The design of the new Mullaperiyar dam, which would replace the ageing one, would be ready in two months as experts are busy working on the hydrological safety of the proposed structure.
The dam is back in news after Tamil Nadu opened the shutters of the dam on Friday following heavy rain in the catchment area and Kerala evacuating families living in the downstream areas. Kerala has also restarted its campaign for constructing a new dam.
Mullaperiyar dam had evolved as a high-voltage socio-political issue in both Kerala and Tamil Nadu. Though the dam would be designed by Kerala, it would require the concurrence of Tamil Nadu for the State to go ahead with the construction. The new design and its detailed project report will have to be handed over to Tamil Nadu, according to experts.
While designing the new dam, the probable maximum flood that can happen in the region needs to be taken into account. Earlier, an IIT-Delhi study had estimated that 3.06 lakh Cusec water could reach there in case of an extreme flood event. Kerala also needs to take into account 2018 and 2019 floods. The new dam shall be designed in such a way to withstand the future floods and heavy inflow of water, according to those at the Irrigation Design and Research Board (IDRB) of the State Irrigation Department.
According to R. Priyesh, Director, IDRB, the hydrological safety is of utmost significance given the steep nature of the catchment area of the dam, which is spread over 620 sq km. The rain received in the catchment area can reach the dam in no time. As the State is witnessing extreme weather events frequently, the new dam shall be designed to resist the possible flooding caused by such events, he said.
Once the hydrological safety aspects are addressed, the structural and seismic safety aspects will be looked into.
Kerala had been highlighting the hydrological, seismic and structural safety aspects of the old dam in its Supreme Court litigations. The height of the new dam, its water holding capacity and the spillway levels are yet to be finalised. The new dam could cost around over ₹2,000 crore and take four years to complete, said Mr. Priyesh.
