Mekedatu Project: Karnataka Seeks Tamil Nadu's Cooperation on the Cauvery Reservoir

The Mekedatu project is a large dam and reservoir that Karnataka plans to build on the Cauvery river at Mekedatu, in Kanakapura taluk, just before the river enters Tamil Nadu. A "balancing reservoir" is a reservoir that stores water and releases it in a controlled way, so that supply stays steady through the year. Karnataka says its main purpose is drinking water for Bengaluru and the generation of electricity. Tamil Nadu, the downstream state, opposes it because it fears less water will flow to its delta farmers.

The Cauvery Water Dispute is a long fight between Karnataka and Tamil Nadu, with Kerala and Puducherry also involved, over how to share the water of the Cauvery. Karnataka is the upstream state, where the river starts and much of its water is collected. Tamil Nadu is downstream, where the river feeds the large paddy fields of the Cauvery delta. The dispute was settled in law by a tribunal award in 2007, changed by the Supreme Court in 2018, and is now managed by a permanent body.

Pumped storage hydropower is a way to store electricity using water and two reservoirs at different heights. When there is extra electricity in the grid, for example at noon when solar plants produce a lot, the plant uses it to pump water up to the upper reservoir. When demand is high, for example in the evening, the water flows back down through turbines and makes electricity again. You can think of it as a giant water battery.