Fish Observations and Hydraulic Measurements on a Nature-Like Unstructured Block Ramp

The hydraulic design of nature-like unstructured block ramps is based on empirical approaches hampering the proof of passable migration corridors for fish. The research project “MigRamp” aims at identifying and quantifying migration corridors of upstream migrating fish on nature-like unstructured block ramps by linking fish trajectories, bed topography, and local flow field. For this purpose, combined fish-biological and hydraulic investigations were carried out on an existing nature-like unstructured block ramp in the field and laboratory tests. This paper describes the field measurements and reports preliminary results of an identified migration trajectory of a brown trout and its correlation with hydraulic parameters.