As soon as it rains in the Kenyan project area of arche noVa, most of the precipitation flows off in temporary river courses.
Most of the year it is dry, some water points remain in the river courses. Last, people have to dig up the ground to get water here.
The dry season is an opportunity to build a dam wall.
In the first rainy season after the dam construction, not only some water is dammed. Above all, the first sediments (called sand for short) are deposited.
When the dam is mature, a layer of sediment several meters high is formed. It is enriched with water during the rainy season. At the same time, most of the water flows downstream and can also be used there. The dam does not interfere with the course of the river or the ecosystems.
In the dry season, the sand surface serves as a storage medium for the water. Evaporation is avoided. The inhabitants of the neighboring communities draw the water from the foot of the storage area with the help of hand pumps. The sand also serves as a filter.
