How can we help people in Africa, Sand Dams?

Reducing water supply problems in rural areas.

Ephemeral watercourse in Tanzania. Image by the author.

Sand dams are concrete and rock weirs built over ephemeral (flow only after rain) or intermittent rivers (dry or very low discharge in one season), that have sand over rock river beds, and are designed to retain some water and sand, hence the name sand dams.