Futility of warning systems
India’s current flood warning systems do not provide adequate data, while mitigation advocacy relies on unproven methods
Himanshu Thakkar Delhi
When I saw the purple patch on NASA’s 24-hour rain accumulation map on the morning of August 11, and that the patch had moved to the west the next morning, it was clear that the Brahmaputra and Ganga basin were in for massive floods in the coming days. The map should have been sufficient warning for the government, both of the centre and the respective states, in these basins to be prepared and alert vulnerable areas.
Multiple river gauging sites on the Central Water Commission (CWC) flood forecasting website first beeped pink (river water levels above danger level), then orange (river water levels within 0.5 m of highest recorded flood levels), and subsequently some turned red (river water level crosses HFL).A massive number of sites in orange and red is rarely seen simultaneously, a warning of the unprecedented scale of the impending disaster not only for India, but also Nepal and Bangladesh. Our articles for the Brahmaputra basin on August 12 and for the Ganga basin on August 15 should have provided adequate information to the governments about the floods, and spurred them to take all possible preparatory and disaster minimising steps. One does not see any reflection of this on the CWC flood forecast site, where forecasts come a few hours in advance at best, and some of those are estimates that are erroneous or inaccessible.
On August 19, nine sites were orange in the Brahmaputra basin, while one of them (the Tufanganj site on the Raidak-I river) had crossed HFL. In the Ganga basin, 11 sites were marked orange, and at least five had already crossed HFL. These sites included those along the Kosi (two sites), Mahananda (two sites), Rapti (two sites), Ghagra (two sites), Bagmati, Kamlabalan and Gandak all northern tributaries of the Ganga and flowing from Nepal. As NASA maps had already indicated, Nepal was also facing heavy floods. In Bihar, already over 150 people have been declared dead, while over one crore are affected. In Nepal, 131 people have died and 32 are missing, almost 10,000 houses have been destroyed, over three lakh people are affected and 45,000 families are displaced in 12 districts, crops worth tens of millions of dollars have been destroyed and nearly 70,000 heads of livestock have perished.
While the situation in the Brahmaputra basin (affecting North Bengal and Assam) has eased, the Ganga basin shows all signs of prolonged flooding.
Questions about dams, other interventions in NE
Floods in the North-east eventually focus on the role of dams, hydropower projects and embankment breaches, and questions about their efficacy. Similarly, government attempts at dredging rivers, creating waterways, and building roads-cum-embankments on both sides of the Brahmaputra were also questioned. There is already a demand for decommissioning of the Ranganadi hydro project in Arunachal Pradesh and the Loktak hydro project in Manipur, in addition to the Dumbur dam in Tripura earlier. There are calls for the Lower Subansiri project on the Arunachal Pradesh-Assam border to be scrapped. West Bengal Chief Minister Mamata Banerjee has consistently raised the question of dams on the Damodar creating avoidable flood disasters for several years and has demanded a revamp of the Damodar Valley Corporation this year. The latest CAG report on flood management has also raised the question of how the Hirakud dam created avoidable disasters more than once in the past.
The role of the CWC has come into sharp focus with questions about how useful its flood forecasting is. In many areas where floods occur (like along the Ranganadi), there is no flood forecasting by the CWC while at other locations, the forecast arrives too late, is erroneous or unavailable to the right people at the right time. CWC forecasts do not include crucial elements like the IMD’s short-term rain forecasts, actual dates of rainfall in the catchments or the state of rivers and their carrying capacity. Unfortunately, there is no accountability in the CWC’s flood forecasting.
The Indian government recently complained that China has not provided flood data for the Sutlej or Brahmaputra basins despite an agreement. The complaint was raised in mid-August, but flood data was supposed to be shared since May. More worryingly, no one knows what happens to the data that China shares.
In contrast, Bangladesh’s flood forecasts are, in many respects, better than India’s. They provide, for each location, a graph that shows actual water observation for the past week and also the forecast for the next five days. Despite access to better resources, the CWC hasn’t provided such information. There is no information on changes in water levels, nor any trends or forecasts similar to Bangladesh’s.
Further, upstream dams like the Bansagar in the Sone basin in Madhya Pradesh (which triggered the August 2016 floods in Bihar by suddenly releasing huge quantities of water while the downstream river was flooded) and Tehri in Uttarakhand are almost full and could add to the crisis if they decide to release large quantities of water. The cumulative impact of the floods in the northern tributaries of the Ganga is bound to travel to the main stream, even though rains have decreased in tributary catchments. The role of the Farakka barrage in creating siltation, drainage congestion and backwater flooding, is once again likely to be analysed in the days to come, as in August 2016. Bihar Chief Minister Nitish Kumar blamed the barrage for the flood crisis in Bihar last year.
Unscientific obsession with dredging
The chief ministers of all flood-affected states seem to be obsessed with river dredging and advocate massive-scale dredging as a solution. This is partly triggered by the rivers-as-waterways advocacy of Nitin Gadkari and partly by the need to show to people that they are doing something new. It was Nitish who last year first mentioned the accumulation of millions of tons of silt along the Ganga due to the backwater impact of the Farakka dam.
This year, Assam Chief Minister Sarbananda Sonowal has spoken about dredging the Brahmaputra as a solution to Assam floods, as did Banerjee regarding the Damodar river to avoid floods in her state. Such advocacy is misleading, unscientific and baseless. How much-dredged material is to be removed from rivers? Where will you deposit that material? Has the economic viability, environmental impacts or social acceptability of such proposals been discussed? Have any impact assessments or public consultations been done? The advocacy is completely ill-informed and unstudied, and the earlier it is abandoned, the better India can deal with floods.
While most of India celebrated Independence Day, north Bihar, large parts of the North-east and North Bengal were flooded. We need to learn from our experience how to minimise the damage by accepting that floods are a regular phenomenon and fix accountability for the lack of maintenance of embankments, rivers and dams. At the same time, the destruction of water-holding capacity in catchments is worsening the floods. Rainfall patterns are also becoming more irregular, with greater frequency of high-intensity flood events, with a changing climate. We have refused to learn any lessons from the floods in Uttarakhand, Kashmir or Chennai, to name only a few recent ones. The systematic, continuous and persistent neglect and inattention to all these issues will invite more disasters.