Freshwater - State and impacts (Norway)
Environmental conditions in Norwegian rivers and lakes are good compared with those in most other countries in Europe. A preliminary survey of the status of all Norwegian water bodies shows that around 50 per cent probably will meet the EU objectives for the freshwater environment, while around a quarter are at risk. The rest lacks data or has uncertain status. There are wide regional variations, and not surprisingly, environmental conditions are poorest where the population density is highest.
Norway has nine of the world’s 20 highest waterfalls but water flow in seven of these has been affected by hydropower regulations. More than 70 per centof Norway’s largest rivers are regulated for hydropower production.
Only around 7 per cent of Norway’s fresh water is characterised as ground water, and accounts for a mere 15 per cent of the water consumption. This is very low compared to many other countries in Europe and is due to the country’s abundant supply of surface water.
However, in later years there has been an increase in the use of ground water in districts with a scattered population. Every year, around 6000 new wells are drilled, but only 40 per cent of these wells are used for water consumption. The rest are used for energy production.
Emissions of hazardous substances have been substantially reduced since the 1980s. However, even in the most remote lakes in Norway, we find these substances due to transboundary pollution. The deposition of airborne mercury originating from other countries is estimated to be twice that of Norwegian emissions in total.The levels of mercury in fish from lakes in the Norwegian Arctic are in the same order of magnitude as in fish from lakes in Southern Norway, and the levels of PCB cause reduced fertility in birds and mammals.PCB and newer substances such as brominated flame retardants and perfluorinated compounds are so high that weakened immune response, hormone disruptions and elevated death risk for the offspring of birds and mammals are expected.
Eutrophication is still a problem in many rivers and lakes despite the introduction of numerous measures in recent years. Environmental monitoring shows that the situation has remained unchanged in the last ten years.Climate change is oneprobablefactor causing eutrophication.The following map shows the effect of phosphorous on water quality in rivers and lakes.
Acidification used to be an escalating issue in Norway up until the late 1980s. More than 15.000 fish stocks became extinct or affected. 25 salmon stocks have been lost due to acidification, and at least 20 have been affected. Thanks to international cooperation, the situation has improved. A reduction in emissions, together with the liming of rivers and lakes has reduced the total area affected by acidification by 38 per cent from 1990 to 2006. However, long-range transboundary pollution is still a problem, especially in Southwest Norway, and the top impact on Norwegian water courses.
The wild salmon is threatened
The Norwegian wild salmon is threatened by several pressures, some of the most severe being the increase in numbers of sea lice in coastal areas with extensive aquaculture industry, escaped farmed salmon invading the rivers and the invasive parasite Gyrodactylus salaris. Extensive aquaculture industry has led to an increase in numbers of sea lice in the fjords, representing a threat especially to migrating smolts heading for the ocean. Escaped farmed fish enter the rivers, disturbing spawningwild stock both by damaging spawning areas and by genetic mixing as they participate in the spawning. The salmon stocks are specially adapted to each river, and genetic mixing interferes with this unique adaptation and result in lesser production of salmon in the rivers.
Several rivers are undergoing treatment to remove Gyrodactylus salaris, and treatment will continue for years to come. Stocks also meet pressure from watercourse regulation, and due to acidification, liming is still needed to prevent stocks from extinction. Norway has an international responsibility to protect its stocks of wild salmon, and faces many challenges in this respect as pressure is increasing.
According to the 2006 Norwegian Red List, there are 327 endangered freshwater species, and a major challenge in Norway is loss of species and habitats due to morphological alteration associated with watercourse regulation, dumping, dredging, embankments in littoral zones and infilling of ponds. In addition, water quality is affected by nutrient runoff, pollutants and liming etc, putting additional strain on species. Alien species represent a threat through the invading of habitats and spreading of parasites and diseases. Climate change is considered to be a threat to 12 per cent of red-listed freshwater species.
For references, please go to http://www.eea.europa.eu/soer/countries/no/freshwater-state-and-impacts-norway or scan the QR code.
PDF generated on 10 Dec 2016, 11:53 AM