▁under ▁ ▁( ▁rise ) ▁of ▁water ▁was ▁directed ▁toward ▁Lake ▁Man it oba ▁rather ▁than ▁W inn ip eg ▁and ▁the ▁Red ▁River , ▁this ▁number ▁being ▁more ▁than ▁three ▁times ▁the ▁volume ▁of ▁the ▁ 1 9 7 6 ▁flo od . ▁After ▁considering ▁the ▁fact ▁that ▁without ▁the ▁existence ▁of ▁the ▁Port age ▁D ivers ion , ▁some ▁water ▁would ▁flow ▁into ▁Lake ▁Man it oba ▁near ▁D elta ▁Beach ▁through ▁ox bow ▁la kes ▁and ▁channels ▁which ▁were ▁at ▁one ▁time ▁the ▁original ▁channels ▁of ▁the ▁Ass in ib o ine ▁River ▁when ▁it ▁flow ed ▁to ▁Lake ▁Man it oba ▁naturally ▁around ▁ 2 0 0 0 ▁years ▁ago , ▁it ▁is ▁estimated ▁that ▁the ▁Port age ▁D ivers ion ▁contributed ▁to ▁at ▁least ▁ ▁of ▁a ▁rise ▁in ▁water ▁levels ▁on ▁Lake ▁Man it oba , ▁account ing ▁for ▁most ▁of ▁the ▁rise ▁of ▁the ▁lake . ▁The ▁volume ▁of ▁water ▁di vert ed ▁through ▁the ▁Port age ▁D ivers ion ▁in ▁ 2 0 1 1 ▁d war fs ▁the ▁annual ▁normal ▁contributions ▁of ▁the ▁two ▁major ▁trib ut aries ▁of ▁Lake ▁Man it oba ▁as ▁the ▁Water hen ▁and ▁Wh item ud ▁R ivers ▁contribute ▁ ▁and ▁ ▁respectively ▁on ▁average ▁to ▁the ▁lake , ▁although ▁the ▁contributions ▁of ▁these ▁two ▁rivers ▁are ▁higher ▁in ▁ 2 0 1 1 ▁as ▁there ▁has ▁been ▁above ▁average ▁precip itation ▁in ▁the ▁waters h eds ▁of ▁Lake ▁Man it oba ' s ▁major ▁trib ut aries .