Session A6- Use of nature-like fishways for passage at high head dams

Given the relatively flat design slopes typically associated with nature-like fishways, these are typically only considered to be viable passage options for low head dams. In addition to the shallow slopes, the typical intake configuration only allows operation of these types of fish ways over a limited range of water surface elevations. These characteristics often rule out the use of a nature-like fish way for storage reservoirs or other impoundments where the water surface can fluctuate over a wide range of elevations. As nature-like fishways can provide other benefits such as rearing habitat while also being relatively simple to operate, it can often times be advantageous to find an approach that extends the applicability of this design beyond that normally considered . This paper ·will present information on two projects where nature-like fishways were utilized to provide fish passage at relatively high head dams with fluctuating water surface elevations and how these conditions were overcome