The last 12 months or so has been a water shed period for the Cauvery River Basin thanks to poor Southwest Monsoon in 2016 that got aggravated by an even more poor Northeast Monsoon. Dams across the Cauvery River Basin are possibly at their lowest levels for the past few months with inflows mostly in a trickle. The last few years have seen most of the dams in the Cauvery River Basin struggle to reach Full Reservoir Level with 2014 possibly the last time most dams reached FRL.
With June 12th the annual opening date of Mettur dam not only a couple of days away it is possibly an ideal time to understand how the current storage levels are across the Cauvery Basin and possibly what should be our expectations in terms of possible support for the farmers from the Reservoirs in the region.
As the table indicates almost all of the dams are at their worst levels as things stand. Even Harangi which is the smallest dam among all major reservoirs is also at less than 20% of the Full Reservoir Level. In this context it becomes extremely vital for Southwest Monsoon 2017 to start in an extremely good manner to ensure the inflows into the dams pick up pace without any delay. The inflows into KRS was 438 cusecs yesterday while Kabini was 145 cusecs indicating how monsoon conditions are still to pick up in the catchment areas like Madikeri, Wayanad, Hassan districts. Even in the case of Mettur the inflow yesterday was only 130 cusecs.
Keeping the context in mind we have tried to estimate the timelines of when these reservoirs in Cauvery River Basin could reach FRL at various daily inflow rates. To give a perspective the highest discharge level in Cauvery has been about 2.61 lakh cusecs during the year 1961 while recently in August 2005 the river saw a discharge of about 1.17 lakh cusecs. 2014 the last good year for Cauvery Basin saw discharges reach up to 85000 cusecs. But one needs to keep in mind these discharge levels are for short period for a couple of days.
Taking a median of about 10000 cusecs of daily inflow it will be in all probability end July before KRS possibly sees FRL. Keeping in mind possibly we are going to see inflows into Mettur increase only after the storage levels improve in Karnataka we are possibly going to see a scenario of Mettur Reservoir not reaching FRL this year also unless a good Northeast Monsoon supports it.