Published by the Norwegian Environment Agency Lag rapport Les på norsk

Norway’s rivers and lakes provide a rich and varied freshwater environment, which is under less pressure from human activity than many countries in Europe. Challenges still remain as many rivers and lakes are affected by pollution, urbanisation, invasive alien species and hydropower regulation.

Conditions in rivers and lakes are generally good

Environmental conditions in Norwegian rivers and lakes are good compared with those in many other countries in Europe. For Norway as a whole, more than 60 per cent of all rivers and lakes have good or high ecological status. There are wide regional variations, and not surprisingly, environmental conditions are poorest where the population density is highest.

Norway has ten of the world’s 35 highest waterfalls, but water flow in several of these has been affected by hydropower regulations. More than 70 per cent of Norway’s largest rivers are regulated for hydropower production.

Only around seven 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.

The map shows the water quality in the area around the Trondheim Fjord. You can zoom in to investigate further. You can click on each water body and read fact sheets (in Norwegian only). You can also click on "Explore maps" to see other topics, such as protected rivers and river regulation.

40 per cent of Norway's watercourses at risk

Around 40 per cent of Norway’s water courses have less than good ecological status. Long range transboundary pollution still causes acidification and brings hazardous substances to lakes and rivers, most severely in the south and in the north eastern part of the country. Partly as a result of this, concentrations of mercury are so high that advice against consumption of fish by pregnant and breastfeeding women has been issued.

Despite the introduction of numerous measures in recent years, acidification, eutrophication, hazardous substances, altered water flow, migration stops and spreading of invasive alien species still pose a problem. In the future, climate change is likely to escalate the problems, particularly with regards to increased run off and the spreading of alien species. 

The wild salmon is threatened

The Norwegian wild salmon is threatened by several pressures, the most severe being the increase in numbers of sea lice in coastal areas with extensive aquaculture industry and escaped farmed salmon invading the rivers. 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 spawning wild 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.

According to the Norwegian Scientific Advisory Committee for Atlantic Salmon Management, the invasive parasite Gyrodactylus salaris, acid rain, regulation for hydropower purposes and physical alteration of river systems are threats that have been brought under control. Several rivers are undergoing treatment to remove Gyrodactylus salaris, and treatment will continue for years to come. 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.

Threatened freshwater species

According to the 2015 Norwegian Red List, there are 147 endangered freshwater species. 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 acid rain etc, putting additional strain on species. Alien species represent a threat through the invading of habitats and spreading of parasites and diseases.

Pollution, alteration and biological pressures

In the last 50 years, there have been major changes in settlement patterns and patterns of leisure activity in Norway. More and more people have moved from rural districts to urban areas, and major improvements have been needed in the way wastewater from towns and urban areas is managed and treated. The changes in settlement patterns have put more pressure on watercourses near the largest urban areas. However, Norway utilizes only one per mil of its water resources, and water extraction puts little pressure on water resources.

Environmental pressures on Norwegian rivers and lakes can be divided into three main groups:

  • pollution: includes point sources, emissions, and long-range transboundary pollution, which may result in acidification, eutrophication and the spread of hazardous substances
  • physical alteration: mainly as a result of hydropower developments, but other examples are transport infrastructure, which may act as a barrier to fish migration, and canalisation of rivers for agricultural purposes
  • biological pressures: include the introduction of alien species such as minnows and pondweed, the escape of farmed fish, and parasites such as salmon lice.

The most important pressures on Norwegian water bodies are long-range pollution and morphological alterations of water bodies, followed by pollution from agriculture and wastewater and invasive alien species.

Climate change an important future driver

Climate change is expected to cause an increase in nutrient runoff and may reduce the effect of measures to alleviate this problem. The need for additional measures to achieve runoff reductions is thus expected to increase. Climate change will make our watersheds more hospitable to alien species, and can pose a threat to some freshwater species.

The infrastructure for wastewater treatment is not dimensioned for the increase in precipitation, which most likely will be caused by climate change, resulting in increased discharges of pollutants to water bodies.

Integrated management of water resources

The EU Water Framework Directive is incorporated into Norwegian law. The Norwegian Regulation on a Framework for Water Management, normally referred to as Vannforskriften (The Water Regulation), provides the basis for a comprehensive and sound management of freshwater resources with the aim of achieving good ecological and chemical conditions in freshwater, coastal waters and groundwater.

The Water Regulation divides Norway into river basin districts managed by eleven river basin district authorities; they are responsible for each river basin district. We also cooperate with our neighbouring countries Sweden and Finland in six water regions, mainly located in Sweden and Finland.