Climate Adaptation Option for Water Shortage in India’s Pong Reservoir

A study by Adebayo J. Adeloye and Quan V. Dau investigated the adaptive capacity of static and dynamic hedging in India’s Pong water reservoir to support its performance during climate change.  

Water reservoirs are major components of the water supply system using river resources. They store excess water to meet domestic, industrial, and agricultural needs.  

Analysts plan reservoir operations based on historical runoff data, such as how much water to retain and how much to release. Problems arise when runoff shifts or changes radical.

Climate change is projected to reduce water inflows and variability and increase the reservoir’s vulnerability. These anticipated changes due to climate change have pushed researchers to develop effective mitigation and adaptation strategies.

Water reservoir operators use rule curves to guide them in releasing the quantity of water needed based on the water availability at the beginning of each month. Rule curves show target storage levels that must be maintained in the reservoir to meet demands.

Rule curves are easy to deploy but are subject to vulnerability due to large single-period shortages, which may be exacerbated by climate change.  Some studies show vulnerability indices of 67% and 88% for both domestic and industrial water allocations.  

Water rationing or hedging during normal operational periods is carried out to improve the effectiveness of rule curves in mitigating vulnerability.

This means that a moderate cutback of about 25% through hedging will minimize the impact on water users when there is sufficient water.

The study has developed optimised static and dynamic zone-based hedging or water rationing policies to enhance the performance of the irrigation water supply during water shortage due to climate change causes.

Hedging policies were applied in the Pong reservoir in India for the study, then compared with its performance with a no-hedging policy to test the adaptive and mitigating capacity of water rationing climate-change-induced water shortages.

A genetic algorithm determines the rationing ratio and target storage that leads to the monthly hedging.

Simulations show that without hedging, reservoir performance deteriorated with climate change-induced dry days and low water flows. Vulnerability increased by up to 60%.  

Implementing hedging, specifically dynamic hedging, significantly reduced the number of large single-period water shortages, reduced vulnerability, and outperformed the static hedging policy.

Although this study is used in the Pong reservoir in India, it can be replicated in other water reservoirs worldwide.

PHOTO CREDIT: By Vadobill – Own work, CC BY-SA 4.0, Link