Use of freshwater resources - outlook from EEA
Justification for indicator selection
Water stress is a measure of the pressures that water abstraction for use in different economic sectors places on water resources and aquatic ecosystems, and reducing water stress is important when working towards good status of water bodies (e.g. Water Framework Directive of the EU) - and a prerequisite for ensuring safe access to drinking water (e.g. Millennium Development Goal).
Water stress, expressed as the water exploitation index at the river basin level, indicates imbalances in the quantitative and/or ecological status of water bodies. Severe water stress usually results in competition between different water users, and possibly results in reduced water availability to downstream users, especially in low-flow or drought periods.
Outlook information on change in water stress can help to assess how expected changes in water use will impact the status of water bodies. Furthermore, it allows comparing the relative importance of changes in water abstraction (due to changes in water use) with expected changes in water availability (due to climate change).
Definition: The water exploitation index (WEI) is the annual total abstraction of freshwater divided by the annual total renewable freshwater resource, expressed in percentage terms. This indicator can be computed at the country level or, preferably, by river basin. A region is characterized as being under water stress, if it the water exploitation index exceeds 20%, and under severe water stress if it exceeds 40%. This indicator combines data on water availability and water withdrawals, and has thus also been referred to as withdrawals-to-availability index.
Alternatively, the underlying data can be used (i.e. data on water availability and water withdrawals for domestic use, industrial use, an agricultural use, respectively) to indicate seperately:
The water availability index is defined as the average freshwater resources available per person in a country or river basins. Regions can be labelled as water scarce if this value drops below 1000 m3 per person - however as the indicator uses population as a proxy for water uses it is less accurate.
Changes in annual water availability indicates the change in freshwater resources in a country or river basin over a given time period, primarily due to changes in upstream water use or climate change.
Changes in annual water abstraction indicates the change in water use in a country or river basin over a given time period. Changes can be presented separately for different socio-economic activities, i.e. water for domestic use, for use in manufacturing and electricity production, and for agricultural purposes.
Model used: WaterGAP
Ownership: European Environment Agency
Temporal coverage: 2000 - 2030
Geographical coverage: Austria, Belgium, Denmark, Cyprus, Czech republic, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Lichtenshtain, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Spain, Sweden, Swetzerland, Slovakia, Slovenia, United Kingdom
Policy context and targets
The indicator can be used to monitor a wide range of policies at global, regional and national levels. It provides, for example, the information on efficiency of water-use management plans.
Global policy context
At the global level problems of fresh water use and water stress are becoming ones of the most actual. The central aims were emphasized within UN "Millennium Development Goals" (7th goal to ensure environmental sustainability) and include reduction of proportion people without access to safe drinking water.
Pan-European policy context
In 2002 the EU launched a Water Initiative (EUWI) designed to contribute to the achievements of the Millennium Development Goals (MDGs) and World Summit for Sustainable Development targets for drinking water and sanitation, within the context of an integrated approach to water resources management. The EUWI covers EU region as well as EECCA regions.
The UNECE Convention on the Protection and Use of Transboundary Watercourses and International Lakes was signed by 34 UNECE countries and the European Community. The Convention establishes main principles and rules for its Parties to develop and promote coordinated measures of sustainable use of water and related resources of transboundary rivers and international lakes, as well as of institutional mechanisms to be created for it. The UNECE Convention on the protection and Use of Transboundary Watercourses and International Lakes is an important instrument for the protection of freshwater resources and the development of transboundary water cooperation.
EU policy context
Achieving the objective of the EU's Sixth Environment Action Programme (2001-2010), to ensure that rates of extraction from water resources are sustainable over the long term, requires monitoring of the efficiency of water use in different economic sectors at the national, regional and local level. The WEI is part of the set of water indicators of several international organisations such as UNEP, OECD, EUROSTAT and the Mediterranean Blue Plan. There is an international consensus about the use of this indicator.
The indicator describes how the total water abstractions put pressure on water resources identifying those countries having high abstractions in relation to their resources and therefore prone to suffer water stress. The changes in WEI help to analyse how the changes in abstractions impact on the freshwater resources by adding pressure to them or by making them more sustainable.
There is a number of agreements relate to European river water use management, for example of the oldest one is the International Commission for the Protection of the Rhine (ICPR). (Basel on July 11, 1950).
EECCA policy context
EECCA Environmental Strategy promotes sustainable water use based on long-term projection of available water resources. It sets goals to improve quality of waters (ecological, chemical) in national level as well in regional through the developed management of municipal water supply and sanitations. Also, the EECCA environment strategy has actions on development and implementation of integrated water management programmes based on river basin principles.
Some sub-regional policies aim to stimulate development and implementation of action plans to improve water resource management systems.
A regional Cooperation strategy to promote the rational use and conservation of water resources in Central Asia focus on the sustainable use of freshwater in the Aral Sea Water Basin. The strategy helps to support achievability of targets set in the Aral Sea Basin Water Vision 2025 developed with support from UNESCO (SABAS vision). The document provides recommendations for water distribution, particularly within agriculture sector, as well as an accent on improving hydro electricity technologies with 'less losses of water' over the 2025 horizon.
Number of transboundary rivers negotiations focus on sustain river's water use and are implemented for such river basins as Neman (Nemanus) and Western Dvina (Daugava); also for Dniester between Ukraine and Moldova.
LInks to other related policies:
There is no specific targets, however, some of them could influence indirectly on the indicator's issues in particular, share of domestic water withdrawal:
- to halve by 2015 the proportion of people who are unable to reach or afford safe drinking water (MDGs)
- to launch action plans to achieve aims in accordance with MDGs
- to improve management of river basin's water use (IUCN)
There is no qualitative targets. However several document put some action oriented targets, for instance, EU Water Initiative aims to establish water resource management plans by 2005 and the UNECE Convention on the Protection and Use of Transboundary Watercourses and International Lakes aims to implement rational and sustain water use within all Europe river basins and lakes for all countries (UNECE).
There are no specific agreements as to the quantitative targets related to this indicator. The EU requires all countries to promote sustainable water use based on long-term projection of available water resources and to ensure a balance between abstraction and recharge of groundwater. Both the Water Framework Directive and the 6th Environment Action Programme set out the goal to achieve a 'good status' (ecological, chemical and quantitative) for all EU water bodies by 2015. More generally, a warning threshold of at 20 % water exploitation index is widely used to indicate a river basin is water stressed, while sever water stress is indicated by values above 40 %. While this may indicate strong competition for water resources, this may (but does not necessarily have to) trigger frequent water crises, depending on the socio-economic and environmental context within river basins.
- to sustain water use within river basins (Baltic region, Black sea's region and Central Asia)
- to improve quality of safe drinking water (EECCA Environmental Strategy, Aral Sea Vision, regional agreements for river water use);
- to implement integrated management systems for water resource use (EECCA environmental strategy)'
- to implement new technologies for irrigation and hydro power plants (Aral Sea Vision, Water and Energy strategy for Central Asia)
- to contribute more than 20 km3 water for ecological services within Aral region by 2025 (Aral Sea Vision);
Related policy documents
Sixth Environment Action Programme
DECISION No 1600/2002/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 22 July 2002 laying down the Sixth Community Environment Action Programme
Water Framework Directive (WFD) 2000/60/EC
Water Framework Directive (WFD) 2000/60/EC: Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy.
World Summit on Sustainable Development Plan of Implementation
UN 2002: 'Plan of Implementation of the World Summit on Sustainable Development'
Key policy question
K: Is the abstraction rate of water use sustainable?
Specific policy question
Is the use of water by sectors sustainable?
Methodology for indicator calculation
Indicators to approximate current Water Stress and/or to give an Outlook on future Water Stress can be calculated using the WaterGAP model (Water: Global Assessment and Prognosis; version 2.1). This is a global model that computes both water availability and water use on the river basin scale.
The model, developed at the University of Kassel, Germany, has two main components: A global hydrology model and a global water use model.
WaterGAP's global hydrology model simulates the characteristic macro-scale behaviour of the terrestrial water cycle to estimate water availability. The model uses both land use and climate data at a 0.5 x 0.5 degree latitude-longitude grid. Thus it can compute water availability for both past and present temperature and precipitation regimes, as well as using output from climate models for expected future conditions
WaterGAP's global water use model consists of four main sub-models that compute water use for the domestic, manufacturing, energy, and agriculture sectors. For domestic, manufacturing and energy water use most calculations are conducted at a country level, and subsequently distributed across a 0.5 x 0.5 degree latitude-longitude grid depending on the distribution of population and power plants. For agricultural activities, most computations are conducted on a 0.5 x 0.5 degree latitude-longitude grid, based climatic condition and a world-wide map of irrigated areas.
A drainage direction map then allows the analysis of the water resources situation (including water stress) in all larger river basins. This methodology allows calculating water related indicators both on the country level and on the river basin scale, depending on what is more relevant to address specific policy questions.
A more detailed version of the model exists for EEA member states (except Iceland). Compared with the global version, the European model sees (i) improved country-level calibration for domestic water use, based on better abstration data available in this region; (ii) the use of a data on the geographical explicit location of power station and their cooling water requirements; and (iii) estimates of water use for manufacturing presented seperately for six water intensive industrial activities.
Methodology for gap filling
The water use models for domestic, industrial and electricity-related water use have been calibrated against observed past trends on the country level, where reliable data to do so is available. Where this is not the case, parameters derived from regional averages have been used. For more detail see Floerke & Alcamo (2004) and Alcamo et al. (2003).
- Development and testing of the WaterGAP2 global model of water use and availability Alcamo , J., Doell, P., Henrichs, T., Kaspar, F., Lehner, B., Roesch, T. & Siebert, S. 2003: Development and testing of the WaterGAP2 global model of water use and availability. Hydrological Sciences Journal 48(3): 317-337. Abstract: Growing interest in global environmental issues has led to the need for global and regional assessment of water resources. A global water assessment model called "WaterGAP 2" is described, which consists of two main components--a Global Water Use model and a Global Hydrology model. These components are used to compute water use and availability on the river basin level. The Global Water Use model consists of (a) domestic and industry sectors which take into account the effect of structural and technological changes on water use, and (b) an agriculture sector which accounts especially for the effect of climate on irrigation water requirements. The Global Hydrology model calculates surface runoff and groundwater recharge based on the computation of daily water balances of the soil and canopy. A water balance is also performed for surface waters, and river flow is routed via a global flow routing scheme. The Global Hydrology model provides a testable method for taking into account the effects of climate and land cover on runoff. The components of the model have been calibrated and tested against data on water use and runoff from river basins throughout the world. Although its performance can and needs to be improved, the WaterGAP 2 model already provides a consistent method to fill in many of the existing gaps in water resources data in many parts of the world. It also provides a coherent approach for generating scenarios of changes in water resources. Hence, it is especially useful as a tool for globally comparing the water situation in river basins.
- European Outlook on Water Use Floerke M. and Alcamo J. (2004) European Outlook on Water Use, Center for Environmental Systems Research - University of Kassel, Final Report, EEA/RNC/03/007.
- An Integrated Analysis of Changes in Water Stress in Europe Henrichs, T., Lehner, B. & Alcamo, J. 2002: An Integrated Analysis of Changes in Water Stress in Europe. - Integrated Assessment 3(1): 15-29.
EEA data references
- No datasets have been specified here.
External data references
- Input data to WaterGAP model - climate projections - output from ECHAM4/OPYC3 model data
- Input data to WaterGAP model - climate projections - output from HadCM3 model data
- Input data to WaterGAP model - population growth - output from UNSTAT data, medium scenario
- Input data to WaterGAP model - population distribution - output from CIESIN data
- Input data to WaterGAP model - electricity production - output from IMAGE 2.1 data
- Input data to WaterGAP model - GDP growth - output from IMAGE 2.1 data
- Input data to WaterGAP model - irrigated area - output from digital map provided by Siebert and Döll (2001)
- Output data from WaterGAP - Water availability and water withdrawals, water exploitation index
Data sources in latest figures
Floerke and Alcamo (2004) presented a list of some of the main factors determining water use that are particularly uncertain in the European version of WaterGAP. In general, these also hold true for the global version.
Domestic – In most European countries the relationship between future income and water use seems to be well defined. However, in a countries undergoing a major economic transition, it is not possible to define a reliable relationship between income and water use. Another source of uncertainty in estimating future water use in the domestic sector is the future population of water users.
Manufacturing – The water use intensity of different industries is a major uncertainty in most countries. But perhaps more important is the water use of industries that are not now important but will become important over the next 30 years. Key questions are, what will these industries be and how much water will they use?
Electricity Production – Major uncertainties in this sector are the use lifetime of power stations, the percentage of new power stations having tower versus once-through cooling, and their future geographic location. Also important is the uncertainty of future thermal electricity production, and general electricity production trends.
Agriculture – Major unknowns in the agriculture sector are the future extent of irrigated crops, the types of crops to be irrigated, and future climate conditions.
Additional to the above, the uncertainty of the model's estimates on future water availability depend much on the reliability of the land use and climate data used.
Data sets uncertainty
See above 'methodological uncertainties'.
Additionally, data on current and past water use need to be considered with reservation due to the lack of common European definitions and procedures for calculating water abstraction and freshwater resources. For some countries in the European, Caucasus and Central Asia no reliable time series on water use by sector exist.
These data uncertainties affect model calibration and are propagated through to the modeled results.
Water stress indicators give an aggregate measure of the pressures that anthropogenic water use places on freshwater resources and related environmental systems. While this a good first categorization of water stress in different countries and river basins, this approach is not likely to be precise in distinguishing the different reasons of water stress due to data and model uncertainty.
It should be stressed, that this water stress indicator is calculated solely based on quantitative information and does not directly address water quality issue. Nevertheless it has been argued that high quantatitive water stress values often also imply some qualitative water stress.
While higher levels of water stress often coincide with higher frequency in droughts, no direct relationship exists. Thus this indicator should only be used with care when addressing assessing droughts (although, with some methodological modifications this can, and has been, done)
Please note that water stress indicators are most useful when presented at the river basin scale, as country values are at risk of missing water stress prone river basins due to averaging. Thus any water stress indicator should always (also) be reported at the river basin level, if possible.
Short term work
Work specified here requires to be completed within 1 year from now.
Long term work
Work specified here will require more than 1 year (from now) to be completed.
Responsibility and ownership
EEA Contact InfoAnita Pirc Velkavrh
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
For references, please go to www.eea.europa.eu/soer or scan the QR code.
This briefing is part of the EEA's report The European Environment - State and Outlook 2015. The EEA is an official agency of the EU, tasked with providing information on Europe’s environment.
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