What is a Sand Dam?

The funds gathered at the 2012 Northern Michigan Relief Sale through Penny Power, the Traveling Water Quilt, Kid’s World, and other children’s activities are all being directed toward the construction of sand dams and related technologies in Africa.

The idea behind Sand Dams is very simple.  It draws from generations of knowledge that water can be found in the sandy beds of streams that are dry much of the year.  The work that produced the first sand dam came as a result of a community striving to improve their lives in the midst of severe drought conditions.  Like many technical discoveries, it came about almost by accident.

Villagers were used to digging holes into stream beds to find water, but during a coule of years of decreased rainfall, the ground water level would drop and ever deeper holes were required to reach the water.  At one village, a series of concrete dams were built across a stream that carried abundant flows of water during the rainy seasons, but did not flow during the dry seasons.   The hope was to catch water for use rather than let it flow downstream to the ocean.  The first year saw a series of pools that could be accessed by people and animals for water.  However, as the flood water slowed, it dropped it’s load of sand into the bottoms of those pools, and by the third year, the pools were completely filled by deposited sand.   Villagers drew on their ancestral knowledge and dug into the sand to find water.   The end result was that the water trapped in the sand behind the dams lasted longer and was cleaner than the water in the first year pools.   Sand Dam technology was born.

Sand Dams are often paired with extensive terracing of adjoining stream banks.  Fruit trees are planted along side the sand reservoir to shade the sand, use the stored water, and stabilize the stream banks in time of seasonal flooding.  The photo below shows a small scale model of what  a sand dam with stream bank terraces might look like.

This video link from the MCC website provides additional information on what a sand dam is and how one is built… http://www.mcc.org/stories/videos/what-sand-dam