Computational fluid dynamics modelling of forebay hydrodynamics created by a floating juvenile fish collection facility at the Upper Baker River Dam, Washington

Abstract

The Upper Baker River Dam utilizes a combination of a floating surface collector (FSC) and a guide net to facilitate the downstream migration of anadromous juvenile fish. The FSC generates attraction currents by withdrawing water from the forebay, upstream of the guide net. The withdrawn water is discharged at the rear of the FSC by two pumps. A three-dimensional (3D) computational fluid dynamics (CFD) model of the forebay of the dam is presented in this paper. The objective was to investigate forebay hydrodynamics generated by the FSC and operation of the powerhouse. The CFD model, consisting of approximately one million computational cells, was validated against field data. Model results were analyzed, using a recently proposed strain-velocity-pressure (SVP) hypothesis, to identify hydrodynamic cues responsible for attracting juvenile fish to the FSC. The CFD model indicates that the FSC pumps generated high velocity jets dominate the circulation pattern downstream of the guide net. Upstream of the guide net, the velocities are weak, except in the region impacted by attraction currents. The sweeping and normal velocities on the guide net are smaller than those suggested by regulatory agencies for designing screens at juvenile fish collection facilities.

Thinking Like a Fish: A Key Ingredient for Development of Effective Fish Passage Facilities at River Obstructions

“…The use of internally implantable PIT‐tags (Prentice et al , ), acoustic tags (Ehrenberg and Steig, ) and radio tags (Aarestrup et al , ; Moser et al , ; Burke and Jepson, ; Keefer et al , ), along with the ability to estimate 3‐D positions of fish from underwater acoustic arrays (Hockersmith et al , ; Johnson et al , ), can provide information on upstream or downsteam behaviour of fish in relation to hydrodynamic conditions as they approach river obstructions. Computational fluid dynamic models provide the ability to estimate the hydraulic characteristics in forebays and tailraces of obstructions through which tagged fish pass (Khan et al , ), and others have developed modelling tools to combine the fish behaviour with the hydraulics (Goodwin et al , 2006, 2007). These types of field techniques along with laboratory experimentation to develop flow conditions through which fish will pass can provide the information needed for species for which we presently have little data.…”

Predicting Oil Slick Migration at a Pipeline River Crossing on the River Niger Using Hydraulic Geometry

“…Other areas of research where velocity is also used to estimate variables appear to follow similar assumption or at least assume river velocity plays a role. Such variables include sediment transport and turbidity dynamics (Lawler 2005, Lawler et al 2006, dam sediment intakes and channel bed-sediment accumulation (Varaki et al 2009, Roca et al 2009), downstream fish migration (Khan et al 2008), river biomass and vegetation (Doncker et al 2009), reach-scale aquatic habitat quality (Shields and Rigby 2005) and seed suspension and deposition (Groves et al 2009). Although these variables would probably have different density ratios compared to water, which might differ from the oilwater density ratio of 0.8699-1.00 g cm -3 respectively.…”

Modelling mitigation measures for smolt migration at dammed river sections

“…Nestler, Goodwin, Smith, Anderson, and Li () explored hydrodynamic cues used by outmigration juvenile salmon and concluded that their swimming path can explained by fluid dynamics and geomorphology and linked to sensory capacities of the fish. Khan, Roy, and Rashid () utilized the same approach and demonstrated how CFD models could help to assess complex hydraulic engineering problems in relation with juvenile fish migration over dams. However, the potential for in situ combination of telemetry data with 3D hydraulic modelling to obtain successful downstream migration solutions is largely unexplored.…”