RTI reply reveals serious gaps in live storage capacity and silt accumulation data in Cauvery reservoirs since 2009
Mysuru: At a time when the Cauvery water-sharing dispute between Karnataka and Tamil Nadu has intensified, with farmers and activists protesting the release of water to the neighbouring State, the Cauvery Water Management Authority (CWMA) has admitted that it has no updated information on silt accumulation, live storage loss or sediment management in Karnataka’s four major Cauvery reservoirs.
In a reply under the Right to Information (RTI) Act to Dr. Sadananda Heggadalmath of Kottur in Vijayanagara district, the CWMA said it does not possess updated data relating to Krishna Raja Sagar (KRS), Harangi, Kabini and Hemavathi reservoirs.
Dr. Heggadalmath told Star of Mysore that he had filed the RTI application on June 20, 2026. In its reply dated July 23, CWMA Central Public Information Officer Sandeep Kumar Vishwakarma stated that the Authority has not received any hydrographic or remote-sensing survey reports on live storage capacity loss since 2009.
Seeking clarity on the condition of the reservoirs, Dr. Heggadalmath had sought year-wise siltation survey data from 2010 onwards. The CWMA replied that “no such information is available.”
The Authority also said it had no information on any communications, file notes or decisions since 2018 concerning siltation, live storage loss or their impact on inter-State water sharing.
Further, the CWMA said it had no information on whether it had directed or proposed a joint survey by the Central Water Commission (CWC) and the Karnataka Engineering Research Station (KERS) to assess the current loss of live storage capacity.
‘No such information is available’
Similar responses were given to queries on whether siltation-induced storage loss had been factored into water release calculations under the Supreme Court’s 2018 order and whether the Authority had issued any communication on the impact of siltation on interstate water sharing.
Even a query on whether siltation data and reservoir inflow-outflow figures were being made publicly available through the CWMA dashboard drew the response: “No such information is available.”
“The RTI reply exposes a serious gap in transparency and technical oversight. With no updated data for more than 15 years, questions arise over how the CWMA regulates water releases and addresses sedimentation in reservoirs that are central to the Cauvery water-sharing dispute,” Dr. Heggadalmath said.
He pointed out that crores of tonnes of silt have accumulated in the Cauvery basin reservoirs over the decades, reducing their actual live storage capacity by an estimated 15 to 20 percent.
Writes to CWC
In a separate representation to the Chairman of the Central Water Commission, Dr. Heggadalmath urged the agency to address the issue, stating that water-sharing and drought-management decisions continue to rely on outdated reservoir capacities.
He appealed to the CWC to direct the CWMA to immediately update sedimentation survey data for all reservoirs, assess the aggregate loss of live storage due to siltation and ensure that future water allocation and drought-management decisions are based on actual live storage capacity.
He has also urged the Commission to place the updated reservoir data in the public domain.
This post was published on August 2, 2026 7:30 pm