Umïam dam Umïam Dam, which impounds the lake, was built by the Assam State Electricity Board in the early 1960s. The dam's original purpose was to store water for hydroelectric power generation. The Umïam Stage I powerhouse, north of the lake, has four 9-MW turbine-generators, which entered commercial operation in 1965. Umïam Stage I was the first reservoir-storage hydroelectric project commissioned in the northeastern region of India. (Umtru Hydroelectric Project, a
run-of-river project with an original capacity of 8.4 MW, began operation in 1957). Three more stages of the Umïam Project were subsequently built downstream. Before the construction of the dam for electricity, Khasi communities inhabited the Umïam Valley now flooded by the lake. Apart from the Gauhati-Shillong Road, the valley consisted of
Ri-Kynti (public) and
Ri-Raid (clan) land. When the
Assam State Electricity Board conceptualised the hydroelectric project in June 1958, the plan envisioned submerging part of the valley, where Khwan and Umsaw villages were located. Two hundred families were scheduled to be displaced for the reservoir, dam, and powerhouse. People of Khwan and Umsaw initially opposed the plan to flood their villages. ==Tourist destination==