Reasons behind Kerala Flood - Post Analysis

Why in news?

According to official reports mismanagement of dams was the primary reason for the kerala floods.

What is the role of dams in water management?

• One of the major functions of dams is flood protection to attenuate the flow of water and its impact downstream.
• The golden rule followed in dam management is to maintain a flood cushion (buffer) in case of unexpectedly high rainfall.

What is the brief structure of Kerala dams?

• Kerala has 39 major dams, their maintenance is shared between the Kerala State Electricity Board (KSEB) and the Water Resources Department.
• The Periyar is the longest river in Kerala and has the highest discharge potential.
• The major dams across this river that are maintained by the KSEB are Idukki, Lower Periyar, and Madupetty.
• The water from Lower Periyar, Madupetty and Mullaperiyar drains into the Idukki reservoir consisting of the Idukki dam and the Cheruthoni dam.
• The water from the Idukki reservoir and Idamalayar drains directly into the Bhoothathankettu dam, which is the lowermost in the Periyar system, just 15 km from Kothamangalam town.

What are the primary reasons of Kerala floods?

• According to India Meteorological Department’s study, the rainfall in August was only the sixth highest in the past 143 years (1875-2017) in Kerala.
• All dams in kerala reached their full reservoir level by July-end, and were thus incapable of containing the water flow from torrential rainfall in August.
• This forced the State government to open the gates of 34 major dams, thereby submerging all the major towns downstream.
• Admittedly, the change in topography due to human interventions and climate change have contributed to the sporadic and excess rainfall.
• The proliferation in illegal stone-quarrying activity has been a major reason for widespread landslides.
• The decision of the incumbent government to reduce the boundary of a quarry from residential buildings to 50 metres has facilitated the mushrooming of the stone quarrying mafia.

What are the official findings on flood?

• According to the data released by the State Disaster Management Authority, 85,300 litres of water was released every second from Kakki-Anathode dam, and 47,000 litres from Pampa dam at 4 p.m. on August 14.
• The shutters of both dams were raised at night. By 10 p.m., 4.68 lakh litres of water started gushing out of both dams.
• The State government also failed miserably in coordinating with the Tamil Nadu government on the release of water from Upper Sholayar despite the State heading the joint water regulatory board.
• Data posted by the KSEB reveals that the water released into the Periyar river basin from the Idukki and Idamalayar dams surged from 46.26 mcm/day on August 14 to 200 mcm/day the next day. This caused the towns downstream to be totally submerged.
• An analysis of spill from these dams reaffirms the gross mismanagement in the operation of dams.

What measures needs to be considered in this regard?

• The operation and maintenance of dams is governed by the guidelines of the Central Water Commission and water management protocols.
• The safety, precautions and evacuation measures to be followed while declaring different alerts (blue, orange, red) are clearly mentioned in these guidelines.
• The guidelines state that the reservoir control schedule, release procedure and gate operation procedure have to be done only after assessing the potential impact of the procedures.
• The State government and the KSEB opened 34 of the 39 major dams simultaneously, controlled release from these dams would have reduced the gravity of the calamity.
• Apart from that the disaster management system needs to be revamped by roping in experts from different areas.
• The State government must also order a judicial inquiry into the gross mismanagement of dams in the State.

Source: The Hindu