Dam floods · Kerala

Open Letter to Kerala Chief Secretary about Monsoon preparedness and disaster risk reduction

On May 7, 2020, a number of groups in Kerala wrote this letter to Kerala Chief Secretary on the important issue of Monsoon preparedness and Disaster Risk Reduction, with particular focus on Reservoir operations during Monsoon. This is an excellent initiative worth emulating by a lot of us in different states and at national level. Hence we are happy to Share this here with permission from the authors.


The South-West monsoon is scheduled to arrive at Kerala by around June 1st. Early predictions on the monsoon by different agencies including the Indian Meteorological Department (IMD) suggest normal to above normal rainfall in India. The South-Western coast and adjoining regions are expected to get very good rainfall this year. It may be recalled that the state had to face extremely high-intensity rainfall incidents and consequent disasters in the last two years. Hence, the state needs to be well prepared to face any eventuality during the coming monsoon. The following concerns may be addressed and suggestions may be considered.

Kerala dam diagram James Wilson Print 130918

Covid 19 and the Monsoon

The Indian monsoon this year is arriving at a time when the whole world is clouded by the pandemic, Covid 19. While the state of Kerala has so far managed to contain the virus spread through a series of well thought out measures, the nation as a whole is witnessing a rapid increase in the number of infected people as well as in the number of people who have lost the battle against the virus. Global experience would suggest that the threat of the virus will continue for several months, if not beyond that. Various models suggest that India is likely to witness peaking of the pandemic in the coming months.

The influence of monsoon on the pandemic is unknown at the moment, and we do hope that the health and disaster management experts are together looking into this. With normal to above normal monsoons anticipated it is more than likely that many vulnerable places that experience regular floods will be affected this year too. The probability of larger floods, affecting more regions cannot be ruled out. Hence, it is likely that many people will have to be shifted to safer places, including relief camps on one or more occasions during the monsoon. It will be a big challenge to do the rescue and relief operations while observing the Covid protocols. We request that special safety protocol for Covid 19 for rescue and relief operations, in the eventuality of floods, landslides, and debris flow, shall be prepared.

A large number of people are expected to return from other countries and other states over the next couple of months. It is learned that many LSGs are in the process of identifying places for quarantine of a part of these people. Care shall be taken to ensure that these places are outside flood-prone zones.Besides, it is better to identify buildings and locations with the help of the LSGIs for relief camps in the case of an eventuality.

Reservoir management and operation

During the 2018 floods, the people of Kerala had to pay heavily for the flawed operation of many dams in the state. Since then, the concerned authorities have prepared rule curves and operating procedures for some dams. However, these were prepared unilaterally by the agencies operating the dams, without having wider stakeholder consultations. Some specific concerns regarding dam management are pointed out below.

  • Storage level at Idukki and a few other reservoirs remain uncomfortably high at present. If the storage is not brought down substantially before the end of the water year, these reservoirs may get filled up very soon, in the eventuality of good monsoons in June and July. Live storage in the hydro reservoirs on 30-04-2020 is sufficient to generate1657 million units (MU) (http://sldckerala.com/index.php). Inflow for generating about130 MU is anticipated in May. The storage requirement on the 31st of May as the reserve for June, in case of delay/ failure in monsoon,is that for generating about 700 MU. However, at the current rate of daily hydroelectricity generation of about 20 MU, the hydro reservoirs together will have storage for about 1150 MU by the end of the water year. To ensure that these reservoirs will not have excessive storage at the beginning of monsoon, we request that the KSEBL shall be directed to immediately enhance the daily hydroelectricity generation from the present rate of around 20 MU to an average of 35 MU per day. The storage position at Irrigation reservoirs also may be reviewed and brought down to comfortable positions.

The main contributor to this high storage in the State of Kerala is the Idukki reservoir. At Idukki, live storage as on 30-04-2020 is 677 Million Cubic Meters (MCM). This is 46 percent of its live storage capacity and this is sufficient to generate 996 MU of electricity. At present, the average daily generation at the Moolamattam powerhouse is about 8 MU only and the average reduction in storage is only about 5 MCM/ day. At this rate, the reservoir will have about 500 – 550 MCM on 31-05-2020 (sufficient to generate about 800 MU of electricity), which is about 35 percent of its live storage capacity. It may kindly be noted that the storage on 31st of May in 2018 was about 25 percent and the reservoir storage rose to more than 95 percent even before the end of July. Having very high storage at Idukki before the onset of monsoon, especially with the forecast for normal to above normal rainfall will be a big risk for the Periyar river basin as well as the lower reaches of Chalakudypuzha basin. Immediate measure may be taken to reduce the live storage capacity at Idukki and to bring it down to around 15 percent.

  • During the 2018 floods, shutters and sluices at some dams, regulators, and barrages were dysfunctional. This resulted in reduced discharge capacity from these mechanisms, compounding the floods. We request that the concerned departments/ agencies shall be directed to ensure that all the facilities for water discharge/ regulation are made fully functional. A status report of the same shall be published by around 25th of May 2020.
  • We appreciate the preparation of rule curves for some reservoirs in the state. However, these were prepared by the agencies operating the dams only. It can be further improved through consultations with stakeholders. It is requested that,
  • The concerned agencies shall be directed to have consultations with stakeholders including the Local Self Government (LSG) authorities and independent experts for each reservoir, before the onset of monsoon.
  • The rule curves shall be evaluated from a river basin perspective. In the case of river basins with multiple reservoirs, integrated operating plans shall be developed. For example, flood monitoring at the Periyar river basin shall be based at Bhoothathankettu barrage and KSEBL, Water Resources Department, Disaster Management Authority and LSGD shall be part of the planning, monitoring, and management team.
  • Precautionary principle shall prevail in the preparation of the rule curves.
Mullaperiyar Dam Sign Board
  • There are four reservoirs inside Kerala that are operated by the state of Tamil Nadu and another one managed by Kerala exclusively for Tamil Nadu. Huge release from Mullaperiyar and Parambikulam during 2018 floods was one of the main contributing factors to the extreme floods. A huge release from Tamil Nadu Sholayar in Tamil Nadu to the Kerala Sholayar reservoir had also contributed to the extreme floods at the Chalakudypuzha basin. Rule curves for these reservoirs have not been prepared. Since the reservoirs inside Kerala territory falls under the jurisdiction of the State Dam Safety Authority, the Authority can and should ask for preparation of rule curves for these reservoirs. Since the operation of TN Sholayar is having a direct consequence on the Chalakudypuzha basin, the Government shall negotiate with the Government of Tamil Nadu and the Government of India to ensure rule curves and operating procedures for TN Sholayar too, to ensure efficient flood management. The provisions in the Periyar Lease Deed and the Parambikulam – Aliyar Project Agreement, that is detrimental to effective flood management shall be reviewed immediately, without prejudice to other provisions in the agreements or other disputed facts regarding these agreements. The Government may move the Supreme Court, in case the Government of Tamil Nadu is unwilling to cooperate.
  • The guidelines for flood management, prepared by the National Disaster Management Authority (NDMA) in 2008 require Flood Management Plans (FMPs) to be prepared at multiple levels. We request that FMPs shall be prepared for all the rivers in the state at River basin level, LSG level,and at concerned department levels. The River basin level FMPs shall include flood models and detailed flood-prone area maps in cadastral scale.
  • The availability of timely and comprehensive data and information is key to disaster preparedness and risk reduction. Since the preparedness has to start from an individual level, it is of paramount importance that all have access to these data. We request you to ensure the availability of all monsoon related data and information on a real time basis in the public domain.
  • Real-time weather and hydrological monitoring at multiple levels including at river basin level can help in ensuring better flood preparedness. A people’s monitoring done at Chalakudypuzha basin during 2019 flood, based on reliable weather updates, available data/ information on reservoir storage and operations and on-field monitoring of rainfall and river water levels and also utilising the Learnings from 2018 floods had proved effective. A participatory real-time monitoring mechanism shall be developed at each river basin.
  • During the 2018 and 2019 monsoons, many locations in the state had experienced extremely heavy rainfall of more than 30 cms in 24 hours and even more than 40 cms in a day at some places and consequent landslides and land piping. Climate scientists have been warning of such extreme precipitation due to the climate crisis. Hence we should be anticipating such extreme rainfall events and associated natural disasters in the coming years too. Special protocols for reservoir monitoring during high and extreme rainfall events need to be developed. During extreme rainfall events, hourly or half-hourly monitoring of rainfall in the catchments, inflow into and outflow from the reservoir, and reservoir water level shall be ensured. The rainfall-runoff rate shall also be continuously monitored. This shall be made available on a real-time basis and shall be utilised for river basin level management.

We thank you in advance for considering these suggestions. We are ready to provide further details if required.

Yours sincerely

Prof. Dr. S. Sitharaman, President, All Kerala River Protection Council

Dr. K. Soman, President, Energy Conservation Society (ECS)

Dr. S. Abhilash, Associate Director, Advanced Centre for Atmospheric Radar Research (ACARR), CUSAT

Er.G. Krishnakumar, Society of Energy Engineers and Managers (SEEM)

Er. S. Unnikrishnan, River Research Centre, Thrissur

Dr. Shaju Thomas, Moovattupuzha Nadi Samrakshana Samithi

Nibha Namboothiri, “Puzha”, Cherpulassery

Eby Emmanuel, Secretary, Meenachil Nadi Samrakshana Samithi

S.P.Ravi, Secretary, Chalakudypuzha Samrakshana Samithi (spravi.18@gmail.com)

Copy to:

  1. Principal Secretary, Revenue and Disaster Management
  2. ACS, Water Resources Department
  3. Secretary, Power Department
  4. Principal Secretary LSGD
  5. Chairman and CMD, KSEBL
  6. Member Secretary, KSDMA

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