Updating reservoir water release protocol

The sudden release of water from the Panyor Hydroelectric Project reservoir located upstream of the Ranganadi River at Yazali in Arunachal Pradesh by NEEPCO, wreaking havoc in downstream areas in the Lakhimpur district in Assam, lays bare critical gaps in managing flood risks associated with hydropower projects in the Northeast region. A probe ordered by Chief Minister Dr Himanta Biswa Sarma into the alleged unannounced release of water from the reservoir will bring to light if there was laxity on the part of NEEPCO in issuing the alert well in advance that would have given adequate time to the district administration to disseminate it to the people in vulnerable areas to shift to safer locations. The aftermath of the sudden release of water has also raised questions about adherence to standing guidelines on the release of water which are aimed at reducing downstream flood intensity. Chief Minister Sarma rightly pointed out that there was a lack of communication from NEEPCO’s end to the Lakhimpur district administration when they had already come to know from weather bulletins that there was a possibility of heavy rainfall on the night of May 29 at 7.30 pm. NEEPCO released water from the reservoir on May 30 at 1.40 am. The review meeting also brought to light that a suggestion given by Chief Minister Sarma during his earlier visit to the project site to set up a hotline communication between NEEPCO and the Lakhmipur Deputy Commissioner so that an emergency situation at the reservoir can be directly and instantly communicated to the district administration is yet to be implemented. Lessons must be learnt from the resultant disastrous flood situation claiming two lives and affecting 243 villages, and the expeditious establishment of the hotline needs to be prioritised to bridge the communication and coordination gap. The “Report of the Committee Constituted for Formulation of Strategy for Flood Management Works in Entire Country and River Management Activities and Works Related to Border Areas (2021–26)” brought out under the aegis of the NITI Aayog has explained the role of reservoirs in moderating flood intensity and timing of the incoming floods. The report states that reservoirs store water during periods of high discharges in the river and release it after the critical high flow condition is over so as to be ready to receive the next wave of floods. “Their effectiveness in moderating floods would depend on the reservoir capacity available at that time for absorbing the flood runoff and their proximity to the likely damage centre. They are operated with a carefully planned regulation schedule which takes into account both the safety of the dam and related structures and the safe carrying capacity of the lower reaches of the river in their present condition,” it adds. The report also asserts that reservoirs are more effective for flood management if, apart from the incidental moderation available for any type of storage on a river, a specific flood cushion is earmarked. The Committee constituted by the NITI Aayog made important recommendations which are highly relevant for all reservoirs of run-of-the-river projects in the region, including the 405 megawatt Panyor project, the 2000 MW Lower Subonsiri hydropower project and other such projects in Arunachal Pradesh in respect of downstream impact during floods and heavy rainfall during the monsoon. A key recommendation is that the rule curve/level for all reservoirs should be prepared and updated, accounting for changes in rainfall trends and changing demands over the years due to rapid increases in population, urbanisation and industrialisation, and guidelines for major reservoirs, where flood cushions are not in-built, need to be reviewed to have some dynamic flood cushion for the major part of the flood season. It also recommended that the Standard Operating Procedure for water releases be made mandatory for all reservoirs and that water release information for downstream areas should be provided with sufficient response time and channel encroachment in downstream stretches of dams should be removed. NEEPCO apparently retained incoming flood water to create a flood cushion instead of releasing it gradually, but due to heavy rainfall, the reservoir level rose dangerously, and they were compelled to release the excess water at once for dam safety. Chief Minister Sarma suggested a pragmatic solution to NEEPCO: that instead of allowing the incoming flood level to rise to a very high level at the reservoir, the release of water during heavy rain should start well in advance so that a flood cushion can be kept at a safer level and prevent turning into a “water bomb” and triggering an emergency situation. Strict adherence to standing guidelines on the release of reservoir water during flood situations is necessary, but the Central Water Commission updating the guidelines based on a review of disasters in the downstream areas due to the sudden release of Panyor reservoir water is essential to prevent the recurrence of such disasters. The rise in inclement weather on account of climate change impact also needs to be incorporated in reservoir water release protocol.