The Cauvery River at Biligundlu — the river's entry point into Tamil Nadu — recorded a sharp surge in flow to 18,000 cusecs on Tuesday morning, 4 August, driven by increased discharge from Karnataka's reservoirs following heavy rainfall across the Cauvery catchment. The sudden spike is expected to boost storage at the Mettur Dam and offer much-needed relief to farmers in the water-stressed Cauvery delta.

How the Inflow Built Up

Officials confirmed that increased releases from Karnataka's Kabini and Krishna Raja Sagara (KRS) reservoirs began arriving at Biligundlu in the early hours of Tuesday. The inflow, which stood at a mere 500 cusecs on Monday evening, climbed to roughly 1,000 cusecs by early Tuesday morning. It then accelerated to 8,000 cusecs by 7 a.m. before more than doubling to 18,000 cusecs by 10 a.m.

Karnataka is currently releasing more than 27,000 cusecs from the Kabini and KRS reservoirs combined, with continued heavy rainfall in the upstream catchment sustaining the discharge. Officials expect the inflow at Biligundlu to rise further in the hours ahead.

Current Situation at Mettur Dam

Despite the upstream surge, conditions at the Mettur Dam remain subdued for now. The reservoir's water level stands at 73.18 feet against its full reservoir level of 120 feet. Inflow into the dam is currently just 68 cusecs, while outflow stands at 1,500 cusecs to meet downstream irrigation requirements — meaning the dam is presently drawing down its storage.

Officials expect the fresh surge recorded at Biligundlu to reach Mettur by Tuesday evening or night, at which point inflow into the reservoir is anticipated to rise sharply. The water released at Karnataka's reservoirs travels through Biligundlu before entering the Mettur reservoir, making transit time a key variable.

What It Means for Delta Farmers

The development has renewed hope among farming communities in the Cauvery delta districts of Tamil Nadu, where water availability for cultivation has been a persistent concern this season. Mettur Dam serves as the primary irrigation source for these districts, and its storage level directly governs the quantum of water released into the delta canal network.

Notably, this surge comes at a critical juncture in the agricultural calendar, when delta farmers are preparing for the kuruvai and samba crop seasons. Sustained releases from Karnataka over the coming days could meaningfully improve prospects for the current cultivation cycle.

Monitoring and Outlook

Officials are closely tracking discharge levels from the Kabini and KRS reservoirs as well as inflow readings at both Biligundlu and Mettur. Continued rainfall in the upstream catchment areas of Karnataka is expected to sustain — and potentially strengthen — the flow into Tamil Nadu over the next several days. The situation remains fluid, with authorities on alert for any rapid changes in reservoir levels.