Fish Passage Resting Pool

Designing Fish Resting Pools Using Hydrodynamic and Fish Energetics Modeling

Location: Corte Madera Creek, Ross California
Clients and Partners: Marin County Flood Control & Water Conservation District, Friends of Corte Madera Creek

Michael Love & Associates (MLA) evaluated existing steelhead passage conditions and developed feasible improvements within the concrete flood control channel on Corte Madera Creek. Steelhead are regularly observed attempting to swim through the flood control channel, with limited success. Project partners and participating agencies included the Marin County Flood Control District, the ACOE, Jeff Anderson & Associates and Friends of Corte Madera Creek. The project involved:

  1. Development of a calibrated 2-dimensional hydraulic model of the channel for use in identifying challenging fish passage conditions,
  2. Installing staff plates and crest gages throughout the floodway to obtain data for model calibration,
  3. Use of video monitoring by local volunteers to evaluate hydraulic conditions within the channel at various flows and to document fish performance within the channel, and
  4. Development and analysis of alternatives to improve fish passage while maintaining required channel capacity.

MLA developed a new probabilistic-based fish energetics and locomotion modeling system (Fish-REALMS) integrated with a 2-dimensional hydrodynamic model to identify locations and severity of exhaustion barriers for adult steelhead. The results were used to design and locate fish resting pools.

The study involved determining acceptable fish passage design flows based partially on observed migration timing, establishing design criteria for resting pools, a sediment mobility analysis within the pools, and evaluation of impacts on base flood elevation.

Recommendations were accepted by California Department of Fish and Game and NOAA Fisheries. ACOE is considering them in their NEPA scoping process as mitigation for proposed upstream flood control activities.