What are sand dams and how to do they help communities?
Water is essential for life. Although there is enough fresh water for everyone on Earth, 40% of the global population don’t have an adequate supply of water. As weather patterns change, this figure is expected to rise. The constant search for water traps millions of people living in drylands in a vicious cycle of subsistence. Women and children bear the heaviest burden, typically spending hours each day collecting water, often from unsafe sources. Reliable and convenient access to safe drinking water is vital to human health, wellbeing, dignity and safety.
Sand dams transform people's lives by providing a local and reliable supply of water.
In dryland regions, rainfall is often erratic. When it does rain, downpours can be heavy. Water runs off the dry land and much of it is eventually lost to the oceans, taking valuable fertile soil with it. In many areas, a changing climate is causing desertification, leading to water and food insecurity, conflict, displacement and loss of biodiversity.
Capturing precious water where it falls is essential for improving environments and livelihoods. Sand dams are an effective and inexpensive way of doing this. A sand dam is a reinforced concrete wall built across a seasonal riverbed. During the rainy seasons, it captures water and sand behind the sand dam wall. The water trickles through the trapped sand and provides a reservoir from which water can be taken through pipes and pumps.
A sand dam can store up to 40 million litres of water, protecting it from evaporation and contamination by holding it safely within sand, yet each sand dam captures only a small proportion of the overall flow, enabling downstream communities to have their share too.
How do sand dams empower communities?
The reservoir created behind a sand dam not only provides a vital source of water for drinking and domestic uses - it can also empower local communities:
- It protects the environment of the region, reducing desertification and raising the water table over a period of years, supporting biodiversity.
- This allows communities to establish more sustainable forms of agriculture, through planting of trees, establishing seed banks, terracing of the land and diversifying crops. This produces better crop yields, improving diets and increasing household incomes.
- It helps to improve the prospects for children and their education, by reducing the amount of time they spend collecting water and being away from the classroom.
- Increased family incomes allow more children to attend secondary schools. In this way, sand dams support several of the United Nations Sustainable Development Goals.
- Being stored within the sand, the water is not a harbour for waterborne diseases, and losses to evaporation are much lower than from open water sources.
- Improved water and soil conservation helps to avoid the conflicts both between water users, and between humans and wildlife.
Sand dams provide a cost-effective means of achieving a sustainable supply of water for all. Please do get in touch for more information, or to make a donation.