Dam-break scenarios for KRS, Kabini, Chikkahole reservoirs analysed, Emergency Action Plan prepared

Emergency action plan prepared as part of dam safety measures

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.

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.

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.