Applications of the CASiMiR Model
Fish Migration Simulation
The CASiMiR Migration module developed by sje Ecohydraulic Engineering GmbH, allows for studies on fish migration and in particular on the attraction of bypasses at migration barriers. Same as in the habitat simulations, preferences of fish are taken into account, which however, do not refer to the use of riverine habitats, but are related to the movements when approaching an obstacle. Such kind of investigations are possible for upstream and downstream migration facilities, e.g. at trash racks in front of hydropower turbines or pumps.
Besides purely hydrodynamic calculations and the consideration of e.g. flow velocity thresholds, agent-based investigations are another, advanced approach integrating virtual fish following specific behavioural rules into the numerical modeling. They can be used to calculate and analyse potential fish pathways for the approach or passage of fish migration facilities.
In the case of fishways, studies can be conducted on the detectability, suitable flow, and most favourable location of the fishway entrance or the dotation discharge.
To gain further knowledge about fish behaviour during downstream migration, research projects have been and are currently carried out (Memo, RETERO, RIBES). Main goal of these research projects is to develop a modelling tool for the assessment and optimisation of bypass design. The model development is based on ethohydraulic experiments in which fish movements are tracked in laboratory and real world experiments with high temporal and spatial resolution.
Example of a telemetry study: Observed path of a tagged grayling towards a fishway (left) and modelled path with simulation tool CASiMiR Migration (right)