The Kerala government, insisting on the construction of a new dam, told the Supreme Court that the 126-year-old Mullaperiyar dam, which is a composite gravity dam, is in a deteriorating condition due to age and it should be decommissioned.
In a note, the Kerala government said: "The catchment area of Mullaperiyar reservoir is 624 sq km. The gross storage capacity is only 12.758 TMC ft at 142 ft. Mullaperiyar, therefore, is exceptionally vulnerable because it has a large catchment area and limited storage capacity".
The government further added the water level in the Mullaperiyar reservoir increases rapidly compared to Idukki which has a catchment area of 650 sq km and has a capacity of 70.5 TMC ft.
The state government emphasized that the consequences of any failure of this dam could be extremely catastrophic and beyond human imagination. "The apprehensions of the government of Kerala regarding the life and safety of more than 30 lakh people of 5 districts residing downstream of the dam has to be given due importance and consideration", said the government.
It further added, "seismic forces were not considered in its design. In spite of strengthening measures taken twice, presently the dam is in deteriorating condition due to its age. There would be an exponential increase in the water pressure and uplift pressure acting on the dam when the water level is raised from 136 ft to 142 ft (i.e. from 859.167 to 936.648 tonnes per meter length of the dam)".
It added, the coming monsoon that is to set off during this week too would likely affect the inflow into the dam and reiterated its stand to increase the outflow to the maximum possible extent.
The state made it clear that the logical next step is the construction of a new dam to ensure water to Tamil Nadu and security to people living downstream and to decommission the existing dam.
The top court is hearing a plea by the Kerala government to ensure that the water level is not allowed to exceed 139 feet. In 2018, the Supreme Court passed an order to maintain water level at 139 feet during the Kerala floods as a temporary arrangement.
Citing the recent torrential rains which led to an increase in water level in the dam's reservoir, the Kerala government asked for similar relief.
