FIO-SARM-R95B-USFWS-Biological-Opinion_23July2015.pdf

United States Department of the Interior

FISH AND WILDLIFE SERVICE

In Reply Refer To:

FWS-OR-0880408-15F0592

Colonel Kimberly M. Colloton District Commander

Ecological Services Carlsbad Fish and Wildlife Office

6010 Hidden Valley Road, Suite 101 Carlsbad, California 92011

U.S. Army Corps of Engineers, Los Angeles District 915 Wilshire Boulevard, Suite 930 Los Angeles, California 90017-3409

Attention: Eduardo DeMesa Hayley Lovan us.

FISH & WILDI.IFE

SERVICE

JUL 2'3 201J

Subject: Reinitiation of Formal Section 7 Consultation on the Santa Ana River Mainstem Flood Control Project to Address Proposed Reach 9 Bank and Bridge Protection Components (Phases 4, SA, 58, and BNSF Bridge Project) along the Santa Ana River in San Bernardino, Riverside and Orange Counties, California

Dear Colonel Colloton:

This document responds to your letter dated January 23, 2015 , requesting reinitiation of formal consultation on the Santa Ana River Mainstem Flood Control Project (SARP) to address the addition of the Reach 9 Bank and Bridge Protection Project to the overall SARP and the associated effects of the additional project components on the endangered least Bell's vireo (Vireo beflii pusillus; vireo) and the threatened Santa Ana sucker (Catostomus santaanae) and its designated critical habitat, in accordance with section 7 ofthe Endangered Species Act of 1973 (Act), as amended (16 U.S.C. 1531 et seq.).

Your January 23, 2015, letter requesting reinitiation of formal consultation was received by us on January 30, 20 15. The additional project components consist of a series of bank and bridge protection measures associated with the SARP, also often termed the Santa Ana River: Reach 9 Phases 4, SA, 58, and BNSF Bridge Project. The proposed project and associated environmental documentation supplements a previous Federal Project, the SARP, which is designed to provide flood risk reduction to areas susceptible to floods ranging from 1 00-year to 190-year frequencies in San Bernardino, Riverside, and Orange counties, as described in the Final Supplemental Environmental Impact Statement/Environmental Impact Report for Prado Basin and Vicinity, Including Reach 9 and Stabilization ofthe BluffToe at Norco Bluffs [2001 SEIS/EIR; U.S. Army Corps of Engineers (Corps) 2001].

Your request for consultation also included the federally threatened coastal California gnatcatcher (Polioptila californica californica; gnatcatcher). Based on our review of the Draft Supplemental

Colonel Kimberly Colloton (FWS-OR-08B0408-15F0592)

Reach 9 Phases 4, 5A, 5B and BNSF Bridge Project (Draft SEA; Corps 2013a) and additional information provided during the consultation period, we have determined that the proposed action is not likely to adversely affect the gnatcatcher or its designated critical habitat. We reached this conclusion for the following reasons:

1. Although gnatcatchers have been observed in the project vicinity, no gnatcatchers have been reportedly observed within 300 feet of the construction direct footprint (including staging areas or haul and access routes); therefore, none will likely be directly affected. Expected construction noise and other disturbances (e.g., dust) are not expected to disrupt gnatcatchers in the area. The Corps will perform directed protocol surveys in advance of construction. If gnatcatchers are detected within the project footprint or project-related high noise areas, the Corps will consult informally with our agency, the U.S. Fish and Wildlife Service (Service), to determine whether additional measures can be implemented to prevent gnatcatchers from being adversely affected. If adverse effects to gnatcatchers cannot be avoided, the Corps will reinitiate formal consultation to address these impacts.

2. The construction area in or near potential gnatcatcher habitat areas is already high in ambient continuous noise due to its proximity to the SR-91 freeway and other road and railroad infrastructure. As such, most construction noise reaching any nearby gnatcatchers will be at least partially masked by existing noise. Conservation measures that will be implemented to minimize the potential for disturbance to nesting vireo in the area (e.g., installation of sound walls adjacent to the construction boundary and haul routes) will further reduce the potential for disturbance to any gnatcatchers in the project vicinity;

3. The proposed project will permanently impact 13.90 acres of gnatcatcher designated critical habitat, including about 11.16 acres of primary constituent elements (PCEs)1, in Unit 9, East Los Angeles County-Matrix/NCCP Subregion of Orange County, which includes a portion of the Santa Ana River Canyon (72 FR 72010). The 13.90 acres of permanent impact is a fraction (0.08 percent) of the total acreage in Unit 9 (17,552 acres). The primary noted function of critical habitat within the Santa Ana River Canyon is to maintain connectivity and genetic interchange between significant gnatcatcher populations in the Santa Ana Mountains and those in the Chino/Puente Hills (72 FR 72010). The project will permanently impact narrow strips of habitat along the edges of the Santa Ana River floodplain and is anticipated to have an insignificant effect (i.e., one that cannot be meaningfully measured, detected, or evaluated) on connectivity and genetic interchange between gnatcatcher populations in the Santa Ana Mountains and those in the Chino/Puente Hills.

4. The proposed project will temporarily impact 45.26 acres of critical habitat, including 39.49 acres of PCEs for the gnatcatcher. Although the overall acreage of PCEs will be temporarily reduced in Unit 9, the temporary impact area will be restored following completion of the project using a native seed mix, irrigated native sage scrub container plants, and exotic plant

1 Gnatcatcher PCEs include sage scrub and non-sage scrub vegetation communities that support gnatcatcher foraging, nesting, rearing of young, intra-specific communication, roosting, dispersal, genetic exchange, or sheltering. For this consultation, we included all areas of undeveloped open space other than perennial rivers and streams. Bare areas affected by previous projects are included as PCEs because they would have been restored with native vegetation suitable for supporting the gnatcatcher behaviors identified above.

control to expedite the restoration process. Because existing non-native upland vegetation and bare ground in the project footprint will be relatively quickly replaced with higher-function native scrub vegetation, there will likely be an overall increase in the function, carrying capacity, and area of available PCEs in Unit 9. Thus, the proposed action will not diminish the primary functions of Unit 9 or the value of designated critical habitat for recovery of the species.

This reinitiation of the SARP December 5, 2001, biological opinion does not consider or cover the newly identified effects of operations of Prado Dam that were not addressed by 2001 SARP biological opinion or subsequent amendments. During the period between 2008 and 2011, it became apparent to the Corps and Service that new information existed regarding predicted long-term scour and riverbed degradation to portions of the river channel within Reach 9 that were likely to result from high flow releases from Prado Dam planned to occur during infrequent flood events [e.g., see Department of the Interior (DOI) 2008, Orange County Flood Control District (OCFCD) 2010, Medak 2010 pers. comm., Corps 2011, Corps 2012c, Corps 2013b, Corps 2015a]. For example, Chang (2008) estimated in Reach 9 "that upwards of 26 feet of the Santa Ana River will down cut due to lack of sediment replenishing the area." Similarly, an estimated scour depth of 16 feet below the current river thalweg2 resulting from a future 30,000 cubic feet per second release from Prado Dam (Figures 27 and 28) was provided by the Corps for a design flood event for the Phase 5A portion of the proposed project in Reach 9 (Corps 2015a).

While some degradation of the river channel in Reach 9 over time was predicted in our 2001 SARP opinion, the extent of potential additional scour and degradation noted above, and its potential scope of effects on listed species, were not known to the Service in 2001 and have not as yet been analyzed or formally consulted upon. While estimates of maximum scour depths during storm flow events in several point locations in Reach 9 have been provided to the Service, overall effects of long-term degradation across the morphology and ecosystems of Reach 9 have not been predicted, modeled, or quantified. Additionally, new information on increased and/or accelerated sediment deposition in the river upstream of Prado Dam have not been analyzed for effects on listed species or formally consulted upon. Similarly, the potential effects of operations of Seven Oaks Dam on fluvial processes and water flows downstream and these effects on Santa Ana sucker and its critical habitat have not been formally consulted upon.

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 the 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 the effects of operations under the SARP not previously addressed by the 2001 SARP biological opinion or its amendments.

The analysis and conclusions provided herein are based on: (1) your January 23, 2015, letter requesting reinitiation of consultation; your letter dated April 15, 2015, providing additional project

2 Thalweg is the deepest portion of a river channel information; and an email messages dated May 5 and 29, 2015, from your staff with additional project conservation measures; (2) information provided in the Draft SEA dated January 2015 for the proposed project; (3) a series of meetings, conference calls, and email exchanges between Corps and Service staff between April and July 2015; and (4) correspondence, notes, and information compiled during the course of our consultation with the Corps on the subject project. The information and other references cited in this 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 Service’s Carlsbad Fish and Wildlife Office (CFWO).

CONSULTATION HISTORY

The Service has issued a series of biological opinions (i.e., Service 1980, 1989, 1993, 2000a, 2000b, 2001a, 2001b, 2002a, 2002b, 2003, 2004, 2012, 2013a, 2013b, 2013c) addressing the effects of constructing, operating, and maintaining the SARP on federally listed species and their critical habitat. In 2012, the Service expressed significant concerns to the Corps regarding potential effects of ongoing operations at Prado Dam and proposed changes to the operations of Seven Oaks Dam on the Santa Ana sucker and its designated critical habitat.

As a result of discussions with the Service and others, the Corps committed to work with the Service to assess how operations of these dams are potentially affecting geomorphology, hydrology, sediment transport, and other factors important to maintaining suitable habitat conditions for the Santa Ana sucker. The Corps also committed to coordinate with the Service on management measures that may be implemented to avoid and minimize adverse effects to sucker and its designated critical habitat (Corps 2012b). The Corps initiated the Prado Basin Feasibility Study, in part, to determine if bypassing sediment around Prado Dam could improve the aquatic environment and help ameliorate the substantial bed degradation downstream of Prado Dam that is known to be due in large part to the presence and long-term operation of the dam (Corps 2012b). However, no management measures have yet been implemented and habitat conditions for the Santa Ana sucker within the river have continued to degrade to the point where the species is increasingly vulnerable to extirpation on the river (Service 2011, 2014a, 2014b).

The SARP was addressed initially in a biological opinion issued on October 1, 1980 (Service 1980).

As noted above, a subsequent series of biological opinions and amendments have been issued. On 5 December 2001, we issued a biological opinion (2001 biological opinion) that addressed, in part, components of the SARP that were added to protect existing infrastructure in Reach 9 of the Santa Ana River (floodplain between Prado Dam and Weir Canyon Road Bridge). These project components are generally referred to as “Reach 9 Projects” (also referred to as Reach 9 features and Santa Ana River Reach 9 Flood Control Projects). The Corps has completed the following Reach 9 Projects to date: Green River Mobile Home Park Levee, Lower Highway 91 Embankment, Car Wash/Strip Mall Bluff Stabilization, the Reach 9 Phase 2A Project (including the Upper Highway 91 Embankment and Green River Housing Estate Embankment), the Reach 9 Phase 2B Project (Green River Golf Club Embankment), and the Reach 9 Phase 3 (replacement of existing soil cement embankment located adjacent to State Route 91).

On March 27, 2012, we issued an amendment (2012 amendment) to the 2001 biological opinion to address proposed changes to the mitigation approach for the SARP3 that will be applied to the remaining SARP components (Service 2012a); that document is incorporated by reference herein.

On January 23, 2015, we received a letter from your agency requesting reinitiation of formal consultation to address the addition of the proposed Reach 9 Bank and Bridge Protection Project to the SARP; we initiated formal consultation on this date. On March 5, 2015, your staff confirmed by an email that formal consultation was requested for the preferred alternative identified in the Draft SEA as the herein proposed project. On March 31, 2015, we responded to your January 23, 2015, letter with a request for additional information. On April 15, 2015, you responded by letter with additional information.

On April 23, 2015, our staffs met to discuss aspects of the proposed project, including conservation measures. On May 29, 2015, we were provided a revised project description by email. In May and June 2015 our respective staffs held several conference calls and exchanged emails regarding project measures and likely impacts; these included modifications to the proposed project to reduce impacts (such as modified slope protection alignments/types/boundaries) and improve conservation measures (including changes in minimization and offsetting measures and expected funding/costs).

The Corps had previously been coordinating with the Service on potential Santa Ana River red algae eradication strategies to offset impacts to federally listed species from the recently completed Reach 9 Phase 3 project. During consultation on the herein proposed project, the Corps determined in coordination with the Service that substitution of the measure “2.54 Acre Scour Enhancement” (within the Description of the Proposed Action, Specific Conservation Measures for the Santa Ana Sucker, below) will provide equal or greater benefits to the Santa Ana sucker as compared to algae control and is more closely aligned with Corps capabilities.

A draft of the 2015 amendment to the 2001 SARP biological opinion was provided to the Corps for review and comment on July 15, 2015. Comments were received on July 17, 21, and 22, 2015, and incorporated or addressed, as appropriate, in this final 2015 amendment to the 2001 SARP biological opinion.

BIOLOGICAL OPINION

DESCRIPTION OF THE PROPOSED ACTION

A detailed description of the SARP may be found in the Supplemental Final Environmental Impact Statement/ Environmental Impact Report (Corps 2001) and 2001 biological opinion, which are herein incorporated by reference. This 2015 amendment to the 2001 biological opinion concerns the potential effects of the proposed Santa Ana River Reach 9 Phases 4, 5A, and 5B projects and the BNSF Railroad Bridge Protection Project, also known as the Reach 9 Bank and Bridge Protection Project, on the vireo and Santa Ana sucker and its designated critical habitat. As indicated in your January 23, 2015, letter, the proposed project footprint will begin about 2.25 miles downstream of Prado Dam at the Burlington Northern and Santa Fe (BNSF) Railroad Bridge crossing in

3 The revised Conservation Measures are included in Service (2012a).

Riverside County and continue another 5 miles downstream along the Santa Ana River into Orange County (Figure 1).

Proposed Corps Project and Non-Federal Sponsors

The Corps and non-Federal sponsors: OCFCD, Riverside County Flood Control and Water Conservation District (RCFC&WCD), and San Bernardino County Flood Control District entered into a local cooperation agreement (LCA) on December 13, 1989, to implement the SARP and provide flood damage reduction along the Santa Ana River. The Corps is the lead agency under the National Environmental Policy Act, and the OCFCD is the lead agency under the California Environmental Quality Act. RCFC&WCD will primarily be responsible for maintenance of the BNSF Bridge project segment and will also take subsequent discretionary actions including, but not limited to: utility relocation, property acquisition, obtaining easements, issuing encroachment permits, and entering into cooperative agreements (Corps 2015a).

Project Background

The Santa Ana River flows through Orange, Riverside and San Bernardino counties in California.

Several major modifications to flood risk management features on the Santa Ana River were approved as part of the Corps Los Angeles District’s SARP (Corps 2013b). The SARP is a flood risk management system located along a 75-mile reach of the Santa Ana River (Figure 2). The purpose of the overall SARP is to extend the flood risk management to areas within the watershed that are susceptible to flooding during storm events ranging from 100-year through 190-year frequencies.

The segment of the Santa Ana River between the mouth of the river at the Pacific Ocean and Prado Dam - about 30.5 miles in length - is known as the Lower Santa Ana River channel. The SARP includes various project features within the Prado Dam Basin and along the Lower Santa Ana River channel. These project features, most of which have been implemented already, are part of a flood risk management system to: increase the storage capacity within the Prado basin; release higher flows through the dam’s outlet works; convey higher flows through the Lower Santa Ana River channel; and provide additional bank protection, as required, to withstand the erosion forces caused by flow impingement and higher velocities (Corps 2013b). The Lower Santa Ana River channel is divided into 10 reaches (Reach 1 through Reach 10). Reach 1 begins at the Pacific Ocean, and Reach 9 ends at the Prado dam outlet works (Corps 2013b).

Reach 9 extends about 8.3 miles from Prado Dam in Riverside County, California, downstream to the Weir Canyon Road/Yorba Linda Boulevard Bridge, in the City of Yorba Linda, Orange County (Figure 1). Phase 1, Phase 2A, Phase 2B, and Phase 3 have been constructed. Phase 4, Phase 5A, Phase 5B, and the BNSF railroad bridge constitute the proposed project addressed by this 2015 amendment to the 2001 biological opinion. Technical studies completed since the 2001 SEIS/EIR indicate that the potential for riverbed degradation and scour in the Reach 9 area is more severe than contemplated in 2001 (Corps 2015a). An Engineering Document Report (EDR) for the Santa Ana River Mainstem Project Lower Santa Ana River Channel – Reach 9 Orange and Riverside Counties, CA (Corps 2013b) was prepared by the Corps to evaluate technical solutions to fortify and stabilize the Santa Ana River banks to reduce the risks to life, safety or property damage that could result from the additional bed degradation in Reach 9. The proposed project will implement structural measures in Reach 9 as described in the EDR.

In 2012, a Corps study evaluating the hydrology, hydraulics, and sedimentation in Reach 9 identified that planned Reach 9 improvements were not sufficient to withstand a release of 30,000 cubic feet per second from Prado Dam (Corps 2015a). The Corps determined that existing local flood risk management measures (bank protection) composed largely of soil cement and riprap within Reach 9 did not provide the sufficient fortifications necessary to withstand the potential 30,000 cubic feet per second releases from Prado Dam and related long-term scour (Corps 2015a).

Proposed Project

The purpose of the proposed project phases is to prevent undercutting or erosion of Santa Ana River embankments and railroad bridge piers. High-velocity discharges from Prado Dam could undermine the toe of existing channel embankments in certain locations and could erode foundation materials underneath the BNSF bridge piers. To operate the SARP as designed, it is necessary to be able to release 30,000 cubic feet per second from Prado Dam (Corps 2015a). Protection is reportedly needed in areas where existing bank armoring does not exist (i.e., portions of Phase 4 and Phase 5B) or where the buried toe of existing bank protection does not extend deep enough (i.e., Phases 5A and 5B and portions of Phase 4) to withstand the design flow (Corps 2015a). At the BNSF Bridge, the piers do not extend deep enough to withstand design flow releases from Prado Dam (Corps 2015a).

The January 2015 Draft SEA provides details for various elements and tasks associated with the proposed action, including construction phasing; water diversion and dewatering; staging areas;

access; roads; storm drain outlets; construction equipment; construction schedule; site preparation;

and operations and maintenance of the proposed facilities.

All staging areas and temporary work areas (outside of the river low-flow diversion needed for construction of the proposed BNSF bridge segment) will be modified in the field so as to be located out of the existing low-flow channel and well-outside of any recent low-flow channels so as to reduce the potential for flooding of these areas and associated potential impacts during the construction period.

This consultation considers future maintenance of the proposed slope and bridge protection structures and habitat restoration areas, subject to the conservation measures included in the 2012 amendment, as modified below. Identified maintenance roads at the base or top of the structures will be used to access the sites for maintenance purposes. Structure maintenance involves routine inspections, structural repairs, and vegetation removal from the structure surfaces and identified maintenance roads. All proposed project operations and maintenance will be limited to the above-ground portions of proposed structures and maintenance roads occurring within the project permanent footprints shown in Figures 3 through 25.

A summary of each proposed phase or segment is provided below.

Phase 4

Phase 4 is proposed to be located along the south bank of the Santa Ana River, beginning about 3.5 miles downstream of the outlet from Prado Dam, in the vicinity of Coal Canyon Road, and will extend 3,150 feet (0.59 mile) downstream (Figures 3-10). At its downstream limit, Phase 4 will tie into Reach 9, Phase 3, which was recently constructed, and at its upstream limit will tie into State of California, Department of Parks and Recreation (State Parks) land downstream of Reach 9, Phase 2B.

To protect SR-91 from sustained impinging flows from the Santa Ana River, California Department of Transportation (Caltrans) constructed and upgraded four sections of bank protection along the south bank of the Santa Ana River (Corps 2015a). The structural integrity of the existing bank protection for locations where there is no river setback between the low-flow riverbank and the freeway is unknown because the toe is submerged by the low-flow adjacent to the freeway embankment. Therefore, the adequacy of the existing toe depth and structural soundness of the Caltrans constructed measures against maximum scour, estimated at 16 feet below the current thalweg, could not be verified (Corps 2015a). Thus, the purpose of Phase 4 is to provide additional bank protection to replace the Caltrans bank protection (Corps 2015a).

As proposed, an approximate 3,150-foot-long soil cement structure will be constructed as part of Phase 4. The structure will be about 30 feet in height and 10 feet in width and placed at a 1:1 slope.

About 10 feet of the structure will be exposed above-ground, with the remaining buried. Areas of the exposed and buried portions of the soil cement structure will each be about 1.5 acres. A trapezoidal cut will be excavated to place the soil cement structure. The excavation footprint will be about 100 feet wide along the 3,150-foot span. Excavated material will be temporarily stored in staging areas during construction before being replaced within the excavated trench.

Existing soil cement structures may be encountered during excavation for Phase 4. If encountered, soil cement will be demolished with the option to dispose offsite or process it for reuse as backfill, if it is deemed suitable for construction. Any excavated material that is not suitable for the soil cement mix or for backfill will be disposed of offsite. The temporary construction easement (which, along the identified staging area boundaries, constitute the project footprint limits; Figures 3 and 4) for Phase 4 is about 35 acres and will include the footprint of the new soil cement structure, haul roads, staging areas, stockpile areas, location of batch plant, the temporary bike path during construction, and the restored bike path (Figures 3 and 4).

A 16-foot wide road of decomposed granite will be installed immediately along the south side of the soil cement structure (Figure 11). The road will serve dual purposes – it will be used for future operations and maintenance (O&M) and as a pedestrian trail. The road will traverse both Phase 4 and Phase 3, which was completed just west of Phase 4. Installation of the road through both of these phases will occur under the Phase 4 construction contract. Additionally, a 12-foot wide paved bike trail will be installed adjacent and south of the new road (Figure 11). This permanent trail will replace the temporary bike trail that currently passes through Phases 3 and 4. Installation of the new road and trail will occur within the temporary construction easement of Phase 4 (Figures 3 and 4). No maintenance road or future vegetation clear zone is proposed north of the base (river flow side) of the proposed bank protection.

Equipment anticipated to be used for construction of the soil cement structure will include excavators, front-end loaders, bulldozers, dump trucks, soil cement compactors (e.g., sheep-foot and smooth-wheel rollers), a grader, concrete pump trucks, water trucks, and a soil cement batch plant.

Additionally, delivery trucks will be associated with imported materials.

Clearing and grubbing is expected to begin in fall or winter 2015. The installation of the dewatering system and excavation will begin mid-April 2016, or later. Excavation and stockpiling will require about 3 months, and the placement of soil cement will require about 5 months. Backfilling and compaction of the toe will require about 2 months. Construction of the restored permanent bike path and demolition of the temporary bike path will have an expected duration of 3 months, followed by about 4 months of hydroseeding and replanting. Construction is expected to continue until about December 2017. Daily construction will occur between 8:00 a.m. and 5:00 p.m.

The project will require dewatering during excavation, placement of soil cement, and backfilling, but diversion of the river’s low-flow is not anticipated as part of Phase 4 (Corps 2015a). About 5.7 acres of land will be used for staging, stockpiling, and the soil cement batch plant. Staging areas are proposed to be located parallel to the proposed soil cement alignment, on the river side of the project inside the channel.

During formal consultation on the proposed action, the Corps in June 2015 committed to reduce the length of the Phase 4 project by removing about 450 feet from the upstream end of the proposed bank protection structure. This upstream portion will be reanalyzed and may be redesigned by the Corps, at which time it would be addressed under a separate consultation/amendment. The project’s permanent and temporary footprints have been reduced accordingly.

Additional Work to Be Conducted under Phase 4 -- State Parks, Phase 2B Gully Erosion Repair:

During Reach 9, Phase 2B construction (already completed), the construction contractor encroached upon State Parks property in the vicinity of Coal Canyon. As reparation for the encroachment, OCFCD, State Parks, and the Corps agreed that the Corps will repair two off-site gully erosion areas just east of Phase 4 (Figures 4, 5, and 7). This repair will take place as part of the Phase 4 construction contract.

Repair of the two gully erosion areas will cover about 0.35 acre and will include: stabilizing; grading areas to 2:1 slopes or flatter; revegetating; establishing vegetation; monitoring; and removing non-natives for a total of 5 years.

Phase 5A

Phase 5A is proposed to be located along the north bank of the Santa Ana River, parallel to East La Palma Avenue. It will extend from the recently completed Reach 9, Phase 1 (existing bank protection) at the Mercado Del Rio Plaza, 4,083 feet (0.77 mile) upstream to the vicinity of Via Lomas De Yorba-West Road (Figures 12-15). Phase 5A will include a 90-degree bend in the embankment of the Santa Ana River currently protected by ungrouted riprap revetment of the Lomas De Yorba-Sur (LDY-S) Levee.

Fortification and deepening of the existing bank protection within the Phase 5A is proposed by the Corps to prevent future lateral erosion into the north river bank and protect adjacent infrastructure consisting of East La Palma Road, the Santa Ana River Trail, industrial facilities, and existing commercial and residential development (Corps 2015a). An existing 4,083-foot section of the LDY-S Levee consisting of ungrouted stone bank protection will be replaced by 980 feet of a grouted stone structure and 3,273 feet of steel sheet pile wall. The excavation footprint for grouted stone protection will be about 80 feet wide along the 980-foot reach.

No diversion or control of water in the active river channel (e.g., low-flow) of the Santa Ana River will be required during construction of Phase 5A. Dewatering will occur for the proposed grouted stone construction but not for the proposed Phase 5A sheet pile construction.

Equipment to be used for construction of the grouted stone structure will include excavators, front-end loaders, bulldozers, dump trucks, a grader, concrete pump trucks, and water trucks. Additionally, delivery trucks will be associated with imported materials. Equipment to be used for construction of the sheet pile protection will include a hydraulic hammer and heavy-duty cranes. Construction is expected to take 24 months to complete beginning with clearing and grubbing in about August 2015.

Construction is expected to continue to about August 2017. Daily construction will occur between 8:00 a.m. and 5:00 p.m.

Staging areas for Phase 5A will be located at the upstream and downstream ends of Phase 5A as shown in Figures 12 through 15 and occupy areas of 1. 4 and 1.38 acres of the river channel, respectively. Staging areas will be used for storage of construction equipment and materials and as turnaround areas.

Access routes will occur within the temporary construction easement (noted on Figures 12 through 14), and no new haul roads will be developed for construction. The existing Santa Ana River Trail at the top of the north bank will be used for routine inspections and O&M. The existing dirt access road along the base of the levee will remain upon construction completion and will be used for O&M on the new grouted stone and sheet pile structures. This dirt road will also be extended from its terminus at the downstream (west) end of the project, for about 300 feet to the west (Figures 12-14). The road extension will be installed on top of the buried toe of the grouted stone structure.

Sheet Pile

The proposed sheet pile wall will be situated along the top edge of the existing north bank to minimize excavation for installation of tiebacks and minimize environmental impacts. Installation of tiebacks requires an approximate 8-foot vertical excavation of the existing bank, from the top of the existing bank. The sheet pile will be a 2-foot-wide “Z”-shaped steel wall with tiebacks, and will be driven vertically down into the existing bank to a design elevation; height of the sheet pile varies from 45 to 50.5 feet (Figure 16). Removal and reuse of the existing riprap stone and compacted earth fill will be required and needed for sheet pile tieback installation. Backfill to restore the compacted earth fill embankment will be required after completion of sheet pile tieback installation. The final configuration of backfill will match the original embankment configuration. It is anticipated that most, if not all, excavated material will be used for construction of Phase 5A.

Grouted Stone

The proposed grouted stone structure, which will be placed against the existing bank, will be 24 inches thick and have a 2:1 slope (Figure 17). The grouted stone structure will be about 37.5 feet tall, measured vertically from 1 foot below the design scour line to top of the structure, and buried about 18 to 20 feet below the channel invert. In addition, a minimum 3-foot-thick riprap stone will be installed at the toe of the 24-inch-thick stone for additional scour protection. Existing riprap stone along the bank will be re-used. Construction of riprap stone and 24-inch grouted stone revetment will require excavation of a trapezoidal trench about 80 feet wide by 980 feet long. Stone will be transported to the site from a quarry site near Prado Dam; 16 daily truck trips are anticipated. Excess excavated material will be hauled to appropriate disposal sites.

Phase 5B

Phase 5B, as proposed, will extend from Phase 5A upstream about 3.7 miles to an existing locally constructed existing sheet pile wall that functions to protect the BNSF rail line (Figures 8, 9, 10, 11, and 12). Phase 5B will extend nearly 3,000 feet upstream of the limit of the existing LDY-S Levee (Corps 2015a).

In Phase 5B, bank protection is reportedly necessary to prevent future lateral erosion into the bank line and protect infrastructure consisting of East La Palma Avenue; the Santa Ana River Trail;

industrial, commercial, and residential development; and the BNSF rail line (Corps 2015a).

Maximum scour in this area is anticipated to reach a depth of 14 feet below the current thalweg during this design release (Corps 2015a). Bank protection in Phase 5B is reportedly necessary to replace the LDY-S Levee through Phase 5B and extend beyond the current upstream limit of the LDY-S Levee (Corps 2015a).

As proposed, grouted stone will replace existing riprap of the LDY-S Levee and be installed on the river bank upstream of the existing levee, where the river bank is currently unprotected. The new grouted stone structure will be 24 inches thick and have a 2:1 slope. The grouted stone structure will range in height from 30 to 45 ft., with the buried portion of the grouted stone slope about 25 feet deep. Construction of grouted stone revetment will require excavation of a trapezoidal trench about 80 feet wide by about 19,700 feet long (the length of the proposed protection). Excess excavated material and unsuitable stone will be hauled to appropriate disposal sites.

No diversion or control of water in the active river (e.g., low-flow) channel of the Santa Ana River will be required during construction of Phase 5B. Dewatering will occur for grouted stone construction within the project footprint for Phase 5B.

Equipment to be used for construction of the grouted stone structure will include excavators, front-end loaders, bulldozers, dump trucks, a grader, concrete pump trucks, and water trucks. Additionally, delivery trucks will be associated with imported stone; 20-40 daily truck trips are anticipated.

Construction is expected to take about 24 months to complete. Clearing and grubbing is proposed to begin in August 2016. Construction is expected to continue to about August 2018. Daily construction will occur between 7:00 a.m. and 5:00 p.m.

Three staging areas will be required for Phase 5B: two along the main Phase 5B construction area, and a third location for the extension of bank protection near the BNSF rail line is at the upstream end of the Phase 5B segment (Figures 18 and 20). Precise locations of the staging areas have not yet been determined, although each will be about 1 acre in size or less. The Corps is exploring ways to potentially eliminate or reduce the size of at least one of the three staging areas. Staging areas will be placed out of the way of higher river flows, and new disturbance will primarily be limited to communities composed of non-native plant species. Access to the Phase 5B construction area will occur via East La Palma Avenue and the Santa Ana River Trail along the top of the LDY-S Levee.

Existing ramps off East La Palma will provide access to an existing dirt access road at the base of the levee. No new access roads will be required. The existing 15-foot-wide dirt access road along the base of the levee will be restored upon completion of construction and used for subsequent O&M activities for Phase 5B structures.

Along the upstream 2,900 feet of the proposed Phase 5B structures no dirt access road will be constructed or maintained along the base of the slope protection (directly parallel to the railroad tracks), to reduce impacts overall and to wildlife movement, including Brush Canyon.

During formal consultation on the proposed action, the Corps in June 2015 committed to modify the designs for Phase 5B for the upstream end of the proposed bank protection structure; the proposed plans for about 300-400 feet of the upstream end of Phase 5B (along the BNSF railroad tracks) was changed from grouted stone to the use of sheetpile (Figures 18-20). The project’s permanent and temporary footprints at the upstream end of Phase 5B will be reduced proportionately with the noted modification (since both the permanent and temporary footprints for use of sheetpile are typically narrower than those for grouted stone). This modification was proposed by the Corps due to concerns expressed by the Service regarding potential impacts to aquatic and wildlife movement resources at the upstream end of Phase 5B with the original design. This redesign will allow the Corps to construct slope protection at the upstream area of Phase 5B without diverting the nearby active low-flow of the Santa Ana River (as will likely be necessary if a grouted stone design was used in this location). If sheetpile is utilized for slope protection more than 300 feet west from the current upstream end of the proposed Phase 5B structure, then a series of access ramps over the new sheetpile will be constructed to maintain important wildlife movement across the slope (to/from the Santa Ana River area and the Chino Hills). These wildlife movement ramps will be constructed in such as fashion to accommodate predicted channel degradation and erosion for the area, including the potential for ramps to be constructed out of a combination of rip-rap, cobble, and a covering of river-gravel. The proposed project footprint area for all of these substitute measures will be smaller than shown for the grouted stone slope protection.

BNSF Railroad Bridge

The proposed BNSF bridge project segment consists of 3 separate bridges with one railroad track per bridge. These BNSF railroad bridges cross the Santa Ana River and bisect the recently completed Phase 2A bank protection project. The Green River Housing Estates/Green River Home Owners Association property (GRHE/GRHOA) is just upstream/north of the BNSF bridge and the Green River Mobile Home Park (GRMHP) is south of the bridge. Both residential areas are on the left bank of the river. The Corps' 2011 hydraulic analysis revealed new potential impacts to the existing BNSF bridge pier and abutment foundations (Corps 2013b). This analysis provided revised scour estimates to the Corps that indicated increased local pier scour and abutment scour in addition to increased long term general scour that could expose the bridge foundation to an unacceptable level and result in bridge stability concerns (Corps 2013b).

The purpose of the proposed BNSF bridge project segment is to provide additional scour protection measures to maintain bridge stability and avoid catastrophic collapse of the BNSF bridge during a 30,000 cubic feet per second design flow release (Corps 2015a).

Reinforced concrete walls, sheet pile and reinforced concrete diaphragm walls, and grouted stone protection will be constructed to provide additional scour protection to the BNSF bridge piers and abutments, and tie previously constructed bank protection along the east bank of the channel into the existing eastern bridge abutment (Figure 22, 23, and 25). Reinforced concrete enclosure walls will be installed around Pier Nos. 2 through 5 and reinforced concrete pier nose extension walls will be constructed immediately upstream of these piers. Construction will include sheet pile and reinforced concrete diaphragm walls with tieback anchors parallel to existing Pier Nos. 1 and 6 to guide the design flow safely under the bridge. Additionally, 24-inch grouted stone bank protection will be installed to tie the existing bridge abutment along the east bank of the river channel (Pier No. 1) into bank protection installed upstream (Phase 2A) and downstream (Phase 2B) of the BNSF bridge.

The active river channel and a high groundwater table occur in the BNSF Bridge project area, which will require dewatering to install proposed bridge protection features. The active channel of the Santa Ana River currently flows between Pier Nos. 4 and 5 and a water diversion will be required to dewater the active channel for installation of bridge pier nose walls and enclosure walls at these piers. The specific method and location of the river diversion will be proposed by the contractor.

Staging will occur within and throughout the temporary construction easement as needed to construct the project (Figure 22-25).

Construction access to the BNSF bridge project area will occur via SR-91 and Green River Road, and on temporary access/haul roads on the golf course adjacent to the Green River Mobile Home Park levee.

A new emergency ingress and egress road will be provided for the Green River Home Owner’s Association under the railroad bridge during and after construction.

The portion of the existing Green River Mobile Home Park bank protection temporary access road within the southern portion of the project footprint will be removed and restored following project construction. Permanent access to the southern portion of the project segment and the Green River Mobile Home Park levee for maintenance will occur from: (a) the Green River Mobile Home Park itself (through new gated access developed between interior roads within the Mobile Home Park and the existing bank protection road); (b) the existing Phase 2A project access road to the north and the new emergency ingress and egress road under the BNSF bridge; or (c) through development of a new permanent access road between the existing bank protection road and Green River Road, with a new alignment for this access road at the southern end that is more than 200 feet northeast of the current access road alignment (Figures 23-25).4 The temporary access road removal and restoration would be done with the goal of restoring and reducing disturbance to the B Canyon wildlife corridor that traverse the southern end of the footprint of this project segment (Undercrossing 91-17 in Figure 33).5 The former temporary access road alignment in this area would be restored with native upland vegetation, including vegetation appropriate for enhancement of the B Canyon wildlife corridor where appropriate.

4 While shown as a permanent feature in Figures 23-25, the current temporary access road alignment will be removed and revegetated. Permanent access for O&M will be provided as described herein.

5 The culvert entrance/exit for the B Canyon wildlife corridor is about 80 feet west of the junction of the existing temporary access road and Green River Road.

Equipment to be used for construction of bridge and bank protection features will include cranes, bulldozers, excavators, compactors, dump trucks, rollers, pickup trucks, earth augers, vacuum trucks, pile drivers, low overhead drill rigs, and low headroom hydromill. Additionally, delivery trucks will be associated with imported materials; 20 daily truck trips are anticipated on average. Construction is expected to take about 3 years to complete. Clearing and grubbing is proposed to begin in 2016 and will be completed outside of the bird breeding season (February 15 through August 15). Construction is expected to continue to about 2019. Daily construction will occur between 7:00 a.m. and 4:00 p.m.

Additional Project Work

A portion or all of the following activities may be conducted at the same time as construction of the above-listed features, and small portions may be included in Corps construction contracts where work limits overlap. This consultation does not address any of the following activities that would occur outside the mapped temporary or permanent footprint of the proposed project (i.e., Figures 3- 25), nor those that will include any permanent features outside of mapped project permanent footprint areas.

Santa Ana River Interceptor (SARI) Line Abandonment/Severing

SARI Line relocation construction is nearing completion and the contractor is scheduled to proceed with pipe abandonment of the existing SARI Line. The activity consists of sewer pipe abandonment procedures such as cleaning and flushing the system and sand or slurry fill of the abandoned pipeline.

However, due to concerns associated with potential impacts on river flow by leaving the pipeline intact, the Corps has required that the existing pipeline be severed at five locations where it crosses the low-flow channel as part of the abandonment plan. The severing process will likely employ steel piles driven into the pipeline to fracture the concrete and sections will be filled with sand and slurry plugs. In addition, the top section of existing manholes will be removed, the shaft filled with sand or slurry, and the base of the manhole shaft perforated (Corps 2015a).

SARI Line Emergency Rock Removal

For many years, the potential for erosion-related damage to the existing SARI Line has been a cause of concern for the California Regional Water Quality Control Board and for Orange County Sanitation District (OCSD), the owner of the SARI Line. In 2005, rock riprap was placed in the river by OCSD initially as an emergency measure to protect the SARI Line from riverbed degradation/scour. Over the ensuing years, OCSD has added more rock to the river as a maintenance activity to protect the SARI Line. OCSD has placed about 30,000 tons of large rock in the river at five major locations between Weir Canyon Road and the Green River Golf Course. The Corps – Regulatory Division issued a Clean Water Act section 404 Permit to OCSD for the emergency and maintenance work, which included a condition that requires the removal of all rock after the completion of the SARI Line Project. OCSD is continuing to coordinate the details and timing of rock removal with the Corps and other agencies. It is anticipated that one of the emergency rock piles located inside the footprint of the Phase 4 project will be removed by the Corps as part of proposed construction site preparation (Corps 2015a).

Changes to the Conservation Measures

Conservation measures previously identified in the 2012 amendment will be implemented to offset impacts to habitat for vireo, Santa Ana sucker, and gnatcatcher and to minimize construction-related impacts, including: 1) the size of the construction footprint, 2) disturbance to nesting birds, 3) impacts to water quality, and 4) soil contamination. The Draft SEA includes numerous environmental commitments, best management practices and mitigation measures to avoid, minimize or offset environmental impacts; however, a few of these measures were not fully consistent with the conservation measures in the 2012 amendment. Measures concerning noise impacts, cowbird trapping, Santa Ana sucker, and critical habitat have been modified subsequent to release of the Draft SEA in coordination with the Service.

The following measures from the 2012 amendment will be modified specifically for the proposed Reach 9 Phase 4, 5A, 5B and BNSF Bridge Protection Projects [deletions are in strikeout, additions are underlined below]. To facilitate implementation of conservation measures as addressed by the 2012 amendment and modified below, Enclosure 1 presents a complete description of the conservation measures pertinent to section 7 consultation on the proposed Reach 9 Phase 4, 5A, 5B and BNSF Bridge Protection Projects.