Application of habitat modelling in river rehabilitation and artificial habitat design

Abstract

Over the last years there has been a growing interest in river rehabilitation and the design of artificial habitat funded by an increasing knowledge of the importance of physical habitat for populations of Atlantic salmon and trout. With the current developments in two- and three-dimensional computational hydraulics, a capability of predictive hydraulic modelling has been established and modelling and analysis of the artificial habitats are thereby possible as a part of the planning stage. This have been utilised in a project to integrate hydraulic modelling tools, habitat modelling tools, river editing tools and visualization tools into a system for analysis and design of river rehabilitation projects and artificial habitat construction. Current work includes development a river editing system where the user can edit the bathymetry of the river manually or automatically by inserting standardised habitat features like current deflectors or weirs, and a strengthening of the hydraulic and habitat models to include effects of winter temperatures and ice in the analysis. Early versions and prototypes of the system have been used in the design of artificial habitat for juvenile fish and in construction of migratory habitat for adult Atlantic salmon through weir basins