Both water and population are unevenly distributed in Europe. As a result, countries and sub-regions experience differing degrees of water stress.
Annual average river run-off from rain varies from over 3 000 mm in western Norway to less than 25 mm in southern and central Spain.
Average annual river run-off in Europe
The total renewable freshwater resource of a country is the total volume of river run-off and groundwater recharge generated annually by precipitation within the country, plus the total volume of actual flow of rivers coming from neighbouring territories. This resource is supplemented by water stored in lakes, reservoirs, icecaps and fossil groundwater.
In absolute terms, the total renewable freshwater resource in Europe is around 3 500 km3/year. The Mediterranean islands of Malta and Cyprus and the densely populated European countries (Germany, Poland, Spain and England and Wales) have the least available water per capita.
Inflows from transboundary watersheds can be a significant percentage of freshwater resources in countries, either as surface flow or as groundwater flow. The downstream countries of the Danube basin have the highest dependency on external resources. The Netherlands, Luxembourg and Portugal also receive significant inflows from upstream rivers.