az ias , ▁the ▁Dan ube ▁travel s ▁some ▁ 1 , 0 0 0   km ▁through ▁or ▁along ▁Roman ian ▁territory , ▁forming ▁the ▁southern ▁front ier ▁with ▁Ser bia ▁and ▁Bulg aria . ▁V irt ually ▁all ▁of ▁the ▁country ' s ▁rivers ▁are ▁trib ut aries ▁of ▁the ▁Dan ube , ▁either ▁directly ▁or ▁indirect ly , ▁and ▁by ▁the ▁time ▁the ▁Dan ube ' s ▁course ▁ends ▁in ▁the ▁Black ▁Sea , ▁they ▁account ▁for ▁nearly ▁ 4 0 ▁percent ▁of ▁the ▁total ▁dis charge . ▁The ▁most ▁important ▁of ▁these ▁rivers ▁are ▁the ▁M ure ş ▁River , ▁the ▁O lt ▁River , ▁the ▁Pr ut , ▁the ▁S ire t ▁River , ▁the ▁I alom i ţ a ▁River , ▁the ▁Some ş ▁River , ▁and ▁the ▁Ar ge ş ▁River . ▁Roman ia ' s ▁rivers ▁primarily ▁flow ▁east , ▁west , ▁and ▁south ▁from ▁the ▁central ▁crown ▁of ▁the ▁Car path ians . ▁They ▁are ▁fed ▁by ▁ra inf all ▁and ▁mel ting ▁snow , ▁which ▁causes ▁considerable ▁fl uct u ation ▁in ▁dis charge ▁and ▁occasionally ▁cat ast roph ic ▁flo oding . ▁In ▁the ▁east , ▁river ▁waters ▁are ▁collected ▁by ▁the ▁S ire t ▁and ▁the ▁Pr ut . ▁In ▁the ▁south , ▁the ▁rivers ▁flow ▁directly ▁into ▁the ▁Dan ube , ▁and ▁in ▁the ▁west , ▁waters ▁are ▁collected ▁by ▁the ▁T is za ▁on ▁Hung arian ▁territory . ▁ ▁The ▁Dan ube ▁is ▁by ▁far ▁Roman ia ' s