Ecological status in river Sjoa and Vinstra 2014

Summary

Ecological state of 6 locations in the rivers Sjoa and Vinstra, in county Oppland, Norway, has been classified in accordance to the Water Framework Directive. The results are based on samples collected in 2012 and 2014. The biological quality elements investigated were benthic macroinvertebrates, benthic algae and heterotrophic growth, in addition to selected chemical parameters. The selected quality elements are sensitive to the following pressures: Organic material, eutrophication and acidification. The classification is in accordance with the ‘one out – all out’ principle, which means that the biological quality element with the poorest state determines the total classification of a location. The report provides a thorough description of the methodology and an overview of the results for each quality element. According to the benthic algae, heterotrophic growth and the chemical parameters total phosphorus, total nitrogen and pH, all locations were classified to good or high ecological status based on both acidification and eutrophication. Regarding benthic fauna, one location was classified to moderate status based on the metric for organic material (ASPT), whereas the remaining five locations were classified to good or high ecological status. Benthic fauna (ASPT) was decisive in an overall assessment of ecological status because this quality element was the most sensitive one.