Freshwater ecosystems have enormous biological, environmental, social, educational and economic value and provide a range of goods and services upon which people, and all life, depend. Ecosystems purify fresh water, regulate flows, supply water and food to billions of people, drive the water, carbon and nutrient cycles, harbour exceptional freshwater biodiversity, and enable the productive use of water for drinking, agriculture, energy generation, navigation, employment and tourism. Freshwater ecosystems in the context of the Sustainable Development Goal (SDG) framework are foundational natural resources of the biosphere. Numerous development actions depend on them, and either succeed or fail depending on the functional capacity or integrity of the ecosystem. Any adverse changes in the quantity and quality of freshwater ecosystems ultimately reduce our capacity to develop sustainably. 

It is hoped that readers of this manual will gain an understanding of the role and value of freshwater ecosystems within different sectoral contexts and an overview of actions and management solutions to protect them.