Hydraulic Characteristics of Fish-passes on Inclined Drops with Multifarious Configurations: An Experimental Study

Abstract

This study provides a way to increase the energy dissipation of flow over an inclined drop with environmental and economic considerations. The purpose of this study is to provide a new method for assessing aquatic health on inclined drops and also to provide a method for the dissipation of excess flow energy using fish-pass elements. 81 different experiments were performed on three types of simple inclined drops and inclined drops equipped with without fish-pass elements and with a flow rate of 200-600 lit/min. The findings revealed that when the relative critical depth increases, the energy dissipation values rise and the downstream Froude number falls. With rising relative critical depth, the metrics of relative downstream depth, relative length of the hydraulic leap, and relative aeration length all rise.  Model F7 has the greatest energy dissipation and Model F2 has the highest flow aeration length and relative downstream depth. The use of fish-pass elements, in addition to increasing the aeration rate and dissipating the destructive energy of the flow, significantly reduces the downstream Froude number. Consequently, these elements can be effective regarding scouring the bed and channel walls and increasing the stability of downstream structures. It was also found that non-hole fish-pass elements are suitable for increasing energy dissipation while hole elements are more efficient for designs with environmental aims.