watercourse wadi A valley or ravine, bounded by relatively steep banks, which in the rainy season becomes a watercourse. ENVO ENVO:00000031 EcoLexicon:wadi FTT:157 FTT:158 FTT:159 FTT:160 FTT:161 FTT:163 FTT:164 Geonames:H.WAD Geonames:H.WADB Geonames:H.WADJ Geonames:H.WADS SWEETRealm:Arroyo SWEETRealm:Wash TGN:21167 TGN:21423 TGN:21424 The temporality of wadis is problematic in deciding whether they are watercourses or valleys. Wikipedia:Wadi arroyo coulee gully nullah wadi wadi bend wadi junction wadi mouth wadis wash watercourse valley