Freshwater - Drivers and pressures (Iceland)

Nutrient concentrations in Iceland’s rivers and lakes are low.

Reduced woodland, soil erosion and draining of wetlands by ditching are factors that may have affected lakes and perhaps rivers for a long time. Soil dust and leached chemicals due to erosion may have affected the ionic composition and productivity in lakes as far back as 1500, as is the case with Lake Þingvallavatn. Increased productivity was explained partly by increased wind transported erosion material, but primarily because of increases in leached nutrients as a consequence of reduced vegetation cover (1, c.f. 2).

More recent pressures include road works, bridges and gravel mining in rivers and hydroelectric development. In addition are factors like fertiliser-use in agriculture, pollution discharges and aquaculture (3). A comprehensive study and evaluation of the effects of recent demographic factors, developments and constructions is still missing, but it is worth noting that according to the CORINE Land Cover programme, only 396 km², or 0.38% of the land area, are classified as man-made surfaces (4).

Population density

Around 70 % of the population, out of a total of around 320.000, lives in the southwest of the country, in the Faxaflói bay area. Only about 6 % of people live in rural areas and fewer than 1 000 people live 200 m above sea level. Population density is therefore not a significant pressure on freshwaters.

Figure 1. Regional distribution of population density in Iceland (mean: 3 inh/km²).

Use of freshwater resources

Over 95% of Iceland's drinking water is untreated groundwater extracted from springs boreholes and wells. Surface water constitutes around or less than 5 % of Iceland's drinking water. Surface water used for drinking is obtained from mountain lakes and from river basins.

The freshwater resources are estimated to be around 170 000 million m³ of which 6 000 million m³ of groundwater are available for extraction.

Total annual gross extraction is estimated at 165 million m³ of which public water use is an estimated 67 million m³ per year.

Use of geothermal water

Around 90% of households in Iceland are heated with geothermal water or geothermally heated fresh water from district heating services. Nine percent is heated with electricity and one percent with oil. The district heating services use advanced technologies for the processing, transferral, and use of geothermal heat. Most district heating utilities sell water according to measured water use; however, three sell previously determined quantities and two according to measured energy use.

Of the electric power produced in Iceland, 18% is produced geothermally. Other uses of geothermal heating are for swimming pools, snow melting, greenhouse farming, aquaculture and industry. Measured or estimated hot water consumption in 2005 was more than 118 million m³, 23,462 TJ, most of it for space heating (c.f. 5).

Water use in the Reykjavík area

Reykjavik Energy (Orkuveita Reykjavíkur) provides, as a public water service, cold freshwater and hot geothermal or geothermally heated water for Reykjavík city and some areas outside the capital. Overall it serves about 115 000-120 000 people, more than a third of Iceland´s population, with cold water. In 2008, the water use amounted to 460 l/person/day.

Figure 2. Cold water service in the city (bars) and the population served (line).

Reykjavík Energy distributes hot water over a much larger area, in 20 municipalities, of 2 500 km² with a population of 210 000 – approximately 70 % of the population of Iceland (6).

Figure 3. Reykjavík city water service

The services provided by the company reach 20 municipalities, home to approximately 70 % of Icelanders.

The amount of hot water distributed by Reykjavík Energy (Figure 3) is about twice the consumption of cold fresh water. These proportions are perhaps similar for the rest of the country.

Discharges to inland fresh waters

Hazardous substances

In 2008, two landfills with discharges to fresh water were obliged to report according to the European Pollutant Release and Transfer Register (E-PRTR). Discharges from both of them were under the threshold for releases of hazardous substances according to Regulation No. 166/2006 of the European Parliament and of the Council concerning E-PRTR. Five agglomerations of more than 2.000 people discharge to estuaries or fresh waters, with a total number of inhabitants of 13.636. Information of any discharges of hazardous substances is not available for those agglomerations.

Nutrients (nitrogen and phosphorous)

The point and diffuse discharges from the dwellings of about 11 % of the population goes to fresh waters or estuaries (Table 1).

Table 1. Estimated sewage discharges to inland fresh waters and estuaries

Use of fertilisers

Agricultural areas cover 2.4 % of the country. Ninety-seven per cent is pastures, the remainder being very small patches of non-irrigated arable land and land under complex cultivation patterns (7).

In 1980, the use of artificial chemical N fertilisers reached a maximum of about 15 000 tonnes per year. The use decreased but rose again to 15 300 tonnes in 2008 (Table 2).

Table 2. Use of artificial chemical fertilizers in Iceland (tonnes).

In 2008, 2 400 tonnes of P was used as fertiliser. It has been estimated that around 2.000 tonnes of N are spread on cultivated fields annually in the form of animal manure. The total N-balance is around 110 kg N/ha for cultivated land which covers just 1.4 % of the country's total area. Combined with low population density and high annual precipitation – averaging 2 000 mm per year, with local variations ranging from 400-4 000 mm – low concentrations in watercourses with limited direct discharges (Table 1 and Figure 1) are not surprising.

References

(1) Hafliði Hafliðason, Guðrún Larsen and Gunnar Ólafsson, 1992. The recent sedimentation history of Thingvallavatn, Iceland. OIKOS 64: 80-95.

(2) Skjelkvåle, B.L. 2001 et. al. Chemistry of lakes in the Nordic region – Denmark, Finland with Åland, Iceland, Norway with Svalbard and Bear Island, and Sweden. NIVA, Acid Rain Research, Report No. 53/2001, Serial No. SNO 4391-2001, 2001.

(3) Jón S. Ólafsson, Gísli Már Gíslason and Hákon Aðalsteinsson. 2002. Icelandic Running waters: anthropological impact and their ecological status. In: Marja Ruoppa and Krister Karttunen (eds.). Typology and ecological classification of lakes and rivers. TemaNord 2002:566. Nordic Council of Ministers, Copenhagen 2002.

(4) Corine Land Classification in Iceland 2000-2006. Report in Icelandic. http://www.lmi.is/Files/Skra_0038437.pdf

(5) Thorgils Jonasson and Sveinn Thordarson. 2007. Geothermal district heating in Iceland: Its development and benefits. A paper presented at the 26th Nordic History Congress 8 - 12 August 2007.

(6) A Dynamic Company – a Leading Power. Report in English. http://www.or.is/media/PDF/ORK%2038077%20Adalbaeklingur_ENS_Lowres.pdf

(7) Corine Land Classification in Iceland 2000-2006. Report in Icelandic. http://www.lmi.is/Files/Skra_0038437.pdf