Sand Dam Technology Transforms Lives in African Drylands
Sand dams are a simple, low-cost and low-maintenance, replicable rainwater harvesting technology. They provide a clean, local water supply for domestic and farming use and are suited to semi-arid areas of the world.
1. Low cost and maintenance: Sand dams are the lowest cost form of rainwater harvesting known – 3 to 100 times lower cost than other technologies. A sand dam is built to last over 50 years, has no operational costs and requires little maintenance.
2. Community owned and managed: Most examples of sand dams are built by members of the communities they serve with support local and international development agencies. Community ownership and management is key to their successful operation.
3. They save time and enable increased food production and tree planting: During drought periods in semi-arid regions, people might have to walk up to 12 hours a day to fetch water, which is often unsafe to drink. Freed from the chore of walking sometimes the whole day to collect the water, farmers are able to improve food production and generate surplus income.
4. They provide a clean, secure and local year-round water supply in water scarce environments: The sand effectively acts as a large slow sand filter resulting high quality potable water. As the water is held under the sand, evaporation is minimal, people are protected from water-borne diseases and mosquitoes can’t breed – reducing the threat of malaria.
5. Wider benefits for health, education and communities: In areas where sand dams have been built, communities have observed a dramatic fall in water related disease, an increase in school attendance and a significant increase in household income and food production.
6. They transform the local ecology: The water held in the sand behind the dam spreads horizontally creating a permanent increase in the water table, allowing trees to grow naturally and transform the local ecology. The dams create a natural buffer that reduces the threat posed by flooding and drought and builds the resilience of communities to cope with the impacts of climate change in semi-arid regions.