Hydraulic optimisation of a system for transporting fish in water vertically at near-atmospheric pressure

Chandelier Room

Reversing worldwide declines in freshwater fish while making sustainable use of water resources will require effective and economical fishways to restore fish migrations. We have developed a proof-of-concept for our innovative pump fishway approach (Harris et al., 2018). This aims to safely lift live fish over vertical distances exceeding 100m without injury. Our horizontal-cylinder design successfully combined the volitional-passage functions of existing fishways with non-volitional transport in a conduit carrying pumped water for young, hatchery-bred, non-salmonid fish. Here, we describe the large-scale transport system designed with minimal moving parts and capable of transporting fish in water vertically over distances exceeding 100 metres. The fish and transported water are contained in a conduit with the transported volume kept at near-atmospheric pressure to minimise barotrauma risks. The system has been optimised to minimise the use of large mechanical pump systems. Under certain conditions, all mechanical pumping is eliminated. The entire system has been demonstrated at a physical model 1 metre vertical scale. A numerical model has been developed, verified against the physical model. Further, the numerical model shows that the system is reliable and can be applied at vertical scales exceeding 100 metres.

This contribution will describe the key principles of the system operation and larger scale (4m lift) experiments with summary hydraulic characterisations of the entire system. This will includes hydraulic approaches which retain the key biological constraints required for successful attraction but also minimise the hydraulic losses during the non-volitional transport phase. We also describe a novel method to determine the hydraulic energy losses of conduits to transport fish in water.