Impact of Climate Change on the Flow Regime and Operation of Reservoirs – A Case Study of Bhakra and Pong Dams

Climate change is severely and more frequently impacting the Satluj and Beas river basins. These basins are experiencing high variability conditions such as longer periods with droughts as well as extreme rainfall events with temporal and spatial variation. Such variability ultimately leads to more frequent low flows in case of droughts and severe flooding in case of extreme rainfall. Meeting drinking and irrigation water needs, energy generation targets and flood control are becoming a challenge for the operation of reservoirs in these basins. Bhakra Beas Management Board (BBMB) operates and manages Bhakra Dam located on the Satluj River, a 225.55m high concrete gravity dam having gross storage of 9.621 billion cubic meter (BCM) and Pong Dam on the Beas River, 132.59 m high, earth core gravel shell dam having gross storage capacity of 8.57 BCM. During the 2018 water year, the Satluj River followed historical minimum to historical maximum daily inflows in a month. Climate variability leads to the lowest summer snowmelt runoff since 1967. On the other hand, extreme events of precipitation led to one of the highest runoff generated in the Satluj and Beas River catchments during these events. This volatility has put enormous pressure on reservoir regulation. Experiences of reservoir regulation, reduced water availability and releases, managing low as well as high water levels, forecasting of water inflows and rainfall, event analysis for the Bhakra and Pong dam reservoirs have been discussed in this paper.