A culvert is a waterway designed to pass floodwaters beneath an embankment. In practice, the total cost of the structure must be minimum, and the optimum hydraulic design is the smallest barrel size allowing for inlet control operation. The adverse role of culvert crossing on the riverine ecology has been recognised for the past decades, because the culverts limit the longitudinal connectivity of streams for fish movement. Culvert fish passage is inhibited by a wide variety of parameters, including barrel velocities, culvert length, and insufficient water depth, which can influence fish swimming performance. One primary ecological concern is the potential velocity barrier to upstream fish passage resulting from high velocities in the culvert barrel. Baffles may be installed along the barrel invert to provide locally smaller velocity, but the discharge capacity may be adversely affected.
Detailed research is conducted at the University of Queensland, combining engineering and biology researchers, to gain a better understanding of the interactions between turbulence and fish.
WANG, H., CHANSON, H., KERN, P., and FRANKLIN, C. (2016). "Culvert Hydrodynamics to enhance Upstream Fish Passage: Fish Response to Turbulence." Proceedings of 20th Australasian Fluid Mechanics Conference, Australasian Fluid Mechanics Society, G. IVEY, T. ZHOU, N. JONES, S. DRAPER Editors, Perth WA, Australia, 5-8 December, Paper 682, 4 pages (ISBN 978 2 74052 377 6).
WANG, H., and CHANSON, H. (2017). "Baffle Systems to Facilitate Upstream Fish Passage in Standard Box Culverts: How About Fish-Turbulence Interplay?" Proceedings of 37th IAHR World Congress, IAHR & USAINS Holding Sdn. Bhd. Publ., Editors Aminuddin Ab. Ghani, Ngai Weng Chan, Junaidah Ariffin, Ahmad Khairi Abd Wahab, Sobri Harun, Amir Hashim Mohamad Kassim and Othman Karim, Kuala Lumpur, Malaysia, 13-18 August, Vol. 3, Theme 3.1, pp. 2586-2595.