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  • What is a sand dam?
  1. Why sand dams
  2. What is a sand dam?

What is a sand dam?

Year-round safe water

A sand dam is a reinforced stone masonry wall built across a seasonal sandy river. They have almost no maintenance costs and can last for upwards of 60 years (the oldest known in operation being over 100 years old).

Water behind a sand dam raises the water table in the surrounding area which improves the soil, creating better conditions for crops and grazing. More trees can be planted which ensures that more water infiltrates the ground and less soil is washed away – creating a virtuous cycle of soil and water conservation.

sand dam diagram

During the rainy season, the sand dam fills with sediment-laden water. The heavy sand is deposited behind the dam, while the light silt is carried downstream. As much as 97 to 99% of the water flowing in the river continues downstream.

Within one to four rainy seasons, the dam fills with sand. But, up to 40 million litres of water is stored in the pores between sand particles (enough to provide over 1,000 people with year-round access to clean water). Here it can be extracted through an infiltration gallery that leads to either a water tank, tap or sealed shallow well (topped with a hand pump). 

And as the water is stored safely within the sand, it is protected from evaporation, contamination and disease transmitters, such as mosquitoes and freshwater snails.

Since 2002, Excellent Development has enabled the construction of over 1,000 sand dams which are now supporting over 1 million people living in drylands to transform their own lives with lifelong access to water, food security, and climate change resilience.

Sand dam FAQs
How communities are benefiting from sand dams

Please donate what you can and help dryland communities to access clean water with sand dams

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Published: 11th May, 2018

Updated: 5th November, 2019

Author:

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Registered in England & Wales No. 4432166. Registered charity No. 1094478

Excellent Development, 7-14 Great Dover Street London, SE1 4YR, United Kingdom