Refers to a barrier built across a river or stream to control water flow, often for irrigation, flood control, or water supply. 堰堤 is a technical term; in everyday speech ダム is more common.
堤防 refers to an embankment or levee built along a river or coast to prevent flooding, while 堰堤 is a barrier built across a river to control water flow.
Etymology
Compound of 堰 (en, 'dam' or 'weir') and 堤 (tei, 'embankment'). The reading えんてい is the on'yomi for both characters.
