Session D6 - Modeling fish passage response to instream flows on run-of-river hydroelectric projects
Location
UMass Amherst
Event Website
http://fishpassage.ecs.umass.edu/Conference2012/
Start Date
7-6-2012 4:25 PM
End Date
7-6-2012 4:45 PM
Description
Run-of-river hydroelectric projects do not have many of the environmental issues associated with large storage facilities; however, the flow regimes associated with these projects have the potential to delay migration in streams where anadromous fish are present. These projects are typically designed to maximize head (i.e. elevation differences between the intake and powerhouse), and hence the stream reach subject to reduced flows is generally high gradient, consisting of falls, cascades, and chutes that may only be passable by fish at certain flow levels or impassable altogether. If instream flows are released at a fixed magnitude during the migratory period, flows suitable for fish passage at these obstacles may be less frequent or absent altogether, and fish migration can be delayed or obstructed. Pulsed flow releases that vary in magnitude can be an efficient means of providing the flow levels necessary for fish passage. In contrast to storage-type facilities, a fixed schedule for pulse flow releases on run-of-river facilities is not possible, as flow levels must be present naturally in order to be released. Pulse flow regimes must instead be defined by specifying ideal frequency, flow magnitude, and a period over which releases will take place. We present a mechanistic model to assist in the design of these pulse flow regimes; the model predicts how alternate pulse flow design considerations affect fish passage success relative to natural conditions, based on the stream hydrograph and assumed flow conditions for fish to pass obstacles to migration.
Session D6 - Modeling fish passage response to instream flows on run-of-river hydroelectric projects
UMass Amherst
Run-of-river hydroelectric projects do not have many of the environmental issues associated with large storage facilities; however, the flow regimes associated with these projects have the potential to delay migration in streams where anadromous fish are present. These projects are typically designed to maximize head (i.e. elevation differences between the intake and powerhouse), and hence the stream reach subject to reduced flows is generally high gradient, consisting of falls, cascades, and chutes that may only be passable by fish at certain flow levels or impassable altogether. If instream flows are released at a fixed magnitude during the migratory period, flows suitable for fish passage at these obstacles may be less frequent or absent altogether, and fish migration can be delayed or obstructed. Pulsed flow releases that vary in magnitude can be an efficient means of providing the flow levels necessary for fish passage. In contrast to storage-type facilities, a fixed schedule for pulse flow releases on run-of-river facilities is not possible, as flow levels must be present naturally in order to be released. Pulse flow regimes must instead be defined by specifying ideal frequency, flow magnitude, and a period over which releases will take place. We present a mechanistic model to assist in the design of these pulse flow regimes; the model predicts how alternate pulse flow design considerations affect fish passage success relative to natural conditions, based on the stream hydrograph and assumed flow conditions for fish to pass obstacles to migration.
https://scholarworks.umass.edu/fishpassage_conference/2012/June7/26
Comments
Katie Healey is a Senior Analyst at Ecofish Research Ltd. in Vancouver, Canada. Katie has a background in applied mathematics and ecological modelling. Her primary responsibility includes quantifying the environmental effects of water use through instream flow modelling and statistical analysis, and research and development of tools to aid in planning for successful fish migration on existing and future hydro projects.