The Norwegian electric energy supply system is based on hydropower. Environmental flows are gaining increasing attention in Norway and are a strategic element in the management of hydropower development. The new Water Resources Act in Norway of January 2000 emphasizes on greater flexibility and more emphasis on taking into account ecological, aesthetic and economic considerations, thus increasing the need for site-specific knowledge. Norwegian licensing procedures imply specific instream flow requirements. Environmental needs encompass a wide range of aspects. In addition to new schemes, many old licenses are due for renewal and will require an assessment of the adequacy of present flows. SINTEF in cooperation with NTNU have developed The River System Simulator, a habitat modelling framework, and several other Environmental flow assessment models. These models have been used in Norway, Sweden and Canada for modelling changes resulting from hydropower development, with salmonid fish as the target species.

 

Mesohabitat classification and modelling

The traditional method of habitat assessment studies have been limited to detailed studies of selected river reaches on a micro scale. However, river management agents and others express a need for support tools that include real data for an entire river. Advanced sampling equipment is available at SINTEF/NTNU to collect field data in an efficient way, which makes it possible to cover greater part of rivers than before concerning velocity and geometry measurements. New generations models are handling considerable more data than before, and habitat assessment models like fish population models are designed to simulate rivers at a macro scale. More extensive, but less intensive, stream sampling via larger spatial units, namely meso- or macro habitats, have the potential to reduce time and cost by a uniform river classification system based on a combination of defined hydraulic and biological criteria.

 

Photo: Studies of phyical impacts on wild salmonids, benthos and water vegetation in the indoor Aqua channel . Photo: Ole D. Hesledalen

 

Contact:

Hans-Petter Fjeldstad  og