QA

Fish Guidance System Study

STY-021

Identity

NameFish Guidance System Study
IDSTY-021
COA reference10.26
ParentIncorporation of Fish Guidance System into the North Delta Intake Structures

Timing

Rolled-up spanApr 2026 – Dec 2028min start → max end across all tasks in this branch
Water yearsWY2026–WY2029

Funding plan

Planned$3.0M · WY2026–2029
Water yearOwnRolled upTotal
WY2026—$450k$450k
WY2027—$1.4M$1.4M
WY2028—$950k$950k
WY2029—$180k$180k
Total$0$3.0M$3.0M

Status roll-up

Rolled up from 2 sub-studiesAt risk
7 tasks5 on track1 at risk0 blocked1 complete
Constraints & notes
  • Recommended fish-guidance plan due to CDFW by January 2030 — one year before 30% design finalization
  • Tightest timelines in the science plan: field work must land winters 26/27 and 27/28

Focal Species

Winter-run Chinook salmonSpring-run Chinook salmonStriped bass

Listed winter-run and spring-run Chinook salmon out-migrants are the target species a fish-guidance structure would be designed to protect; predator species (striped bass) are relevant because guidance structures can concentrate predation. The species framing is contested — CDFW objects that the sketch presupposes a guidance technology before the need is established.

Project Effect Links

Near-field. The north Delta intakes alter approach velocity, sweeping velocity, and the hydrodynamic field at the screen face. A floating fish-guidance structure (FFGS) is one candidate measure to reduce near-field impingement and improve guidance past the intakes — but whether such a structure is warranted is the open question this evaluation is meant to answer, not assume.

Objectives, Research Questions & Hypotheses

Convene a fish-guidance working group and evaluate whether, and how, a guidance system should be incorporated into the north Delta intake structures, providing CDFW a recommended approach no less than one year prior to finalizing 30% design. The evaluation moves from baseline velocity mapping through fish tracking, individual-based-model calibration, and behavioral-response evaluation to an FFGS design evaluation.

  1. Does near-field hydrodynamics and observed fish behavior at the intake screens indicate a need for an engineered fish-guidance measure?
  2. If a measure is warranted, which guidance configuration best improves guidance and survival without concentrating predation?
  3. Can the STAIRS individual-based model reliably predict fish response to candidate guidance configurations?

Background

The fish-guidance working group convenes at least two years prior to 30% design. The evaluation draws on the intake hydraulic models (COAs 10.25.1–10.25.4) and prior FFGS applications elsewhere in the Delta and Central Valley. The STAIRS individual-based model is proposed as the predictive tool, but it has not yet been independently reviewed.

Methods

Study area. The north Delta intake reach of the Sacramento River, focused on the near-field of the intake screen structures.

FFGS Evaluation

Methods / protocols
  • Baseline Velocity Mapping
  • Fish Tracking at the Intakes
  • STAIRS Individual-Based-Model Calibration
  • Behavioral-Response Evaluation
  • FFGS Design Evaluation
Performance metrics
  • Near-field approach and sweeping velocity distribution
  • Fish guidance efficiency by configuration
  • Predicted predation exposure by configuration
  • STAIRS calibration/validation goodness-of-fit

Data Management

Velocity-mapping, fish-tracking, and model-calibration datasets are versioned with provenance to the contributing intake hydraulic models; STAIRS model versions, calibration data, and validation results are archived for independent review.

Reporting Requirements

Draft Study Plan and Final Study Plan; a CDFW-approved recommended approach delivered no less than one year prior to finalizing 30% design. Working-group concurrence is required before advancing to design evaluation.

Agency Review — CDFW11

8 open3 addressed0 resolved

Pinned to: Objectives, Research Questions & Hypotheses

  • C
    CDFWCDFW2026-02-05§ 3.5.8Scope disputeOpen

    The sketch is premature. It presupposes that a floating fish-guidance structure is the answer. The objective must first establish whether ANY engineered guidance measure is warranted before evaluating FFGS configurations. Do not presuppose the technology.

Pinned to: Background

  • C
    CDFWCDFW2026-04-06§ 3.5.8Fix COA cross-referenceOpen

    Background cites the intake hydraulic models as 10.25 generically; cite the specific contributing COAs (10.25.1–10.25.4) so the dependency is traceable.

  • C
    CDFWCDFW2026-04-20§ 3.5.8Fix COA cross-referenceAddressed

    The cross-reference to the velocity-criteria COA is wrong — this study informs design, not the 10.27 velocity-testing compliance series. Correct the linkage.

    • GM
      Greenwood, Marin2026-05-01

      Removed the erroneous 10.27 linkage; background now references only the design-feeding COAs (10.25.1–10.25.4) and 10.18.2.

Pinned to: Study Area

  • C
    CDFWCDFW2026-03-23§ 3.5.8Add / adjust metricOpen

    Baseline velocity mapping must report approach AND sweeping velocity across the full operating range, including the high-diversion condition where guidance matters most.

Pinned to: Methods

  • C
    CDFWCDFW2026-02-05§ 3.5.8Scope disputeOpen

    The "FFGS Design Evaluation" step cannot be the terminal output of a study whose first question is whether a structure is needed. Restructure the component so design evaluation is contingent on a positive need finding.

  • C
    CDFWCDFW2026-02-12§ 3.5.8Model peer-review / documentationOpen

    The STAIRS individual-based model has not been independently reviewed and is being used as the basis for design decisions. Provide full model documentation before it is relied upon.

  • C
    CDFWCDFW2026-02-12§ 3.5.8Model peer-review / documentationOpen

    Provide the STAIRS calibration dataset and the calibration procedure. Without the calibration data we cannot assess whether the model is fit for predicting fish response at the intakes.

  • C
    CDFWCDFW2026-02-26§ 3.5.8Model peer-review / documentationAddressed

    A formal validation step — out-of-sample comparison against observed fish tracks — must be added before STAIRS output informs any design recommendation.

    • GM
      Greenwood, Marin2026-03-12

      Added an out-of-sample validation step to the STAIRS calibration method; validation must pass before the behavioral-response evaluation proceeds.

Pinned to: Performance Metrics

  • C
    CDFWCDFW2026-02-26§ 3.5.8Add / adjust metricOpen

    Add a predator-exposure metric for each candidate configuration. Guidance structures can concentrate predators; a guidance-efficiency gain that increases predation is not a net benefit.

Pinned to: Reporting Requirements

  • C
    CDFWCDFW2026-03-09§ 3.5.8Governance / approvalOpen

    The fish-guidance working group must reach documented concurrence before the study advances from need-evaluation to design-evaluation. State this gate in the reporting requirements.

  • C
    CDFWCDFW2026-03-09§ 3.5.8Governance / approvalAddressed

    The recommended approach delivered to CDFW one year prior to 30% design requires written CDFW approval, not merely transmittal. Clarify the approval requirement.

    • GM
      Greenwood, Marin2026-03-24

      Reporting requirements now state the recommended approach requires written CDFW approval prior to finalizing 30% design.

STY-021Edit record
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WY2027
WY2028
WY2029
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