It is stated by Kerala that said rain gauge station has been constructed by the state of Tamil Nadu on land, which is not a part of the land covered by the lease Deed of 1886- "As pointed out in the counter affidavit filed by Kerala to the IA 28/2017 in O.S 3/2006 in 01.03.2017 before the Hon'ble Supreme Court, the state of Kerala has not barred access to the said rain gauge station but only regulated it by insisting on plying through the boat maintained by the Forest Department of Kerala. In the 9th meeting of the Supervisory Committee held on 07.07.2016 the officials of Kerala informed about their decision to establish an inflow forecasting system in the catchment of Mullaperiyar dam. The Installation work has been completed at all 13 stations. But at present there are issues with retrieving the complete set of data for 24 hours from all the stations due to dense forest cover, wildlife and accessibility problems. The format of data from the instruments has been communicated to the Chairman, Cauvery Technical Cell, Tamil Nadu as per their request for generating the File Transfer protocol in Tamil Nadu Cloud server for sharing the rainfall data of Mullaperiyar. The non-validated raw data recorded in the 11 Automatic Rain Gauges and 2 Automatic Weather Stations available from Jan 2020 till Nov 2021, is shared to Tamil Nadu as per their request. Copy of letter is attached as Annexure R2/1 (Page No. 43 ). Once the rectification of the instruments as well as the validation process is completed, data can be shared with Tamil Nadu on real-time basis. Therefore, with this state-of-the-art rainfall network, which will provide real time data, the demand of Tamil Nadu for access to Mullaikodi rainfall gauging station to collect rainfall data does not survive."
"The Mullaperiyar dam with faces in uncoursed rubble masonry in lime mortar and core in lime surkhi concrete is passing through its 126 year of existence, and the dam structure would have become so porous and weak that grouting cannot improve the quality of the deteriorated material remaining in the dam body. The 126 year old dam is not amenable to withstand the designed pressure through the process of pressure grouting and it makes the dam more unsafe rather than grouting. Moreover, the efficiency of grouting extends only up to a maximum of 5 to 8 years and it is only a temporary strengthening measure", it is advanced.
It is stated that it is imperative that a century old dam should have all necessary instruments for monitoring deformation, seepage/leakage quantity and quality, uplift pressure, pore water pressure, temperature, reservoir level and seismicity, as per the guidelines of Central Water Commission viz. Guidelines for the instrumentation of Large Dams (2018)- "There is no comprehensive instrumentation plan including seismic instrumentation for Mullaperiyar dam which is essential for monitoring the safety of large dam which is 126-year-old dam and the relevant instruments embedded in the dam to monitor various parameters mentioned in the CWC guide lines for instrumentation of large dams, are not working."
It is stated that Mullaikodi rain gauge station has been constructed by the state of Tamil Nadu, which is not a part of the land covered by the lease Deed of 1886; and in any case the State of Kerala has not barred access to the said rain gauge station but only regulated by insisting on plying through the boat maintained by the Forest Department of Kerala.
It is submitted that, though the Empowered Committee concluded that the Mullaperiyar will remain safe, the Committee had also pointed out that, ".....a possibility cannot be ruled out that at some point of time in future, in spite of requisite upkeep of the Dam, it may suffer some distress due to reasons beyond anybody's control. The Committee recommended that in that case, the dam may need restoration/ strengthening measures which may take years for implementation. It also might need temporary evacuation of the reservoir level to facilitate implementation of restoration"- "The Empowered Committee also suggested two alternatives as 'Way Forward - Towards An Amicable Resolution' of the issue for the consideration of the Court wherein the construction of new dam and providing low level outlets of adequate capacity to lower the reservoir water level to a specified elevation was suggested as two alternatives and this Hon'ble Court in its judgment has endorsed the same in the judgment dated 07.05.2014 in OS 3 of 2006. It is further stated that the spatial and temporal variability in rainfall, recent incidents of heavy erratic rainfall over Kerala specifically in the Mullaperiyar catchment over the last four years, consequent sudden rise in the reservoir water level, projected change in rainfall patterns due to climate change and its impact on floods, the age of the Mullaperiyar dam and its safety, has caused concerns on the safety of the structure and lives of lakhs of people residing downstream of dam."
The state of Kerala has denied that the said status report of the CWC states that Kerala is obstructing maintenance works or strengthening measures as alleged or at all- "It is an admitted position that the Supervisory Committee during its routine yearly inspections of Mullaperiyar dam is only conducting visual inspection and no detailed inspection as per CWC guidelines are being done. It is stated that the existing Mullaperiyar dam is one of the oldest gravity dams of its kind and nature currently existing in the world. The dam is not provided with a comprehensive instrumentation plan including seismic instrumentation. Though the state of Kerala has been persistently requesting for a comprehensive instrumentation plan, the same has not been installed. The seismic accelerographs as recommended by the DSARP Panel has not been installed even after three decades. The seepage noticed in the dam is not the actual seepage of the dam as the seepage measuring devices are not installed in the old main dam. Hence any disaster will be a threat to the lives and property of people in the downstream of dam. It is therefore not admitted that, it is not justifiable to have a fresh review before carrying out the strengthening measures ordered by this Hon'ble Court."
It is denied by Kerala that the various parameters of the dam are within acceptable limits or that there is no necessity to have a fresh review on the safety of the dam for storing water +142ft, as alleged or at all. It is submitted that the statement that Mullaperiyar dam is behaving well in all respects is devoid of merits.
It is stated that the Central Water Commission in their Guidelines for their safety inspection of the dams in 2018 as well as National Committee on Dam Safety has prescribed Comprehensive dam safety evaluations for all dams at regular intervals to ensure their safety irrespective of whether rehabilitation works have been carried out in the dam or not. Further, after the dam safety evaluation by independent experts, necessary rehabilitation works if any required will be suggested, which needs to be implemented.
"The Mullaperiyar dam and the catchment area received two major floods after the pronouncement of the judgment (2014) and the catchment received erratic heavy rainfall in recent years. Also, many tremors/earthquakes have been reported near the dam site during the last years. All the above phenomena have caused impact on the safety of the structure", it is emphasised.