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Independent regulatory commissions

National Marine Fisheries Service Raises Concerns Over Norristown Dam Hydroelectric Project

Strategic Insights

— 1 min read

The National Marine Fisheries Service (NMFS) has expressed concerns over the proposed Norristown Dam Hydroelectric Project, citing inadequate studies on upstream fish passage and downstream fish passage survival. The NMFS is worried that the project may threaten the continued existence or future recovery potential of diadromous species such as alewife, blueback herring, American shad, and striped bass.

Key Takeaways:

  • The NMFS requested a pre-implementation field assessment of upstream fish passage and a technical input to the downstream fish passage survival analysis, which were not included in the proposed study plan.
  • The proposed desktop assessment of upstream fish passage feasibility lacks the rigor necessary to produce the desired data to inform fishway modifications needed to ensure safe, timely, and effective upstream fish passage.
  • A 2017 inspection by the U.S. Fish & Wildlife Service (USFWS) found numerous issues that make it challenging for diadromous species to find and successfully navigate the fishway at Norristown Dam.
  • The NMFS recommends using a combination of tracking technologies to establish baseline data to determine Project effects and inform any fishway modifications that may be required.
  • The proposed study will use outdated deterministic blade strike models that ignore other facility components that can present equal or greater risk to entrained fish relative to turbine blades or buckets.
  • The Biological Performance Assessment (BioPA) Toolset, which combines computational fluid dynamic modeling results with laboratory fish injury studies, should be applied in the study to select turbine specifications that minimize the potential of injury or mortality to emigrating diadromous fish.

Statistics:

  • 7 diadromous species are reliant on safe, timely, and effective upstream and downstream passage at dams and other anthropogenic barriers in order to complete their life cycles: alewife, blueback herring, American shad, striped bass, American eel, sea lamprey, and hickory shad.
  • 55-page technical memo on estimating downstream survival of diadromous fishes at hydroelectric facilities was published by NOAA in 2024 (Lake et al., 2024).
  • 2017 inspection by the U.S. Fish & Wildlife Service (USFWS) found numerous issues with the fishway at Norristown Dam (USFWS, 2017).

Sources:

  • National Marine Fisheries Service - Comments on Final Proposed Study Plan (accession # 20250731-5027)
  • Lake et al., 2024. Estimating Downstream Survival of Diadromous Fishes at Hydroelectric Facilities. NOAA Tech. Memo. NMFS-OHC-13
  • USFWS, 2017. PA Technical Fishways: USFWS Fish Passage Engineering Assessments. United States Fish and Wildlife Service.

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