Maintenance of functioning of ecosystems
Terrestrial and aquatic ecosystems need water to maintain their functioning: plants evaporate and transpire water; animals drink water; fish and amphibians need water to live in. Water is also used by upper-watershed ecosystems, like forests, shrublands and woodlands.

Water resource inputs maintain a dynamic in ecosystems
Downstream, wetlands, floodplains, and mangroves need freshwater inputs. This water is used to maintain a (semi)-natural dynamic, often of a seasonal nature. To prevent degradation and destruction of ecosystems, it is important to have enough water of the right quality and with the right seasonal variability.