Natural or lined catchments (including ponds/lakes) capture runoff from surface- or rainwater. An installation typically consists of a dam or an impermeable lining (made of cement, brick, clay or plastic) to obstruct and collect the water-flow. Used for domestic supply (after treatment), or irrigation and livestock production. A permeable bottom allows groundwater recharging. Typical capacity range between 20-2000 m3.
Dams USD 3 per m3, ponds with lining USD 6.5 per m3. Costs often determine size! Large system requiring community-level financing and implementation. O&M costs low including cleaning rock to masonry repairs. De-silting and treatment for drinking may be expensive.
Applied at community- or multiple community-level and therefore a water management committee is required to manage water use and O&M. Also applied at farm level. Micro-financing can only be applied as community loans, but successful systems are financed by own local contributions and subsidies. Land ownership is often an issue.
Runoff and rainwater imply sustainable use. If groundwater recharged: positive impact on water availability. The ecological footprint is low, especially with natural surface or material use (clay and stones). Water retention and recharge improve community resilience against climate change impact.
Dams are medium- to low-tech. Lifespan of 20 - 50 years, plastic lining shorter. If applied directly for drinking, open system with contamination risk requires treatment. If water is to recharge groundwater resources: contamination assessment needed at abstraction point.
Awareness-raising campaign to justify community ownership. Expected willingness-to-pay: medium to high. Utilization level: high – agriculture benefits economically. Sustainability: medium – siltation is a problem; pesticide in runoff may degrade environment. Gender-inclusive governing recommended. Ease and frequenct of use depends on siting.
No relevant remarks for Natural catchment and storage.
Akvopedia - Ground Catchment - general
SSWM - Man-made Reservoirs
Small Reservoirs Project - Small Multi-purpose Reservoir Ensemble Planning