Sand dams to improve access to water

Since its launch in 2022, the British NGO Sand Dams Worldwide (SDW) has been supporting rural communities in certain arid areas by strengthening their access to water. They rely on the sand dam mechanism. What is it? It is a reinforced concrete wall built on the bedrock of a seasonal riverbed. During short but intense rains, water flows over the dam, depositing sand behind the wall where water is stored, protected from evaporation, contamination, or diseases. The benefits are twofold:

• A mature sand dam stores up to 40 million liters of water each rainy season, supporting more than 1,000 people with clean water.
• Sand dams raise groundwater levels by capturing rainwater that would otherwise be lost as runoff. This allows water to seep into the ground, leading to vegetation recovery and limiting soil erosion. Ecosystems with sand dams show greater resistance to drought.

The program supported by the Veolia Foundation is being implemented in Ukambani, a region in southeastern Kenya. In this semi-arid area, food and water shortages are common. About 44% of the population lives below the poverty line, compared to 38% nationally, and the rainy seasons are increasingly irregular and unpredictable.

SDW plans to build a sand dam there for just over 2,000 people living in Machakos, Makueni, and Kitui. The project will be carried out with the Kenyan NGO Africa Sand Dam Foundation (ASDF), SDW's long-standing partner.