Kogin Nyabarongo
Nyabarongo (ko Nyawarungu) babban kogi ne a Ruwanda, wani ɓangare na saman kogin Nilu. Tare da tsawon tsawon 351 kilomita (218 mi) mafi tsayi kogi gaba ɗaya a Rwanda. An faɗaɗa shi kilomita 421 (262 mi) a Tafkin Rweru gami da hanyar kilomita 69 (43 mi) a saman tafkin Kagera kafin ya shiga cikin Kogin Ruvuvu don ƙirƙirar Kogin Kagera. Kogin yana farawa ne daga mahadar kogunan Mbirurume da Mwogo a Kudu maso Yammacin ƙasar. Wadannan kogunan guda biyu da kansu sun fara ne daga dajin Nyungwe, kuma wasu suna ganin shine tushen mafi nisa daga kogin Nil. Daga farkonsa, Nyabarongo ya bi arewa zuwa kilomita 85 (mil 53), kuma ya samar da iyaka tsakanin Yankunan Yamma da Kudancin. A haɗuwa tare da kogin Mukungwa, kogin ya canza hanya kuma ya gudana zuwa gabas na kilomita 12 (mil 7.5), sannan zuwa wani tafkin Kudu maso gabas na ƙarshen kilomita 200 na ƙarshe (mil 124). Ga mafi tsayi na wannan kwas ɗin, kogin ya zama iyaka tsakanin lardunan Arewa da Kudancin, sannan tsakanin garin Kigali da Lardin Kudancin, kuma daga ƙarshe tsakanin Birnin Kigali da lardin Gabas.

Kogin sannan kafin ya shiga Lardin Gabas kuma ya ƙare hanyarsa kusa da kan iyaka da Burundi. Kogin Nyabarongo ya fado duka a tafkin Rweru da Akagera a cikin karamar Delta mai rikitarwa. Kogin Akagera ya malala daga Tafkin Rweru, mai tazarar kilomita 1 kawai daga gaɓar Nyabarongo. Kusan dukkanin rassa na yankin Nyabarongo delta fanko ne a cikin tabkin, sai dai, wani reshe na yankin ya fice kai tsaye a cikin kogin Akagera da aka kafa. Kogin Akagera daga ƙarshe ya kwarara zuwa Kogin Victoria kuma ya samar da Kogin Nilu.

Asali 
Kogin Nyabarongo ya samo asali ne daga kudu maso yammacin Rwanda zuwa gabashin tafkin Kivu. Tushen kogin ya tashi a cikin dutsen da ke rufe mafi yawan yamma na uku na Rwanda, zuwa gabashin Kyautar Albertine. Babban ruwan da ke cikin tsaunukan dazuzzuka, wanda ya samo asali a tsawan mita 2,600 zuwa 2,750 (8,530 zuwa 9,020 ft) sama da matakin teku, sune kogin Mbirurume da Mwogo. Mafi tsayi daga rafin da yake kawo Mwogo shine Rukarara, wanda ya tashi a Dajin Nyungwe. Rukarara yana gudana kudu sannan gabas, yana ɓoye cikin Kogin Mwogo. Mwogo yana gudana arewa, yana haɗuwa da Kogin Mbirurume kudu da Bwakira. Daga wannan haɗuwa, kogin ya ɗauki sunan Nyabarongo. Tushen Rukarara yana gwagwarmaya ne don asalin tushen Nilu, ruwan da ke nesa da ruwa.

Hanya 

Nyawarungu yana tafiya zuwa arewa ta cikin dutsen mai nisa a cikin kwari mai zurfi wanda yayi daidai da tafkin Kivu kuma kusan tsawan da ya kai kimanin mita 1,500 (4,900 ft). A Muramba yana juyawa zuwa kudu maso gabas. A gefen hagu na Kogin Nyabugogo yana sadar da ruwa daga Tafkin Muhazi. A kewayen Kigali ana amfani da kogin don girki, sha da wanka. Hakanan tana karɓar najasa da shara daga masana'antu da noma. Kimanin kilomita 35 (mil 22) ya gangaren kogin Akanyaru ya shiga bankinsa na dama, zuwa kudu maso yamma na Kigali.

Haɗin kogin da ke haɗuwa yana gudana gabas sannan kuma kudu maso gabas ta hanyar babban kwari mai fadama. A kan iyaka da Burundi ya malale Tafkin Rweru. Daga nan sai ya kwarara zuwa gabas kusa da kan iyakar tsakanin Rwanda da Burundi, sannan tsakanin Rwanda da Tanzania, har zuwa inda ya haɗu da Kogin Ruvuvu. Daga can ana kiranta Kogin Kagera, babban mawadatar tafkin Victoria, wanda yake malala zuwa Kogin Nilu. Kogin ya shayar da gabashin tsaunuka da kuma tsakiyar yankin tsakiyar Ruwanda.

Dausayi 

Ba da daɗewa ba bayan da Akanyaru suka haɗu, masu haɗar kogin da ke gabas zuwa kudu sannan ta hanyar hadaddun tabkuna da dausayi a cikin kwari mai faɗi wanda ke gudana a cikin hanyar SSE, kilomita 35 (22 mi) faɗi, wanda yake ambaliya don ƙirƙirar yankin na dindindin fadama da tabkuna. Tafkin Mugesera yana gefen gabashin kogin, kuma shi ne babban tabki na Rwandan a cikin hadadden. Tafkuna Birara da Sake suma suna kwance a gefen hagu na kogin. Tekuna a bankin dama, daga arewa zuwa kudu sune Gashanga, Kidogo, Rumira, Maravi, Kilimbi, Gaharwa, Rweru da Kanzigiri. Tafkin Rweru, wanda galibi ya ta'allaka ne a cikin Burundi, yana malalewa ta hanyar arewa maso gabas zuwa cikin kogin ta wani ɗan gajeren sashe mai dausayi.

Kodayake kusa da ekweita, iklima tana da kwatankwacin yanayi saboda tsawa. Lokacin damina daga Maris zuwa Mayu ne kuma daga Satumba zuwa Disamba. A cikin manya-manyan wuraren dausayi ana samun ambaliyar ruwa ne lokaci-lokaci. Gaba gaba, shuke-shuke gama gari sune Ficus verruculosa, Myrica kandtiana, Phoenix reclinata da Cyperus papyrus. Ruwan yana kusan 25°C (77°F). Kifi yana da yawa, kuma akwai nau'ikan tsuntsaye masu yawa na ruwa. Sauran dabbobin sun hada da kunkuru na ruwa, kada, masu sa ido, macizai da kuma otters.

Dausayin Kogin Nyabarongo yanki ne wanda ba shi da kariya wanda ke kewaye da hanyar Nyabarongo, kuma ya mamaye murabba'in kilomita 142.62 (55.07 sq mi). Yana da matukar mahimmanci ga kiyaye halittu, musamman tsuntsaye, tare da nau'ikan halittu irin su kogin Malagasy mai hatsari (Ardeola idae), da gagararren papyrus gonolek (Laniarius mufumbiri), mara nauyi mai launin toka (Balearica regulorum), da sitatunga (Tragelaphus spekii). Dausayi suna cikin matsi mai tsanani daga harkar noma.

Wadannan jinsunan dake cikin dausayin kogin Nyabarongo an lasafta su a matsayin wadanda ke da hatsari: papyrus gonolek (Laniarius mufumbiri), Cricoico na Carruthers (Cisticola carruthersi), masu fuka-fuka masu fuka-fuka-fuka-fukai (Bradypterus carpalis), papyrus yellow warbler (Chloropeta gracilirostris) -babbler (Turdoides sharpei), mai saƙa mai launin ruwan kasa ta arewa (Ploceus castanops), mai hade da farin zaitun (Nesocharis ansorgei), da papyrus canary (Serinus koliensis). {{sfn | BirdLife IBA Factsheet}

Manazarta 
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