Sand Dams

What is a Sand Dam?

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!  Water is collected either from the pipe on the lower side of the dam, or by digging holes in the sand behind the dam to access the water. Each dam provides a clean water supply for up to 1,200 people, animals and nurseries for trees and vegetables. Furthermore, the effect of improving water availability in a 20km radius means that a sand dam may indirectly benefit up to 100,000 people.

What are the benefits of Sand Dams?

The benefits of sand dams are staggering, impacting on health, education, food supply and much more.

A dam provides a year-round source of water so people do not have to spend long back-breaking hours during the drought season collecting water from far away. Children go to school more often - not just because they don't collect water themselves, but because they don't have to stay at home looking after children whilst their mother takes 8 hours to collect just 20 litres of water.

Time saved means more time can be spent on other activities, such as growing food - vital for life and for income to pay school fees.  The water is also much cleaner, having been filtered through the sand and protected from parasites, so children are less likely to get ill. Instances of typhoid and diarrhoea are virtually eliminated.

A sand dam also transforms the environment, as its presence raises the water table level both upstream and downstream of the dam. This increases the tree survival rate and allows other crops to grow that would not normally survive. More trees and plants means more food for humans and animals, increasing overall biodiversity and making it possible for people to create a sustainable livelihood in harmony with their environments.