Changes

[[Image:RiverbedHandDugWell.jpg|thumb|right|400px| Hand-dug wells situated in riverbeds must be equipped with a well-head to prevent the well shaft being filled with sand during floods such as this hydro-dynamic well-head used in Sudan. It is shaped as a wedge to break the force of floods. © E. Nissen-Petersen, Kenya.]]

[[Image:NewRiverbedWell.jpg|thumb|right|400px| New riverbed well. The new well's ''hydro dynamic'' design means it won't be washed away or destroyed by fast flowing rivers during the rainy season. These wells provide cleaner, fresher water, and are safer than climbing into unprotected holes. They are time saving too as traditional wells have to be re-dug each dry season. Photo: Jane Beesley.]]

==Suitable conditions==