Fish protection

General problems of fish protection in streams, rivers and lakes include artificial destratification in reservoirs, placement of multiple level outlets in dams, control of instream flows, control and reduction of gas supersaturation and protection measures at inlets to such structures as canals, pump stations for process industries, thermal power stations and turbines in hydroelectric power stations. The protection measures at these inlets include track-racks, screens of different kinds (travelling screens, resolving drum screens, plane inclined screens), louver diverters with a bypass and velocity caps on intake structures. These measures for the protection of fish have been discussed well by Clay (1961) and in the recent ASCE manual on the design of water intake structures for fish protection (1982). Reviews of environmental impacts of stream and lake regulation are available in Baxter & Glaude (1980) , Davies & Walker (1986) and others. This chapter is confined to a discussion of the hydraulics of another class of structures used for fish protection in the aquatic habitat namely fishways including culverts with fish passing arrangements; the latter are referred to simply as culvert fishways.