Hydraulic and turbulence structure of triangular labyrinth weir‐pool fishways

Dizabadi, Shahram; Azimi, Amir H.

doi:10.1002/rra.3581

Cited by 11 publications

(5 citation statements)

References 51 publications

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“…If d/w > 1.5, their Q + values are close to each other. Similar observations were made in a pool-weir fishway with square pools[18].…”

supporting

confidence: 73%

“…There are studies, though limited, that demonstrate the potential of a labyrinth weir in improving the performance of a pool-weir fishway. Dizabadi and Azimi [18] find it suitable for a variety of species because of its diversified flow fields. For low-head projects, Savage and Brenchley [19] conceive a fish pass with a broad-crested labyrinth weir, in which conducive regions for migration are created.…”

Section: Labyrinth Weir Layoutsmentioning

confidence: 99%

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Evaluation of Pool-Type Fish Passage with Labyrinth Weirs

Yang

Ansell

2022

Sustainability

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Due to the construction of dams and sluices, habitat fragmentation of riverine species is an issue of concern in hydropower projects. An artificial fishway aims to restore flow connectivity and facilitate migration. As an alternative to the conventional layout with straight walls, labyrinth layouts are introduced, consisting of either triangular, trapezoidal, or rectangular weirs. Three-dimensional CFD simulations are performed to examine their influences on the fishway hydraulics. The labyrinth layouts exhibit an appreciable three-dimensional flow structure in a pool, featuring flow fluctuations in both cross- and along-channel directions, which is indicative of the potential for multiple species with distinct swimming preferences. The streamwise reduction in mean flow velocity is correlated with the Froude number, with the labyrinth weirs leading to a somewhat lower reduction than the conventional one. The dimensionless pool water depth declines with specific flow discharge. The turbulence kinetic energy is the lowest in the triangular layout and the vorticity in the conventional one. Among the labyrinth layouts, the differences in volumetric power dissipation are small. An equation is developed for dissipation estimation. All the labyrinth layouts generate higher energy loss than the conventional one. With optional weir configurations, the findings provide reference for engineering design.

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“…If d/w > 1.5, their Q + values are close to each other. Similar observations were made in a pool-weir fishway with square pools[18].…”

supporting

confidence: 73%

Section: Labyrinth Weir Layoutsmentioning

confidence: 99%

Evaluation of Pool-Type Fish Passage with Labyrinth Weirs

Yang

Ansell

2022

Sustainability

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“…Figure 11 shows different ranges for each flow regime based on the slope of the bed and the distance between the pools in this study. The results of Baki et al [21], Ead et al [6] and Dizabadi et al [22] were used for this comparison. The distance between the pools affects the changes in the regime of the fish ladder.…”

Section: Flow Regime and Discharge-depth Relationshipmentioning

confidence: 99%

An Investigation on Hydraulic Aspects of Rectangular Labyrinth Pool and Weir Fishway Using FLOW-3D

Mirkhorli,

Ghaderi,

Alizadeh Sanami

et al. 2024

Arab J Sci Eng

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Two different arrangements of the weir (i.e., straight weir and rectangular labyrinth weir) were used to evaluate the effects of geometric parameters such as weir shape, weir spacing, presence of an orifice at the weir, and bed slope on the flow regime and the relationship between discharge and depth, variation and distribution of depth-averaged velocity, turbulence characteristics, and energy dissipation at the fishway. Computational fluid dynamics simulations were performed using FLOW-3D® software to examine the effects on flow conditions. The numerical model was validated by comparing the calculated surface profiles and velocities with experimentally measured values from the literature. The results of the numerical model and experimental data showed that the root-mean-square error and mean absolute percentage error for the surface profiles and normalized velocity profiles of plunging flows were 0.014 m and 3.11%, respectively, confirming the ability of the numerical model to predict the flow characteristics of the pool and weir. A plunging flow can occur at values of L/B = 1.83 (L: distance of the weir, B: width of the channel) and streaming flow at L/B = 0.61 for each model. The rectangular labyrinth weir model has larger dimensionless discharge values (Q+) than the conventional model. For the conventional weir and the rectangular labyrinth weir at submerged flow, Q is proportional to 1.56 and 1.47h, respectively (h: the water depth above the weir). The average depth velocity in the pool of a conventional weir is higher than that of a rectangular labyrinth weir. However, for a given discharge, bed slope, and weir spacing, the turbulent kinetic energy (TKE) and turbulence intensity (TI) values are higher for a rectangular labyrinth weir compared to conventional weir. The conventional weir has lower energy dissipation than the rectangular labyrinth weir. Lower TKE and TI values were observed at the top of the labyrinth weir, at the corner of the wall downstream of the weir, and between the side walls of the weir and the channel wall. As the distance between the weirs and the bottom slope increased, the average depth velocity, the average value of turbulent kinetic energy and the turbulence intensity increased, and the volumetric energy dissipation in the pool decreased. The presence of an opening in the weir increased the average depth velocity and TI values and decreased the range of highest TKE within the pool, resulted in larger resting areas for fish (lower TKE), and decreased the energy dissipation rates in both models.

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“…To maintain fluvial geomorphological connectivity and aquatic ecological function (i.e., fish passage) in ecosystems impacted by urban development, river restoration is required [5][6][7]. Vortex rock weirs (VRWs) are one of the most commonly constructed nature-like fishways [8][9][10] and provide physical channel stability, habitat enhancement, and the hydromechanics to allow upstream fish passage for local fish species. VRWs have conflicting goals in terms of function, where they are installed as a high flow feature to ensure channel stability but provide conditions for low flow processes such as fish passage [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Balancing Physical Channel Stability and Aquatic Ecological Function through River Restoration

Mielhausen

Cockburn

Villard³

et al. 2023

Water

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Vortex rock weirs (VRW) are often used in natural channel design applications to maintain channel form and function, provide physical channel stability, and enhance aquatic habitats. A balanced approach is required to address (often) conflicting goals of VRWs, which include providing erosion protection and grade control while facilitating fish passage for target species. This research evaluated a sequence of modified VRWs in a small-scale watercourse in Southern Ontario, Canada. To determine passage suitability for the target fish species, the water level, water temperature, and channel geometries at 10 VRWs and 11 adjacent pools were monitored under different water level conditions. The structural dimensions and velocity at each VRW were compared to the burst swim speed of local small-bodied fish species to determine fish passage suitability and identify the best practices for VRW design and construction. The results concluded that VRWs provided suitable passage for small-bodied fish species through gap and over-weir flow pathways, particularly during low water level conditions. Further, appropriate design considerations based on the VRW gradient, VRW width, keystone size, and pool length contributed to 100% fish ‘passability’ under all water level conditions. The methodology is provided for predicting the velocity and small-bodied fish passage suitability through VRWs, informing the best practices for VRW design and construction while balancing the requirements for channel stability and fish passage, and contributing to fish population management strategies.

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Hydraulic and turbulence structure of triangular labyrinth weir‐pool fishways

Cited by 11 publications

References 51 publications

Evaluation of Pool-Type Fish Passage with Labyrinth Weirs

Evaluation of Pool-Type Fish Passage with Labyrinth Weirs

An Investigation on Hydraulic Aspects of Rectangular Labyrinth Pool and Weir Fishway Using FLOW-3D

Balancing Physical Channel Stability and Aquatic Ecological Function through River Restoration

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