Idukki Dam released water when Kerala was in floods. Could this have been avoided?


By Himanshu Thakkar*

There are still two months of South West Monsoon for Kerala. Then large parts of Kerala also get benefits from North East monsoon that follows in Oct-Dec. In fact, the only two occasions (1981 and 1992) since the Idukki Dam was commissioned in 1975, were both during North East monsoon, never in SW monsoon.  So they could have easily taken advance action to release water from Idukki when Kerala was not facing floods. They obviously did not and now, when Kerala is facing floods, Idukki is adding to Kerala’s misery.

In fact, just about ten days back, on July 31, 2018[i], the media was full of stories of possible release of water with water level in Idukki crossing 2395 ft, with FRL at 2403 ft. If they had started water in the intervening relatively dry period, Idukki dam need not have added to Kerala’s flood disaster misery. They did not. Why? Why they again waited to be in TINA state when Kerala is also facing floods?

In fact, basic objective of Idukki Dam is power generation. Idukki dam has six turbines with 130 MW capacity each. One expected that this year Idukki power generation would have broken all records, since never before has the dam water level and inflows into the dam been so higher.

kerala_drainageBut when one looks at daily and monthly power generation figures from National Power Portal of Central Electricity Authority (CEA) and CEA’s own past records, one is shocked to see that during June-July 2018, Idukki generated about 325 Million Units (MU) of power, which was below power generated during at least four years in just last decade: below that in 2008, 2012, 2014 and 2015. In 2014, the highest generation year for June-July, Idukki generated over 50% more than it generated in June July 2018. If Idukki had generated more power, that could have also help reduce water level.

So why did Idukki power not generate more power when so much water was available? National Power Portal[ii] provides the answer: one of the six 130 MW units of Idukki has been under shut down since Aug 1, 2017 for Renovation/ modernisation and another 130 MW unit is under shut down since June 26, 2018 for annual maintenance. Its of course a mystery why the second unit was taken out for annual maintenance during monsoon, when it could have been done in dry season. But the consequences of this actions are that Idukki produced less power and it also added to flood disaster misery of Kerala.

In fact, even before the SW monsoon set in this year, on May 31, 2018, Idukki’s live storage capacity was 25% full, much higher than normal and higher than previous year or average of last ten years. That also contributed to the dam filling up sooner. Why such high water storage before the onset of monsoon is a question that the Idukki managers will need to answer.

Kerala Rainfall As per IMD (India Meteorology Department) figures, till Aug 9, Kerala received 20% above normal rainfall. Idukki districts tops with 50% above normal rainfall and also highest rainfall among all districts of Kerala so far: 2433.5 mm. Palakkad (44%), Kottyam (36%) and Ernakulam (33%) are some other districts having high surplus rainfall. But it’s possibly the bouts of high intensity rainfall that has created the current situation.


CWC has no flood forecasting sites at all in Kerala 

The unprecedented floods and dam water releases also raise the questions about flood forecasting and advance action by Central Water Commission (CWC), India’s only flood forecasting agency. When we see CWC’s FF website, we are shocked to find that CWC has absolutely NO flood forecasting sites, neither level forecasting, nor inflow forecasting. CWC has only flood monitoring sites in Kerala, and as the table below shows, at least one of them is non functional. Its high time that CWC includes some key dams like Idukki and Idamalayar and some key locations in its flood forecasting.

In conclusion, its clear that major storage dams of Kerala like Idukki and Idamalayar, by releasing water when Kerala is facing floods due to widespread heavy rainfall, are adding to the flood misery of Kerala. This could have been avoided if the dam operators had started releasing water in advance rather than waiting for dams to be filled up, when they have no alternative but to release water. Its also clear that there was sufficient time and relatively dry period when they could have released water, rather than when Kerala is facing floods.

If the Idukki power unit that was taken out or operation from June 26, giving “Annual Maintenance” as reason was in stead taken for annual maintenance during drier summer months, that would have helped, particularly when one unit is already out for renovation. If the water level in Idukki was lower before the onset of monsoon, it would have helped. CWC’s absence in flood forecasting is also additional handicap.

All this requires action. Possibly one of the first things, post current phase of rescue and emergency, that Kerala govt can do is to institute an independent inquiry into these issues, so that such situations do not recur, when dams, in stead of helping moderate the floods, add to the flood misery.

End Notes



*With South Asia Network on Dams, Rivers and People (SANDRP). Contact:

Slightly abridged. Original article with more details can be accessed here:

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