▁d ams . ▁It ▁eventually ▁emer ges ▁from ▁the ▁fo oth ills ▁at ▁what ▁was ▁once ▁the ▁town ▁of ▁Mill erton , ▁the ▁location ▁of ▁Fri ant ▁Dam ▁since ▁ 1 9 4 2 , ▁which ▁forms ▁Mill erton ▁Lake . ▁ ▁Below ▁Fri ant ▁Dam ▁( R M 2 6 7 ), ▁the ▁San ▁Jo aqu in ▁flows ▁west - s outh west ▁out ▁into ▁the ▁San ▁Jo aqu in ▁Valley ▁– ▁the ▁southern ▁part ▁of ▁the ▁Great ▁Central ▁Valley ▁– ▁passing ▁north ▁of ▁F res no . ▁With ▁most ▁of ▁its ▁water ▁di vert ed ▁into ▁aqu ed uct s , ▁the ▁river ▁frequently ▁runs ▁dry ▁in ▁a ▁ 1 5 0 - mile ▁section . ▁This ▁lack ▁of ▁river water ▁begins ▁in ▁the ▁ ▁between ▁Fri ant ▁Dam ▁and ▁M end ota , ▁where ▁it ▁is ▁only ▁re pl en ished ▁by ▁the ▁D elta - M end ota ▁Canal ▁( R M ▁ 2 0 5 ) ▁and ▁the ▁F res no ▁Sl ough , ▁when ▁the ▁Kings ▁River ▁is ▁flo oding . ▁From ▁M end ota , ▁the ▁San ▁Jo aqu in ▁sw ings ▁north west , ▁passing ▁through ▁many ▁different ▁channels , ▁some ▁natural ▁and ▁some ▁man - made . ▁N ortheast ▁of ▁D os ▁Pal os , ▁it ▁is ▁only ▁joined ▁by ▁the ▁F res no ▁and ▁Ch ow ch illa ▁R ivers ▁when ▁they ▁reach ▁flo od ▁stage . ▁Fif ty ▁miles ▁( 8 0   km ) ▁down stream , ▁the ▁Mer ced ▁River