Water exploitation index, plus (WEI+) (source: EEA)

The Water Exploitation Index plus (WEI+) is a measure of total fresh water use as a percentage of the renewable fresh water resources (groundwater and surface water) at a given time and place. It quantifies how much water is abstracted and how much water is returned after use to the environment. The difference between water abstraction and return is regarded as water use and illustrates the pressure on renewable freshwater resources due to water demand. In the absence of Europe-wide agreed formal targets, values above 20% are generally considered as an indication of water scarcity, while values equal or bigger than 40% indicate situations of severe water scarcity, i.e. the use of freshwater resources is clearly unsustainable. The indicator is presented as annual average values. Annual calculations at national level, however, cannot reflect uneven spatial and seasonal distribution of resources and may therefore mask water scarcity that occurs on a seasonal or regional basis. The indicator is a result of estimations by EEA based on data from the WISE SoE - Water quantity database (WISE 3) and other open sources (JRC, Eurostat, OECD, FAO) and including gap filling methods.