Umiam Lake

Umiam Lake, also known as Bara Pani, is a reservoir in the hills 15 km north of Shillong in the state of Meghalaya, India. It was created by damming the Umiam River in the early 1960s. The principal catchment area of the lake and dam is spread over 225 km2.

Geography
Two rivers, namely, Wah Umkhrah and Wah Umshyrpi, feed into the Umiam lake.

Umiam dam
Umiam 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 Umiam Stage I powerhouse, north of the lake, has four 9-MW turbine-generators, which entered commercial operation in 1965. Umiam 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 Umiam Project were subsequently built downstream.

Before the construction of the dam for electricity, Khasi communities inhabited the Umiam 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
The lake serves as a major tourist attraction for the state of Meghalaya. It is also a popular destination for water sport and adventure facilities. Tourists visit this spot for kayaking, water cycling, scooting, and boating.

Ecological effect
Apart from storing water for electricity generation, the lake also provides numerous ecosystem services at micro, meso and macro levels. Downstream irrigation, fisheries, and drinking water cater to local anthropogenic needs.

Toxic threat and silting
Due to the rising population of Shillong upstream of the lake, the lake is starting to become highly polluted. The rivers, Wah Umkhrah and Wah Umshyrpi, have become drains in Shillong city. They carry household and market sewage, and industrial waste which drains into the lake.

Also, there is the heavy problem of silting. An estimated 40000 m3 of silt enters Umiam Lake every year. Causes range between upstream encroachments, deforestation, blockage of natural drainage systems, and unscientific mining et al. in the catchment area. Excessive silt load in the lake has lowered the storage.