Narmada valley again facing flood disaster, exacerbated by Sardar Sarovar dam 'mismanagement'

The environmental advocacy group South Asia Network on Dams, Rivers and People (SANDRP) has issued a warning, supported by detailed diagrams, that the Sardar Sarovar Dam (SSD) is at risk of causing flash floods in the Narmada Valley this year, similar to incidents that occurred last year. 

SANDRP noted that, as previously reported on September 1, 2024, the Narmada River Basin is once again facing a potential flood disaster, exacerbated by the mismanagement of the Sardar Sarovar Dam in Gujarat and other major dams including Indira Sagar, Omkareshwar, Bargi, and Tawa in Madhya Pradesh. Currently, these dams are near or at full capacity, and the Indian Meteorological Department (IMD) had issued a Flash Flood Bulletin at 7:30 AM on September 11, 2024, indicating ongoing or imminent flash floods in various districts of the Narmada Valley. 

The IMD bulletin states that, based on merged mean areal precipitation data, some areas received massive rains, and the districts affected include Dindori, Jabalpur, Katni, Narshimapura, Dewas, Dhar, Harda, Khandwa, Hoshangabad, and Mandla, among others. 

The situation at the Narmada Valley dams is critical: Indira Sagar Dam, the largest reservoir, stood at 261.89 meters as of 7:00 AM on September 11, approaching 98% capacity with an expected inflow of 2,400 cubic meters per second (cumecs) by 6:00 PM the same day. The water levels and inflows are anticipated to continue rising, which will also increase outflows. 

The Bargi Dam, situated upstream, is currently at 423.4 meters—exceeding its Full Reservoir Level (FRL) of 422.76 meters—indicating a storage capacity of about 110%, with an anticipated inflow of 3,400 cumecs on September 11. 

The floodgates at Bargi are already open, and further outflows are expected. The Tawa Dam, located on a tributary of the Narmada, is sitting at 355.356 meters, which is over 99.5% full, with a forecasted inflow of 1,500 cumecs projected for 8:00 PM on September 11. Omkareshwar Dam, further downstream, is currently at 195.67 meters, with rising levels towards its FRL of 196.6 meters. 

The Sardar Sarovar Dam itself was at 135.75 meters, which is about 86% full, with a forecast of 4,167 cumecs expected by 10:00 AM on September 11. Earlier this year, the outflow had reached as high as 11,600 cumecs on August 26 without resulting in downstream flooding, suggesting there is significant capacity to increase outflows now to mitigate future flooding. 

As of September 11, 2024, the Highest Flood Levels (HFL) was already breached at two locations within the Narmada Valley. At Mukki, water levels reached 680.2 meters, surpassing the HFL of 678.96 meters. Similarly, at Balai in Narayanganj, the water level was recorded at 423.5 meters, exceeding the previous HFL by 0.48 meters. 

Observations at downstream sites such as Garudeshwar and Bharuch suggest there is room to elevate the outflows from the Sardar Sarovar Dam without surpassing critical flood levels there. 

"Immediate action is crucial; the outflows from the SSD must be increased to prevent an avoidable flood disaster similar to those experienced in September of previous years. This proactive measure would create additional storage capacity in the dam to manage the anticipated surge in inflows in the coming days", SANDRP insisted.

"The IMD had predicted that inflows could exceed 16,000 cumecs by September 13, and again rise above 14,000 cumecs by September 17. With the Narmada Valley dams already operating at full or near-full capacity, there is limited ability to accommodate any further inflows unless immediate releases are initiated", it added. 

SANDRP further said, "These facilities appear to be neglecting essential management protocols, given the rainfall forecasts and IMD flood bulletins. In light of this, it is imperative for authorities, including the Governments of Gujarat and Madhya Pradesh, Sardar Sarovar Narmada Nigam Limited, the Narmada Control Authority, and the Central Water Commission, to take swift action to mitigate the risk of significant flooding in the days ahead."

SANDRP underlined, "With the Narmada Valley dams already operating at full or near-full capacity, there is limited ability to accommodate any further inflows unless immediate releases are initiated. These facilities appear to be neglecting essential management protocols, given the rainfall forecasts and IMD flood bulletins."

"In light of this, it is imperative for authorities, including the Governments of Gujarat and Madhya Pradesh, Sardar Sarovar Narmada Nigam Limited, the Narmada Control Authority, and the Central Water Commission, to take swift action to mitigate the risk of significant flooding in the days ahead", it added.