HAHD_RFP Attach 10 - USFWS_2022_BIOP.pdf

g3endllg Text Box Howard A. Hanson Dam - Fish Passage Facility 35% DDR ATR-BCOES Submittal g3endllg Text Box Attachment 10 g3endllg

USFWS 2022 BIOP

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INTERIOR REGION 9

COLUMBIA–PACIFIC NORTHWEST

Idaho, Montana*, Oregon*, Washington

*PARTIAL

United States Department of the Interior

FISH AND WILDLIFE SERVICE

Washington Fish and Wildlife Office

510 Desmond Dr. S.E., Suite 102

Lacey, Washington 98503 In Reply Refer To:

01EWFW00-2014-F-0198

X-Ref: 1-3-00-F-1381

Colonel Alexander L. Bullock, District Commander

U.S. Army Corps of Engineers, Seattle District

4735 E. Marginal Way South, Building 1202

Seattle, Washington 98134-2388

Dear Colonel Bullock:

Subject: Biological Opinion on Howard A. Hanson Dam Continued Operations

This letter transmits the U. S. Fish and Wildlife Service's (Service) Biological Opinion (Opinion) on continued operations of, and proposed fish passage at, Howard A. Hanson Dam, located in the

Green/Duwamish River, King County, Washington, and effects on the bull trout (Salvelinus confluentus) and designated critical habitat for the bull trout. The Service conducted this formal consultation on the proposed action in accordance with section 7 of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.) (Act). The Service received your February 14, 2014, request for formal consultation on February 19, 2014.

The Service based the enclosed Opinion on information provided in the Supplemental Biological

Assessment (SBA) (2014), the Draft Integrated Validation Report and Supplemental

Environmental Impact Statement (2021), prior Opinions, e-mail and telephone conversations, and other sources of information cited in this Opinion. A complete record of this consultation is on file at the Washington Fish and Wildlife Office in Lacey, Washington. An electronic copy of this Opinion will be available to the public approximately 14 days after it is finalized and signed.

A list of Opinions completed by the Service since October 1, 2017, are located on the Service’s

Environmental Conservation Online System or ECOS website at:

https://ecos.fws.gov/ecp/report/biological-opinion.html.

Colonel Alexander L. Bullock 2

In the SBA, the U.S. Army Corps of Engineers (Corps), Seattle District, made additional “no effect” determinations for species and critical habitats that occur in King County. Those determinations rest with the Federal action agency. The Service has no regulatory or statutory authority for concurring with “no effect” determinations, and no consultation is required. The

Service recommends that the Corps document their analysis and maintain that documentation as part of their project files.

If you have any questions regarding the enclosed Opinion, our response to your concurrence request, or our shared responsibilities under the Act, then please contact Molly Good

(molly_good@fws.gov) and/or Curtis Tanner (curtis_tanner@fws.gov).

Sincerely, Brad Thompson, State Supervisor

Washington Fish and Wildlife Office

Enclosure(s) cc:

Corps, Seattle, WA (L. Boerner)

Corps, Seattle, WA (F. Goetz)

Corps, Seattle, WA (N. Gleason)

Corps, Seattle, WA (V. Pepi)

USFWS, Portland, OR (J. Bernstein)

CURTIS

TANNER

Digitally signed by

CURTIS TANNER

Date: 2022.02.02

20:56:13 -08'00'

Endangered Species Act - Section 7 Consultation

BIOLOGICAL OPINION

U.S. Fish and Wildlife Service Reference:

01EWFW00-2014-F-0198

Howard A. Hanson Dam Continued Operations Project

King County, Washington

Federal Action Agency:

U.S. Army Corps of Engineers

Consultation Conducted By:

U.S. Fish and Wildlife Service

Washington Fish and Wildlife Office

Lacey, Washington

Brad Thompson, State Supervisor Date

Washington Fish and Wildlife Office

CURTIS

TANNER

Digitally signed by

CURTIS TANNER

Date: 2022.02.02

21:00:20 -08'00'

TABLE OF CONTENTS

ii

1 INTRODUCTION

2 CONSULTATION HISTORY

3 BIOLOGICAL OPINION

4 DESCRIPTION OF THE PROPOSED ACTION

4.1 Howard A. Hanson Dam

4.2 Proposed Action

4.3 Continued Operations and Maintenance of HAHD

4.3.1 Flow Management Operations

4.3.2 General Reservoir and Flow Management

4.3.3 Gravel Nourishment

4.3.4 Wood Debris Management

4.3.5 Reservoir Habitat Stewardship Activities

4.3.6 Monitoring, Maintenance, and Inspection

4.4 Downstream Fish Passage System

4.4.1 Fish Attraction and Collection

4.4.2 Downstream Fish Passage and Release

4.4.3 Debris Management

4.5 Conservation Measures

4.5.1 Continued Operations and Maintenance of HAHD

4.5.2 Downstream Fish Passage System

4.6 Action Area

5 ANALYTICAL FRAMEWORK FOR THE JEOPARDY AND ADVERSE

MODIFICATION DETERMINATIONS

5.1 Jeopardy Determination

5.2 Adverse Modification Determination

6 STATUS OF THE SPECIES: Bull Trout

7 STATUS OF CRITICAL HABITAT: Bull Trout

7.1 Primary Constituent Elements

8 ENVIRONMENTAL BASELINE: Bull Trout and Designated Bull Trout Critical

Habitat

8.1 General Baseline Conditions

8.1.1 Green/Duwamish River Basin

8.1.2 Howard A. Hanson Dam

8.1.3 Tacoma Headworks Trap-and-Haul Facility

8.1.4 Section 1135 Ecosystem Restoration Project

8.2 Current Condition of the Species and Critical Habitat in the Action Area

8.2.1 Current Condition of the Species in the Action Area

8.2.2 Current Condition of the Critical Habitat in the Action Area

8.2.3 Factors Responsible for the Condition of the Species

8.2.4 Factors Responsible for the Condition of Critical Habitat

8.3 Conservation Role of the Action Area

8.4 Climate Change

8.4.1 Climate Change, Bull Trout, and Designated Critical Habitat

TABLE OF CONTENTS

iii

9 EFFECTS OF THE ACTION: Bull Trout and Designated Bull Trout Critical Habitat .. 34

9.1 Exposures to, and Effects on, Bull Trout

9.1.1 Continued Operations and Maintenance

9.1.2 Downstream Fish Passage System

9.2 Effects on the PCEs of Designated Bull Trout Critical Habitat

10 CUMULATIVE EFFECTS: Bull Trout and Designated Bull Trout Critical Habitat

10.1 Bull Trout

10.2 Designated Bull Trout Critical Habitat

11 INTEGRATION AND SYNTHESIS OF EFFECTS: Bull Trout and Designated Bull

Trout Critical Habitat

11.1 Bull Trout

11.2 Designated Bull Trout Critical Habitat

12 CONCLUSION: Bull Trout and Designated Bull Trout Critical Habitat

13 INCIDENTAL TAKE STATEMENT

14 AMOUNT OR EXTENT OF TAKE

15 EFFECT OF THE TAKE

16 REASONABLE AND PRUDENT MEASURES

17 TERMS AND CONDITIONS

18 CONSERVATION RECOMMENDATIONS

19 REINITIATION NOTICE

20 LITERATURE CITED

Appendices

Appendix A Status of the Species: Bull Trout

Appendix B Status of Designated Critical Habitat: Bull Trout

FIGURES

Figure 1. The Green/Duwamish River and vicinity

Figure 2. Howard A. Hanson Dam and reservoir

Figure 3. Howard A. Hanson Dam reservoir storage volumes and general allocation(s)

Figure 4. Fish passage facility excavation at Howard A. Hanson Dam

Figure 5. Conceptual drawing of a multiport collector and steep slope bypass structure

Figure 6. Water temperature measured in 2007 immediately upstream of the Howard A.

Hanson Dam reservoir (HAHD inflow), downstream of the reservoir at the existing tailwater monitoring station (outflow), and at the Auburn stream gage iv

TABLES

Table 1. Fish passage design options

Table 2. Green/Duwamish River subbasins and reaches

Table 3. The anticipated incidental take of bull trout as a result of the proposed action

Table 4. Turbidity levels and duration when bull trout will be harmed

ACRONYMS AND ABBREVIATIONS

ac-ft acre-feet

Act Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.)

AWSP Additional Water Storage Project

BA Biological Assessment

BMP Best Management Practices cfs cubic feet per second

CHSU Critical Habitat Subunit

CHU Critical Habitat Unit

CRU Coastal Recovery Unit

DAM destruction or adverse modification

DPS Distinct Population Segment

Draft Validation Report Draft Integrated Validation Report and Supplemental Environmental

Impact Statement

EIS Environmental Impact Statement

FMO foraging, migratory, and overwintering

FPF fish passage facility ft feet

GRFMCC Green River Flow Management Coordination Committee

HAHD or project Howard A. Hanson Dam

HCP Habitat Conservation Plan

ITS Incidental Take Statement

LW large wood

M&I municipal and industrial m2 square mile

MIS Modular Inclined Screen

NEPA National Environmental Policy Act

NMFS National Marine Fisheries Service

NTU nephelometric turbidity unit

Opinion Biological Opinion

PBF physical and biological features

PCE primary constituent element

PED Pre-Construction, Engineering, and Design

PSFTF Puget Sound Federal Task Force

PSMU Puget Sound Management Unit

PSP Puget Sound Partnership

Recovery Plan Recovery Plan for the Coterminous U.S. Population of Bull Trout v

ACRONYMS AND ABBREVIATIONS

RM river mile

RPA Reasonable and Prudent Alternative

RPA 1 RPA Action Item 1

RPA 2 RPA Action Item 2

RPM Reasonable and Prudent Measure

SBA Supplemental Biological Assessment

SEIS Supplemental Environmental Impact Statement

Service U.S. Fish and Wildlife Service

Tacoma Tacoma Public Utilities

U.S. United States

USGS U.S. Geological Survey

WDFW Washington Department of Fish and Wildlife

WRDA Water Resources Development Act

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1 INTRODUCTION

This document represents the U.S. Fish and Wildlife Service's (Service) Biological Opinion

(Opinion) based on our review of the proposed Howard A. Hanson Dam (HAHD) Continued

Operations project located in King County, Washington. The Opinion addresses effects to the bull trout (Salvelinus confluentus) and designated critical habitat for the bull trout in accordance with section 7 of the Endangered Species Act of 1973, as amended (16 U.S.C. 1531 et seq.)

(Act). The Service received your February 14, 2014, request for formal consultation on February

19, 2014.

The Service based this Opinion on information provided in the Supplemental Biological

Assessment (SBA) (2014), the 2021 Draft Integrated Validation Report and Supplemental

Environmental Impact Statement (SEIS) (Draft Validation Report), prior Opinions, e-mail and telephone conversations, and other sources of information cited in this Opinion. A complete record of this consultation is on file at the Washington Fish and Wildlife Office in Lacey, Washington.

2 CONSULTATION HISTORY

The following is a summary of important events associated with this consultation:

On October 10, 2000, the Service provided an Opinion to the U.S. Army Corps of

Engineers (Corps), Seattle District, for continued operations and maintenance of the

HAHD and reservoir, and execution of Phase 1 of the Howard Hanson Additional Water

Storage Project (AWSP) (Ref No: 1-3-00-F-1381; USFWS 2000). The Opinion addressed the effects of proposed changes to flood control, flow augmentation, water storage and release, fish passage, and habitat restoration (i.e., maintenance of in-stream and stream-corridor habitat, plantings, placement of large wood1 [LW], culvert replacement, and gravel nourishment) on bull trout. Through the analysis, the Service determined that the project was not likely to jeopardize the continued existence of bull trout. Rather, the Service concluded that the project was likely to result in adverse effects on bull trout and their suitable habitat due to: 1) significant water withdrawal and storage

(i.e., 20,000 acre-feet [ac-ft] of water for Tacoma’s municipal and industrial water supply, and up to 29,200 ac-ft of water for instream flow augmentation); 2) increased sedimentation; 3) increased turbidity; and, 4) the implementation of a variety of habitat improvement measures (e.g., placement of LW). The Service had not yet designated critical habitat for the bull trout and, therefore, the Opinion did not address potential effects to designated critical habitat.

In July 2001, the Service published an Opinion for the issuance of a section 10(a)1(B)

Incidental Take Permit to the Tacoma Public Utilities (Tacoma) for the Habitat

Conservation Plan (HCP) for the Green River Water Supply Operations and Watershed

Protection Habitat Conservation Plan (Ref No: 1-3-01-FWF-0101, 13410-2001-F-0027;

1 For the purposes of this consultation, the U.S. Fish and Wildlife Service defines large woody debris or large wood to either be greater than 12 inches in diameter at its midpoint and at least 20 feet long or any piece of wood containing a root ball greater than 4 feet in diameter (Corps 2014).

USFWS 2001). Tacoma had prepared the 50-year HCP to seek coverage for water supply operations at their headworks facility and various timber resource management actions in the upper Green River. In their Opinion, the Service analyzed the effects of these operations and actions on 26 fish and wildlife species, including bull trout.

Through the analysis, the Service determined that the project was not likely to jeopardize the continued existence of bull trout. Rather, the Service concluded that the project was likely to result in adverse effects to bull trout and their suitable habitat due to: 1) the capture and transport of bull trout in the upstream trap-and-haul facility; 2), forestry and/or timber resource management actions (e.g., logging, road construction); 3) downstream fish passage at the Tacoma Headworks Diversion Dam; and, 4) increased sedimentation. The Service did not describe effects to designated critical habitat.

Since August 2012, the Service has participated in meetings and regular conference calls with the Corps and other Federal and non-Federal partners (e.g., Tacoma) regarding modifications of, and additions to, the proposed action (i.e., operations and maintenance) and other elements (e.g., downstream fish passage) from the Service’s 2000 Opinion.

On February 14, 2014, the Corps, the Federal action agency, sent the SBA to the Service.

On February 19, 2014, the Service acknowledged receipt of the SBA, and initiated formal consultation.

On April 6, 2015, the Service inquired with Corps staff regarding the timing of delivery of the Opinion. The Corps requested that the Service wait to issue their Opinion until the

National Oceanic and Atmospheric Administration’s National Marine Fisheries Service

(NMFS) issued their Opinion. However, on October 11, 2016, the Corps requested that the Service finalize their Opinion since the NMFS Opinion remained unfinished.

On November 8, 2016, the Service requested from the Corps an extension to finalize the

Opinion by March 1, 2017. The Corps granted this request.

On March 2, 2017, the Service sent a draft Opinion to the Corps for their review. The

Service requested from the Corps another extension—to either April 1, April 15, or May

1—based on the Corps’ availability to complete the review. The Corps granted this request, and both agencies agreed to an April 15, 2017, extension.

On April 3, 2017, the Corps completed their review of the draft Opinion and shared their feedback with the Service.

On May 2, 2017, the Service requested from the Corps another extension to finalize the

Opinion by May 31, 2017. The Corps granted this request. However, the Service did not finalize the Opinion by this deadline as NMFS was still working to complete their

Opinion.

On February 15, 2019, the NMFS published their Opinion on the HAHD project. In this

Opinion, the NMFS determined that the project was likely to jeopardize the continued existence of Puget Sound Chinook salmon (Oncorhynchus tshawytscha), Puget Sound steelhead (O. mykiss), and Southern Resident killer whales (Orcinus orca), and that it would destroy or adversely modify designated critical habitat for these species. The

NMFS outlined in their Opinion two Reasonable and Prudent Alternatives (RPAs) to avoid jeopardy and adverse modification/destruction of designated critical habitat. RPA

Action Item 1 (RPA 1) requires the Corps to design and construct a permanent downstream fish passage system for HAHD (see Appendix C in the NMFS 2019

Opinion), while RPA Action Item 2 (RPA 2) provides stipulations for interim actions that would modify operations to minimize redd scour in the Green River (see Appendix D in the NMFS 2019 Opinion). To achieve compliance with this Opinion, the Corps is required to address each RPA by December 2030.

In 2020, the Corps received Federal funding to develop a preferred alternative for a feasibility-level design for the permanent downstream fish passage system for HAHD.

To gather feedback regarding this process, the Corps held two, multi-day stakeholder workshops in December 2020 and May 2021, with Federal, non-Federal, and Tribal fish passage experts to review different designs and offer recommendations (see Section 2.3 in Corps and Tacoma 2021 for additional details). Service biologists (Molly Good and

Tim Romanski) participated in these workshops.

In July and August 2021, Corps staff and Service biologists met to review the 2014 SBA, discuss the Service’s unfinished Opinion from 2017, and outline a schedule for finalization and delivery of the Opinion.

In November 2021, Corps staff and Service biologists met to clarify their understanding of any updated elements of the proposed action outlined in the Corps 2014 SBA. The

Corps asked that the Service include RPA 1—the final design and construction of the permanent downstream fish passage system for HAHD—as part of the proposed action.

The Service agreed to analyze this revision to the proposed action in this Opinion rather than consult on multiple elements of the proposed action over time.

On November 22, 2021, the Corps confirmed via phone a “likely to adversely affect” effect determination for bull trout. On December 22, 2021, the Corps confirmed via e-mail that the proposed action should include evaluation of RPA 1 of NMFS 2019 Opinion

(F. Goetz in litt. 2021).

On December 22, 2021, the Service sent a partial draft Opinion, including the description of the proposed action, to the Corps for their review.

On December 30, 2021, the Service sent a complete draft Opinion to the Corps for their review.

Between January 10, 2022, and January 21, 2022, the Corps provided their feedback to the Service on the draft Opinion.

On February 3, 2022, the Service sent a final Opinion to the Corps.

3 BIOLOGICAL OPINION

4 DESCRIPTION OF THE PROPOSED ACTION

A Federal action means all activities or programs of any kind authorized, funded, or carried out, in whole or in part, by Federal agencies in the United States (U.S.) or upon the high seas (50

CFR 402.02).

4.1 Howard A. Hanson Dam

The Corps completed construction of HAHD in 1962 for the purposes of flood risk management and fish conservation. The Rivers and Harbors Act of 1950 provides authorization for the dam, and current operation and maintenance of HAHD is 100 percent federally funded. HAHD is an earth-and-rock fill embankment, located at river mile (RM) 64.5 on the Green River near

Ravensdale, King County, Washington (Figure 1).

Figure 1. The Green/Duwamish River and vicinity.

(Corps 2014)

At RM 11, the Green River joins with the Black River to form the Duwamish River, which empties into Elliott Bay in the Puget Sound. The river is often referred to as the

Green/Duwamish River (Corps 2014).

The dam is 450 feet (ft) long and 235 ft high from bedrock to crest, and total length of the dam, including the spillway and abutment structures, is 675 ft. The project encompasses 627 acres, and the Corps retains more than 1,500 acres of easements for the reservoir, road access, and monitoring locations (Figure 2). The Corps 2014 SBA includes additional details regarding the project’s primary elements (i.e., spillway, bypass pipe, outlet and drainage tunnels, reservoir debris booms, and buildings) and infrastructure.

Figure 2. Howard A. Hanson Dam and reservoir.

(Corps 2014)

4.2 Proposed Action

In line with the Corps 2014 SBA, the proposed Federal action includes continued operations and maintenance of HAHD and implementation of Phase 1 of the AWSP. The proposed action excludes Phase 2, which outlines additional water storage and habitat improvement projects. In

2000, the Corps prepared a Biological Assessment (BA) (2000) to evaluate the effects of the continued operations and maintenance of HAHD and the implementation of Phase 1 of the proposed AWSP. The same year, the Service (2000) completed a formal consultation with the

Corps that addressed these activities. Since then, resource agencies have listed new species under the Act and designated critical habitat for Puget Sound/Coastal bull trout. There have also been changes to cost sharing, the prioritization of project purposes, and the feasibility of specific project elements proposed in the Corps 2000 BA. The Corps produced the SBA to reflect these changes and ensure that continued operations and maintenance of HAHD will remain in compliance with the Act (2014). Appendix A in the Corps 2014 SBA includes a summary table of the unique elements, and overlapping elements, between the proposed actions outlined in the

2000 BA and the 2014 SBA.

The proposed action also includes the finalization of the design and construction of a fish passage facility (fish passage facility or FPF) to restore downstream fish passage at HAHD, authorized in the Water Resources Development Act (WRDA) of 1999 as a restoration component of the AWSP (F. Goetz in litt. 2021). In the Corps 2000 BA, the proposed action

(i.e., full implementation of Phase 1 of the AWSP) included the construction of a permanent downstream fish passage system at HAHD to enhance connectivity between high-quality riverine and stream habitat and other river reaches (Corps 2014). The Service’s 2000 Opinion analyzed the anticipated effects of construction of the FPF on bull trout and their suitable habitat. While the Corps began designing and some construction of a downstream FPF in 2003, they suspended further construction due to an anticipated Section 902 cost limit exceedance in 2011. Since then, the Corps has halted all construction, though Corps staff continue to monitor critical dam structure stability on-site (2021).

Implementation of this action is now necessary to meet the performance criteria outlined in RPA

1 in the NMFS 2019 Opinion, as a reasonable and prudent alternative to avoid jeopardy to listed species and/or the destruction or adverse modification of designated critical habitat. RPA 1 requires the Corps to design and build an FPF at HAHD according to the project development milestones described in Appendix A and Best Management Practices described in Appendix B of the NMFS 2019 Opinion. The new FPF must meet the passage performance criteria provided in

RPA 1, which includes:

95 percent (or greater) collection of fishes attracted to the fishway (from the fish collection efficiency line into the trap) for two consecutive years of post-construction evaluation;

98 percent survival of fishes collected and passed through the FPF to their release downstream of HAHD; and, An overall mortality and/or injury rate of less than or equal to 2 percent of the total number of fish collected.

The FPF should provide safe downstream fish passage for salmonids according to the performance measures described in Appendix C of the NMFS 2019 Opinion (Corps and Tacoma

2021).

The proposed action also includes specific modifications to operations at HAHD that attempt to minimize redd scour, thereby increasing egg survival, in the Green/Duwamish River.

Implementation of this interim action, to occur between the issuance of this Opinion and the completion of construction of the FPF, is necessary to meet the performance criteria outlined in

RPA 2 of the NMFS 2019 Opinion. RPA 2 requires the Corps to decrease flows in the winter

(i.e., between October 15 and February 28) (see Appendix D of the NMFS 2019 Opinion for more details). Once downstream fish passage is available at HAHD, additional spawning habitat above the dam may reduce the necessity for redd scour reduction downstream of the dam.

For the purposes of this consultation, the timeframe for the effects analysis is 30 years from implementation of the proposed action. The Corps bases this timeframe on the projected length of time that will pass before they expect to implement Phase 2 of the AWSP. Phase 2 includes additional water storage and habitat improvement projects (Corps 2014).

4.3 Continued Operations and Maintenance of HAHD

The Corps proposes to operate HAHD in perpetuity for the purposes of: 1) flood risk management of the Green/Duwamish River; 2) low-flow augmentation for fish conservation during the summer and fall; 3) ecosystem restoration; and, 4) water supply for municipal and industrial (M&I) purposes. The purpose of low-flow augmentation for fish conservation is to provide “for the preservation of fish life” through improvements to habitat conditions for fisheries resources (Corps 2014). The Corps has conducted operations for flood risk management and low-flow augmentation since 1962. Since 1998, the Corps has implemented the Section 1135 ecosystem restoration project (see Section 3.3.5 in Corps 2014), which has added additional low-flow augmentation storage. The Corps has implemented additional ecosystem restoration projects including gravel nourishment and LW placement, annually, since

2003 and 2004, respectively.

Since 2007, the Corps has stored water to 1,167 ft elevation during the spring, annually, to provide water for flow-augmentation and fish conservation, and M&I water for Tacoma (2014).

However, the Corps has not fully implemented the M&I water storage and use for Tacoma.

While the Corps is currently capturing and storing 20,000 ac-ft of water in the reservoir for later use during the spring, summer, and fall, the Corps relegates the water to a subordinate level of priority compared to requirements imposed by natural resource concerns. Under current operations, the Corps accrues natural resource benefits by using at least 10,000 ac-ft, or 50 percent, of the stored M&I water to augment flow to protect steelhead redds from dewatering, improve spawning conditions for Chinook salmon, and improve juvenile salmonid summer rearing habitat conditions. Under proposed operations, following implementation of Phase 1 of the AWSP, the Corps could discharge up to 20,000 ac-ft of water, annually, for use by Tacoma.

For the purposes of this consultation, the Service assumes that the Corps will divert this entire volume of water from HAHD for M&I use at the Tacoma Headworks Diversion Dam, located at

RM 61 on the Green River. However, in adherence to Tacoma’s 2001 HCP, Tacoma will retain discretion to manage the actual use of this water (see Section 3.3.6 in Corps 2014; NMFS 2019).

The following subsections summarize the proposed operations and maintenance activities that the Service anticipates will affect bull trout and designated critical habitat for the bull trout. The

Corps 2014 SBA includes additional details about these activities.

4.3.1 Flow Management Operations

Winter Flood Risk Management

The Corps operates HAHD during the late fall and winter (from November to February) solely for flood risk management purposes, and the project is authorized to provide maximum flood storage up to 106,000 ac-ft. However, since 1962, sedimentation in the reservoir has led to a reduction in overall storage capacity to 104,000 ac-ft (Figure 3). During a flood event, the Corps releases water from the dam and targets a desired maximum flow of 12,000 cubic feet per second

(cfs), measured at the Auburn U.S. Geological Survey (USGS) stream gage at RM 32. This flow is the leveed channel capacity of the river within the lower Green/Duwamish River. To provide a margin of safety against errors in forecasted local inflow, the Corps proposes to regulate the project outflow to a flow objective of 10,000 cfs at Auburn on the rising limb of a flood hydrograph. The Corps could increase the flow objective to 12,000 cfs during a flood recession

(once the peak of uncontrolled inflows downstream of HAHD have passed) to evacuate stored floodwater as rapidly as practicable.

Figure 3. Howard A. Hanson Dam reservoir storage volumes and general allocation(s).

(Corps 2014)

During an extreme flood event (i.e., 0.7 percent of events, approximately a 1 in 140 year annual chance flood), the Corps proposes to use the spillway to discharge water from the project in order to maintain adequate reservoir storage, as needed, to prevent overtopping of the dam. In this situation, it is likely that flows downstream of the dam will exceed the 12,000 cfs threshold at Auburn (NMFS 2019). To date, the Corps has not used the spillway.

On rare occasions, the Corps could discharge potentially no flow from the dam in order to maintain flows below 12,000 cfs (2014). Outside of flood events, the Corps proposes to hold the project with no pool storage all winter so that the maximum potential storage volume would be available to store water from severe storm events (NMFS 2019).

Winter Non-Flood Reservoir Operations

To accommodate flood events and/or avoid discharging water that is excessively turbid, the

Corps proposes to hold the pool to a minimum level (approximately 1,074 ft to 1,076 ft) all winter (see Figure 3-1 in Corps 2014). This minimum operating pool or low-winter pool, referred to as the turbidity pool, will remain at the lowest reservoir elevation (600 ac-ft) that can be held without releasing fine sediments, which have been deposited into the reservoir over time

(Figure 3). To avoid increased sediment accumulation that could be discharged into, and therefore reduce available storage capacity in, the reservoir, the Corps will annually draft the reservoir to: 1) locate, to the extent possible, the precise elevation range of the turbidity pool;

and, 2) remove the veneer of fine sediment that will have accumulated in the reservoir over the prior year, particularly at the lower elevations (but above 1,074 ft) (2014). As part of this operation, the Corps will lower the reservoir until a noticeable increase in discharge turbidity occurs (i.e., a one- to two-day process). The Corps will attempt to keep outflow turbidity below approximately 30 nephelometric turbidity units (NTU) throughout the operation, though short-term and/or temporary exceedances may occur (NMFS 2019).

The Corps also proposes to operate the project to maintain a low elevation reservoir

(approximately 1,074 ft to 1,076 ft) for one to two weeks in order to conduct maintenance activities (e.g., intake tunnel trashrack inspections and cleaning, maintenance of staff gages, and debris boom inspection) at the dam. The Corps will schedule these maintenance activities to align with relatively low (and constant) project inflows to maintain a constant reservoir elevation

(2014).

Spring Reservoir Refill

The Corps proposes to capture and store water behind the dam in the spring (from late February to June). While the Corps will employ various strategies to capture water (i.e., changes in timing and rate) for storage, depending on the authorized project purposes, the water capture rate—for all project purposes—will range between 0 percent to greater than 50 percent of the inflow rate.

At full reservoir, the water storage includes approximately 24,000 ac-ft for fish conservation, 5,000 ac-ft for ecosystem restoration, and 20,000 ac-ft for Tacoma’s use in its M&I water supply

(Figure 3). Given this storage, project discharge would be less than inflow by an average of 266 cfs (i.e., 166 cfs for fish conservation and ecosystem restoration plus 100 cfs for the AWSP)

(Corps 2014; NMFS 2019). The Corps will adaptively manage storage in consideration of the individual viewpoints expressed by the members of the Green River Flow Management

Coordination Committee (GRFMCC), a stakeholder group representing various resource agencies and interested parties.

If the reservoir is not filled to 1,167 ft in a given year, then the Corps proposes to allocate stored water based on the historical implementation dates for the various storage purposes (i.e., those implemented earlier will receive priority). In order of priority, the Corps will allocate stored water as follows: for flow augmentation in support of fish conservation, flow augmentation in support of the Section 1135 ecosystem restoration project, and then M&I water supply (2014;

NMFS 2019).

Summer Conservation Flows

In the late spring, the Corps proposes to pass inflow and maintain the full reservoir until they need water from storage. The allocation and/or release of stored water for flow augmentation in support of fish conservation will follow a reservoir guide curve (see Figure 3-3 in Corps 2014), which ensures that sufficient water is reserved in the reservoir to achieve at least 110 cfs with a reliability of 98 percent, measured at the Palmer USGS stream gage at RM 60.5. The Corps will base minimum discharge on the 110 cfs flow target, derived from the original authorizing documents, plus 113 cfs or reservoir inflow—whichever is least—for Tacoma’s first diversion water right claim (2014). Similar to how the Corps manages spring reservoir refill, the Corps will adaptively manage flow augmentation in consideration of the individual viewpoints expressed by the members of the GRFMCC to monitor and account for hydrologic conditions.

4.3.2 General Reservoir and Flow Management

Normal Reservoir Operations

Throughout the year, the Corps maintains a reservoir of varying size behind HAHD and discharges water into the Green/Duwamish River through dam-regulating gates (i.e., a gate that controls the 19-foot outlet tunnel, and a gate that controls the 48-inch bypass pipe). During the low flow period (from mid-July to mid-September), the Corps will discharge water from the

48-inch bypass pipe, which allows for finer control of the discharge. Corps staff will conduct gate changes manually, as necessary, and perhaps more frequently depending on weather forecasts (2014).

The Corps may deviate from normal operations to complete certain maintenance activities and inspections and during monitoring or testing for fisheries resources. The Corps would consider these deviations on a case-by-case basis, and any modifications to flow will be coordinated with resource agencies.

Upramping

The Corps proposes to manage the project to ensure that the tailwater gage height does not rise at a rate greater than 1 ft per hour, except during flood events. This limit will help deter the establishment of hazardous environmental conditions in the Green/Duwamish River (Corps

2014). This rate is uncertain to result in adverse effects on fishes (NMFS 2019).

Downramping

The Corps proposes to manage the project to ensure that the rate of reducing discharge does not result in the stranding of fishes downstream of HAHD. Rapid downramping rates may dewater areas of the river before fishes can move away from them, causing stranding (Bradford et al.

1995; Irvine et al. 2009). Thus, to the extent practicable, the Corps will adhere to the

Washington Department of Fish and Wildlife’s (WDFW) downramping guidelines for the

Green/Duwamish River (see Table 3-1 in Corps 2014).

4.3.3 Gravel Nourishment

Current operations at HAHD modify and, in some cases, obstruct the downstream movement of sediment in the Green/Duwamish River. Thus, the Corps proposes to place up to 14,000 tons of spawning gravel, as necessary (annually), to replicate historic physical and biological processes and enhance habitat conditions for salmonids. The Corps will place spawning gravel on either of two designated gravel nourishment sites, separated by 0.25 mile, near RM 60. These sites are situated just downstream of the Tacoma Headworks Diversion Dam at RM 61. Typically, the

Corps will place gravel in August, but they could wait to place gravel in the winter months during which naturally occurring high winter stream flows would likely more evenly distribute sediment downstream (2014). The Corps will adaptively manage gravel augmentation (i.e., via changes to composition, quantity, size, and timing of gravel nourishment) based on monitoring data and hydrologic conditions to ensure the project benefits salmonids.

4.3.4 Wood Debris Management

The accumulation of wood behind HAHD is episodic and can range in number from hundreds of trees (during years with large flood events) to few or zero (during years with mild winters).

Agreements between the Corps and Tacoma affect the transport and disposition of wood throughout the Green/Duwamish River. Through the AWSP, the Corps maintains responsibility for transporting 50 percent of the LW received in the reservoir downstream into the river.

Through the HCP, Tacoma maintains discretion to use LW and allocate any remaining LW among various habitat priorities and cultural uses by the Muckleshoot Indian Tribe (Corps 2014).

In order to enhance in-stream habitat complexity, the Corps proposes to continue transporting up to 50 percent of incoming LW received at HAHD, downstream of HAHD at the two designated gravel nourishment sites near RM 60. Typically (in low wood volume years), the Corps will transport LW in the summer, immediately following the winter after they receive the wood. The

Corps and Tacoma may also transport some quantity of small wood (Tacoma 2001). During the following summer high pool, the Corps will distribute the wood debris according to a variety of objectives stated in Section 3.5.2 of the SBA (2014). Wood debris that is not immediately useful for habitat enhancement projects will be stored on site, chipped, or, as a last resort, burned in accordance with the requirements of Puget Sound Clean Air Agency regulations, if the accumulated debris posed a dam-safety threat (NMFS 2019; PSCAA 2021). Overall, the Corps will adaptively manage LW depending on project purposes, needs, and the nature of wood inputs to the reservoir.

4.3.5 Reservoir Habitat Stewardship Activities

The Corps proposes to continue conducting two habitat stewardship activities on the reservoir, including maintenance of the Baldi habitat boom to provide overhead cover and riparian habitat complexity in the reservoir, and a loon nesting platform to enhance loon nesting success and survivability (Corps 2014).

4.3.6 Monitoring, Maintenance, and Inspection

The Corps proposes to continue to monitor the project and environmental/hydrologic conditions

(e.g., precipitation, temperature, wind, water flow, turbidity and water quality, water levels) at established monitoring sites and inspect and maintain project facilities (2014; NMFS 2019). The

Corps will also continue to conduct routine and non-routine maintenance, as necessary, of all facilities associated with HAHD. The SBA outlines these maintenance activities, which include mechanical equipment improvements, debris and vegetation control, road and ditch grading, stilling basin repairs, trashrack cleaning, tower gates/emergency stop log rehabilitation, and left bank slope stabilization (see Section 3.4.2 and Tables 3-2 and 3-3 in Corps 2014).

4.4 Downstream Fish Passage System

The Corps proposes to update and finalize the design of, and construct, an FPF at HAHD. With this design, the Corps proposes to meet the fish collection efficiency and survival criteria outlined in NMFS 2019 Opinion using the least-cost methodology for collection and transport of fishes (Corps and Tacoma 2021). The Corps proposes to complete construction of the FPF by

2030 in an effort to provide operational downstream fish passage by 2031 (NMFS 2019). Initial testing of FPF operations to provide fish passage according to the RPA 1 performance criteria will occur during the initial 10 years of construction. In this Opinion, the Service assumes that initial testing of FPF operations, which includes required monitoring, is likely to extend past the period of construction, up to 15 years. The purpose of constructing the FPF is to restore downstream fish passage for anadromous fishes at HAHD. Together, the FPF at RM 64.5 and a fully functioning trap-and-haul facility at the Tacoma Headworks Diversion Dam at RM 61 will facilitate both downstream and upstream movements and/or migration, respectively, for listed, anadromous fishes in the Green/Duwamish River (Corps and Tacoma 2021).

In 1998, the Corps prepared an Environmental Impact Statement (EIS) and, three years later, signed a Record of Decision in compliance with the National Environmental Policy Act (NEPA) regarding the FPF and projected effects resulting from its construction (1998; 2001). The Corps and Tacoma 2021 Draft Validation Report includes updates (from the Corps 1998 EIS and 2000

BA) to cost increases of, and details about, the design and construction plans for the FPF. The

Corps has not yet finalized these plans. The Final Integrated Validation Report and SEIS (to be finalized in 2022) will present the updated cost estimate for the selected FPF design and include additional details about cost share/cost allocation of the proposed action. The Corps does not expect to conduct additional NEPA analyses beyond what is included in their 2021 Draft

Validation Report.

To date, completed construction of the FPF includes installation of a temporary cofferdam situated on the left bank of the river just upstream of, and connected to, HAHD for building in the dry and excavation of the space for the fish collection structure. This space is approximately

60 ft wide by 180 ft long, and by 100 ft deep (Figure 4). Rock anchors, shotcrete, and drains stabilize the excavation walls. A soldier pile wall with tieback anchors and permanent concrete facing retains soil along the south side of the excavation. The Draft Validation Report includes seven fish passage design options (Table 1) that were initially identified in the stakeholder workshops to most likely meet NMFS’s 2019 Opinion requirements at least cost. The Corps later brought forward two of these seven design options (i.e., Design Option 1 and 4) in their consideration of the final FPF design with stakeholders. Sections 2.2 through 2.4 in the Draft

Validation Report include additional details about these design options, the stakeholder workshop discussions, and the final design evaluation and selection process (Corps and Tacoma

2021).

Figure 4. Fish passage facility excavation at Howard A. Hanson Dam.

(Corps and Tacoma 2021)

Table 1. Fish passage design options.

Design Option Title

1 Movable Single Port Collector with Fish Lock to Shallow Slope Bypass

2 Movable Single Port Collector with Steep Slope Bypass

3 Fixed Multiport Collector with Fish Lock to Shallow Slope Bypass

4 Fixed Multiport Collector with Steep Slope Bypass

5 Fixed Multiport Collector with Helix to Shallow Slope Bypass

6 Adjustable Weir with Wet Well

7 Fixed Multiport Collector with Fish Lock up to Trap-and-Haul

For the purposes of this consultation, the Service analyzed the effects of Design Option 4—the

Tentatively Selected Plan and preferred alternative—outlined in the Draft Validation Report.

4.4.1 Fish Attraction and Collection

Based on the Corps’ preliminary design, 280 cfs will be the minimum total HAHD outflow required to operate the FPF, which consists of 230 cfs through the facility and 50 cfs passed through existing outlets to maintain flow in the stilling basin. Thus, the Corps proposes to operate the FPF with a total water flow range from 230 cfs to 1,200 cfs (depending on river flow), to meet the NMFS 2019 Opinion requirement (i.e., 95 percent, or greater, collection of fishes attracted into the facility) (Corps and Tacoma 2021).

Design Option 4 includes a fixed multiport collection structure that would allow fish collection and passage from a set of intake ports at multiple water levels as the reservoir elevation changes

(Figure 5). At low forebay elevations, the lower ports will open, and, at higher forebay elevations, the lower ports will close and the higher ports will open. Depending on the forebay elevation, multiple ports will be open/used at one time. The Corps will design the ports to withdraw water flows ranging from 230 cfs to 600 cfs; thus, two ports could operate at one time for a total withdrawal of 1,200 cfs of water (Corps and Tacoma 2021). The Corps will use incline screens to limit water flow per port to safely screen for, and successfully pass, fishes

(NMFS 2011).

4.4.2 Downstream Fish Passage and Release

Downstream fish passage will occur via steep slope bypass pipes (Figure 5). The fish passage route from the fixed multiport collector to the downstream release site will most likely cut through the left abutment of HAHD, but it could also run along the downstream side of the dam or connect to an existing bypass structure pending further design development. The Corps proposes to decelerate water velocity gradually within the bypass before discharging to the tailrace to minimize exposure of fishes to shear. While final details are currently lacking, the

Service expects that the bypass pipe(s) will include either a shallow bend at the base or another feature to dissipate energy/slow down water velocity before release (Corps and Tacoma 2021).

The Corps proposes to place the transport pipe exit for fish release on the reach of

Green/Duwamish River immediately downstream of the stilling basin (Corps and Tacoma 2021).

The location of the exit must be situated: 1) to minimize predation on fishes at various life history stages (i.e., control for avian predation); 2) to avoid eddies and reverse flow(s); 3) to have river velocities that are greater than 4 feet per second; and, 4) at a sufficient depth to avoid injuries at all river and bypass flows.

Figure 5. Conceptual drawing of a multiport collector and steep slope bypass structure.

(Corps and Tacoma 2021)

4.4.3 Debris Management

The Corps proposes to design and construct the FPF to handle debris (i.e., organic, woody material) that enters the reservoir from upstream sources (Corps and Tacoma 2021). The Corps will most likely use a submerged Modular Inclined Screen (MIS) to allow for an increased rate of total attraction water flow. The Corps will incorporate several other features (see Section 5.5 in this Opinion) into the final FPF design to improve exclusion of debris and debris management.

4.5 Conservation Measures

The following subsections summarize conservation/ minimization measures in addition to those stated above in the description of the project and proposed action.

4.5.1 Continued Operations and Maintenance of HAHD

The Corps will implement some of those conservation measures that they developed for the proposed action included in the 2000 BA (i.e., either fully, with modifications, or not at all).

Appendix A in the Corps 2014 SBA includes a summary table of these conservation measures.

Additionally, the Corps will adhere to the following general Best Management Practices (BMP) in carrying out all routine and non-routine maintenance activities:

The Corps will clean equipment near/adjacent to the water prior to carrying out maintenance activities;

The Corps will regularly check equipment for drips and/or leaks; and, The Corps will ensure that at least one fuel spill kit with absorbent pads will be onsite at all times.

The Corps will implement specific BMPs for other maintenance activities (see Table 3-4 in

Corps 2014).

4.5.2 Downstream Fish Passage System

In the final design and construction of the FPF, the Corps will adhere to the following guidance and BMPs, outlined in the NMFS 2019 Opinion and other documents:

Design process and criteria for the Green/Duwamish River permanent downstream fish passage system, included in Appendix A (NMFS 2019);

BMPs for in-water work (NMFS 2019);

A Water Quality Monitoring Plan (Corps 2021a); and, Criteria, rationale, and guidelines for designing proper fish passage facilities for the safe, timely, and efficient downstream passage of anadromous fishes created by artificial structures and/or altered instream hydraulic conditions (NMFS 2011).

The Corps will continue to implement RPA 2, outlined in the NMFS 2019 Opinion, which affects operations between October 15 and February 28 each year and reduces outflow rates at

HAHD to a maximum of 5,000 cfs during moderately high (i.e., still less than 12,000 cfs) inflow events. Reductions in water flow lead to less scouring and displacement of salmonids and their redds, thereby enhancing survival during egg to migrant life history stages (Corps and Tacoma

2021; NMFS 2019).

To provide the greatest possible protection of pH, turbidity, and other water quality parameters, the Corps will develop, and adhere to, a Care and Diversion of Water Plan as well as an

Environmental Protection Plan, as part of the construction contract documents (Corps and

Tacoma 2021). These documents will include all BMPs for the protection of water quality, including those required in NMFS 2019 Opinion.

The Corps will also develop BMPs to minimize negative impacts to migratory birds. For example, the Corps’ timing of the most potentially disruptive construction activities (e.g., rock blasting for excavation) will take into account the location, and breeding opportunities, of the nesting pair of loons and other nesting birds.

The Corps will need to refine the exact set of conservation/minimization measures and BMPs for the final design and construction of the FPF during the Pre-Construction, Engineering, and

Design (PED) phase of the project. Thus, Corps will continue to coordinate with resource agencies, especially during the PED phase, as additional details about construction methodologies, strategies, and activities and the timing of these activities become available.

Debris Management

The Corps will incorporate a variety of features, at minimum, into the final FPF design to improve all aspects of debris management (e.g., receiving incoming debris, handling debris, attracting and collecting fishes, and full-flow bypass). While the exact configuration of these features will require further analysis during the PED phase, these features will sufficiently address concerns regarding fish access to the multiport collector and general screen maintenance.

Section 2.6 in the Corps and Tacoma 2021 Draft Validation Report includes additional details about these features.

4.6 Action Area

The action area is defined as all areas to be affected directly or indirectly by the Federal action and not merely the immediate area involved in the action (50 CFR 402.02). In delineating the action area, the Service evaluated the farthest reaching physical, chemical, and biotic effects of the action on the environment.