Muvumba River
Muvumba  ni uruzi ruherereye mu majyaruguru .y'uburasirazuba bw'u Rwanda no mu majyepfo y'uburengerazuba bwa Uganda . Ibice byo hejuru  byamazi ya  Nili . Kuri Birometero 170 z'uburebure, ni rumwe mu nzuzi runini 'mu Rwanda haba mu bunini no mu bukungu. Amzi yuru Ruzi Yifashishwa mu guhinga icyayi mu butumburuke bwo mu majyaruguru yu Rwanda no mu majyepfo y’iburengerazuba bwa Uganda. Inzira yacyo yo hasi itanga amazi kubice byumye bya Nyagatare, byorohereza kuhira imirima yumuceri nibindi bihingwa kimwe no gutanga amazi y'inka muri kano gace kugirango borore inka.

Amasomo 
Uruzi rufata isoko i Rukomo mu karere ka Gicumbi hafi y'umujyi wa Byumba mu misozi miremire yo mu majyaruguru y'u Rwanda. Mwisoko , yitwa uruzi rwa Mulindi . Uyu mugezi ni ingenzi cyane mubukungu kuko ikibaya cyacyo n’ibibaya by’inzuzi zacyo birumbuka kandi birimo ibihingwa by’icyayi. Rumwe mu ruganda runini rw'icyayi mu Rwanda, Uruganda rwa Mulindi Factory tea ruherereye ku uru  ruzi. Mulindi itemba mu majyaruguru kuri 28 km hanyuma yinjira muri Uganda.

rumaze kwinjira muri Uganda, ruhindura izina ruva mu ruzi rwa Mulindi ruhinduka uruzi rwa Rwabakazi . Rwabakazi ikomeza mu majyaruguru, hanyuma imaze kugera mu mujyi wa Kabale, uruzi ruhindura inzira kandi rutemba mu cyerekezo rusange cyo mu majyepfo y'iburasirazuba yerekeza mu Rwanda. Iki gice cyumugezi wa Muvumba muri Uganda (Umugezi wa Rwabakazi) gifite uburebure bwa km 55. Uruzi rusubira mu Rwanda mu Karere ka Nyagatare rugafata izina Umugezi wa Muvumba. Ihita itemba yerekeza mu majyaruguru y'uburasirazuba bwa kilometero 87 ikisuka mu ruzi rwa Akagera ahitwa Kagitumba, inyabutatu ihuza u Rwanda, Uganda na Tanzaniya. Kuri kilometero 30 yanyuma yinzira zayo, uruzi rugize umupaka uhuza u Rwanda na Uganda.

Ubukungu 
Muvumba river ifite ikibaya  gihingwa cyane. Inzira yo hejuru yinzuzi mu misozi yintara yamajyaruguru mu Rwanda no mu Karere ka Kabale muri Uganda ifite ibibaya bigufi bikoreshwa cyane nko guhinga icyayi. Uruzi rutanga amazi kumigezi itabarika ifasha kuvomera imirima. Kubera iyo mpamvu, uruzi rwangiritse igice kinini ahantu henshi kugirango igenzure amazi kandi irebe ko haboneka amazi no mugihe cyizuba. Mu bice bidahingwa byicyayi, ikibaya gikoreshwa mubuhinzi butunze Benci.

Iyo uruzi rwongeye kwinjira mu Rwanda, rutemba mu turere tw’imisozi ahantu hahanamye kandi hahanamye cyane. Inzira zose z'ikibaya cy'umugezi wa Muvumba zikunda kwibasirwa n'umwuzure kubera imvura nyinshi igwa mu misozi yo mu majyaruguru yayo. Ibi bizwiho kuzana imyuzure ikabije ndetse no mu bice byo hepfo yuruzi ubusanzwe bitagira imvura nyinshi. Iyi myuzure ishobora guhagarika inzira yo hepfo yuruzi, igafunga imihanda nikiraro mugihe nayo yangiza cyane ibihingwa.

Ibinyabuzima ni Bimera 

Hanze  y'ubuhinzi bunini, imigezi yo hepfo   ishyigikira ishyamba rinini. Iri shyamba rifunganye rirashobora kuba ryinshi kandi ntirishobora kwambuka, kandi rikubiyemo ubwoko bwinshi bwibiti bya savanna. Ubwoko bwinshi bwinyoni buboneka muri kariya gace, ubwinshi muri bwo ni heron na egrets. Amatungo magufi y’inyamaswa n’ibikururukanda  Inyamaswa nini zo mu mazi nka Invubu, ningona za Nili zishobora kandi kuboneka mubice byegeranye n’isangano ry'umugezi munini wa Akagera. Izi nyamaswa zizwiho kugenda zerekeza hejuru cyane cyane mugihe cyumwuzure utera guhitana abaturage baho batabizi batamenyereye aya matungo kuba kure cyane.

Reba 

Inkomoko
 

http://en.igihe.com/IMG/pdf/Hydrological_Bulletin_No_06.pdf