Why in News?

• A two-person team from IIT Gandhinagar studied the hydroclimatic changes in the catchment areas and their implications for hydropower generation in 46 major dams located in north, central and south India. The findings have been published in the journal iScience.
• According to their study, hydropower, which accounts for 13% of total power generation, is a significant contributor to clean global electricity generation.
• The team looked at the increase in rainfall in the catchment areas and the resultant inflow into all the 46 major reservoirs in the near (2021–2040), mid (2041–2060), and far (2081–2100) periods against the reference period (1995–2014) for two shared socioeconomic pathway scenarios.

Projected Increase:

• Under a warmer climate, hydropower production is expected to increase across the country as precipitation increases, resulting in increased inflow to reservoirs.
• Based on selected hydroelectric dams, the projected increase in hydropower potential in India is 10-23%. 
• A warmer and wetter climate is projected to bring about 5%-33% increased rainfall. As a result, hydropower production is very likely to increase by 9%-36% for most dams due to increased inflow (7-70%) into the dams. 
• The potential hydropower generation is projected to rise by more than 50% in Tehri, Ramganga, Kadana, Omkareshwar, Maheshwar, and Sriramsagar dams in the far period.
• In  south India, eight out of eleven dams are projected to experience a decline in hydropower potential. 
• Dams in central India are expected to generate more hydropower than dams in the north and south of the country.
• Significant warming forecast for north India may reduce snow and glacial storage, lowering snowmelt water contribution in the long run. However, a significant increase in rainfall is more likely to compensate for the loss from snowmelt in north India.

Impact on Reservoirs:

• Extreme rainfall caused by global warming will result in an increase in extreme inflow and high reservoir storage conditions for the majority of dams.
• High and sudden inflow from extreme rainfall, particularly when reservoirs are already full, can complicate reservoir operations and create a flood-like situation due to sudden water release.
• Chennai in 2015 and Kerala in 2018 witnessed massive flooding due to heavy inflow into already full reservoirs.
• Compared with central and south India, north India is projected to experience higher warming in the future. 
• According to the study, north India will experience the greatest warming (about 5 degrees Celsius), while central and southern India will experience warming of 3-4 degrees Celsius.
• The study found that inflow to a few dams in Ganga, Mahanadi, Brahmani, and west-coast river basins is projected to decline in the future. 
• This reduction in inflow is due to increase in atmospheric water demands in response to the considerable warming compared to increase in precipitation.