Yankin Chadi

Tafkin Chadi shine mafi girma a cikin tafkin tekun endorheic a Afirka, wanda ke tsakiyar tafkin Chadi. Ba ta da hanyar shiga teku kuma tana ƙunshe da manyan yankuna na hamada mara bushewa da savanna. Ruwan magudanar ruwa yana da kusan coterminous tare da kwandon ruwa mai suna iri ɗaya, amma ya kara gaba zuwa arewa maso gabas da gabas. 

Kogin ya mamaye kasashe hudu na zamani, gami da mafi yawan Chadi da babban bangare na Nijar, Najeriya da Kamaru. Haɗin madatsun ruwa, ƙara ban ruwa, Canjin yanayi, da rage ruwan sama suna haifar da karancin ruwa. Tafkin Chadi yana ci gaba da raguwa.

 Ilimin ƙasa 
Yankin geological, wanda ya fi karami fiye da kwandon ruwa, wani kwandon Phanerozoic ne wanda aka kafa a lokacin bambancin farantin da ya buɗe Tekun Kudancin Atlantic. Kogin yana tsakanin Craton na Yammacin Afirka da Craton Congo, kuma an kafa shi kusan lokaci guda da Benue Trough. Ya mamaye yanki na kimanin  kilomita 2,335,000 (902,000 sq .  Ya haɗu da Iullemmeden Basin zuwa yamma a rata ta Damergou tsakanin Aïr da Zinder massifs. An yi bene na kwandon ne da dutse na Precambrian wanda aka rufe shi da fiye da mita 3,600 (11,800  na ajiyar sedimentary.

Wataƙila kwandon ya samo asali ne daga haɗuwa da "Aïr-Chad Trough" da ke gudana NW-SE da kuma "Tibesti-Cameroon Trough" wanda ke gudana NE-SW. Wato, ɓangarori biyu mafi zurfi sune tsawo na Benue Trough wanda ke gudana daga arewa maso gabas zuwa gefen kwandon, da kuma wani tsawo da ke gudana tun daga ƙasa da tafkin yanzu zuwa ƙasa da tsarin Ténéré rift zuwa gabashin Aïr massif. Yankin kudancin kwandon yana ƙarƙashin wani ɓacin rai mai tsawo. Wannan yana gudana a cikin hanyar ENE kuma ya shimfiɗa daga hannun Yola na Benue trough . 

A wasu lokuta, wasu sassan kwandon suna ƙarƙashin teku. A arewa maso gabashin Benue Trough inda ya shiga cikin Chadi Basin akwai ruwan da ke cikin ruwa daga Late Cretaceous (100.5-66 Ma). Wadannan turɓaya suna da yawa sosai zuwa arewa maso gabas. Boreholes a ƙarƙashin Maiduguri sun sami zurfin ruwa mai zurfi mita 400 (1,300 , yana kwance a kan zurfin nahiyar mita 600 (2,000 . Tekun da alama ya koma baya daga yammacin ɓangaren kwandon a cikin Turonian (93.5-89.3 Ma). A cikin Maastrichtian (72.1-66 Ma) yamma ba na ruwa ba ne, amma kudu maso gabas mai yiwuwa har yanzu yana da ruwa. Ba a sami wani ruwa na ruwa daga Paleocene (66-56 Ma). 
Ga mafi yawan Quaternary, daga shekaru miliyan 2.6 da suka gabata zuwa yanzu, kwandon yana da alama ya kasance babban fili, mai ruwa sosai, tare da koguna da ruwa da yawa, mai yiwuwa wadata da rayuwar shuka da dabba. Zuwa ƙarshen wannan lokacin yanayin ya zama mai bushe. Kimanin shekaru 20,000-40,000 da suka gabata, dunes na yashi na eolianite sun fara samuwa a arewacin kwandon. A lokacin Holocene, daga shekaru 11,000 da suka gabata har zuwa kwanan nan, wani babban "Lake Mega-Chad" ya rufe yanki sama da  kilomita 350,000 (140,000 sq  a cikin kwandon. Zai narke zuwa Tekun Atlantika ta hanyar Kogin Benue. Rubuce-rubucen Stratigraphic sun nuna cewa "Mega-Chad" ya bambanta da girman yayin da Yanayi ya canza, tare da matsakaicin kimanin shekaru 2,300 da suka gabata. Ana samun ragowar kifi da molluscs daga wannan lokacin a cikin abin da ke yanzu yankunan hamada.

 Yankin tafkin ruwa 
Yankin Chadi ya rufe kusan kashi 8% na nahiyar Afirka, tare da yanki na kimanin  kilomita 2,434,000 (940,000 sq . Duwatsu ne ke kewaye da shi. Duwatsun Aïr da Termit Massif a Nijar sun samar da iyakar yamma. A arewa maso yamma, a Aljeriya, akwai tsaunukan Tassili n'Ajjer, gami da mita 2,158 (7,080  Jebel Azao. Duwatsun Tibesti zuwa arewacin kwandon sun haɗa da Emi Koussi, dutse mafi girma a cikin Sahara a mita 3,415 (11,204 . Ennedi Plateau yana arewa maso gabas, yana tashi zuwa mita 1,450 (4,760 .  Yankin tsaunuka na Ouaddaï yana gabas. Sun hada da Dutsen Marrah a Darfur har zuwa mita 3,088 (10,131  a tsawo. Filayen Adamawa, Filayen Jos, Filayen Biu, da Dutsen Mandara suna kudu.

A yammacin kwandon ya rabu da ruwa daga Kogin Neja, kuma a kudu an raba shi da wani bene mai zurfi daga Kogin Benue. Daga gaba zuwa gabas, ruwa ya raba shi daga Kogin Kongo da Kogin Nilu.

Mafi ƙasƙanci na tafkin ba tafkin Chadi ba ne, amma Bacin ran Bodélé, a nisan kilomita 480 (300 mi) zuwa arewa maso gabashin tafkin. Damuwar Bodélé tana da nisan mita 155 (509 ft) a saman matakin teku a cikin mafi zurfin yanki, yayin da saman tafkin Chadi ya kai mita 275 (902 ft) sama da matakin teku.

Basin ya ratsa sassan kasashe takwas. Wadannan su ne: 
KasarMai zaman kansaYankin da ke cikin kwandon (km2) % na jimlar yankin kwandon% na ƙasar a cikin kwandonAljeriya196293,4513.9%3.9%Kamaru196050,7752.1%10.7%Jamhuriyar Afirka ta Tsakiya1960219,4109.2%35.2%Chadi19601,046,19643.9%81.5%Libya1947 -<1%<1%Nijar1960691,47329.0%54.6%Najeriya1960179,2827.5%19.4%Sudan1956101,0484.2%4.0%Jimillar2,381,635100%

 Yanayi da muhalli 
Rabin arewacin rafin hamada ne, wanda ya ƙunshi hamadar Ténéré, Erg na Bilma da Desert Djurab. Kudancin wannan shi ne yankin Sahel, bushewar savanna da ƙaya mai ƙaya. Manyan kogunan sun hada da dazuzzukan magudanan ruwa, da ambaliyar ruwa ta savannas da wuraren dausayi. A kudu mai nisa akwai busassun dazuzzuka. Ruwan sama ya bambanta sosai daga shekara zuwa shekara. Adadin ruwan sama na shekara-shekara kadan kadan ne a arewacin rafin, yana karuwa zuwa milimita 1,200 (47 in) a kudu.

Tun daga shekara ta 2000, basin ya kasance gida ga yawan namun daji. A yankin Sahel wadannan sun hada da tururuwa irin su addax da dama gazelle, sannan a cikin savanna akwai korrigum da jajayen barewa. Ana samun crane mai kambin baki da sauran tsuntsayen ruwa a cikin dausayi. Akwai yawan giwaye, raƙuma, da zakuna. Bakar karkanda ta yamma ta kasance ruwan dare amma yanzu ta kare. Giwaye sun kusa bacewa a karshen karni na sha tara saboda bukatar kasashen Turai da Amurka na hauren giwa, amma hannun jari ya farfado.

 Ma'adanai na ruwa 

 Koguna 
Kogin Korama na zamani da ke kudancin Nijar bai isa tafkin Chadi ba. Najeriya ta hada da wasu rafuka guda biyu da ke kwarara zuwa tafkin Chadi. Yankin Hadejia – Jama’are – Yobe a arewa yana dauke da kogunan Hadejia da Jama’are, wadanda ke samar da dausayi mai fadin murabba’in kilomita 6,000 (2,300 sq mi) Hadejia-Nguru. Sun hadu suka kafa Yobe, wanda ke bayyana iyakar Nijar da Najeriya tsawon kilomita 300 (190 mi), wanda ke kwarara zuwa tafkin Chadi. Kimanin kilomita .5 cubic (0.12 cu mi) na ruwa yana kaiwa tafkin Chadi a shekara. Gina madatsun ruwa na sama da haɓakar ban ruwa sun rage kwararar ruwa, kuma wuraren da ambaliyar ruwa ke bushewa. Kogin Yedseram-Ngadda da ke gaba kudu ana ciyar da kogin Yedseram da kogin Ngadda, wadanda suka hade don samar da fadama mai fadin murabba'in kilomita 80 (31 sq mi) zuwa kudu maso yammacin tafkin. Babu wani mahimmin kwararar ruwa daga fadamar zuwa tafkin.
Jamhuriyar Afirka ta Tsakiya (CAR) ta ƙunshi tushen kogunan Chari da Logone, waɗanda ke kwarara arewa zuwa cikin tafkin. Adadin ruwan da ke shiga Chadi a shekara daga CAR ya ragu daga kimanin kilomita 33 (7.9 cu mi) kafin shekarun 1970 zuwa kilomita 17 (4.1 cu mi) a cikin shekarun 1980. Karin kilomita 3 (0.72 cu mi) zuwa kilomita cubic 7 (1.7 cu mi) na ruwa a kowace shekara yana kwarara daga Kamaru zuwa Chadi ta kogin Logone. Tsarin Chari-Logone ya kai kusan kashi 95% na ruwan da ke shiga tafkin Chadi.

 Ruwa 

Bayanan Kula

Manazarta