Similar to we wrote on Sept 1 2024[i], but possibly with even greater flood prospects and urgency, the situation in Narmada River Basin is once again moving towards a massive avoidable flood disaster due to imprudent management of Sardar Sarovar dam in Gujarat and dams including Indira Sagar, Omkareshwar, Bargi and Tawa dams in Madhya Pradesh. All of these dams are full or almost full with IMD Flash Flood Bulletin (FFB, bulletin is updated thrice a day) as at 0730 hrs on Sept 11 2024[ii] warning about the ongoing or imminent flash flood in Narmada Valley districts.
The IMD flash flood Bulletin (the bulletin is based on: “Based on Merged Mean Areal Precipitation at 0530 IST, rainfall is up to 272 mm in last 6 hours and up to 320 mm in last 24 hours over few watersheds and neighborhood of AoC (Areas of Concern).”) at 0730 hrs on Sept 11 2024 includes following Narmada Valley districts: Dindori, Jabalpur, Katni, Narshimapura, Dewas, Dhar, Harda, Khandwa, Hoshangabad, Harda, Mandla, among others.
The Narmada Valley dams are almost full: The biggest reservoir, the Indira Sagar Dam is at 261.89 m at 0700 hrs on Sept 11, about 98% full with inflow forecast of 2400 cumecs (Cubic Meters per second) for 1800 hrs on Sept 11. The level and inflows are likely to rise, so also outflows.
The upstream most dam, Bargi dam is at 423.4 m, even above the FRL of 422.76, the storage thus now is at about 110% with inflow forecast of 3400 cumecs for 1800 hrs on Sept 11. Eleven gates of the dam are already open and outflows are only going to go up.
The Tawa Dam, on a tributary of Narmada is at 355.356 m. with over 99.5% storage full as FRL is at 355.4 m with inflow forecast of 1500 cumecs for 2000 hrs on Sept 11.
The Omkareshwar Dam, downstream from Indira Sagar Dam, is at 195.67 m with rising trend with FRL at 196.6 m.
The Sardar Sarovar Dam (SSD) in Gujarat is at 135.75 m, with FRL at 138.68 m, the dam is already about 86% full, with inflow forecast of 4167 cumecs at 1000 hrs on Sept 11. The outflow was 3039 cumecs at 0700 hrs on Sept 11. The releases had gone upto 11600 cumecs on Aug 26 2024, without creating any flood disaster in the downstream. So it is clear that there is huge scope of increasing the outflow so that there is no flood disaster at a later date.
At least at two locations in the Narmada Valley, the Highest Flood Level (HFL) have already been breached on Sept 11 2024. One of these is at Mukki, where the water level at 0900 on Sept 11 was 680.2 m, way above the HFL of 678.96 m.
At Balai at Narayanganj, water level at 1100 hrs on Sept 11 was 423.5 m, 0.48 m above the earlier HFL of 423.02 m.
Looking at the water levels at Garudeshwar and Bharuch, both downstream from SSD, there is sufficient scope for increasing the outflows from SSD, without breaching the danger level at either of these locations, the only ones downstream of SSD on the CWC flood forecasting mechanism.
It is thus urgently necessary that water releases from SSD are immediately increased, else, like in Sept 2023[iii] (and also in 2019 and 2020[iv]), SSD could end up bringing avoidable flood disaster in the downstream Gujarat areas. This will create additional space in SSD to absorb the higher inflows into SSD likely in coming days. As described above, there is sufficient actionable information available based on IMD FFB, actual rainfall in the upstream, reservoir situation in the upstream and also river levels in the upstream.
This is also necessary considering the 7day forecast of CWC for SSD, which says the inflows are likely to go above 16000 cumecs by Sept 13 and again above 14000 cusecs on Sept 17.
Similar 7day forecasts for Indira Sagar, Tawa and Bargi show rising trend over next two days and another peak on Sept 17.
All the Narmada Valley dams in the upstream have very little capacity to absorb additional inflows likely in coming days as they are all full or almost full as shown above. In fact, all these dams seems to be violating the rule curves and prudent dam management, ignoring the rainfall and IMD bulletins about the floods in the upstream. These dams also need to start releasing water immediately to create space for the likely inflows in coming days and inflows as predicted by IMD in FFB mentioned above and also other forecasts about developing low pressure area.
Thus there is urgent need to start releasing water from the Narmada Valley Dams to create space to absorb the likely inflows. These advance actions will help flood management in next couple of weeks, and avoid unnecessary flood disasters. We hope Gujarat and Madhya Pradesh governments, Sardar Sarovar Narmada Nigam Limited, Narmada Control Authority, Central Water Commission, CWC’s flood forecasting division and Union Jal Shakti Ministry will act urgently.
SANDRP (ht.sandrp@gmail.com)
[i] https://sandrp.in/2024/09/01/will-sardar-sarovar-again-create-avoidable-flood-disaster-in-sept-2024/
[ii] https://mausam.imd.gov.in/responsive/flashFloodBulletin.php
[iii] https://sandrp.in/2023/09/17/unaccountable-sardar-sarovar-operators-again-bring-avoidable-floods-in-downstream-gujarat/, https://sandrp.in/2023/09/20/avoidable-flood-disaster-from-unaccountable-sardar-sarovar-operation-why-was-river-bed-power-house-stopped-since-sept-6/, https://sandrp.in/2023/09/17/%e0%a4%b8%e0%a4%b0%e0%a4%a6%e0%a4%be%e0%a4%b0-%e0%a4%b8%e0%a4%b0%e0%a5%8b%e0%a4%b5%e0%a4%b0-%e0%a4%ac%e0%a4%be%e0%a4%81%e0%a4%a7-%e0%a4%b8%e0%a4%82%e0%a4%9a%e0%a4%be%e0%a4%b2%e0%a4%a8-%e0%a4%95/, https://sandrp.in/2023/09/20/%e0%a4%b8%e0%a4%b0%e0%a4%a6%e0%a4%be%e0%a4%b0-%e0%a4%b8%e0%a4%b0%e0%a5%8b%e0%a4%b5%e0%a4%b0-%e0%a4%aa%e0%a4%b0%e0%a4%bf%e0%a4%af%e0%a5%8b%e0%a4%9c%e0%a4%a8%e0%a4%be-%e0%a4%a8%e0%a4%bf%e0%a4%b0/
[iv] https://sandrp.in/2020/09/02/sardar-sarovar-creates-avoidable-flood-disaster-in-bharuch/, https://sandrp.in/2020/09/13/how-ssnnl-violated-its-own-flood-memorandum-2020-during-recent-ssd-induced-floods/
SANDRP 