Potter Valley Project 1 Fish Passage Options 2 Scott Dam 3 Cape - - PowerPoint PPT Presentation

Potter Valley Project

Fish Passage Options

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Ad Hoc Committee Meeting | October 2, 2019 Appendix D | Fish Passage Presentation to Ad Hoc

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Scott Dam

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Cape Horn Dam

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Fish Passage Working Group

´ Charge: The Fish Passage Working Group (FPWG) is developing information and recommendations on fish passage for the

Potter Valley Project Ad Hoc Committee. The FPWG is composed of Potter Valley Project stakeholders charged with

identifying a prioritized list of conceptual-level passage options that would meet three fish passage objectives for targeted anadromous fish species beyond Cape Horn and Scott

dams, located within the upper mainstem Eel River, California. If these fish passage objectives are

achieved, recommended fish passage options will promote the recovery and long-term viability of currently depressed fish populations in the Eel River. The FPWG strives to identify fish passage

• ptions that meet the following objectives for each targeted fish species:
• 1. Population viability of upper Eel River anadromous fishes:

§ Viable Fish Population (VFP)Concept: abundance, productivity, spatial structure, and diversity.

• 2. Access to abundant high quality habitat:

§ Access to sufficient habitat quantity and quality to complete essential life stages and promote long-term population viability. § Avoid exposing fish to low quality habitat that harbors introduced predatory fish species.

• 3. Functional fish passage:

§ Safe, timely, reliable, and effective upstream and downstream passage. § Fish passage options that minimize stress, injury, delay and mortality ~ while maximizing efficiency.

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Approach

• 1. Developed conceptual passage scenarios with options.
• 2. Developed a Passage Scoring Matrix.
• 3. Refined passage scenarios with detailed assumptions for each option.

This provided the “fish passage scorers” a defined concept for each passage option.

• 4. Scored options independently and collectively as a group.
• 5. Reviewed and discussed trends in the scores.
• 6. Documented assumptions, unknowns, areas of agreement and diverse

perspectives. 6

Fish Passage Scenarios

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1 Fishway at

Existing Scott Dam Options

2 Trap &

Haul

3 Partial Scott

Dam Removal

4 Remove Scott

Dam and Modify Cape Horn Dam

Options

1. 1.1 1 Semi- Na Natural, Low- Gradient Bypass ss Ch Channel 1. 1.2 Original Me Mead & Hunt (M (M&H) Fish sh La Ladder 1. 1.3 Modified M&H Fish sh La Ladder 2. 2.1 Tr Trap & Ha Haul, Van Arsd sdale to Sc Scott Dam 2. 2.2 2 Trap & Ha Haul, at Sc Scott Da Dam 3. 3.1 Lo Lower Scott Da Dam to 80 80’ – Meet PVID demand and environmental flows 3. 3.2 Lower Scott Da Dam to 50’ – Retain accumulated sediment 4. 4.1 Re Remove Scott Da Dam and Modify Ca Cape Horn Dam 4. 4.2 Re Remove bot

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Sc Scott Dam and Ca Cape Horn Dam 1) With Diversion (provides another baseline for flows and fish) 2) No Diversion

Scenarios & Options

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• 1. Fishway at existing Scott Dam

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1.1 - Semi-Natural, Low-Gradient Bypass

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1.2 and 1.3 - M&H Fish Ladder

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1.3 Modified M&H Fish Ladder:

• Taller exit gallery
• Downstream

migrating fish can use extended fish ladder/ exit gallery 1.2 M&H Fish Ladder:

• 2. Trap & Haul

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• 2. Trap and Haul

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2.1 - Trap at CHD Release at tributary 2.2 – Trap at SD Release in middle of reservoir

• 3. Partial Scott Dam Removal

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• 3. Partial Dam Removal

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• 4. Dam Removal / Modification

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• 4. Remove SD, Remove/Modify CHD

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Scoring the Options

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Fish Passage Scoring Matrix|Example

19 SCORING APPROACH ESSENTIALS ü Clearly define criteria parameters and option assumptions ü Score independently from other

• ptions

ü Document range of scores ü Take detailed notes on assumptions, unknowns, and diverse perspectives

Fish Passage Scenarios & Options Table | Example

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Link to Table

Scoring Key

(see Scoring Passage Matrix for complete parameter definitions)

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Results: Averages ~ HAPPY!

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Results: Ranges ~ Uncertainty…..

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Results: Averages and Ranges ~ Non-Biological (e.g., Ops and Engineering Feasibility)

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Averages Ranges

Results: Important Factors for Salmonids

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Preliminary Trends from the Scores

´ Dam removal benefits all species and life stages evaluated. However, without other water supply options, may not satisfy two-basin solution. ´ Upstream passage options available for adult salmonids (juveniles?) and lamprey (with varying long-term biological viability), but success likely achievable. ´ Different perspectives on value of Scott Dam releases during dry season and associated water quality conditions downstream. ´ Downstream passage challenges for both salmonids and other species (lamprey) of interest à Likely most limiting factor for fish passage options that retain Scott Dam ´ Engineering passage with aging infrastructure may be major challenge. ´ Assumes Cape Horn Dam / Van Arsdale Fish Station meet NMFS/CDFW standards.

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Looking Forward

´ Integrate work with Water Supply Working Group ´ Issues requiring further investigation and/or additional expertise:

´Downstream passage options ´Non-biological factors ´Alternative flow schedules ´Cape Horn Dam conditions (e.g., flow Rx’s) ´Other non-passage factors described in report

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Suggested Studies

´Flow Rx’s associated with desired water quality and habitat conditions downstream of Scott Dam ´Fish production and life cycle modeling ´Predatory fish suppression techniques ´Fish behavior / response to reservoir habitat conditions

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For Reference: Other Options / Equipment

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Lake Pillsbury Water Surface Elevations

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Trap & Haul – Example Design

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Fish Weir Example

Weir at entrance to a fishway (Nimbus Hatchery fish weir/ladder) 32

Surface Spill Bypass Example for Outmigration

(Wanapum Dam, Columbia River)

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Floating Surface Collector Concept

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Upper Baker Lake Floating Surface Collector

Guide Nets

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