Interdisciplinary design of a fish ramp using migration routes analysis

•A bottom ramp model is designed to improve the longitudinal connectivity of a stream.•Numerical simulations of 3D steady free-surface flow are performed using a SPH model.•A complex configuration is obtained for the ramp's geometry after optimization.•Resulting velocity fields allow the quantification of possible fish migration routes.•Fish resting zones are quantified based of their size, position, and mutual distance.