METHOD AND APPARATUS FOR FACILITATING MIGRATION OF FISH PAST DAMS AND OTHER BARRIERS IN WATERWAYS

摘要

Method and apparatus for fish migration past dams and other water barriers. A preferred embodiment (100) comprises a conduit (101) passing from downstream side (22) of water barrier (10) to upstream side (21) of the barrier, flow-controlling valves (102 and 105) disposed in series within conduit (101), and actuators (103) for opening valves (102 and 105) in the presence of fish. Fish (30) are attracted by flow (130) passing through conduit (101) at controlled rates by means of flow-through devices in valves (102 and 105). On entering forechamber (104) and swimming upstream the fish pass actuators (103), which cause first valve (102) to open. As first valve (102) opens, water flow through conduit (101) remains controlled and substantially uniformly turbulent under action of second valve (105). With valve (102) open fish (30) may swim to mid-span section (140) of the conduit. When no further fish are present in forechamber (104) or passing actuators (103), or enough fish are present in section (140), the first valve closed and fish passing actuators (103) in the direction of valve closes. With valve (102) closed and fish passing actuators (103) in the direction of valve (105) in mid-span section (140), valve (105) opens. As value (105) opens flow (130) through the conduit is controlled by now closed valve (102). Upon opening of valve (105) fish (31) are free to swim past valve (105) and exit conduit (101) through sally port (141), and to swim away from barrier (10) into upstream side (21) of waterway (20). Expanded sections (180) of conduit (101) are provided as rest stations for long transits against strong currents.