A structure built to block a river's flow, creating a reservoir used for water storage, flood control, or hydroelectric power (a dam).
川の上流に新しいダムが建設された。
A new dam was constructed upstream of the river.
ダムは洪水対策や発電に役立つ。
Dams are useful for flood control and power generation.
夏になるとダム湖で釣りをする人が増える。
In summer, more people go fishing at the dam lake.