KARNATAKA, India — Karnataka may be forced to release nearly double the mandated volume of water into the Cauvery river system to ensure that stipulated allocations reach the border with Tamil Nadu. Officials familiar with hydrological calculations indicate that the state may need to increase releases from 3,500 cusecs to approximately 6,500 cusecs to compensate for significant losses occurring across a dry riverbed stretch leading to the Biligundlu measuring gauge.
The discrepancy between the volume of water released from upstream reservoirs and the volume recorded at the border highlights a critical operational challenge: the physical reality of a degraded riverbed that absorbs a substantial portion of the flow before it can be officially measured.
The Operational Challenge
The core of the issue lies in the stretch of the river between the Krishna Raja Sagara (KRS) dam or the Kabini reservoir and the Biligundlu gauge, located at the Karnataka-Tamil Nadu border. Under the current framework, Karnataka is required to maintain a specific flow of 3,500 cusecs. However, because the riverbed in this region has become excessively dry, a significant volume of water is lost to seepage and evaporation before it ever reaches the measuring point.
To ensure that the mandated 3,500 cusecs are actually recorded at Biligundlu, Karnataka’s water resources department suggests that the initial release must be scaled up to roughly 6,500 cusecs. This means the state would effectively be releasing nearly 3,000 additional cusecs of water—not as an extra allocation to Tamil Nadu, but simply to “prime” the dry channel and offset the losses inherent in the current state of the riverbed.
Why It Matters
This technical requirement has significant implications for Karnataka’s internal water security and its legal standing in the long-standing Cauvery water dispute. Water is a finite and highly contested resource in the region, and the requirement to release nearly double the stipulated amount puts additional pressure on the state’s reservoirs.
For Karnataka, every additional cusec released to compensate for riverbed loss is water that cannot be used for local irrigation or drinking purposes. In years of poor monsoon performance, this “invisible loss” becomes a point of severe contention. If the state releases only the stipulated 3,500 cusecs at the source, the resulting reading at Biligundlu will fall short of the legal requirement, potentially leaving Karnataka vulnerable to accusations of non-compliance with the Cauvery Water Disputes Tribunal (CWDT) award.
Conversely, if Karnataka releases 6,500 cusecs to meet the target, it bears the full burden of the conveyance loss, effectively subsidizing the delivery of water through a degraded infrastructure.
Background and Context
The current state of the riverbed is not a natural phenomenon but a legacy of decades of human intervention. The construction of numerous upstream dams, diversions, and the alteration of natural flow patterns have left significant portions of the Cauvery without consistent water coverage. This has transformed parts of the river into a seasonal or intermittent stream, where the soil becomes highly porous and desiccated.
The Biligundlu gauge serves as the official “checkpoint” for interstate water sharing. The CWDT award relies on the readings at this specific point to determine if Karnataka has met its obligations. However, the award largely treats the river as a theoretical conduit. It does not explicitly account for the “conveyance efficiency”—the percentage of water that actually survives the journey from the dam to the gauge.
The calculation of these losses involves complex hydrological modeling. Officials must account for:
– Groundwater Interaction: In dry periods, the riverbed acts as a sink, with water infiltrating the ground to recharge depleted aquifers.
– Evaporation Rates: Exposed riverbed surfaces and slow-moving water in shallow stretches increase the rate of evaporation.
– Geological Seepage: The porous nature of the geological formations in certain segments allows water to leak through the bed.
– Channel Efficiency: The lack of a continuous, deep channel means water spreads thin across the bed, increasing friction and loss.
What to Watch Next
The resolution of this issue will likely require a shift from purely legal arguments to technical, data-driven collaboration between Karnataka and Tamil Nadu. Observers should monitor whether the two states agree on a standardized “loss coefficient” to be applied to the Biligundlu readings.
Furthermore, the state government may explore riverbed restoration or channelization projects to reduce seepage. However, such interventions often face environmental scrutiny and high costs. There is also the possibility that Karnataka will seek a formal modification of the delivery terms, arguing that the “point of release” (the dam) should be the legal benchmark for compliance rather than the “point of receipt” (Biligundlu).
As the region faces increasingly volatile monsoon patterns due to climate change, the margin for error in water management is shrinking. The tension between the theoretical mandates of the CWDT and the physical realities of the riverbed is likely to intensify during the next dry season.
Conclusion
The necessity of releasing 6,500 cusecs to achieve a 3,500-cusec result is a stark illustration of the gap between legal frameworks and hydrological reality. While the CWDT award provides a legal roadmap for water sharing, it does not account for the environmental degradation of the river itself. Until the issue of conveyance loss is formally addressed and quantified, Karnataka will continue to face the dual challenge of meeting its interstate obligations while managing the physical inefficiencies of a dry riverbed.
Analysis: The dry riverbed phenomenon highlights how infrastructure development and altered hydrology can create operational challenges that existing water-sharing agreements may not explicitly address. Karnataka’s potential need to nearly double releases to meet stipulated allocations reflects the difference between theoretical water rights and practical delivery constraints. The technical adjustments required for channel losses suggest that interstate water disputes may require ongoing technical collaboration and a modernization of measurement standards alongside legal frameworks. The burden of conveyance loss currently falls on the upstream state, creating an inherent imbalance in how “compliance” is measured and enforced.
Sources
The Hindu – National https://www.thehindu.com/news/national/karnataka/karnataka-may-have-to-release-nearly-double-the-stipulated-3500-cusecs-owing-to-dry-riverbed-till-biligundlu/article71278110.ece
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Story synopsis gathered from: The Hindu – National — source
