Downstream Fish Passage Technologies for Medium-To-Large Hydropower Plants: Part II

Abstract

Hydropower plants (HPPs) can block or delay fish migration and cause fish injuries or mortalities during the turbine passage. As a consequence, fish populations in many fresh water systems decline. Mechanical and behavioral Fish Guidance Structures (FGS) with vertical bars and large bar spacing are effective solutions to protect and guide downstream migrating fish at water intakes of medium-to-large HPPs (Bates & Vinsonhaler, 1957; Electric Power Research Institute [EPRI] & Dominion Millstone Laboratories [DML], 2001; Amaral et al., 2001 and Boes & Albayrak, 2017). However, the current design of such FGSs, namely louvers, angled bar racks and modified bar racks (MBR) leads to high head losses and unfavorable upstream and downstream flow fields, which are critical factors for their successful implementation at HPPs. In the scope of the EU Horizon 2020 research project “Fishfriendly Innovative Technologies for hydropower” (FIThydro), we have developed two innovative curved-bar shapes for FGSs, assessed their hydraulic performance for a range of parameters and developed a hydraulic head loss formula. In this paper, we give a short introduction on the current and new bar design of FGSs, present the classic trash rack formulas and the new head loss formula for FGSs and their application for two Swiss HPPs, discuss the results and draw conclusions.