Hirakud Dam is built across the Mahanadi River, about 10 kilometres from Sambalpur in the state of Odisha in India. It is the longest earthen dam in the world. Behind the dam extends a 55 km long lake, Hirakud Reservoir. From Wikipedia
Reservoirs across the Krishna and Mahanadi basins have neared capacity, prompting large-scale gate openings to relieve water levels
