dia, 12.53 km long Surge Shaft - 22.86 m dia x 125 m high Penstocks - Three 4.877 m split to six 3.353 m Dehar Power House - 6 × 165 MW Pandoh Dam The tall Pandoh Dam is an embankment dam on the Beas River. The dam was commissioned in 1977 and its primary purpose is hydroelectric power generation. Part of a run-of-the-river power scheme, it diverts the waters of the Beas to the southwest through a long system of tunnels and channels. The water is used for power generation at the Dehar Power House before being discharged into the Satluj River, connecting both rivers. Pandoh Lake Pandoh Lake is created by Pandoh Dam and is located about upstream from Mandi on the River Beas. Operation Water diverted by the Pandoh Dam is first sent through the 7.62 m diameter, long Pandoh-Baggi tunnel which terminates at the beginning of a long channel. At the end of the channel, the water is stored at the Sundar Nagar Balancing Reservoir at . The reservoir has a live capacity of . From the balancing reservoir, water is again sent south through the 8.53 m dia, long Sundar Nagar Slapper tunnel. The tunnel ends just before the Dehar Power Plant at . It splits into three 4.877 m dia followed by six 3.353 m dia penstocks before reaching the power house. The 22.86 m dia 125 m tall surge shaft at the end of the tunnel is designed to take any backfow due to sudden shutdown of the power plant and avoid tunnel rupture due to water hammer. Dehar Power Plant The Dehar Power Plant is situated on the banks of the Satluj at the Slapper bridge. Water from penstocks is fed into a six 165 MW Francis turbine-generator and then discharged in the Satluj. The power house has an installed capacity of . The change in elevation affords a hydraulic head of . It is managed by the Bhakra Beas Management Board (BBMB), which is engaged in regulation of the supply of water and power from Bhakra Nangal Dam and Beas Projects to the states of Punjab, Haryana, Rajasthan, Himachal Pradesh and Delhi. Diverted waters from Beas also increased the generation capacity of the Bhakra Dam downstream of Dehar Power Plant. Ecology The Pandoh dam diverts 256 cumecs (9000 cusecs) of Beas to river Satluj. Diversion of the Beas water has done