Tributaryn bishaan ya'u yokan laga yoo ta'u, kunis gara laga birra (parent river yokan laga dura) yokan Qamma Bishaani (body of water)iit ya'u yoo ta'u, kan garu gara gallana cisetti hin senne dha. orography kessatti tributaryiin kan gargari itti bafaman, kan gara Burqaa lagat dhihoo ta'ani jalqabe kan hanga Afaan bishaanit dhihoo ta'anit gargari bafamani qoqodamu. confluenciin bakka ""tributary""iin lama yokan lagni lama waliin ademani dha.