Freshwater - State and impacts (Finland)

SOER 2010 Common environmental theme (Deprecated)
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Freshwater - State and Impacts
Published: 26 Nov 2010 Modified: 11 May 2020


Surface waters [1]

Finland is rich in surface waters, with a total of 187 888 lakes and ponds larger than 500 square metres, and rivers totalling 25 000 kilometres in length. Almost a tenth of the country‘s land area is covered by water. Finland’s lakes contain only 235 cubic kilometers of water (Main characteristics of the surface waters in Finland). Finland’s shallow lakes are easily contaminated by pollution. Even relatively low concentrations of excess nutrients, acidic deposition or other harmful contaminants can easily disrupt their sensitive aquatic ecosystems.


Discharges of harmful substances into Finland’s inland and coastal waters have fallen considerably during the last few decades.


The monitoring and state of surface waters[2]

The monitoring is composed of both administrative monitoring and compulsory inspections by industrial operators and other businesses. The frequency of water quality observations and the factors under analysis vary according to local needs. Biological monitoring has been expanded, and the process will continue over the coming years.


Ecological and chemical state of surface waters[3]

Most of Finland’s classified water bodies[4] are in a high or good ecological state. Waters with lower ecological status than ‘good’ include almost a third of the classified lakes, half of the classified stretches of rivers, and more than half of the total extent of coastal waters. With a few exceptions, the chemical state of the water is good.


New classification system for the surface waters

The classification in 2008 was carried out to meet the obligations under the EU Water Framework Directive and related national legislation. A target has been set that all surface waters should have a good or excellent ecological status by 2015, and conditions in waters already classed as good or excellent should not deteriorate.


The amount of work needed to achieve the goal of a good ecological status is greatest for rivers and coastal waters. Particularly in southern, western and southwestern Finland, many rivers are still only in a poor or passable state. Problems include diffuse loads of nutrients from farmland, and constructions such as dams along watercourses. In northern Finland, most rivers are in an excellent or good state.


Currently, the ecological quality status of most of Finland’s inland waters is either good or high. However, the quality of over 40% of total river length and 60% of the coastal water areas included in the plans is moderate, poor or bad. The water quality of Finland’s lakes is generally better. Only 2% of the groundwater resources important to and suitable for water supply purposes are classified as bad, even though approximately 500 groundwater areas are at significant risk from human activity.


The status of lakes is worst for small and medium-sized lakes in agricultural areas, where problems associated with eutrophication, such as algal blooms, are widespread.


Table 1: Ecological status of surface waters by proportion of total length (rivers) or surface area

Ecological status



Coastal waters

High or good




Moderate, poor or bad





Figure 1: Ecological status of surface waters by proportion of total length (rivers) or surface area

WATER Figure1 


Link to a more detailed figure:

Ecological status of surface waters assessed by river length and surface area of lakes and coastal waters


Map of the ecological state of Finland’s surface waters[5]

A provisional map of the ecological state of Finland’s surface waters has been completed. Water bodies are classified largely according to monitoring data mainly compiled over the period 2000–2007.


Map 1: the ecological status of the surface waters




Link to a more detailed map:

Ecological state of surface waters

See also:



Chemical status of surface waters[6]

The chemical state of surface waters is classified on the basis of environmental quality norms defined for 42 harmful or hazardous substance and substance groups. The norms, which refer to annual average concentrations of the substances in aquatic environments, were included in Government Decree 1022/2006 on Substances Dangerous and Harmful to the Aquatic Environment. Some of the norms applied in evaluating the chemical state of water bodies have not yet been fully enacted in official legislation, but they still serve as useful guidelines in the classification procedure.


The concentrations of harmful and hazardous substances measured in Finland’s surface waters have generally been below the provisionally defined norms (environmental quality standards), and in many cases the substances have not been detected at all. Chemical statuses worse than “good” have been assigned to several rivers in Ostrobothnia which flow through regions with acidic, sulphate-rich soils, and contain high concentrations of substances including cadmium. Some of the metals that affect the chemical state of water bodies also occur naturally, and this factor must be considered in classifications to ensure that statuses are not misleadingly lowered by naturally high concentrations of metals.

Map 2: Finnish lakes classified by total phosphorus levels (median in 2005-2010). Total P levels were compared to status class boundaries of total p in different lake types.




Figure 2: Annual medians of total phosphorus and total nitrogen in 1970-2008 calculated for a group of 33 Finnish rivers. Linear trend line is shown.

WATER Figure2



The earlier general usability classification[7]

The general usability classification of water bodies gives an idea about the average suitability of the water bodies for water supply, fishing and recreation in Finland. The quality class is determined based on the natural quality of the water and human impacts. The water bodies have been classified as: excellent, good, satisfactory, passable and poor (Criteria for the general water quality classification in Finland).


The latest classification was based on data from the period 2000–2003. It covered 82 % of the total area of lakes larger than one square kilometre, 16 % of the total length of rivers more than two metres wide as well as the sea area inside the Finnish territorial waters.


The quality of water was excellent or good in 80 % of the classified lake area. In general, the water quality in rivers was worse than in lakes, because human activities, such as agriculture and development, are concentrated along rivers. Moreover, many rivers are sensitive to the effects of nutrient loading because of their low flow rates. The quality in 43 % of rivers is classified as excellent or good. These rivers are mostly located in northern Finland (Map of water quality of lakes, rivers, and sea areas in 2000-2003), (Comparison of classifications in 1984-2003).


Water quality affected by diffuse loading

In the vicinity of towns and industrial plants, water quality had improved considerably already at the beginning of the 1990s, because of long-term measures for water protection. These measures were further improved during the 1990s. However, a similar improvement in the state of water bodies has not been observed in areas with heavy diffuse loads.


See also: Large lakes in good condition; problems in rivers and coastal waters



Acidification problems first became evident in the 1960s. It took some time for action to be taken, and ultimately international agreements were signed to curb harmful emissions. The concentrations of sulphur compounds declined and buffering capacity increased in all types of lakes in Finland during the 1990s. Some 5 000 smaller lakes in Finland are now considered to be recovering well from serious acidification problems.


Declining atmospheric deposition has also reduced acidification problems in Finland’s groundwater reserves, although it may take decades for groundwater to recover completely.



In water bodies, eutrophication particularly boosts the growth of planktonic algae. Its effects can be seen in reduced water clarity and the increased growth of filamentous algae and aquatic plants. In the worst cases, eutrophication may result in the increased occurrence of massive blue-green algal blooms, oxygen depletion in winter, and in dramatic changes in fish stocks.


Eutrophication is basically a natural phenomenon. Certain lakes or habitats are naturally poorer in nutrients than others are, but over time they may become richer in nutrients through natural processes. Where nutrient pollution is widespread, however, eutrophication often becomes a problem.


Badly affected lakes can be restored to some extent by removing nutrients from the ecosystem through selective fishing or the removal of excess plant growth. The nutrient-rich silt on lake-beds may also be dredged or covered over. During the winter, air may also be pumped into lakes to improve the oxygen content of their deeper waters and slow the release of nutrients from bottom sediments.


See also:


Toxic substances[10]

Information on concentrations of toxic substances is mainly limited to major point sources of emissions, such as large industrial plants. Municipal wastewater treatment plants, for instance, routinely measure only variables linked to eutrophication and heavy metal concentrations in their treated effluent and sludge. Calculations and extrapolation are also used to estimate the point loads and diffuse loads.


EU legislation and Finland’s other international commitments mean that in future, environmental loads of hazardous substances must be monitored much more widely than they have been so far.



Finland’s groundwater reserves are replenished in the spring when the winter snow and ice melts, and often again in the autumn – typically the rainiest season.


Although Finland has plenty of aquifers – a bit over 6 000 – these resources are not distributed evenly across the country. Water is typically clean, well oxygenated, and often also easily extractable. Especially the Salpausselkä deposits in southern Finland hold important aquifers.


Groundwater can be found in almost every part of Finland, but is particularly widespread in areas with extensive deposits of permeable sands and gravels formed during the last ice age. The depth of the water table may vary from less than a metre to more than thirty metres, but is typically about two to five metres below ground level.


Groundwater reserves can be significantly reduced, and the water table lowered, due to the excessive use of groundwater, or after major groundwork or excavation, as well as following droughts.


In Finland, groundwater is widely used by local residents and by waterworks, since it is often much purer and better protected from contamination than the water in lakes and rivers. Groundwater can usually be consumed safely without any treatment.


Approximately 60 % of the total water supply distributed by Finland’s waterworks consists of groundwater. This figure also includes water from artificially maintained reservoirs of groundwater fed from lakes and rivers.




Groundwater quality[12]

The aquifers in Finland’s glacial deposits rank in quality among the best reserves of groundwater in the world. Groundwater in Finland is generally soft, with low concentrations of dissolved substances and low pH (6-7).


Most of Finland’s groundwater is of good quality, since it is better protected against contamination than surface water. Harmful concentrations of arsenic, fluorine and radon as well as iron and manganese occur in certain areas due to local geological features. Groundwater reserves in Finland do not normally suffer from contamination on a wider scale, since individual bodies of groundwater tend to be small. Considerable contamination may be caused locally where salts are used to de-ice slippery roads, on over-fertilised farmland, at garages and service stations where oils may accidentally enter the soil, and following accidents involving chemicals.


See also:


Water resources in Finland[13]

During the period 1961-1990, the Finnish territory received a mean precipitation of 660 mm. Of this amount, 341 mm evaporated, while 318 mm flowed into the seas or passed over the national borders. The water storage was increased by 1 mm during this period. The mentioned value 318 mm corresponds to a mean discharge of 3400 m3/s.


The study of some main hydro-meteorological variables (precipitation, snow cover, river discharge) since early 1980s show decreasing snow volumes in southern and central Finland. Consequently, some decrease in spring high flows have been observed in these areas. Precipitation does not reveal statistically significant trends or changes in general.  The study of longer time series – starting from 1910s or 1960s – highlights some increasing wintertime river discharges. 


The water plants deliver over 1.1 million m3 water daily, and the households consume 3/5 of the water. About 60 % or 0.7 million m3/day of the water is groundwater or artificial groundwater. Supply networks of water plants cover about 90 % and sewage networks about 80 % of Finnish households.


The Water exploitation index[14] (WEI) is one of EEA’s core set indicators. The WEI is the ratio between the annual total water abstraction and the available long-term freshwater expressed as a percentage. The WEI for Finland is about 2 % that is one of the best WEI values in Europe, and far below the value 20 % that is seen as the critical value of WEI.


See also:       


Water-borne diseases in Finland[15]

The notification of food or water-borne epidemics came into effect in February 1997. The municipal health authorities are responsible for the reporting. It is clear that the identification of a water-borne epidemic is not always straightforward.


A total of 56 epidemics were reported in 1998–2006 with about 16 800 persons fallen ill. In more than 90 % of the cases, the municipal waterworks had delivered the water. Private water supply was used in the rest of cases, for example in different holiday or camping centres or rehabilitation centres. Of the waterworks, most were small units with less than 500 customers. Almost always, the reason for the epidemic is some harmful microbe infecting the drinking water. Even if the groundwater in general is cleaner than the surface waters, the water-borne epidemics are more often caused by the groundwater. WHO publishes regularly fact sheets of outbreaks of water-borne diseases. However, the level of monitoring and the quality of reporting varies greatly between countries.


International evaluations of water policies in Finland[16]

Finland has been placed near the top or at the top in several recent international comparisons of the water and environmental sectors. Water policies in Finland are described in more detail in the report to the UN: Country Profile: Freshwater and Sanitation, Finland, 2004.


United Nations World Water Assessment Programme

United Nations/UNESCO World Water Assessment Programme (WWAP) monitors freshwater issues in order to provide recommendations, develop case studies, enhance assessment capacity at a national level and inform the decision-making process. In the first World Water Development Report in 2003 water quality indicator values were assessed in 122 countries and Finland was ranked number one in this assessment. WWAP has published three reports, the most recent one in 2009.


Water Poverty Index, 2003

In the international Water Poverty Index published by the Centre for Ecology and Hydrology in 2003, Finland was ranked the best in the world. A total of 147 countries were included in the comparison. The study assessed the extent of water resources, the comprehensiveness of water supply, and water use, as well as environmental impacts and general readiness for addressing water-related concerns.

[1] Source: Surface waters. Finnish Environment Institute

[2] Source: The state of Finland’s surface waters. Finnish Environmental Administration

[3] Source: Ecological and chemical state of surface waters. Finnish Environmental Administration

[4] Surface water bodies include distinct and significant sections of river systems, i.e. lakes; reservoirs; streams, rivers or canals in their entirety or parts thereof; as well as specific areas of Finland’s coastal waters.

[5] Source: Map of the ecological state of Finland’s surface waters. Finnish Environmental Administration

[6] Source: Chemical state. Finnish Environmental Administration

[7] Source: The general usability classification of surface waters. Finnish Environmental Administration

[8] Source: Acidification. Finnish Environment Institute

[9] Source: Eutrophication. Finnish Environment Institute

[10] Source: Toxic substances. Finnish Environment Institute

[11] Source: Groundwater. Finnish Environment Institute

[12] Source: Groundwater resources, Finnish Environment Institute

[13] Source: Water resources in Finland. Finnish Environmental Administration

[14] Source: Water exploitation index. European Environment Agency

[15] Source  Drinking water (in English) and Vesiepidemiat (in Finnish). National Institute for Health and Welfare

[16] Source: International evaluations of water policies in Finland. Finnish Environmental Administration


The country assessments are the sole responsibility of the EEA member and cooperating countries supported by the EEA through guidance, translation and editing.