s outh ▁band ▁of ▁hyd rom orph ic ▁so ils ▁at ▁the ▁border ▁with ▁Ch ad . ▁The ▁remainder ▁of ▁the ▁territory , ▁the ▁Diam ar é ▁P lain ▁and ▁the ▁El ▁Be ï d ▁River ▁valley , ▁is ▁made ▁up ▁of ▁fer ru gin ous ▁so ils . ▁The ▁province ' s ▁dry / w et ▁season al ▁variations ▁create ▁relatively ▁shall ow , ▁f err ous ▁or ▁later it ic ▁so ils . ▁ ▁D rain age ▁A ▁number ▁of ▁rivers ▁cr iss - cross ▁the ▁territory , ▁many ▁of ▁them ▁rising ▁in ▁the ▁Mand ara ▁Mountains . ▁The ▁May o ▁K é bi , ▁May o ▁L out i , ▁and ▁their ▁trib ut aries ▁form ▁part ▁of ▁the ▁Niger ▁River ▁bas in . ▁The ▁L out i ▁r ises ▁in ▁the ▁Mand ar as , ▁passing ▁and ▁sw elling ▁the ▁K é bi ▁in ▁the ▁North ▁Province . ▁The ▁K é bi ▁r ises ▁south ▁of ▁Y ag ou a ▁and ▁flows ▁into ▁western ▁Ch ad . ▁ ▁The ▁province ' s ▁other ▁rivers ▁are ▁part ▁of ▁the ▁Ch ad ▁Bas in . ▁The ▁El ▁Be id ▁River ▁flows ▁north west ▁from ▁the ▁Kal am al ou ▁National ▁Park ▁and ▁forms ▁the ▁northern most ▁stretch ▁of ▁the ▁border ▁between ▁Cam ero on ▁and ▁Niger ia . ▁The ▁May o ▁Ts an aga ▁r ises ▁south ▁and ▁west ▁of ▁the ▁El ▁Bé ï d ' s ▁source ▁and ▁moves ▁east ward ▁at ▁the ▁north ▁of ▁the ▁Diam ar é ▁De