A preventable breach

On 1 September, I visited Paschim Kusaha, where the Kosi Breach occurred on 18 August. In my 30 years of working on water-related issues, I have not witnessed a sight of the kind that greeted me. An almost two-km stretch of Kosi's eastern embankment, 12 km north of the Kosi Barrage, had been washed away. The bulk of the Kosi's flow was making its way out through this gap, hurtling towards north Bihar along what used to be one of the river's old courses. The section at the breach resembled a monsoon-augmented river in downstream Bangladesh. Local fishermen told us that their bamboo poles were not touching the bottom at this site, where the former embankment would have been. This implied that the depth at the breached stretch would be anything above 10 meters.

Though the embankment was breached during a monsoon month, the disaster was manmade, and could have been averted. A river that was not even in spate had gushed through a vulnerable section that had not seen maintenance. According to the locals, the threat of breach had become serious as early as 5 August, and they had raised the alarm. But there was no action.

During the early 20th century, some British engineers had argued that embankments were not an appropriate technology in a region where rivers carry high sediment loads. The silt would be deposited within the levees, making the riverbed higher than the floodplain. At Paschim Kusaha village, a 1996 contour map prepared by the Nepal government shows that the riverbed was almost four meters higher than the land outside the embankment, due to sedimentation.

As elsewhere in the Kosi embankments downstream, the maintenance was inadequate, corruption rife and there was no flood-warning mechanism in place. Given the scale of the disaster, the humanitarian response has been grossly inadequate. Overall, the breach is a failure of human agency and the conventional paradigm of flood control.

~ Ajaya Dixit is a Kathmandu-based engineer and water resource analyst.