Cauvery Basin Decline: Climate Crisis

Cauvery Basin Faces Decline Amid Climate Change Risks

Why in the News ?

A recent IIT Gandhinagar study warns that the Cauvery basin may witness a 3.5% decline in water flow (2026–2050) despite increasing rainfall elsewhere, raising concerns over water sharing disputes and long-term climate change impacts in southern India.

Key Findings of the Study:

• The Cauvery river basin is projected to face a 5% decline in water availability between 2026–2050, unlike most Indian rivers.
• Historically, the basin already recorded a 28% decline in streamflow (1951–2012) based on data from Kollegal station.
• While other rivers like Ganga, Indus, and Krishna may experience increased flows, Cauvery remains an exception.
• The study used CMIP6 climate models along with a constrained modelling approach to improve prediction accuracy.
• Findings indicate near- and mid-term water shortages, making the basin highly vulnerable to climate variability.

Implications: Water Sharing and Policy Concerns

• Reduced water flow may intensify the long-standing Cauvery water dispute between Karnataka and Tamil Nadu.
• Past conflicts, especially during deficit rainfall years, highlight the sensitivity of inter-state water sharing.
• In 2023, Tamil Nadu demanded 24,000 cusecs/day, which Karnataka resisted citing shortages, triggering tensions.
• Experts suggest river interlinking projects like the Godavari–Cauvery link as potential solutions.
• Declining water availability could impact agriculture, drinking water supply, and regional economies.