HYDERABAD: How safe are Srisailam, Nagarjuna Sagar and Pulichintala dams? This issue would be one of the 16 items on the agenda that will come up for discussion at the Krishna River Management Board (KRMB) Board meeting to be held on May 6.
The KRMB is keen that urgent measures are needed to ensure the safety of the three dams. The Board wants the officials of AP and TS to inform it about the actions taken. The Board may like to discuss the role and responsibility of dam owners as per the provisions of the Dam Safety Act (2021), the KRMB agenda, which was circulated to AP and TS on Tuesday, said.
The agenda of the Board meeting will discuss handing over of Srisailam and Nagarjuna Sagar projects to KRMB, approval of detailed project reports (DPRs) of unapproved projects, issue of power generation and mismanagement of Srisailam reservoir and working arrangement for sharing of Krishna water between Andhra Pradesh and Telangana for the water year 2022-23.
The agenda of the proposed KRMB meeting said: “Issues of Dam Safety concerns calling for priority attention. As per the provisions of the AP Reorganisation Act (2014), the newly formed States of AP and Telangana became owners of dam/ barrage/ anicut located within their territories.”
“However, there are three dams on the river Krishna - namely: Srisailam, Nagarjuna Sagar, and Pulichintala - that span across both the States and their reservoirs form common pool resources. Under some mutual understanding reached by the States - for which written records are not available - the ownership of Srisailam and Pulichintala dams were taken over by AP, while the ownership of Nagarjuna Sagar Dam was taken over by Telangana,” the agenda said.
In this arrangement, the operational controls of reservoirs were not fully vested with respective dam owners and thereby the trade-off between operational benefits and the necessities of dam maintenance became somewhat opaque. These dams are therefore not getting the desired level of attention.
Critical issues noticed by KRMB related to three dams
In Srisailam, there is an urgent need for the down stream protection works since huge plunge-pool depression of 40 m (pit depth) has been formed due to heavy spillway discharges. The concrete columns forming the end-wall of stone pitching, and ski-jump bucket of the spillway also need repairs. The cost of all repair works is estimated to be about Rs 800 crore.
In Nagarjuna Sagar, the concrete towards the bottom part of ‘spillway ogee’ in all spillway bays is eroded thereby exposing the underlying masonry/ concrete. The cost of repair works for various issues is estimated to be about Rs 20 crore.
In Pulichintala, during the floods of 2021, one of the radial gates failed and fell below the spillway. Action for the reinstallation of gate is yet to be initiated. It is not known if proper investigation of the failure has been undertaken, or if any learning is assimilated.
Pulichintala: Gates of river sluices jammed
The detached portion of the failed gate is still lying on the river bed - which poses an unwarranted risk for Prakasam barrage. The concrete piers of spillways are of very poor quality and the seal plates of radial gates in the given conditions are prone to damage which can obstruct the smooth movement of gates. The gates of river sluices are reported as jammed. The cost of works for the replacement of the gate/ hoist is estimated to be about Rs 10 crore