The development of fish passage research in a historical context

Fish passage, including fishways and fish screens, ecological flow management for open or ice-covered waters and fish habitat works, such as stream rehabilitation, habitat replacement, erosion and sediment management, are the subject of increased interest worldwide. Research and development in these areas, establishing a foundation of sound science and innovative engineering, has intensified, as a result of widespread recognition of the importance of sustainable and environmentally acceptable use of water resources. Scientific and engineering studies, along with technological advancements have allowed the development of a range of methods and tools for assessing the feasibility of and for providing guidance in seeking effective solutions. Methods and tools range from fairly simple to fairly sophisticated, from long-life rigid structures to adjustable ones, and solutions that are applicable at a variety of projects, scales, site conditions, fish species, aquatic biota, data sources and economic circumstanc...

Developing a toolkit for fish passage, ecological flow management and fish habitat works

This paper presents the results of an experimental study on the hydraulics of vertical slot fishways. Seven designs, including some conventional designs, were tested. A conceptual uniform flow state has been defined for which a linear relation has been found between the dimensionless flow rate and relative flow depth. Non-uniform flow of the M1 and M2 types has been analyzed using the Bakhmeteff-Chow method. Some observations have also been made on the velocity profiles at the slot and circulation patterns in the pools.

Hydraulics of Vertical Slot Fishways

This pape presents the results of an experimental study of the structure of flow in a vertical slot fishway of an effective and simple design. The flow at the slot could be treated as a plane jet, but there are a number of differences from the plane jet. It was found that for a slope of 5%, the main flow travels from one slot to the next through the pool as a 2D curved jet with two recirculation regions—one on each side. For slopes of 10 and 20%, the main flow is 3D. Water flows toward the side wall between the long baffles near the bed and piles up along the side wall; part of the flow rises to the surface and then travels to the outlet. The decay of longitudinal velocity in the pool is much larger than that of the plane jet. The volume averaged velocity head of the water in the pool was found to be ∼12% of Δ\ih, the head drop per pool. The volume of the recirculation region between the short baffles was ∼28% of the volume of the pool for all three slopes and all discharges whereas the corresponding volume of the horizontal eddy just downstream of the long baffles for the two larger slopes was ∼10%. The relative volume of the two recirculation regions was ∼73% for the 5% slope and ∼38% for the 10 and 20% slopes.

Structure of Flow in Vertical Slot Fishway

The restoration of fish passage has been focused on anadromous fish species, whilst studies accommodating passage of coarse species have often been considered incidental, yet frequently these are the predominant group of species encountered in rivers. In addition, fishway designs depend greatly on the interplay between hydraulics and biomechanics, yet very little data are available on the responses to specific hydraulic settings for these species. This study aims to explore the effects of water velocity and turbulence on the behaviour of a cyprinid species - the Iberian barbel Luciobarbus bocagei (Steindachner, 1864) - particularly their upstream movements upon different discharges (38.5 to 77.0 L · s−1), through an indoor full scale pool-type fishway prototype. Larger adults had a higher passage success (mean = 79%) and took less time (mean ± SD (min): 5.7 ± 1.3) to negotiate the entire six pool fishway, when compared to small adults. Correlation analysis between hydraulic variables and fish transit time yielded different results. Correlations were found to be the highest between the horizontal component of Reynolds shear stress and fish transit time, particularly for smaller size-individuals (r = −0.45; p < 0.001), highlighting this variable as a key-parameter which strongly determines the movements of Iberian barbel. The present study identified key factors on Iberian barbel movements that may have direct application to future fishway designs for this species and for other ‘weak’ swimmers. Copyright © 2010 John Wiley & Sons, Ltd.

Effects of water velocity and turbulence on the behaviour of Iberian barbel (Luciobarbus bocagei, Steindachner 1864) in an experimental pool-type fishway

This paper presents the results of an experimental study on the mean and turbulence structures of flow in a vertical slot fishway with slopes of 5.06 and 10.52%. Two flow patterns existed in the fishway and for each one, two flow regions were formed in the pools: a jet flow region and a recirculating flow region. The mean kinetic energy decays rapidly in the jet region and the dissipation rate in most of the areas in the pool is less than 200 W∕ m3 . For the jet flow, the nondimensional mean velocity profile across the jet agrees very well with that of a plane turbulent jet in the central part of the jet with some scatter near its boundaries. Its maximum velocity decays faster compared to a plane turbulent jet in a large stagnant ambient. The jet presents different turbulence structure for the two flow patterns and for each pattern, the turbulence characteristics appear different between the left and right halves of the jet. However, the turbulence characteristics show some similarity for each case. The n...

Mean Flow and Turbulence Structure in Vertical Slot Fishways

Detailed mean flow characteristics generated by a staggered arrangement of boulders in a rock-ramp-type naturelike fish pass were investigated experimentally at three different channel slopes (5%, 3%, and 1.5%). The results showed that this type of fish pass can produce adequate water depth and favorable flow velocity suitable for fish passage. Three different characteristic velocity regions were identified, namely, downstream of boulders (wake region), intermediate region, and upstream of boulders. Some general correlations were developed for predicting the flow depth and velocity in a rock-ramp fish pass as a function of normalized discharge. Moreover, a flow-resistance analysis based on basic concepts for wake-interference flow regime in this fish pass has resulted in a general equation for the average velocity. This study improves the understanding of the complex flow characteristics in a rock-ramp fish pass.

Mean Flow Characteristics in a Rock-Ramp-Type Fish Pass

This paper presents the results of an investigation on the turbulence characteristics of a rock-ramp-type, nature-like fish pass with a staggered arrangement of boulders for slopes of 1.5 and 3% for different discharges. This study showed some major differences between the flow with cluster of boulders (wake-interference flow) and the flow with isolated boulders (isolated-roughness flow) in the decay rate of turbulence and turbulence magnitude. General correlations were derived for the turbulence intensity and turbulent kinetic energy (TKE) as a function of normalized streamwise distance in a rock-ramp fish pass. Turbulence statistics (skewness and kurtosis), energy dissipation rate, and dissipative eddy size in this fish pass were also discussed in relation to fish passage.

Nallamuthu Rajaratnam

Papers

Hydraulics of Vertical Slot Fishways

Structure of Flow in Vertical Slot Fishway

Mean Flow and Turbulence Structure in Vertical Slot Fishways

Mean Flow Characteristics in a Rock-Ramp-Type Fish Pass

Turbulence Characteristics in a Rock-Ramp-Type Fish Pass