Oral Presentation Australian Society for Fish Biology Conference 2024

Design and monitoring of the first bypass fishway on a high weir in tropical Australia (111035)

Andrew P Berghuis 1 , Jim Tait 2
  1. Aquatic Biopassage Services, Bargara, QLD, Australia
  2. Econcern, Wanganui, NSW, Australia

A 10m high weir was constructed in 2017 on Norman Creek in Cape York north of Aurukun. The layout of the weir, remote location and seasonality of the stream indicated the need for a volitional (non-mechanical) fishway. Extensive baseline studies of the fish community indicated a substantial migratory species component ranging in length from 30 mm to over 1000 mm.
A fishway based on the well-developed design principles seen in rock chute fishways was constructed in articulated concrete block (ACB). The fishway incorporated a 1:40 slope ACB chute for each metre of rise and an approximately 60 m long resting pool following each fishway ramp. Incorporated habitat features in resting pools included artificial reef structures and emergent and submergent macrophyte margins. The concept of a series of nature-like fishways ascending a high weir provides fish with an opportunity to approach each fishway section as a separate structure and habitat zone rather than a continuous, single run 10 m ascent.
Monitoring of the performance of the fishway over several years and various flow conditions determined that 17 species of fish, including two species that were not recorded in the baseline studies successfully migrated upstream of the weir via the fishway.