Introduction to Nature-like Fishways for Dams






Dam-related problems include blockage of fish migrations, drowning hazards, failure hazards, reservoir sedimentation, habitat loss, and tailwater erosion.  Some environmental problems can only be addressed through dam removal while other issues, where removal is not a viable option, can be remediated by dam modification and nature-like fish passage. Traditional fish passage projects have typically focused solely on passage of single or few large game species.   As the name implies, nature-like fishways emulate natural river geometry.  Nature-like fish passage includes full width dam modifications that have been applied to address dam and levee stability issues, eliminate dangerous hydraulic undertows, provide spawning habitat, provide recreational boating, grade control or sediment stabilization in dam removal and river restoration, and pass the full spectrum of native fish species.  These broad benefits have drawn a diversity of funding from federal, state, and local sources.  This course will introduce nature-like fishway types, design principles, applications, case examples, and associated benefits

Key Takeaways:

  • An increased understanding of dam-related effects on physical and ecological processes, safety, and other environmental issues
  • Underlying hydraulic, geomorphic, and biological considerations in addressing dam-related problems
  • An introduction to nature-like fishway types and applications
  • Elements of fishway funding, design, and construction
  • Case examples and evaluation of benefits

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