On the morning of August 11, a large purple patch covered parts of the Indian subcontinent on the NASA daily rainfall accumulation map. The patch, which enveloped parts of West Bengal, North East India and Bangladesh, signified that there had been more than 175 mm rainfall in these areas in the past 24 hours. Though this was surprising, it was not unheard of at this time of the year.
Within hours however, an unprecedented wave of floods hit these regions. The purple patch, which typically disappears within a day, lasted for 42 hours. By the weekend, floods were wreaking havoc in parts of Bihar, West Bengal, Assam, Tripura, Nepal and Bangladesh.
At the time of writing this piece on August 12, the Central Water Commission’s flood forecasting website had marked at least seven sites in orange, signifying that water levels in these areas was less than half a metre short of the highest-ever flood level for that region. These included Torsa, Raidak-I, Sankosh, Gaurang, Beki rivers (all northern tributaries of Brahmaputra) as well as the Brahmaputra alone at three sites: Neamatighat, Dibrugarh and Tezpur. Many other sites, marked with a pink dot (signifying that river water level is above the danger mark), were likely to turn orange or red in over the next 24 hours.
Raidak-I river at Tufanganj in Cooch Behar (West Bengal) was already red at the time of writing this article, meaning that the river water level had crossed the highest ever flood level for that site. The river had crossed the earlier highest ever flood level of 36.36 m, recorded 24 years back on September 21, 1993. So, this region was seeing the worst floods in at least a quarter of a century.
Assam and parts of West Bengal that had already experienced several waves of floods earlier in this monsoon were facing the prospects of an even bigger deluge. All indicators showed that neither the state nor the Centre was ready for this new wave of floods.
The table below gives an overview of the sites where the water level was less than half a metre short of highest-ever recorded flood levels from Central Water Commission’s flood forecasting site, as on August 12.
Ganga basin flooded
That the Ganga basin could also face similar unprecedented floods in the coming days was apparent from the flood forecast of the Basua site in the Supal district in Bihar, along the Kosi river, on August 12.
The highest flood level for this site is 49.17 metre (reached on Aug 25, 2010). As of 11 pm on August 12, the river water level here was 49 metre and it was predicted to reach 49.23 m by 7 am on Sunday – meaning it would breach the highest flood level recorded so far. By Sunday at around 1 pm, Basua breached the highest flood level and water levels reached 49.23 metre and water levels were within half a metre of the highest ever level in seven other areas in the Ganga basin.
On Monday, the situation in Bihar’s Kishanganj, Araria, Purnia and Katihar districts worsened and the death toll in the state rose to 13.
Assam’s double deluge
In Assam, which had seen heavy flooding in July, has been hit hard by the second wave of floods and the total death toll has gone up to 99, according to news reports.
Here are numbers from the latest available flood report from the Assam Disaster Management Authority on the damage done so far by the the latest round of floods (as on August 13):
During the earlier round of floods in Assam and other parts of the North East, the role of dams, hydropower projects and embankment breaches had come into focus. Questions had been raised about efficacy of these structures. Similarly, the government’s attempt at dredging the river, creating waterways, building roads and embankments on both sides of the Brahmaputra river was also questioned.
Demands have been raised to decommission the Ranganadi Hydro in Arunachal Pradesh, the Loktak Hydro Project in Manipur, in addition to Dumbur Dam in Tripura earlier and the Lower Subansiri Dam on the Arunachal Pradesh-Assam border.
Questions were also raised about the reliability of the Central Water Commission forecasting ability, as no floods had been predicted in many areas that had went under water during the weekend. Their flood forecasting has been criticised for coming too late, being erroneous or just not available to the right people at right time.
Himanshu Thakkar is Coordinator, South Asia Network on Dams, Rivers and People
This article first appeared on the South Asia Network on Dams, Rivers and People blog on August 12.