike project feature was first proposed, there were only 26 vireo territories recorded within the Prado Basin (Hays 1987).

By 2017, this number had increased to 549 (Pike et al. 2017). Within the Santa Ana River watershed, the number of vireo territories observed in 2017 was 1,757 (Zembal et. al. 2017). It is important to keep in mind that the numbers reported here are for territorial males observed and reported; they do not necessarily represent pairs and they are not exhaustive.

Coastal California Gnatcatcher

The Service listed the gnatcatcher as threatened on March 30, 1993 (58 FR 16742). We designated critical habitat for gnatcatcher on October 24, 2000 (65 FR 63680) and we revised that designation on

December 19, 2007 (72 FR 72010). The status of the gnatcatcher is described in detail in the latest 5-year review for this species (Service 2010a). Please refer to the above documents for detailed information on the habitat affinities, life history requirements, status and distribution, threats, and conservation needs of the gnatcatcher. These documents can be found at:

http://ecos.fws.gov/speciesProfile/profile/speciesProfile.action?spcode=B08X

Yellow-billed Cuckoo Proposed Critical Habitat

Proposed critical habitat for the western distinct population segment of the cuckoo was published in the federal register on August 15, 2014 (79 FR 158). Please refer to this document for detailed information on the habitat affinities associated with cuckoo, including the physical and biological features that provide for the species’ life-history processes, are essential to the conservation of the species, and which may require special management considerations or protection. This document may be found at: https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=B06R

Cuckoo require riparian woodlands with mixed willow-cottonwood vegetation in contiguous or nearly contiguous patches that are greater than 352 feet in width and 200 acres or more in extent.

These habitat patches contain one or more nesting groves, which are generally willow-dominated, have above-average canopy closure (greater than 70 percent), and have a cooler, more humid environment than the surrounding riparian and upland habitats.

Critical habitat is currently proposed to encompass approximately 4,406 acres in Prado Basin and in the Santa Ana River upstream to just before Hamner Avenue, which is Critical Habitat Unit 6, or

CA-6. Prado Basin is important to the conservation of the species because it is the largest remaining block of riparian habitat in this region into which a recovering cuckoo population can expand, and the only remaining site in southwestern California where the species has recently nested. The area also provides a movement corridor between larger habitat patches. The proposed Prado Basin critical habitat unit is one of 80 critical habitat units proposed for the cuckoo, a total area of approximately

546,335 acres located in 9 western states. The Service is considering excluding CA-6 from the final critical habitat designation because 98 percent of the modeled area within Prado Basin falls within the Western Riverside MSHCP.

ENVIRONMENTAL BASELINE

Based on 2017 survey data, there are two vireo territories that lie within the Alcoa Dike project footprint, and an additional eight territories that are located within 200 feet of the project area (based on GIS data on file at the CFWO). The project is expected to permanently impact 5.4 acres of native riparian vegetation and result in the temporary loss of 29.7 acres of native riparian habitat, which the species uses for foraging and nesting. The riparian vegetation in the project area is dominated by mulefat (Baccharis salicifolia), with a limited amount of Fremont cottonwood (Populus fremontii), arroyo willow (Salix lasiolepis), and black willow (Salix goodingii). These trees are scattered and occur in relatively low densities within the project area. Arundo, a highly invasive non-native species, is also a minor component of this community. The riparian plant communities in the vicinity of the project are considered sensitive habitat types for their role in the ecological function of the

Santa Ana River corridor as well as supporting nesting vireo. However, in near proximity to the project site there also exists extensive urban development, airport activities/traffic, water diversion, conveyance (pipelines and canals), water spreading, and flood control activities.

There are several mitigation sites in close proximity to the project site. The closest Corps mitigation site encompasses two of the former wastewater treatment ponds on the northwest side of the Alcoa

Dike that runs along the Temescal Wash. This area is currently undergoing mitigation for impacts to riparian and other floodplain habitat caused by construction of SARP features in Reach 9. Mitigation efforts here include removal of arundo and other non-native vegetation species, habitat restoration, endangered species surveys and cowbird trapping. Additionally, a portion of the dike construction footprint was committed as mitigation by the City of Corona to offset riparian/riverine habitat impacts for the Foothill Parkway Extension Project under the Western Riverside MSHCP. The City has worked out a property exchange with Orange County Flood Control District immediately adjacent to the original mitigation site in order to fulfill this obligation through the MSHCP. It is expected that the proposed Alcoa Dike project will avoid impacts to this and the other mitigation sites in the area, and hydrologic connectivity to surface and groundwater will not be affected.

This project is expected to permanently remove 30.0 acres of designated vireo critical habitat within the Prado Basin/Santa Ana River unit: approximately 0.3 percent of this critical habitat unit, which is

9,892.5 acres. These 30.0 acres represent less than 0.08 percent of the 38,000-acre designated critical habitat over the species range. Of the 30.0 acres of permanent impact, 4.0 acres is riparian vegetation, which is vireo’s primary nesting and foraging habitat, although the species does occasionally forage in adjacent upland habitats. The dike construction is expected to temporarily affect 126.7 acres of designated critical habitat of which 27.8 acres is riparian vegetation. The remaining affected area is developed/landscaped and/or non-native habitat.

Coastal California Gnatcatcher

The proposed borrow site and access road contain 12.8 acres of suitable habitat for gnatcatcher

(native upland/mixed coastal sage scrub) which would be temporarily impacted by the project. This area was previously used for other SARP construction and consists of restored coastal sage scrub.

Several recent observations throughout the Prado Basin and within the Santa Ana River below Prado

Dam (Reach 9) indicate that gnatcatchers have been expanding their range in the last three years. In

November 2017, biologists found one pair of gnatcatchers foraging in the mixed coastal sage scrub habitat within the proposed borrow site. Another individual, or two, were detected along the northern edge of the borrow site. However, in subsequent surveys within the borrow area in spring of 2018, gnatcatchers were not detected within the project footprint. There were, however, multiple gnatcatchers observed in nearby coastal sage scrub just to the west of the borrow site, including two nesting pairs, so it is likely they occasionally use the borrow area, at least for foraging purposes.

The proposed project contains 8.3 acres of proposed cuckoo critical habitat along the northern edge of the borrow site. According to communications and vegetation mapping provided by the Corps, only 0.3 acre of this is riparian habitat. The remainder of this area consists of non-native upland, which does not contain the physical and biological features which provide for the species’ life-history processes that are essential to the conservation of the species, although the project area is adjacent to such habitat (i.e. Prado Basin). The impacted acreage primarily consists of eucalyptus, which will be removed in order to improve drainage and the ability to later restore habitat within the borrow site area. The entire area will be restored with native vegetation.

Prior to 1995, a small but apparently stable population of cuckoos resided within Prado Basin, but they declined in the late 1990s and the last cuckoo in Prado Basin was detected in 2011 (Pike et al.

2017). Therefore, the critical habitat for this species within the project footprint and the adjacent area is not expected to be occupied during the construction of Alcoa Dike.

EFFECTS OF THE ACTION

There were two vireo territories located within the project footprint based on the data provided in the

2001 Corps SEIS/EIR document. Despite the increase of vireos within the vicinity of Prado Basin, there remain only two documented vireo territories within the project footprint, based on 2017 survey data, which will be directly impacted by native riparian vegetation removal during construction activities. These territories are located within the ground-disturbing impact areas: the borrow area, and where clearing and grading for the dike construction will occur. In 2001, the two vireo territories represented approximately eight percent (2 out of 26) of the known vireo territories within Prado

Basin (Corps, 2001). Now, the two vireo territories constitute only 0.4 percent (2 out of 549) of the

Prado Basin population (Pike et. al. 2017), which will not have a lasting or significant effect on the overall population.

The clearing of vireo habitat for project construction will occur outside of the vireo breeding season

(CM 3); therefore, we do not expect that vireo adults, eggs, or nestlings will be killed or injured during the habitat removal. However, vireos are highly territorial and exhibit site fidelity; therefore, these two vireo individuals (or pairs) will lose their current territory and will be forced to relocate.

The vireos may be able to establish new territories elsewhere in the vicinity within the Prado Basin, although as vireos are distributed throughout much of the suitable habitat, the displaced birds will be forced to compete with residents which may decrease reproductive fitness.

A distance of 200 feet from the project footprint was used by the Corps to determine potential noise and other indirect impacts from construction activities. The total amount of riparian vegetation within this 200-foot impact area is approximately 52.0 acres. In 2017, eight vireo territories were detected within 200 feet of the project footprint, and may be susceptible to indirect impacts from construction activities including loud noises, dust, and increased human presence. Such activities could disturb breeding birds, and if nesting, may result in nest failure or abandonment. Two of these eight birds/pairs held territories within 200 feet of the dike construction itself. Some of the construction equipment to be used for dike construction, such as graders and scrapers, typically produce noise at

89 dBA up to 50 feet from the source (per the 2018 DSEA/EIR addendum). We expect that such noise cannot be reduced to a suitable noise level for these pairs, even with the use of sound walls.

Therefore, these two birds/pairs may be forced to relocate their territories and/or their breeding behavior may be affected, such as the ability to establish and defend territories, or locate their young and mates. The remaining six territories are located within 200 feet of the haul road. The 2018

DSEA/EIR Addendum estimates 150 combined maximum daily haul trips from the borrow site to the dike construction site. If these trips occur during the vireo breeding/nesting season, and the implementation of sound walls are unable to sufficiently reduce the noise, it may force these birds also to relocate and/or affect their breeding behavior. To offset these potential impacts, noise monitoring will occur during the breeding season (February 28 through August 15) of each year and impacts beyond 60 dBA, or 5 dBA above ambient, or another agreed upon and documented amount, outside the project footprint, will be mitigated for on a 1:1 ratio per acre impact basis, per year (CM

5). As we anticipate noise impacts to be greater near the dike construction itself, the noise monitoring effort will be doubled in this area, as compared to the other work areas (e.g. haul road, borrow area).

The overall impacts to the local vireo population will be far less than when the Alcoa Dike project was first considered. In the 2001 SEIS/EIR, four vireo territories were reported within 165 feet of the dike footprint. At the time, these four territories represented approximately 15 percent (4 out of 26) of the vireo population within Prado Basin. The eight vireo territories that now fall within this 200-foot impact area constitute 1.5 percent (8 out of 549) of the current vireo population within Prado

Basin. Implementation of CM 4, 5, 6, and 22, including the use of sound walls and noise monitoring, will minimize potential impacts to breeding and nesting vireo due to noise and dust from construction activities. The Corps has stated they will coordinate their noise monitoring plan with the Service prior to start of the 2019 nesting season.

The riparian habitat impact area within vireo designated critical habitat has increased since the design presented in the SEIS/EIR (Corps 2001). Whereas the previous design was expected to permanently impact approximately 1.5 acres of riparian scrub habitat, the total permanent impact to riparian vegetation is now expected to be 5.4 acres. Based on our 2012 biological opinion and CM 12, the habitat will be replaced at a 3:1 or 5:1 ratio. The Corps will either create 16.0 acres of riparian habitat or remove 26.8 acres of arundo from the upper Santa Ana River watershed. Habitat creation and restoration activities will occur during the non-breeding season for vireos (if adjacent to occupied vireo habitat; conservation measure 13). CM 2 and 8 will ensure that no riparian vegetation will be cleared beyond what is necessary for the project, avoiding impacts to additional vireo. The Corps has identified two potential areas in which they can offset both their permanent and temporary impacts.

These locations are the Corps-owned section of Temescal Creek between Auburndale Street and

Lincoln Avenue, as well as a 391-acre parcel to the north and west of the Corona Municipal Airport, within Prado Basin. Because no permanent changes in drainage patterns are anticipated, and no alterations to stream flow within the Temescal Creek or Santa Ana River will occur (Corps, 2018), we do not expect degradation of vireo habitat outside of the permanent impact area.

The Corps’ estimate of temporary impacts to riparian vegetation has increased from 4.3 acres in 2001 to the current estimate of 29.7 acres. In addition, indirect impacts may include minor alterations in existing topography, changes in surface hydrology, soil compaction, erosion and sedimentation, fugitive dust accumulation, disruptions to native seed banks, and colonization by non-native plant species. One or more of these indirect impacts could affect plant establishment and survival, especially of riparian species.

Indirect and temporary impacts will be minimized and mitigated through the use of best management practices and restoration of temporarily disturbed areas with native vegetation. Proposed measures include:

1. Avoidance of unnecessary impacts due to construction activities will be avoided by delineating construction boundaries (conservation measure 2);

2. Minimization of temporary impacts to riparian vegetation will occur on-site by restoring riparian vegetation at a 1:1 ratio. The Corps will also keep all temporarily disturbed areas free of non-native vegetation until native riparian vegetation is reestablished (conservation measure 9);

3. Minimization of temporary impacts to riparian vegetation will occur off-site but within the

Santa Ana River by either removing arundo vegetation at a 1:1 ratio (i.e. an estimated 29.7 acres for the Alcoa Dike project), and then actively managing for the life of the SARP; or removing and maintaining riparian habitat arundo-free for five years at a 3:1 ratio (89.1 acres) (conservation measure 11);

4. Restoration activities will be initiated immediately following the completion of project activities (conservation measure 13).

These measures will offset any temporary impacts to vireo and its critical habitat within the project area.

Coastal California gnatcatcher

The proposed project is anticipated to indirectly affect the 3 to 4 gnatcatchers that may be using the borrow site for foraging during the non-nesting season. Their foraging activities may be disrupted, and they may be forced to relocate if they are in the area during the commencement of sediment hauling activities, which will occur year-round. Previously restored or existing suitable coastal sage scrub/gnatcatcher habitat occurs within the vicinity that appears to be unoccupied, which the gnatcatchers may relocate to if they become displaced during construction activities. Therefore, any effects are expected to be minimal.

While we do not expect gnatcatchers to use the area for nesting, effects to potentially nesting gnatcatchers will be avoided through conservation measure 3, in which vegetation will only be removed during the non-breeding season (prior to February 14). Effects to gnatcatchers in the project vicinity will be minimized by initiating restoration activities through conservation measure 10, 13, and 16. Upon project completion, the construction contractor will grade the borrow site to drain and restore its natural topography, as well as hydroseed it with mulch, soil binders and native seed mix.

However, the Corps states that this area may be disturbed again in the future as a stockpile area for a larger sediment removal project that is being considered as part of the Prado Basin Feasibility Study.

The Corps will compensate for the temporary loss of 12.8 acres of coastal sage scrub gnatcatcher foraging vegetation by restoring this same amount of habitat within an undefined area in proximity to the borrow site and outside of the construction limits (conservation measure 17). The Corps has identified several locations to the south and west of the borrow pit which currently contain non-native grassland habitat that can be restored with coastal sage scrub for the benefit of gnatcatcher.

The 12.8 acres will be managed for eight (8) years post-construction while the borrow site is being restored. Prior SARP restoration efforts within these areas have resulted in an increase of native coastal sage scrub vegetation in the general Prado Dam embankment vicinity, indicating that past restoration techniques used by the Corps in this area will again be successful in establishing coastal sage scrub vegetation.

The proposed project will temporarily affect 8.3 acres of proposed cuckoo critical habitat primarily consisting of non-native upland vegetation, which will be restored with native habitat upon project completion. The 0.3 acres of riparian vegetation which will be temporarily removed by the project is less than 0.1 percent of the proposed cuckoo critical habitat in the Prado Basin. As the Corps has agreed to restore each acre of riparian vegetation that is temporarily disturbed (conservation measure

9),…