As rains continue in Coastal Tamil Nadu, is it time for Plan B in Cauvery Basin?

Cauvery COMK Analysis
Reading Time: 4 minutes

As has been the case since Sunday few places in Coastal Tamil Nadu recorded rains yesterday as well.  In particular the rains were heavy around the Ariyalur to Delta region.   Senthurai in Ariyalur district recorded about 4 cms of rains while closer to the coast Manalmedu & Kollidam recorded about 2 cms.  Little down south Thirumayam also recorded moderate to heavy rains last evening totaling to about 4 cms of rains.  Many parts of South Chennai & suburbs around Tambaram and south of it recording short spells of moderate to intense rains.  Nungambakkam recorded about 3 mm rains till early in the morning.

In Peninsular India  West Coast to the south of Konkan region has been seeing a very poor monsoon for the last month or so with the rainfall pattern being erratic and not helping for the storage of dams.  In particular concern is the Cauvery basin which is struggling under two consecutive years of poor monsoon.  The  deficit rainfall so far in the upper riparian areas particularly around the catchment area is showing up in the poor storage levels of the various dams.  Weather_Update_2

Districts like Wayanad has seen only about 40% of the normal rainfall expected of this season so far while Kodagu district in Karnataka has seen about 75% of the normal rainfall so far this season.  Similar is the case with Hassan district which provides the bulk of the catchment to Hemavati Dam.  It is only when we come to the plateau region of Mysore / Mandya the situation improves with these places receiving above normal rainfall unfortunately these districts contribute far lesser to the overall catchment of the river compared to the ghat areas.  As one can see KRS the biggest among the Karnataka dams in Cauvery basin is less than half of its capacity while closer home in Tamil Nadu Mettur has a storage which is less than 25% of the overall storage capacity.

It is time for the Governments to keep an eye on the developments and possibly look at possible alternate scenarios as we roughly have about 45 days of active monsoon period left.  As the years have progressed Cauvery has become more and more a deficit river basin with the needs far outstripping the available supply from the river.  On on the one hand we have the agricultural needs of the farmers from both riparian states of Karnataka & Tamil Nadu while on the other are the drinking water needs for many towns & cities along the river.  It is time the stakeholders sit together and chalk out a short term plan to mitigate the needs for this year in case the monsoon continues to remain weak for the rest of the season in these areas.  Similarly a long term plan is much needed as well to reduce the dependence on the river may be in terms of better irrigation practices that make our usage of water more efficient and possibly look at the reduction of water intensive crops like Rice which is simply going to become unviable in the days to come.


In the meanwhile the season’s first monsoon depression has intensified into a Deep Depression and now lies over Bangaladesh & Gangetic West Bengal.  It is expected to move along the monsoon trough making slow movement over the next 24 hours or so after which it will start to gradually weaken.  Travelling over the Gangetic Plains and adjacent Central Indian region it is expected to bring heavy rains along its path to many areas of Central India which has been recording heavy rains already this monsoon year.  In Peninsular India the west coast is likely to see a slow down in the rains as the weak off shore trough pushes up the latitude closer to the Gujarat coast.


Coastal Tamil Nadu is expected to see another day of possible thunderstorms in a few areas after what is likely to be a very hot day and possibly sea breeze setting in around 3 PM along the North Coastal Tamil Nadu region.  Places around Pondicherry is best placed for a few spells of moderate to heavy showers later in the evening.