Location

Agriculture Leaders Theater, Oregon State University

Start Date

25-6-2013 4:30 PM

End Date

25-6-2013 4:50 PM

Description

Fish behaviour over space, time, life cycle needs and ecohydraulic conditions may affect the effectiveness of upstream and downstream passage systems. The spacial extent of migratory movements may depend on whether available and suitable habitat which meets the life cycle needs of specific species exists only below or only above a barrier, or in both locations. Highly effective passage systems have the following characteristics: a) their use is compelled by the migratory needs of specific species ;b) are easy to locate by the migratory fish community as they offer topographical and flow conditions that species seek rather than avoid; and c) combine morphological features and hydrodynamic conditions which match their biomechanical capabilities and are suitable for efficient transport.

These factors relate to species motivation (required versus tentative movements), attraction or guidance efficiency (probability that fish will locate the upstream fishway entrance or be actively guided downstream), and passage efficiency (probability fish will move through passage system), respectively. Any one of these factors or any combination of the three may limit overall system passage effectiveness. Field assessments for several species and many passage systems around the globe, supplemented by controlled laboratory studies, have demonstrated considerable variation in attraction or guidance efficiency, as well as passage efficiency. Not surprisingly, biological factors, such as migratory, morphological or ecological characteristics of different species, species abilities, salmonids vs non-salmonids, as well as passage system design features, such as dimensions, velocities, turbulence and appropriate flows, are important. Although available field assessments are based on limited and often non-standardized data, they provide evidence that attraction or guidance efficiency may depend more (but not exclusively) on biological factors. Field and laboratory studies indicate that passage efficiency may depend more (but not exclusively) on passage system design features, particularly when biological requirements and hydraulic conditions are well matched.

Although frequently not well understood or quantified, species motivation and use of habitat below or above barriersmay also affect attraction, guidance and passage efficiency, as fish may utilize fish passage systems for tentative rather than required movements. Innovative fish tracking techniques in field and laboratory studies are providing ways to quantify motivation, attraction/guidance, and passage factors. Ecohydraulic approaches, which integrate improved biological assessments with advanced hydraulics, enhance understanding of fish behaviour and the factors affecting passage effectiveness. Responses of downstream moving fish associated with spillway re-design, bypasses, and bar racks or upstream moving fish associated with habitat use, attraction efficiency to fishway entrances and passage efficiency through submerged orifices or surface weirs or different turbulence characteristics in pools are highlighted.

Results of such ecohydraulic studies are invaluable in calibrating numerical simulations and enhancing biological ground-truthing of CFD modeling for 1, 2 or 3 dimensions. Such modeling may provide additional insights about turbulent flow and fish behaviour. Much more effort on ecohydraulic studies is needed in the field and in the laboratory to quantify responses of species with different migratory needs and biomechanical capabilities. This effort is needed to further improve knowledge, validate fish behaviour assumptions, ground-truth models and assist the development of more robust and effective fish passage systems.

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Jun 25th, 4:30 PM Jun 25th, 4:50 PM

Concurrent Sessions C: Multi-Dimensional Modeling and Fish Passage Restoration - Some Aspects of Fish Behaviour and Hydraulics Which May Affect Passage Effectiveness

Agriculture Leaders Theater, Oregon State University

Fish behaviour over space, time, life cycle needs and ecohydraulic conditions may affect the effectiveness of upstream and downstream passage systems. The spacial extent of migratory movements may depend on whether available and suitable habitat which meets the life cycle needs of specific species exists only below or only above a barrier, or in both locations. Highly effective passage systems have the following characteristics: a) their use is compelled by the migratory needs of specific species ;b) are easy to locate by the migratory fish community as they offer topographical and flow conditions that species seek rather than avoid; and c) combine morphological features and hydrodynamic conditions which match their biomechanical capabilities and are suitable for efficient transport.

These factors relate to species motivation (required versus tentative movements), attraction or guidance efficiency (probability that fish will locate the upstream fishway entrance or be actively guided downstream), and passage efficiency (probability fish will move through passage system), respectively. Any one of these factors or any combination of the three may limit overall system passage effectiveness. Field assessments for several species and many passage systems around the globe, supplemented by controlled laboratory studies, have demonstrated considerable variation in attraction or guidance efficiency, as well as passage efficiency. Not surprisingly, biological factors, such as migratory, morphological or ecological characteristics of different species, species abilities, salmonids vs non-salmonids, as well as passage system design features, such as dimensions, velocities, turbulence and appropriate flows, are important. Although available field assessments are based on limited and often non-standardized data, they provide evidence that attraction or guidance efficiency may depend more (but not exclusively) on biological factors. Field and laboratory studies indicate that passage efficiency may depend more (but not exclusively) on passage system design features, particularly when biological requirements and hydraulic conditions are well matched.

Although frequently not well understood or quantified, species motivation and use of habitat below or above barriersmay also affect attraction, guidance and passage efficiency, as fish may utilize fish passage systems for tentative rather than required movements. Innovative fish tracking techniques in field and laboratory studies are providing ways to quantify motivation, attraction/guidance, and passage factors. Ecohydraulic approaches, which integrate improved biological assessments with advanced hydraulics, enhance understanding of fish behaviour and the factors affecting passage effectiveness. Responses of downstream moving fish associated with spillway re-design, bypasses, and bar racks or upstream moving fish associated with habitat use, attraction efficiency to fishway entrances and passage efficiency through submerged orifices or surface weirs or different turbulence characteristics in pools are highlighted.

Results of such ecohydraulic studies are invaluable in calibrating numerical simulations and enhancing biological ground-truthing of CFD modeling for 1, 2 or 3 dimensions. Such modeling may provide additional insights about turbulent flow and fish behaviour. Much more effort on ecohydraulic studies is needed in the field and in the laboratory to quantify responses of species with different migratory needs and biomechanical capabilities. This effort is needed to further improve knowledge, validate fish behaviour assumptions, ground-truth models and assist the development of more robust and effective fish passage systems.