Features Research
Making salmon and hydropower work together

Boosting salmon numbers in rivers which are also being used to generate increased amounts of electricity is perfectly possible according to a collaborative team of scientists in Norway.

Basing their work on the adoption of a more cooperative approach to river management globally, researchers from Norway’s CENREN Centre, say that aiming for increased hydropower generation and larger salmon stocks in the same water and at the same time is ‘not necessarily a contradiction in terms.’

While accepting that sharing resources between energy and salmon won’t work in all rivers, the CENREN conclusion is that plenty of sites currently exist where working together will produce improved results for both industries.

Research leader, Atle Harby, said that sufficient knowledge was already available to secure increased salmon production without compromising power outputs from many of the world’s regulated rivers. He also claimed that many of the measures which the two industries need to adopt won’t necessarily require major investment.

Managing a river to promote salmon numbers, he added, needed to include the identification of any possible bottlenecks that might limit production, such as a lack of spawning grounds or shelter, potential low-water periods or times of poor water temperature.

Managing the same river for energy production, however, might require an examination of the potential to transfer water from neighbouring rivers at key production points or the need to increase the capacity of plant turbines and waterways to make the operation as flexible as possible.

Planning ahead to ensure both the salmon and the turbines have the water they need when they need it, might require the creation of a ‘flexible water bank’ to cover critical demand points. Equally, some attention might be needed to create more favourable gravel areas for spawning, restoring rapids and pools sequences in the river, while also making shelter areas on the river bed as hiding-places for fish and for the removal of fine sediment.

Computer models, based on CENREN’S research, are already being used to address salmon/energy questions raised by a new hydropower development in southern Norway. The project involves the Sira-Kvina Electricity Company’s plans for hydropower generation in the River Kvina where environmental protection measures are also being developed.

          According to Atle Harby, project simulations show it will be possible to increase the amount of electricity generated by the planned Tonstad Power Station on the River Sira by transferring water from the neighbouring River Kvina while, at the same time, increasing the level of salmon production in the Kvina. This is a result which CENREN describes as a definite ‘win-win’ for both salmon and energy interests in the region.

          CENREN is one of Norway’s designated ‘national teams’ for research into environmentally friendly energy. It’s staffed by scientists from SINTEF Energy, NTNU (Norwegian University of Science and Technology) and NINA (Norwegian Institute for Nature Research). CENREN’s ‘more salmon and more hydropower’ conclusions were recently published in a new environmental handbook, aimed at river managers, utility companies and other interest groups.

– Colin Ley