堰堤[entei] dam
可動堰[kadouzeki] canal gates
堰き止める[sekitomeru] to dam up
堰く[seku] to dam (up) (stream)
井堰[iseki] dam

堰き止湖[sekitomeko] dammed lake (formed by natural damming of a river, esp. by landslide, volcanic eruption, etc.)
堰板[sekiita] sheeting
堰を切ったよう[sekiwokittayou] gushing forth
堰を切る[sekiwokiru] to break a dam and gush forth
堰塞[ensoku] damming (e.g. a pond)

塞爾維[serubia] Serbia
梗塞[kousoku] stoppage
塞栓[sokusen] embolus
充塞[juusoku] plug
人間万事塞翁が馬[jinkanbanjisaiougauma] inscrutable are the ways of heaven

腸閉塞[chouheisoku] intestinal obstruction
脳硬塞[noukousoku] stroke (blocked blood vessel in brain)
八方塞がり[happoufusagari] all doors closed
閉塞[heisoku] closure
要塞[yousai] fort