A dam.
Weir
A dam is a structure built across a river to control the flow of water. It helps regulate water levels, generate hydroelectric power, and provide water for irrigation and drinking. Dams can also prevent floods and create reservoirs for recreational activities.
a dam
The Koyna dam is built across the Koyna River.
The Maharana Pratap Sagar dam is built across the Beas River, in the state of Himachal Pradesh in India.
The Colorado River
A dam.
It is built across the Krishna River in Nagarjuna Sagar, Andhra Pradesh, India.
They built dams.
The Hoover Dam.
Bridges, dams, piers
Nagarjun Sagar Dam is the largest masonry dam of the world built across the river Krishna in Nalgonda district of Andhra Pradesh in India.