A guelta (Arabic: قلتة, also transliterated qalta or galta; Berber: agelmam) is a pocket of water that forms in drainage canals or wadis in the Sahara.[1] The size and duration will depend on the location and conditions. It may last year-round through the dry season if fed by a source such as a spring.[1] When a river (wadi) dries up, there may be pockets of water remaining along its course (c.f. oxbow lake).[1] In Western Sahara, gueltas correspond to oases.[1]
Some examples include Guelta d'Archei in Chad and Timia in Niger.