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(civil engineering)



in a hydroengineering complex, a structure enabling fish to pass upstream, mainly during the spawning migration. Fishways are divided into two basic groups: structures enabling fish to independently pass an obstacle (fish passes) and structures that move fish (locks and fish elevators).

Fish passes are channels through which water flows downstream at a speed making it possible for the fish to swim against the current. There are three basic types of fish passes: trough, pond, and ladder. Some trough passes have slight gradients, smooth walls, and a smooth bottom. The bottom and walls of others are fitted with projections. Another type of trough pass has incomplete partitions (in terms of depth and width).

Pond passes consist of a series of basins, where the fish can rest during their journey. The basins are connected by short channels or troughs. The passes usually are built in the banks, bypassing the dam.

Fish ladders are in the form of stepped troughs divided into a series of basins by cross-partitions having flotation openings. This type of fish pass has proved most effective for many different species of fish.

A dam on the Tuloma River (USSR) has a fish ladder for Atlantic salmon (height, 20 m; length, 513 m), and the McNary dam on the Columbia River (United States) has a ladder for salmon (height, 25 m; length, 610 m).

Fish locks in terms of operation are similar to ship locks. Ordinarily they have two adjacent chambers, each of which has gates separating the chambers from the upper and lower waters. The locks can operate under significant head. However, they require large amounts of water, and their fish-passing capacity is relatively low.

Fish elevators, which lift the fish in a moving flooded chamber or in a special net, operate according to the same principle as mechanical ship-lifting apparatus. Fish elevators, like fish locks, are usually located in separate piers of the dams. Also used as fishways are hydraulic fish elevators, floating fish-lifting devices, and, sometimes, ship locks and spillways of hydroelectric power plants.

It is advisable to locate fishways around the spillways. To guide the fish away from dangerous areas and toward the entrance of a fishway, guiding and protective nets and screens are set out. The subsequent descent downstream of the fish and their young is made possible through the use of all types of fish passes, hydraulic fish elevators, low- and medium-head spillway dams, ship locks, and the water channels of hydroelectric power plants equipped with adjustable-blade and mixed-flow turbines (with a large-diameter rotor, a slow turning speed, and significant clearance between the rotor and the stator). The designs for fishways in modern high-head hydroelectric projects are still insufficiently advanced.


Birznek, O. A., and Z. M. Kipper. Rybopropusknye sooruzheniia. Moscow, 1960.
Grishin, M. M. Gidrotekhnicheskie sooruzheniia. Moscow, 1968.


References in periodicals archive ?
Gilligan DM, Harris JH and Mallen-Cooper M (2003) Monitoring changes in Crawford River fish community following replacement of an ineffective fishway with a vertical-slot fishway design: results of an eight year monitoring program.
Experimental study of 2D instationary flow in vertical slot fishways ans with and without cylinders.
A plan was proposed to reopen the fishway to the alewives while monitoring the basin's smallmouth bass population.
Hydraulic aspects of pool-weir fishways as ecologically friendly water structure, Ecological Engineering, 36(1): 36-46.
In sum, the Ninth Circuit held that 1) the Conservancy lacked prudential standing to bring an APA challenge, and 2) the Ninth Circuit lacked jurisdiction over the Conservancy's claims that Defendants violated Washington's Fishway Law.
Efficiency of fishways and impact of dams on the migration of grayling and brown trout in the Glomma River system, south-eastern Norway, Regulated Rivers: Research and Management 8: 145-153.
Until they built the new fishway in 1977, there were almost none making it through.
However, a major factor concerning the design of a fishway is the migratory fishes' swimming capacity in terms of speed and endurance (Beach, 1984), which makes the dimensioning of efficient fishways in the formerly mentioned neotropical region practically impossible (Quiros, 1989).
Fish ladders, or fishways are a commonly used strategy to bypass blockages.
alternatives to fishways required by the Federal Energy Regulatory
The construction of the Bonneville and Grand Coulee Dams in the 1930's presented serious problems that were only partially solved by the expenditure of millions of dollars for fishways (Bureau of Fisheries, 1917a; U.
Their survival depends on access to healthy river habitat, and once the Sebasticook Fishway is complete, the owners of two downstream hydroelectric dams will be required to install fishways.