Seeking better fishways: the Pump Fishway Program (#155)
People working in fish passage move fish past riverine barriers: aquaculturists, on the other hand, move fish around fish farms. Marrying these two techniques presents an exciting prospect in fishway development. Millions of fish-passage barriers exist globally. A great many of them lack fish passage, while others have under-performing and costly fishways
. These problems contribute to the declining global biodiversity and production of freshwater fish. Better and less-expensive fishway designs are urgently needed to reverse the loss of connectivity, to rehabilitate fish communities and to restore fisheries.
Inter-disciplinary research at UNSW Australia aims to refine and test a novel pump fishway design that integrates fish passage and aquaculture technologies to transform fishway performance and reduce costs. The pump fishway uses a circular, open-lock fishway section to provide sufficient elevation for fish to be gravitated into a transfer chamber, which is then pressurized with reservoir water. This flow carries fish up a rising transfer pipe and into the reservoir.
A pump fishway offers many potential benefits: upstream passage for migrant fish communities; lightweight, modular construction with few moving parts; applicability to diverse sites and barriers >1.5m high; energy-independence; continuous operation with brief transfer cycles; and potential adjustability, flood protection and fewer constraints due to tailwater levels. Large savings on capital and operating costs are predicted. Research and development are under way, aiming to validate and optimise the pump fishway design, using physical and computational hydraulic modelling and animal trials with wild, migrating fish.