Kogin Ikpoba

Kogin Ikpoba wata hanya ce ta ruwa a kudancin Najeriya, tana ratsa Jihar Edo tare da samar da albarkatu ga mazauna birnin Benin da yankunan da ke kusa. Kogin ya taso daga yankin Ishan Plateau, kuma yana ratsa birnin Benin kuma yana malala wani yanki mai fadin murabba'in mita 922 km2 (356 sq mi) . Yana samar da ruwan sha mai tsafta, yana samar da wutar lantarki ta ruwa, kuma yana tallafawa ban ruwa na noma. Ruwan kogin yana shafar bambancin ruwan sama na yanayi. Ruwa mai tsafta yana ba da gudummawa kusan kashi 56% na jimlar fitarsa, yayin da sauran kashi 44% ya fito ne daga kwararar ƙasa. A sassan sama, kogin yana da tsarin magudanar ruwa mai zurfi kuma ruwan karkashin kasa daga Tsarin Benin yana ci gaba da gudana, wanda ke tabbatar da kwararar ruwa mai daidaito a duk shekara. Bincike ya gano ƙarfe masu nauyi kamar cadmium, gubar, da mercury, wanda hakan ya haifar da damuwa game da gurɓatar sharar masana'antu da ta gida.

Beyond its environmental importance, the Ikpoba River holds historical and cultural significance. Since the 15th century, it has been considered a spiritual guardian of Benin City, especially after  Ewuare the Great was believed to have fortified it against external threats. Over time, the river has become an object of religious reverence and is often worshipped during times of crisis. Its name is embedded in the traditions of the Bini people. An infrastructure on the river is the Ikpoba Dam, initially impounded in 1975 and officially commissioned in 1987. The dam functions as a reservoir for public water supply, delivering an estimated  of water to residents of Benin City. However, the reservoir has experienced siltation, resulting in a 23.16% loss of capacity due to sediment deposition. Periodic dredging has been recommended to maintain its efficiency and extend its operational lifespan.

Batutuwan muhalli da ke shafar Kogin Ikpoba sun haɗa da sare daji tare da yankunan da ke bakin teku, wanda ya samo asali ne daga fadada aikin gona da ci gaban birane. Kasancewar gurɓataccen abu daga wuraren giya, wuraren yanka, da wuraren zubar da datti ya shafi yanayin kogin. Don rage waɗannan tasirin, Gwamnatin Jihar Edo ta fara ƙoƙari don hawan kogin, da nufin rage ambaliyar ruwa a yankunan da ke ƙasa na Benin City. Duk da wadannan kalubalen muhalli, Kogin Ikpoba ya kasance hanya ce don kamun kifi, sufuri, da ƙaramin samar da wutar lantarki. Shirye-shiryen yin amfani da ƙarfin wutar lantarki sun ci gaba, tare da binciken yiwuwar da aka kammala tare da hadin gwiwar Ƙungiyar Ci gaban Masana'antu ta Majalisar Dinkin Duniya (UNIDO) don samar da makamashi mai sabuntawa daga madatsar ruwan. Kogin yana taka rawa a ci gaban yanki da dabarun juriya na yanayi.

## Hanyar da ilimin ruwa
The Ikpoba River, a sixth-order river flowing through Benin City in Edo State, Nigeria, originates from the Ishan Plateau and spans a catchment area of approximately . It follows a southward course, beginning in highland regions and meandering through both urban and rural landscapes before joining a larger drainage system. The river's coordinates range from 6°19′12″N, 5°24′0″E to 6°22′48″N, 5°51′7.2″E, indicating its reach across multiple ecological zones. Hydrological studies suggest that, despite minor seasonal variations, the river maintains relatively stable water levels year-round due to a combination of groundwater inflows and surface runoff. In studied sections, the river's width ranges between 10 and 12 meters, with depth fluctuations influenced by precipitation levels and local topography.

Babban tushen ruwan Kogin Ikpoba sun haɗa da ruwan sama kai tsaye, ruwan da ke cikin ƙasa daga Tsarin Benin, da gudummawa daga ƙananan ƙananan ruwa. Binciken hydrograph ya nuna cewa kwararar tushe ta kasance kusan kashi 56% na jimlar fitarwa, yana nuna rawar da ruwa ke shigowa a cikin ruwa wajen kiyaye girman kogin. Sauran kashi 44% sun fito ne daga runoff kai tsaye saboda abubuwan da suka faru na hazo da kuma zubar da ruwa, suna ba da gudummawa ga bambancin matakin ruwa na yanayi. A lokacin rigar, yawanci daga Afrilu zuwa Oktoba, ruwan sama mai yawa yana ƙara yawan kwararar, yayin da a lokacin fari, matakan kwararar suna raguwa, wani lokaci yana fallasa bakin kogi da ajiyar turɓaya.

Yayin da kogin ya ratsa Birnin Benin, abubuwa daban-daban na ruwa na birane sun shafe shi, gami da ruwan sama, ruwan masana'antu, da kuma zubar da ruwa na cikin gida. Ayyuka irin su wanke mota, wanka, da kamun kifi - musamman a cikin Ikpoba Bridge - sun canza yanayin ruwa na halitta, gabatar da gurɓataccen da ke tasiri ga ingancin ruwa. Hadin gwiwar tare da yanayin birane ya haifar da canje-canje a cikin halaye na kwarara, gami da rushewar ƙasa da tarin turɓaya. Tsarin hydrodynamic yana nuna cewa yankunan da ke da matakan birane masu girma suna nuna raguwar ƙimar shiga, wanda ke haifar da karuwar runoff da haɗarin ambaliyar ruwa a lokacin abubuwan da suka faru na ruwan sama mai yawa.

Wani muhimmin fasalin ruwa na Kogin Ikpoba shine tafkin Ikpoba, wanda madatsar ruwan Ikpoba ta kirkira, wanda aka fara kama shi a 1975 kuma yana aiki a matsayin tushen samar da ruwa na farko ga Benin City. Dam din yana taimakawa wajen daidaita kwararar ruwa, rage sauye-sauyen fitarwa na yanayi yayin samar da ruwa don amfani da gida da masana'antu. Koyaya, sedimentation ya zama damuwa, tare da binciken da ya kiyasta cewa kashi 23.16% na ƙarfin ajiyar tafkin ya ɓace saboda tarin laka. Wannan ya bukaci yin amfani da ruwa na lokaci-lokaci da kuma kokarin cirewa don kula da aikin madatsar ruwan da kuma tabbatar da ci gaba da samun ruwa.

Yanayin ruwa na kogin yana shafar canjin yanayi da canje-canjen amfani da ƙasa a cikin ruwa. Kashe gandun daji a yankunan da ke sama ya haifar da karuwar ruwa, rage yawan shiga, da kuma kara lalacewa a bakin kogin. Bugu da ƙari, birane na Benin City ya canza tsarin magudanar kogin, tare da ƙarin shimfidar wurare da ke rage sake dawo da ruwa na ƙasa. Nazarin ya ba da shawarar dabarun kula da ruwa masu ɗorewa don magance waɗannan batutuwan da tallafawa ayyukan muhalli da tattalin arziki na kogin.

## Geology da geomorphology
Kogin Ikpoba ya ratsa Tsarin Benin, wani yanki na ilimin ƙasa wanda ya ƙunshi yashi, dutse, da kuma yumbu wanda ya samo asali daga ƙarshen zamanin Tertiary. Wannan tsari yana daga cikin Basin Delta na Nijar kuma an lura da shi saboda babban porosity da permeability, wanda ke sauƙaƙa sake caji na ruwa a cikin kogi. Hadin gwiwar tsakanin kogi da waɗannan abubuwan da ke ƙasa yana shafar riƙe ruwa, jigilar kayan, da kwanciyar hankali na kogi. Yanayin ƙwayar ƙwayar ƙwaƙwalwar ƙwayar ƙwaya ƙwayar ƙwace ƙwayar ƙwazar ƙwayar ƙwalar ƙwayar ƙwayatar ƙwayar ƙwafar ƙwayar ƙwa ƙwayar ƙwa Ayyukan ɗan adam kamar hakar yashi da sare daji sun canza rarrabawar turɓaya, wanda ya haifar da rushewar ƙasa da bambance-bambance a cikin saurin gudana.

Geomorphology na kogin yana rinjayar hanyoyin ruwa na halitta da kuma tsoma baki na mutum. A samansa, kogin yana ratsa wuraren da ke cikin gandun daji inda ciyayi ke daidaita bankunan kuma yana rage lalacewa. Yayin da yake gudana ta cikin yankuna masu birane na Benin City, tashar ta zama mafi canzawa saboda gine-ginen da aka gina da kuma ƙarfafawa na wucin gadi. Shigar da waɗannan shingen ya rushe jigilar turɓaya ta halitta, yana haifar da saukowa a wasu yankuna yayin da yake hanzarta rushewa a wasu. Ginin madatsar ruwan Ikpoba ya kara tasiri ga yanayin kogin ta hanyar kama turɓaya a sama da kuma canza yanayin kwararar ruwa. Dam din ya haifar da tarawa mai kyau a cikin tafkin, yana rage ƙarfin ajiya a tsawon lokaci. Nazarin ya nuna cewa kashi 23.16% na jimlar adadin tafkin ya ɓace saboda yaduwa, yana buƙatar hawan lokaci-lokaci.

Tsarin rushewa a gefen kogi ya bambanta bisa ga amfani da ƙasa da yanayin ruwa. An lura da yawan lalacewa a kusa da gadar Ikpoba, inda ayyukan ɗan adam kamar wanke motoci, kiwon shanu, da kuma yashi ya lalata bankunan. Wadannan ayyuka suna kara nauyin sediment kuma suna haifar da raguwar banki. Sabanin haka, yankunan da ke ƙasa suna fuskantar raguwar sediment mai mahimmanci, da farko saboda rage saurin ruwa da kwararar masana'antu. Masana'antun giya a wannan yanki suna fitar da ruwa mai guba a cikin kogi, wanda ke haifar da hulɗar sinadarai wanda ke inganta ƙuƙwalwar sinadarai. Wannan ya haifar da yanayin ajiya inda kyawawan turɓaya ke tarawa, suna samar da laka kuma suna canza hanyar kogin.

Yankin rijiya, wanda ya taɓa rufe shi da bamboo na asali (*Bambusa vulgaris*), ya sami lalacewa saboda sare daji don aikin gona da ci gaban birane. Rashin shuke-shuke ya karu, ya rage shigar da ruwa a karkashin kasa, da kuma kara lalacewa. A wasu yankuna, an ƙarfafa bakin kogi tare da katako don hana ƙarin asarar ƙasa. Duk da yake waɗannan gine-ginen suna ba da kwanciyar hankali na wucin gadi, sun canza yanayin hydrodynamics na kogi, suna ƙara saurin kwarara da kuma ba da gudummawa ga rushewar ruwa. Bugu da ƙari, cire tsire-tsire na riparian ya shafi wuraren zama ga nau'in ruwa da na rabin ruwa, yana shafar bambancin halittu.

Sedimentation within the reservoir remains a concern. The total volume of silt in the reservoir is estimated at , reducing its capacity to store water for hydroelectric power generation and urban supply. If unchecked, sediment accumulation could lead to increased overflow risks and reduced efficiency of the dam's operations. The Edo State Government has recognised this challenge and directed dredging of the Ikpoba River to restore its capacity and mitigate flooding risks. The Benin City Rainstorm Master Plan is being updated to integrate erosion control measures specific to the Ikpoba watershed. These efforts aim to balance development needs with ecological sustainability.

## Biodiversity da muhalli
Kogin Ikpoba yana tallafawa tsarin halittu wanda ya haɗa da kwayoyin ruwa da na ƙasa daban-daban. Kogin yana ba da wurin zama ga nau'in kifi, macroinvertebrates na benthic, tsuntsaye na riparian, da tsire-tsire na ruwa. Koyaya, gurɓataccen ƙarfe mai nauyi, fadada birane, da kuma sare daji sun shafi bambancin halittu na Kogin Ikpoba, wanda ya haifar da canje-canje a cikin nau'in jinsuna da matakan yawan jama'a. Bincike ya gano cewa ruwan masana'antu da ruwan gona suna gabatar da gurɓataccen abu kamar cadmium (Cd), gubar (Pb), da mercury (Hg) a cikin kogi, wanda ke haifar da tarin waɗannan abubuwa a cikin kwayoyin ruwa. Kasancewar waɗannan gurbataccen abu an haɗa shi da canje-canje a cikin ƙwayoyin kifi, gami da tasirin gills, hanta, da ayyukan koda.

Al'ummar kifi a cikin Kogin Ikpoba sun haɗa da *Tilapia zillii*, *Clarias gariepinus*, *Clarias anguillaris*, da *Oreochromis niloticus* - nau'in da masunta na yankin suka girbe. Jama'ar Tilapia sun nuna alamun tarin ƙarfe mai nauyi, tare da mafi girman gubar da cadmium da aka gano a cikin kyallen takarda, musamman a cikin samfurori da aka tattara daga sassan da ke kusa da wuraren fitar da masana'antu. Kifi a cikin waɗannan yankuna suna nuna siffofin morphological da rage nasarar haihuwa, suna nuna haɗarin muhalli da ke da alaƙa da gurɓataccen yanayi. Al'ummar da ba su da ƙwayoyin cuta, waɗanda ke aiki a matsayin mai nuna ingancin ruwa, suma sun shafar. Bincike ya gano raguwar wadatar jinsuna a sassan kogin da aka fallasa ga magungunan masana'antu, tare da nau'ikan da ke jure gurɓataccen yanayi sun zama mafi rinjaye. Sabanin haka, yankunan da ke sama da ƙananan gurɓataccen ruwa suna ci gaba da tallafawa yawan macroinvertebrate daban-daban, gami da nau'o'in da ke buƙatar matakan iskar oxygen mai yawa.

Rashin lalacewar mazaunin da gurɓataccen yanayi sun kuma shafi yawan tsuntsaye a bakin Kogin Ikpoba. Nau'in tsuntsaye irin su Pied Kingfisher (*Ceryle rudis*), Little Egret (*Egretta garzetta*), da African Fish Eagle (Haliaeetus vocifer) sun dogara da kogi don abinci, nesting, da kiwo. Rashin tsire-tsire na riparian da karuwar rikice-rikicen ɗan adam sun rage wuraren da ake da su, wanda ya haifar da raguwa a wasu yawan tsuntsaye. Bincike ya gano cewa bambancin tsuntsaye ya fi girma a cikin sassan kogi tare da ciyayi mara kyau, yayin da yankunan da ke fuskantar lalacewar gandun daji da mamaye birane suna nuna raguwa a cikin nau'in tsuntsaye. Cire bishiyoyin bamboo a bakin kogin - wanda ya taɓa ba da mafaka ga tsuntsaye da sauran namun daji - ya ba da gudummawa ga raguwar yawan tsuntsaye. Bugu da ƙari, gurɓataccen masana'antu ya shafi wadatar ganima ga tsuntsaye masu cin kifi, wanda ya haifar da rage nasarar cin abinci tsakanin nau'o'in kamar su kingfishers da egrets.

Shuke-shuke na ruwa na Kogin Ikpoba sun canza saboda jigilar abinci mai gina jiki daga ragowar noma da fitar da masana'antu. Yawan abubuwan gina jiki sun haifar da yaduwar algae da tsire-tsire masu mamayewa, wasu daga cikinsu sun rushe kwararar kogin kuma sun rage matakan iskar oxygen a cikin ruwa. Yaduwar nau'ikan shuke-shuke masu mamayewa, kamar su ruwa hyacinth (Eichhornia crassipes), ya haifar da ƙalubale ta hanyar toshe hanyoyin ruwa da canza wuraren zama ga nau'ikan ruwa. Karin kasancewar algal flooms ya kuma haifar da raguwar iskar oxygen, wani abu da aka sani da hypoxia, wanda zai iya haifar da kisan kifi da rage bambancin halittu.

## Bayanan da aka ambata

### Bayani

### Ayyukan da aka ambata

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