A sand dam is a reinforced concrete wall built across seasonal river beds – 2 to 4 metres high and up to 90 metres across. A pipe is built into the dam, going 20 metres upstream. Over one to three seasons, the dam fills up with water, then sand, which filters water through the pipe built into the dam. About 40% of the volume behind the dam is water, meaning that sand dams can hold an incredible 2 to 10 million litres of water!
Seasonal rainfall leaves riverbeds dry and unable to hold onto any water that arrives.
A concrete dam is constructed by local self-help community groups and Quest volunteers!
Over 2 to 3 seasons water will flow and bring sand to build behind the concrete dam…
The end result is a dry river bed with huge amounts of water being stored and filtered by the sand built up behind the dam. The water table rises, new plants and crops can be grown but most importantly filtered drinking water is available ALL YEAR ROUND.
Fantasticly simple idea that alters hundreds of lives in sub-saharan Africa!