Freshwater - State and impacts (Spain)

SOER 2010 Common environmental theme (Deprecated) expired
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This content has been archived on 21 Mar 2015, reason: A new version has been published
SOER Common environmental theme from Spain
Published: 26 Nov 2010 Modified: 21 Mar 2015

General features: the hydrographical network and precipitation regime

Spain is one of the most mountainous countries in Europe. The mountains map out the presence of three slopes (Cantabrian, Atlantic and Mediterranean) and define the extension of the eight major basins of its principal rivers.



Rivers in Spain


With the exception of the northern and northeastern parts of the country,  the climate has scarce precipitation and intense evapotranspiration, which are characteristic of the Mediterranean climate, leading to a small amount of water that runs across the surface. In general, the rivers on the peninsula have a small absolute flow except for two – the Duero and the Ebro - which have a significant flow.

The amount of rain that falls on a certain territory is of particular importance. The average annual precipitation in Spain from 1941 to 2008 was 663.3 mm, with a maximum of 969.3 mm in 1960 and a minimum of 469.0 mm in 2005.

Water reserves

Spain has a large number of big dams in order to create water reserves for water consumption and energy generation. Of the total capacity of reservoirs containing more than 5 hm3, (55,111 hm3 at the beginning of January 2010), 17 391 hm3 (32 %) were reservoirs used for hydroelectric generation and 37,720 hm3 (68 %) for water consumption, mainly for irrigation and drinking water supply.

The ‘’Peninsular hydraulic reserve’‘ graphs published periodically by MARM in the Hydrological Bulletins (also published in the MARM Status reports) show the situation of these reserves in the last two years and compare them with the average situation in the last five and ten years.

Water use

According to data facilitated by the National Institute of Statistics (INE)  (Survey on water supply and treatment), during 2008, 4 941 hm3 of water was fed into the urban supply public networks in Spain. Of this amount, 75 % (3 732 hm3) was registered as water distributed for use in homes, in the different economic sectors (industry, services and livestock farming) and for municipal use, which represents a 1.2 % reduction from the year 2007. It excludes water used in irrigated agriculture which was 15,313 hm3 in 2008. In the same year, mean water consumption in households was 154 litres per inhabitant and day, 1.9% less than the 157 litres/inhab/day registered in 2007.

There is a dissociation between the upward trend of the GDP in recent years (current prices), and the use of water distributed for public supply. The more efficient use of water can be clearly observed from 2004 until 2007.



General Quality Index

For recent data on water quality, the ‘’General quality index for water’‘ (ICG), taken from ‘’The Environment and Rural and Marine Affairs 2008’‘ can be used. It measures the quality of surface freshwaters without taking into consideration their potential for different uses. The indicator is obtained by combining 23 parameters and by weighing the value of each quality parameter in the indicator total using linear equations. According to this indicator, surface water quality has improved during the period from 1998 to 2008, as measured at control stations throughout all water basins.

The percentage of stations with an ICG value classified as unacceptable has undergone significant reduction from 11 % in 1998 to 0.20 % in 2008. In fact, there has been a rise in recent years in the percentages registered by stations in the categories of ‘intermediate’, ‘good’ and ‘excellent’.


ICGICG caption


For more information, data for nitrate pollution, salinisation of groundwater bodies, organic pollution of rivers (BOD5 and ammonia), processing of waste water and quality of bathing water are available on The Environmental Profile of Spain. An indicator-based report, 2009 and The Environment and Rural and Marine Affairs in Spain - 2009.

One of the negative impacts of precipitation regimes is excess rainfall in very short periods of time, which can lead to flooding, with serious economic consequences and truly dramatic social circumstances and even deaths. Of the 897 fatalities from natural disasters in Spain in the period 1995 to 2008, flooding was responsible for the largest number of victims (29.3 %). 297 persons died from flooding in Spain in the period 1990-2008.


An example of impact in a water environment: breakage of the dam in the Aznalcóllar pond

On 25 April 1998 the dam wall broke in a tailings pond for a pyrite mine in Aznalcóllar (Seville). As a result there was major spillage of acid water and very toxic sludge containing high levels of heavy metals. The spillage amounted to some 4.5 hm3 (3.6 of water and 0.9 of sludge), flooding over the riverbanks of the Rivers Agrio and Guadiamar along some 40 km in the case of the sludge and 10 km more for the waters, with an average width of about 400 m. The toxic spillage from Aznalcóllar destroyed crops, fauna, flora and soil, causing significant economic damages and severely affecting river life (initially, 30 tonnes of dead fish and crabs were removed, asphyxiated by the large number of suspended particles in the water and as a result of extreme acidity).

After several years of restoration work, the polluted zone is relatively clean. A Green Corridor has been created to provide natural protection of the damaged zone and surrounding expropriated land, in order to unite Sierra Morena and Doñana. Fishing, hunting, grazing and harvesting are prohibited in this corridor; reforestation and conservation activities continue, several bird hides have been built as well as different zones for leisure and recreation. In November 2004 the company Boliden-Apirsa was sentenced to pay some EUR45 million in compensation for the damages caused, which is a considerably lower sum than the economic losses suffered and the investments made by the Public Administrations.





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

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