 pilcomayo (in hispanicized spelling) (quechua pillkumayu or pillku mayu, pillku red, mayu river,teofilo laime ajacopa, diccionario bilingÃ¼e, quechua-castellano, castellano quechua, la paz, 2007: mayu - s. rÃ­o. pillku - adj. rojo (sÃ­nÃ³n.: puka). "red river", guarani ysyry araguay ) is a river in central south america. at  long, it is the longest western tributary of the paraguay river. its drainage basin is  in area, and its mean discharge is . along its course, the pilcomayo silts up and splits into two main branches, north and south. after some distance, these branches rejoin to form the lower pilcomayo. the pilcomayo rises in the foothills of the andes mountain range in the bolivian oruro department, east of poopÃ³ lake. the jach'a juqhu river is considered the origin of the pilcomayo.jorge molina carpio, daniel espinoza romero,
ArgentinaaBolivia_border ArgentinaaParaguay_border Border_rivers Geography_of_Formosa_Province Geography_of_Salta_Province International_rivers_of_South_America Rivers_of_Argentina Rivers_of_Oruro_Department Rivers_of_Paraguay Rivers_of_Tarija_Department Tributaries_of_the_Paraguay_River