The Karnataka Water Resources Department has prepared an Emergency Action Plan (EAP) in case of a breach in the Krishnaraja Sagar (KRS), Kabini and Chikkahole dams, and has mapped the downstream areas that could be impacted.
The action plan is based on a hypothetical scenario of a dam break. Authorities have not only mapped the villages and the areas that could be affected, but have also spelt out the response required to minimise loss of life and damage to property.
The plan was discussed at a workshop involving all stakeholders in Srirangapatna taluk of Mandya district on July 8.
The exercise is part of dam safety measures. The KWRD said that preparation of the EAP entailed a slew of exercises, including a dam-break analysis, development of inundation maps for different failure scenarios, calculation of the time of arrival of flood wave, evacuation plans, and marking of shelter points.
Scenario for KRS
The flood hazard mapping for KRS indicates that 2.37 lakh people in 139 villages spread across four districts will be affected in case of a breach in the KRS dam. People living in downstream villages within 13.5 km of the dam will be most vulnerable, as the time required for the water to reach these places is just about 35 minutes.
The EAP has identified potential emergency conditions and prescribes the procedure to be followed to minimise damage to property besides specifying the actions that needs to be taken. Besides, a local evacuation plan has identified 80 shelters, and inundation maps have been assessed to study scenarios arising due to over-topping failure, piping failure and large controlled release from the dam.
Scenario for Kabini reservoir, Chikkahole dam
In case of a breach in Kabini reservoir, 92 villages in Mysuru district and 14 villages in Chamarajanagar district are likely to be submerged, and 11,61,159 people could be displaced or affected. Besides, 6.37 lakh animals could die in the resulting floods, and 15 bridges could be submerged. A local evacuation plan is part of the EAP.
An analysis of a breach in Chikkahole dam indicates that 42 villages downstream in Chamarajanagar district could face submergence, apart from 24 other human habitations, and the devastation could impact 44,639 people.
Roles and responsibilities in an emergency
The EAP defines the roles and responsibilities of agencies concerned, and the standard operating procedure during various stages of emergencies. The role of officials from various departments, including the fire and emergency personnel, revenue officials, SDRF, and NDRF, has been chalked out.
The KWDR said that the EAP document should be used in case of an emergency due to either dam break or significant water release from the spillways and gates.
