Fish passage movable within reservoir at variable level behind dam

摘要

A cage (2) fixed to the top of the upstream face of the dam (1) carries on its outside an element (8) moved up and down with the water level, e.g. by a rack-and-pinion servo mechanism with electronic control linked to a level sensor.A corridor (9) through the cage protrudes through a vertical aperture in its vertical face (5). The lower end of the corridor leans against the base of the cage at the level of a conduit passing through the dam into the water on its downstream side.