Fishway attraction flow: Assessment and optimization using ethohydraulic modelling

  • sje Ecohydraulic Engineering
  • Hydra Buero Muerle & Ortlepp
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Local detectability is one of the key aspects in establishing functional fish passage structures. Herein we present a novel method as extension of the habitat analysis System CASiMiR for assessing the attraction flow towards a fish pass. The method combines state-of-the-art 2D-hydrodynamic-modelling with recent f indings from ethohydraulics. Computed flow velocity fields are evaluated using the "ethohydraulic diagram" allowing for the determination of regions with flow velocities below rheotaxic thresholds as well as those exceeding the critical velocity of target fish species. Additionally, computed pathlines using an agent-based modeling approach allow for the analysis of possible upstream migration paths assuming ideal rheotaxis. The method allows for an adaptive fish passage design including the optimization of an entrance position and geometry in conjunction with the amount of attraction flow.

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p>The European Water Framework Directive (WFD) became a major tool in European water policy. All the member states had to develop River Basin Management Plans (RBMPs). Austria’s first National Water Resource Management Plan was published in 2009 and describes measures to be set. Depending on the catchment size, ecological targets were defined on water body level, to be reached by 2015, 2021 or 2027. A priority goal is the re-establishment of river continuity. Therefore the Austrian Federal Ministry of Agriculture, Forestry, Environment and Water Management published a “Guideline for the construction of fish passes” in 2012. We provide an overview on measures to re-establish river continuity that were recently planned or already established at the Inn catchment, a major tributary to the upper Danube River. Planning principles as well as details from the construction phase and monitoring concepts as well as first results are presented. Founded in 1924 TIWAG started its business with the construction of the HPP Achensee, at the time one of Europe’s largest storage facilities. Since then TIWAG expanded its expertise on engineering, constructing and operating hydro power plants in Tyrol. In the first river basin management cycle at three hydropower plants, located in the“priority river network” (HPP Langkampfen, HPP Kirchbichl and HPP Imst - the latter with the weir Runserau and the water intake at Wenns), measures had to be developed to overcome discontinuity. During planning phase it was tried to apply “standard solutions” according to the Austrian guideline. This was possible for three sites, where we planned vertical slot fish passes in combination with natural bypass channels. To enable upstream migration at the weir Runserau, different alternatives were evaluated, but it was not possible to use a “standard solution”. A review about existing fish lifts was the basis for a promising solution. The chosen design combines a conventional fish migration facility (vertical slot) with a fish lift. Linked together those facilities are offering new, additional possibilities. The characteristics of this new concept and its advantages are presented.</p
Many aquatic species of management interest, such as endangered, sport, or commercially valuable fish, move extensively within a hydrosystem as they use different habitats for spawning, rearing, feeding, and refuge. Engineering tools are presently inadequate to simulate movement by such species as part of the water resources planning and management. We describe how fixed grid-cell methods can be coupled with mobile object-oriented modeling methods (called Eulerian-Lagrangian methods) to realistically simulate movement behavior of fish in the complex hydraulic and water quality fields of aquatic ecosystems. In the coupled system, the Lagrangian framework is used to simulate the movement of symbolic fish (that is, an individual fish, schools of fish, or some aggregate of the population), and the Eulerian framework is used to simulate the physicochemical regimes that influence fish movement behavior. The resulting coupled Eulerian-Lagrangian hybrid modeling method is based on a particle-tracking algorithm supplemented with stimuli-response rules, that is, the numerical fish surrogate.
We describe a Eulerian–Lagrangian–agent method (ELAM) for mechanistically decoding and forecasting 3-D movement patterns of individual fish responding to abiotic stimuli. A ELAM model is an individual-based model (IBM) coupling a (1) Eulerian framework to govern the physical, hydrodynamic, and water quality domains, (2) Lagrangian framework to govern the sensory perception and movement trajectories of individual fish, and (3) agent framework to govern the behavior decisions of individuals. The resulting ELAM framework is well suited for describing large-scale patterns in hydrodynamics and water quality as well as the much smaller scales at which individual fish make movement decisions. This ability of ELAM models to simultaneously handle dynamics at multiple scales allows them to realistically represent fish movements within aquatic systems. We introduce ELAMs with an application to aid in the design and operation of fish passage systems in the Pacific Northwest, USA. Individual virtual fish make behavior decisions about every 2.0 s. These are sub-meter to meter-scale movements based on hydrodynamic stimuli obtained from a hydraulic model. Movement rules and behavior coefficients are systematically adjusted until the virtual fish movements approximate the observed fish. The ELAM model introduced in this paper is called the Numerical Fish Surrogate. It facilitated the development of a mechanistic biological-based hypothesis describing observed 3-D movement and passage response of downstream migrating juvenile salmon at 3 hydropower dams on 2 rivers with a total of 20 different structural and operational configurations. The Numerical Fish Surrogate is presently used by the U.S. Army Corps of Engineers and public utility districts during project planning and design to forecast juvenile salmon movement and passage response to alternative bypass structures.
Interdisciplinary research in hydraulics and ecology for river management and restoration must integrate processes that occur over a wide range of spatial and temporal scales, which presents a challenge to ecohydraulics modelers. Computational fluid dynamics (CFD) models are being more widely used to determine flow fields for ecohydraulics applications. In the Upper Mississippi River (UMR), the mussel dynamics model was developed as a tool for management and conservation of freshwater mussels (Unionidae), which are benthic organisms, imperiled in North America, that are inextricably linked with the hydraulics of river flow. We updated the juvenile dispersal component of the mussel dynamics model by using stochastic Lagrangian particle tracking in a three dimensional flow field output from CFD models of reaches in the UMR. We developed a methodological framework to integrate hydrodynamic data with the mussel dynamics model, and we demonstrate the use of the juvenile dispersal model employed within the methodological framework in two reaches of the UMR. The method was used to test the hypothesis that impoundment affects the relationship of some hydraulic parameters with juvenile settling distribution. Simulation results were consistent with this hypothesis, and the relationships of bed shear stress and Froude number with juvenile settling were altered by impoundment most likely through effects on local hydraulics. The methodological framework is robust, integrates Eulerian and Lagrangian reference frameworks, and incorporates processes over a wide range of temporal and spatial scales, from watershed scale hydrologic processes (decades), to reach scale (km) processes that occur over hours or days, and turbulent processes on spatial scales of meter to millimeter and times scales of seconds. The methods are presently being used to assess the impacts of pre- and early post-settlement processes on mussel distributions, including the effects of bed shear stress, and the sensitivity of the location of the host fish when juveniles excyst, on juvenile settling distribution.
Hydro_AS-2d, ein zweidimensionales Strömungsmodell für die wasserwirtschaftliche Praxis -Benutzerhandbuch
  • M Nujić
Nujić, M.: Hydro_AS-2d, ein zweidimensionales Strömungsmodell für die wasserwirtschaftliche Praxis -Benutzerhandbuch. Rosenheim, 2006.