Before revision: A guelta (or galta or gueltat or agelmam), meaning pool in Arabic , is a pocket of water that forms in drainage canals or wadis in the Sahara.
After revision: A guelta (or qalta or galta or agelmam), from Arabic:قلتة which means a depression in ground between rocks which holds water , is a pocket of water that forms in drainage canals or wadis in the Sahara.