Climate Risks of Indian Dams

According to a new research, hydropower plants, especially those in the Himalayas, are vulnerable to extreme weather conditions. As the climate becomes warmer, these plants are likely to face an increased risk of heavy inflows and flooding. This research, conducted by Indian Institute of Technology (IIT) Gandhinagar, studied the future climate risks of 46 large hydropower plants located across 13 river basins in India.

The team found that the power plants will face varying degrees of challenges in monitoring reservoirs as a result of increased rainfall caused by a warming climate. This will lead to a higher frequency of high inflow events and increased reservoir storage levels.

India has huge hydropower potential. But we have to be careful and aware of the risks involved. We need to relook at the traditional practice of storing more water in the reservoirs, because there are increased risks of sudden heavy inflows in some of these dams,” said one of the authors, Professor Vimal Mishra, from IIT Gandhinagar, adding that the impact may not be uniform across all dams and would require timely warnings.

The researchers used both observations and climate projections to analyze the hydro-climatic changes in the upstream catchments and their impact on the hydropower generation of these major dams in India. They found that a projected climate that is warmer and wetter, with a substantial increase in precipitation, will lead to an increase in inflow to the reservoirs of major dams. The data also indicates that most catchments upstream of the dams will experience higher rainfall in the projected climate.

When there are no dependable systems for predicting and warning about high water levels, dams may have to release water quickly if they reach capacity, which can cause sudden flooding in downstream areas. The floods in Kerala, India in 2018 were an example of this, caused by the filling of reservoirs. Additionally, changes in land use and the construction of new reservoirs upstream of existing dams can affect the flow of rivers and the amount of sediment in reservoirs, and ultimately, the potential for hydropower. It is important to take action now to prepare for future extreme weather events.

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