Thiruvananthapuram: Unlike in 2018, the officials concerned had taken permission from the government 36 hours before opening the dams. However, in several areas, the public was reportedly not made aware, in advance, of the water levels in rivers, major canals and streams through the respective local bodies.
The Opposition had alleged that the large-scale destruction and heavy toll during the 2018 floods were due to the opening of dams without warning.
The government was defensive when a study conducted by the Bangalore-based Indian Institute of Science as per the directive of the Comptroller and Auditor General had pointed out that failure in dam management led to the catastrophe in 2018.
The report also said there was no data available with the government over the rain received or the quantum of the water received by dams for taking necessary precautionary measures.
The Amicus Curiae appointed by the High Court of Kerala had also indicted the government for its failure to properly manage the water levels in dams in 2018.
Later, the state government had given directions to the State Irrigation Department and the Kerala State Electricity Board (KSEB) to take stringent steps to set right the issues related to dam management. As a result, a Rule Curve on the maintenance of the water level was prepared for each dam.
The guidelines issued by the State Disaster Management Authority for opening dams are as follows:
1. The permission of the state government should be taken 36 hours before the opening of the dams. Those should not be opened without the permission of the respective District Collector.
2. The people should be made aware of the opening of the dam through loudspeakers 24 hours ahead of the opening. The local bodies which are likely to be affected by the release of dam water should be informed one day ahead of the opening of the dam.
3. An Assistant Executive Engineer from the Irrigation Department would be posted at the district-level emergency centres round the clock. He should give a report to the state government on a daily basis on the status of the rain and the water levels in the rivers and dams in the respective district.
4. The experts from the Water Resources Department or the Geology Department should be posted on a daily basis at the district emergency centres situated in hilly districts. It is the responsibility of the officer concerned to report to the government the chances of occurrence of landslides based on the intensity of rain.
Timing of low tide taken into consideration
This time, the Idukki dam was opened after taking into account the timing of low tide in the Arabian sea. Today, there was low tide in the sea from 6 am to 4 pm. The high tide was at 11.45 am. Again at 12 midnight, there will be a high tide.
As per the reports, the high tide and the low tide at the sea will be very intense on Tuesday. After considering all these factors, it was decided to open the dam at 11 am. As per the government's calculations, the released water should reach the sea after four to five hours.
Rule curve
A Rule Curve specifies the storage of water which can be maintained in a dam at a regular interval. The expert committee of the Central Water Commission fixes it.
The rule curve for each dam is prepared on the basis of the electricity generated, rate of evaporation, the quantum of rain in catchment areas, the amount of water received and the water received in the previous year at the given point of time.
The maximum permissible limit of water in each dam each day and the appropriate timing for issuing blue, orange and red alerts are also recorded in the rule book.
