Rainfall and soil water are fundamental parts of all terrestrial and aquatic ecosystems which supplies goods and services for human well-being. Availability and quality of water determines ecosystem productivity, both for agricultural and natural systems.

There is increasing demand on water resources for development whilst maintaining healthy ecosystems, which put water resources under pressure. Ecosystem services suffer when rain and soil water becomes scarce due to changes from wet to dry seasons, or during within-seasonal droughts.

Climate change, demand for development and already deteriorating state of ecosystems add to these pressures so that future challenges to sustain our ecosystems are escalating.

There is an immediate need to find innovative opportunities enabling development and human wellbeing without undermining ecosystem services. Among such opportunities one can ask: What potential can rainwater harvesting offer to enable increased human well-being whilst protecting our environment? What role can small-scale decentralised rainfall harvesting and storage play in integrated water resource management? And in which specific contexts may rainwater harvesting create synergies between good ecosystems management and human well-being?

Rain water harvesting is the collective term for a wide variety of interventions to use rainfall through collection and storage, either in soil or in man-made dams, tanks or containers bridging dry spells and droughts.

The effect is increased retention of water in the landscape, enabling management and use of water for multiple purposes.