Cone fishway

Cone fishway

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• Key considerations
• Planning and design
• Construction and operation
• Links and references

Other name/s

Dragon's tooth fishway

Description

Cone fishways consist of a series of prefabricated cone-shaped concrete or plastic baffles installed across a concrete channel. This type of fishway arose from the unavailability of suitable materials to construct rock ramp fishways and for remote areas[4].

Cone fishways are most effective where there is limited headwater variation and relatively low head differential (<1.5 m)[3], however, trials have been successful at head differentials up to 3 m[4]. The conservative hydraulics at low flows (i.e. low velocities and turbulence levels) allow small fish to pass. At higher flows, the velocity and turbulence levels increase, along with the physical dimensions of the gaps between the baffles in the fishway, therefore allowing larger fish to pass[1].

Sub-types

There are two main sub-types of cone fishways, based on the height/s of the cones in the channel: low cone fishway and high/low cone fishways. An example of a high/low cone fishway is the Glenore Weir fishway on the Norman River (Gulf of Carpentaria near Karumba). It was designed to operate over a broad range of river conditions, including high wet season flows, by adapting the design to a broad deep fishway channel with low cones for low flows and high cones for larger flows, but still allowing passage of fish as small as 10 mm long. Despite discharge increasing 20-fold during periods of high flow, with high turbulence through the centre of the channel, the edges remained relatively calm through the taller cones. Monitoring has also recorded ascent of barramundi up to 500 mm long[2]. An example of a low cone fishway is the Fitzroy barrage on the Fitzroy river.

References

1. ^ Jones, M, O'Connor, JP & Arthur Rylah Institute for Environmental Research (2017), Monitoring the performance of fishways and fish passage works. [online] Available at: https://nla.gov.au/nla.obj-664272102 [Accessed 1 March 2021].
2. ^ Marsden, T (2017), Glenore Weir Cone Fishway - Monitoring Report. [online] Available at: http://rgdoi.net/10.13140/RG.2.2.24740.37766 [Accessed 10 November 2020].
3. ^ O’Connor, J, Stuart, I & Mallen-Cooper, M (2015), 'Performance, operation and maintenance guidelines for fishways and fish passage works', Trove. [online] Available at: https://nla.gov.au/nla.obj-480267623 [Accessed 10 November 2020].
4. ^ a b Stuart, IG & Marsden, TJ (2019), 'Evaluation of cone fishways to facilitate passage of small-bodied fish', Aquaculture and Fisheries. [online] Available at: https://doi.org/10.1016/j.aaf.2019.02.003.

Last updated: 30 April 2021