Surface water

In Europe, annual runoff is greatest in western Norway. Considerably less is seen in parts of Spain, central Hungary, eastern Romania and the southern part of Russia.

The differences in river flow regimes are apparent in Western Europe (where flows are at a minimum in summer and late autumn), mountain-fed catchments (where flows are greatest in summer), and Eastern and Northern Europe (where most runoff occurs during the spring-melt period).

Many European river flow regimes are heavily affected by human activities such as water abstraction and damming.