THE IMPORTANCE OF FLUVIAL HYDRAULICS TO FISH-HABITAT RESTORATION IN LOW-GRADIENT ALLUVIAL STREAMS

1. A major cause of degradation and loss of stream fish is alteration of physical habitat within and adjacent to the channel. We describe a potentially efficient approach to fish restoration based upon the rela tionship between fluvial hydraulics, geomorphology, and those habitats important to fish. 2. The aquatic habitat in a low-gradient, alluvial stream in the Ozark Plateaus physiographical province was classified according to location in the channel, patterns of water flow, and stru ctures that control flow. The resulting habitat types were ranked in t erms of their temporal stability and ability to be manipulated. 3. Del ineation and quantification of discrete physical spaces in a stream, t ermed hydraulic habitat units, are shown to be useful in stream restor ation programmes if the ecological importance of each habitat unit is known, and if habitats are defined by fluvial dynamics so that restora tion is aided by natural forces. 4. Examples, using different taxa, ar e given to illustrate management options.