NEWS It is possible to implement measures that provide more environmentally friendly flows in regulated rivers with only small losses in hydropower production. This is shown by new research from Umeå University, Sweden. The study is part of Åsa Widén's doctoral project and is published in Science of the Total Environment.
Grundforsen, Ume River, Sweden.
ImageÅsa WidénIn developed rivers, water flows and water levels can change rapidly, which causes stress and disturbance to the watercourse's animal and plant species. But it also means long periods of zero tapping, ie the hydropower plants stand still for weeks and months.
“We show that the hydropower plants in the Ume River are completely still between 9-55 percent of the time in a normal year, which also means that the water is completely still and rapids are drained” says Åsa Widén, doctoral student at the Department of Ecology and Environmental Earth Science at Umeå University.
The biological effects of zero tapping are poorly studied, but include behavioral changes in fish, less food for filtering aquatic insects and oxygen-free bottom conditions during longer periods of zero tapping.
Åsa Widén, the Department of Ecology and Environmental Science, Umeå University.
ImagePrivatTherefore, Åsa Widén and her staff chose to study zero tapping per hour, ecological regulation described as minimum discharge through a hydropower turbine, potential environmental benefits in the form of habitats for live species and what effects the minimum discharge is expected to have on hydropower production. The study was carried out in the Ume River catchment area and it included all power plants in the Ume River.
The researchers' results show that if it were possible to introduce a ban on zero tapping in the river, which means that all power plants have a requirement for minimum tapping, this would entail only a 0,5 percent loss of hydropower production per year. The environmental benefit is calculated at 240 hectares of newly created and existing stream water habitat.
Åsa Widén explains that research results on zero tapping of power plants and the consequences of environmental measures, where both costs and environmental benefits have been quantified, have never been published before.
"Our results are important in order to be able to preserve biological diversity in regulated watercourses and are relevant because Sweden is facing a national review of all hydropower permits where greater demands must be made on environmental considerations" she says.
About the scientific article:
Widén, Å., Malm-Renöfält, B., Degerman, E., Wisaeus, D., Jansson, R .: Let it flow: Modeling ecological benefits and hydropower production impacts of banning zero-flow events in a large regulated river system . Science of the Total Environment. Volume 783 (2021). https://lnkd.in/eGXnddK