Nature-Like Fishway design and evaluation its performance with habitat simulation model of PHABSIM

The construction of multiple structures disconnects the migration course of fish in the river. Fishways are the most effective solution to re-establish the longitudinal connectivity of the river. The Nature-Like fishway is one of the structures constructed in the last two decades and now that the point of views of river engineers in the world have changed and they seek to rehabilit the rivers, it is necessary that our country's engineers also seek to design Eco-friendly structures, such as nature-like fishway. The purpose of this research is to present the basics of nature-like fishway and to design it for one of Iranian river and to evaluate it with the mathematical model of PHABSIM. The bypass is planned using stone weirs with hydraulic loss of 0.25 meters with pools of width 4 and 5 meters in length, and a volumetric dissipated energy of 98.1 watts per cubic meter, and riffles with a width of 2 meters wide in design were considered. By using the PHABSIM mathematical model, the habitat suitability of the designed bypass channel was investigated and it was observed the fish in the riffles, unlike the pools, chose the channel sides as suitable habitats for more suitable speeds.