Experience and Assessment of Nature-Like Fishways in the Western U.S

Many nature-like fishways have been constructed in the western United States in the last decade.  Nature-like fishways have become the preferred method of reestablishing fish passage for low head diversion dams that are common on western rivers.  These fishways are largely in-river rock ramps or rock bypass channels with boulder weirs.  Many provide passage for multiple native species for which there is little behavioral and physiological data.  Passage performance data for these fishways is also limited and often difficult to obtain in the field.  The inherent complexity of nature-like fishways benefits passage while increasing the difficulty of monitoring passage performance.  The presentation will summarize many in-river and bypass structures now operating in the west; discuss monitoring methods and available passage performance data.