Water-retention potential of Europe's forests

Description

Forests are essential for human well-being and provide a wide range of ecosystem services to society.
Forests can retain excess rainwater, prevent extreme run-offs and reduce the damage from flooding. They can also help mitigate the effects of droughts.
This report, published by the European Environment Agency (EEA), provides a European overview of the role of forests in water retention, defined as the water absorbed or used by forests, based on the Water Accounts Production Database developed at the EEA.
The impact of forests on water retention is measured according to three parameters/characteristics: forest cover, forest types, and the degree of management of the forests. The estimation of the water-retention potential is derived from the relationships between input (rainfall) and output (water run-off into rivers and lakes) as affected by these three forest characteristics. The volume of water retained by forests can depend on characteristics such as forest cover area, the length of vegetation growing season, tree composition and tree density, as well as the age and the number of layers of vegetation cover. Water retention by forests affects the amount and timing of the water delivered to streams and groundwater by increasing and maintaining infiltration and storage capacity of the soil. Forests can soak up excess rainwater, preventing run-offs and damage from flooding. By releasing water in the dry season, forests can also help provide clean water and mitigate the effects of droughts.
The report shows that water retention potential tends to increase along with the extent of forest cover in a water basin. The report shows that water retention has an important role to play in buffering the effects of heavy rainfall and droughts. A better understanding of this role can help develop measures to tackle the effects of climate change and extreme weather events.

Reference information