Author(s): Uli Dumont
Linked Author(s):
Keywords: Fish ramps; Hydraulic and geometric design; Flat ramp; Boulder type ramp; Pool type ramp; Detectivity; Passability; Experience with ramps
Abstract: The restoration of river connectivity at existing dams can be most appropriately achieved by means of nature-like ramps. However, two provisions are essential to this task: • The arrangement of the ramp should guarantee that migrating fish are able to effortlessly find the entrance independently of the flow conditions. • The design of ramps or roughened channels should ensure passability independently of the flow conditions. Consequently, water depths should be sufficient and water flow velocities in the migration corridor should not exceed the swimming capabilities of fish. There exist three different types of nature-like fish ramps: flat ramp, boulder type ramp and pool type ramp. Suitability assessments of the different types must include consideration of the local conditions. Frequently, operation can be optimized by means of combining different types, thus permitting the facility to better accommodate to changing flow conditions in the river.
Year: 2007