Use of freshwater resources

Indicator Specification
Indicator codes: CSI 018 , WAT 001
Created 04 Jun 2015 Published 21 Mar 2016 Last modified 20 Dec 2016, 04:50 PM
Topics: ,
The WEI+ provides a measure of the total water use as a percentage of the renewable freshwater resources for a given territory and time scale.

Assessment versions

Published (reviewed and quality assured)


Justification for indicator selection

Monitoring the efficiency of water use is important for the protection, conservation and enhancement of the EU’s natural capital. It also helps to improve resource efficiency, which is included as an objective of the EU's Seventh Environment Action Programme (7th EAP) to 2020. 

This indicator shows how total water use puts pressure on renewable water resources by identifying areas (sub-basins or river basins) with high seasonal abstraction in relation to the resources they contain, making them prone to water stress. The WEI+ is a water scarcity indicator that provides information on the level of pressure that human activity exerts on the natural water resources of a particular territory. This helps to identify those areas prone to water stress problems (Faergemann, 2012). The purpose of implementing the WEI+ at spatial (e.g. sub-basin or river basin) and temporal (monthly or seasonal) scales, which are finer than the annual average at the country scale, is to better capture the balance between renewable water resources and water use. This is done in order to assess the prevailing water stress conditions across Europe. In some basins, water scarcity is only reflected using monthly WEI+ values, but is not necessarily captured by these values.


Scientific references

Indicator definition

The WEI+ provides a measure of the total water use as a percentage of the renewable freshwater resources for a given territory and time scale.


The WEI+ values are given as percentages, i.e. water use as a percentage of renewable water resources. Absolute water volumes are presented as million cubic meters (million m3 or hm3).


Policy context and targets

Context description

The objective of the EU's 7th EAP to 2020 is to ensure the protection, conservation and enhancement of the EU’s natural capital and to improve resource efficiency. Monitoring of the efficiency of water use in different economic sectors at national, regional and local levels is necessary to achieve this. The WEI+ is part of the set of water indicators published by several international organisations, such as the United Nations Environment Programme (UNEP), the Organisation for Economic Co-operation and Development (OECD), Eurostat and the Mediterranean Blue Plan. There is an international consensus about the use of this indicator.

The indicator describes how total water use exerts pressure on water resources. It identifies areas (e.g. sub-basins or river basins) with high abstraction levels on a seasonal scale in relation to the resources available, and that are therefore prone to water stress. Changes in WEI+ values allow analyses of the changes in water use impact on freshwater resources, i.e. by adding pressure to them or by making them more sustainable.



There are no specific quantitative targets directly related to this indicator. However, the Water Framework Directive (2000/60/EC) requires Member States to promote the sustainable use of water resources, based on the long-term protection of available water resources, and to ensure a balance between abstraction and recharge of groundwater, with the aim of achieving good groundwater status by 2015.

Agreement with regard to WEI+ thresholds is quite important for delineating non-stressed and stressed areas.  Raskin et al. (1997) suggested that a WEI+ value of more than 20 % indicates water scarcity, whereas a value of more than 40 % indicates severe water scarcity. These thresholds are commonly used in scientific studies (Alcamo et al., 2000). In addition, Smakhtin et al. (2005) suggested that a 60 % withdrawal from the annual total runoff would cause environmental water stress. Since no formally agreed thresholds are available for assessing water stress conditions across Europe, in the current assessment, the 20 % threshold as proposed by Raskin at al. (1997) is applied to distinguish stressed from non-stressed areas, while 40 % is used as the highest threshold for mapping purposes.


Related policy documents

  • 7th Environment Action Programme
    DECISION No 1386/2013/EU OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 November 2013 on a General Union Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. In November 2013, the European Parliament and the European Council adopted the 7 th EU Environment Action Programme to 2020 ‘Living well, within the limits of our planet’. This programme is intended to help guide EU action on the environment and climate change up to and beyond 2020 based on the following vision: ‘In 2050, we live well, within the planet’s ecological limits. Our prosperity and healthy environment stem from an innovative, circular economy where nothing is wasted and where natural resources are managed sustainably, and biodiversity is protected, valued and restored in ways that enhance our society’s resilience. Our low-carbon growth has long been decoupled from resource use, setting the pace for a safe and sustainable global society.’
  • Addressing the challenge of water scarcity and droughts in the European Union
    EC (2007). Communication from the Commission to the Council and the European Parliament, Addressing the challenge of water scarcity and droughts in the European Union. Brussels, 18.07.07, COM(2007)414 final.
  • 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.

Key policy question

Is the abstraction rate of water sustainable?

Specific policy question

Water abstraction by source

Specific policy question

Is the use of water by sectors sustainable?


Methodology for indicator calculation

In 2011, a technical working group, developed under the Water Framework Directive Common Implementation Strategy, proposed the implementation of a regionalised WEI+. This differed from the previous WEI+ approach by enabling the WEI+ to depict more seasonal and regional aspects of water stress conditions across Europe. This proposal was approved by the Water Directors in 2012 as one of the awareness raising indicators.

The regionalised WEI+ is calculated according to the following formula:

WEI+ = (abstractions – returns)/renewable water resources.

Renewable water resources are calculated as 'ExIn + P – Eta – ΔS' for natural and semi-natural areas, and as 'outflow + (abstraction – return) – ΔS' for densely populated areas.


ExIn = external inflow
P = precipitation
ETa = actual evapotranspiration

ΔS = change in storage (lakes and reservoirs)

outflow = outflow to the downstream/Sea.

It is assumed that there are no pristine or semi-natural river basin districts or sub-basins in Europe. Therefore, the formula 'outflow + (abstraction – return) – ΔS' is used to estimate renewable water resources.

Climatic data were obtained from the EEA Climatic Database, which was developed based on the ENSEMBLES Observation (E-OBS) Dataset (Haylock et al., 2008). The State of the Environment database was used to validate the aggregation of the E-OBS data to the catchment scale.

Stream flow data have been extracted from the EEA Waterbase — Water Quantity database. This database does not have sufficient spatial and temporal coverage yet. In order to fill the gaps, JRC LISFLOOD data (Burek et al., 2013) have been integrated into the stream flow data. The stream flow data cover Europe, in a homogeneous way, for the years 2002–2014 at monthly scale.

Once the data series are complete, the flow linearisation calculation is implemented, followed by a water asset accounts calculation, which is done in order to fill the data for the parameters requested for the estimation of renewable water resources. The computations are implemented at different scales independently, from sub-basin to river basin district scale. 

Urban wastewater treatment plant data, the European Pollutant Release and Transfer Register (E-PRTR) database, Eurostat population data and JRC data on the crop coefficient of water consumption have been used to quantify the water demand and water use by different economic sectors. Eurostat tourism data (Eurostat, 2013b) and data on industry in production have been used to estimate the actual water abstraction and return on a monthly scale. Where available, state of the environment and Eurostat data on water availability and water use have also been used at aggregated scales for further validation purposes. 

Once water asset accounts are implemented according to the United Nations System of Environmental Accounting Framework for Water (2012), the necessary parameters for calculating water use and renewable freshwater water resources are harvested.

Following this, bar and pie charts are produced, together with static and dynamic maps.


Methodology for gap filling

LISFLOOD data from the Joint Research Centre have been used to gap fill the streamflow data set. The spatial reference data for the WEI+ are European Catchments and Rivers Network System (Ecrins) data (250-m vector resolution). Ecrins is a vector spatial data set, while LISFLOOD data are in 5-km raster format. In order to fill the gaps in the streamflow data, centroids of the LISFLOOD raster have been identified as fictitious (virtual) stations. The topological definition of the drainage network in Ecrins has been used to match the most relevant and nearest fictitious LISFLOOD stations with EEA–Eionet stations and the Ecrins river network. After this, the locations of stations between Eionat and LISFLOOD stations were compared and overlapping stations were selected for gap filling. For the remaining stations, the following principles were implemented: fictitious stations had to be located within the same catchment as the Eionet station and have the same main river segment; in addition, both stations should provide a strong correlation.



Methodology references

  • Alcamo et al. 2000 Alcamo, J., Henrich, T., Rosch, T., 2000. World Water in 2025 - Global modelling and scenario analysis for the World Commission on Water for the 21st Century. Report A0002, Centre for Environmental System Research, University of Kassel, Germany
  • EC 2012a Preparatory Action, Development of Prevention Activities to halt desertification in Europe, Service Contract to contribute to the building of Water and Ecosystem accounts at EU level. Part 1.
  • EC 2012b  Preparatory Action, Development of Prevention Activities to halt desertification in Europe, Service Contract to contribute to the building of Water and Ecosystem accounts at EU level. Part 2.
  • Kurnik, B., Louwagie, G., Erhard, M., Ceglar, A. and Bogataj Kajfež, L., 2014. Analysing Seasonal Differences between a Soil Water Balance Model and In-Situ Soil Moisture Measurements at Nine Locations Across Europe. Environmental Modeling & Assessment 19(1), pp. 19–34.
  • Raskin, P., Gleick, P.H., Kirshen, P., Pontius, R. G. Jr and Strzepek, K. ,1997. Comprehensive assessment of the freshwater resources of the world. Stockholm Environmental Institute, Sweden. Document prepared for UN Commission for Sustainable Development 5th Session 1997 - Water stress categories are described on page 27-29.
  • Smakhtin, V., Revanga, C. and Doll, P. 2005.  Taking into account environmental water requirement in global scale water resources assessment. IWMI the Global Podium.
  • ETC ICM, 2015. CSI 018 Use of freshwater resources in Europe (WAT01). Supplementary document to the draft indicator sheet.  
  • Burek, P., Kniff van der, J., Roo de, A. 2013 LISFLOOD, distributed water balance and flood simulation model revised user manual 2013. European Commission Joint Research Centre Institute for the Protection and the Security of the Citizen. Luxembourg. ISBN: 9789279331909 9279331906  

Data specifications

EEA data references

  • No datasets have been specified here.

Data sources in latest figures


Methodology uncertainty

Reported data on water abstraction and water use do not have sufficient spatial and temporal coverage. Therefore, estimates based on country coefficients are required to assess water use. First, water abstractions are calculated and, second, these values are compared with the production level in industry and tourist movements in order to approximate actual water use for a given time resolution. This approach cannot be used to assess the variations (i.e. resource efficiency) in water use contained in the time series. 

Because reference volumes for reservoirs and lakes are not available, the water balance for reservoirs can be quantified as only a relative change, and not as the actual volume of water. This masks the actual volume of water stored in, and abstracted from, reservoirs. Thus, the impact of the residence time, between water storage and use, in reservoirs is unknown.

The sectoral use of water does not always reflect the relative importance of the sectors to the economy of a given country. It is, rather, an indicator that describes which sectors environmental measures should focus on in order to enhance the protection of the environment.

Population data updates use a new methodology which was developed to disaggregate data from NUTS2 scale to Ecrins functional elementary catchment (FEC) scale. In order to distribute population data across Europe, the Geostat 2011 grid data set from Eurostat was used. Then, further aggregations were performed in the spatial dimension to give the sub-basin and functional river basin district scales. The population within the time frame of one calendar year is regarded as stable. The variations are taken into account only for the annual scale. Deviations from officially reported data are expected because of the nature of the methodological steps followed.

The data used were provided by Eurostat and were on the nights spent per NUTS2 region, at monthly scale, in accommodation establishments. Because of the aggregation/disaggregation steps followed, deviations from officially reported data are expected. The tourist population was included in the calculation as additional to the stable (local residents) population.



Data sets uncertainty


Quantifying water exchange between the environment and the economy is, conceptually, very complex. A complete quantification of the water flows from the environment to the economy and, at a later stage, back to the environment, requires detailed data collection and processing, which is not available at European level. Thus, reported data have to be used in combination with some modelling in order to construct the data for quantifying such water exchange, with the purpose of developing a good approximation of 'ground truth'. However, the most challenging issue is related to water abstraction and water use data, as the water flow within the economy is quite difficult to monitor and assess given the current data availability. Therefore, several interpolation, aggregation or disaggregation procedures have to be implemented at finer scales, with both reported and modelled data.

  1. Because of defects in Ecrins, the coordinates of the stream flow stations reported are not very accurate.

  2. The Danube river basin is accounted for as a single district in Ecrins, so it aggregates a lot of regional and national information.  

  3. The water accounts and WEI+ results have been implemented in the EEA member and Western Balkan countries. However, regional data availability was an issue for some river basins (e.g. Cyprus, Malta, Jarft  (PL), North West (UK) and North East (UK) including Icelandic and Turkish river basins, which have been removed from the assessment.



Rationale uncertainty

Because of the aggregation procedure used, slight differences exist between sub-basin and river basin district scales for total renewable water resources and water use.

Further work

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.

General metadata

Responsibility and ownership

EEA Contact Info

Nihat Zal


European Environment Agency (EEA)


Indicator code
CSI 018
WAT 001
Version id: 2
Primary theme: Water Water

Frequency of updates

Updates are scheduled once per year


DPSIR: Pressure
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)

Related content

Data references used

Data used

European catchments and Rivers network system (Ecrins) European catchments and Rivers network system (Ecrins) Version 1, Jun. 2012 - Ecrins is acronym for European catchments and Rivers network system. It is a geographical information system of the European hydrographical systems with a full topological information. Ecrins is a composite system made from the CCM developed by the JRC, Corine land Cover, WFD reporting elements, etc. It is organised from a layer of 181,071 “functional elementary catchments (FECs)” which average size is ~62 km2, fully connected with explicit identifier (ID) relationships and upstream area. Catchments are grouped as sub-basins, river basin districts (actual and functional to meet hydrographical continuity). The catchments are as well organised according to their sea shore of emptying to meet Marine Strategy delineations. Catchments are drained by 1,348,163 river segments, sorted as “main drains” (connecting together the FECs) and secondary drains (internal to a FEC). river segments mimic the natural drainage, however fulfilling the topological constraint of “0,1 or 2 upstreams, single or 0 downstream”. Each segment is populated with distance to the sea, to ease further processing. They are connected to elementary catchments and nodes documented with altitude. Segments are as well documented with a “dummy river code”, fully populated that earmark each segment with the most distant to the outlet in each drainage basin and, everywhere this has been possible, with a “true river” ID based on river naming. A layer of lakes and dams has been elaborated. Lakes polygons (70,847) are taken from Corine Land cover , WFD Art. 13 and in some cases, from CCM “water layer”. Lakes inlets and outlets are set with the segment ID and where relevant, the dams making the lake is documented. All lakes which depths and volume was found have been updated. Version 1.0 here presented still contain some topological errors (e.g. incorrect segment branching), because inaccurate geometry. They are noted and a correction procedure is underway.

Latest figures and vizualizations

Relevant policy documents

European Environment Agency (EEA)
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