An analysis of the Central Water Commission has said that the inability of the largest lake in Kerala, Vembanad Lake, to absorb much of the water drained into it during an unprecedented level of rain was a major reason for making the flooding severe.
While 1.6 billion cubic metres (BCM) of water drained into it, the lake could absorb only 0.6 BCM, causing it to bulge into three times its size and spilling over to 480 sq km, the Indian Express reported.
The absence of many reservoirs in the upper reaches of the river that drains to the lake added to the condition.
“The capacity of the lake might be less due to the siltation which is a natural process, and there could have been backflow because the outlet was unable to discharge as much into the ocean,” a CWC official told IE.
“This is a coastal lake which also interacts with the backwaters. One possibility was the dredging of the lake but since it is an eco-sensitive zone, dredging was not recommended,” the official added.
According to CWC, Kerala received intense rainfall in two spells — Between August 8-9 and August 15-17 — which was the major reason behind the floods.
The central agency said there was no connection between the opening of the 35 dams in the state and flooding. The dams “neither attenuated the floods nor aggravated them,” an official said.