Kerala might be looking at yet another challenge due to the lockdown. The power consumption in the state has reduced significantly, which has resulted in less water being drawn by hydroelectric dams in Kerala. As a consequence, the storage capacity of the dams is higher than it was the previous year. This, experts warn, could potentially cause another flood in the state if the water is not released from the dams before the monsoon.
Incidentally, the weather agencies have already predicted above normal rainfall for this year in the country. If the state receives more rainfall, the hydroelectric dams under Kerala State Electricity Board (KSEB), including in Idukki, will be opened this year due to excess storage.
According to a group of scientists and environmental experts, who have written a letter to the Kerala government, if a special flood protocol is not chalked out before the monsoon, it could probably lead to a repeat of the floods the state witnessed in 2018.
“The Southwest monsoon is scheduled to arrive in Kerala around the first week of June. Early predictions on the monsoon by different agencies, including the Indian Meteorological Department (IMD), suggest normal to above normal rainfall in India. The southwestern 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,” read the letter submitted by a team of nine scientists and environmental experts, led by professor S Sitharaman, president of the All Kerala River Protection Council.
As per the data from Kerala State Load Despatch Centre on Sunday, the water storage level in hydroelectric dams in the state is at 36%. This was 25.9% during the corresponding period last year, which is a difference of 10 percentage points.
The storage in the hydroelectric dams normally reduces to below 20% in the last week of May. This year, however, due to reduced power consumption, the storage is expected to be over 30% in the last week of May.
“The current power consumption in the state is 70 Million Units (MU) per day. Last year, during the same period, it was 82-88 MU. Because the factories and other industrial officers have been closed, it has resulted in reduced power consumption," said a KSEB official.
As per the live storage capacity (the volume of water in the reservoir that is available for power generation and other purposes) on Sunday, the water in the hydroelectric dams is sufficient to generate 1,484.118 MU power. As per the water use management by KSEB, 700 MU worth of water storage is needed in the last week of May. The average hydroelectric dam power generation of the state is 20 MU per day.
Given the current scenario, on the first day of the monsoon, the water level of the hydroelectric dams is sufficient to generate 1150 MU, estimates the KSEB Load Despatch Centre’s live data.
According to the team of experts, the main contributor to this high storage in Kerala is the Idukki reservoir, which is the largest arch dam in Asia. The storage level on May 31, 2018 was about 25% and the reservoir storage rose to more than 95% even before the end of July, the team pointed out in the letter. Presently, the storage level stands at 43% with weeks to go for the onset of the monsoon.
“Having very high storage in the Idukki dam, 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 the Chalakudy river. Immediate measures may be taken to reduce the live storage capacity at Idukki and to bring it down to around 15%,” read the letter.
The team fears that many vulnerable places that experience regular floods will be affected this year, too. In the eventuality of a flood and/or landslides during the coronavirus pandemic, the team is calling for special COVID-19 safety protocol for rescue and relief operations.
“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 (erosion)... 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-19 protocols,” said the letter.
Scientists have also requested for special protocols for reservoir monitoring during high and extreme rainfall events. “During extreme rainfall, hourly or half-hourly monitoring in the catchments, inflow and outflow from the reservoir, and reservoir water level should be ensured,” they stated in the letter.
SP Ravi, secretary of Chalakudypuzha Samrakshana Samithi (Chalakudy river protection forum), said that the Kerala Disaster Management Authority (KSDMA) should develop special protocols and river monitoring system to prevent the excess rainfall related issues.
In the wake of low power consumption, Ravi said that KSEB should change the rule curve of the water released in the hydroelectric dams. A rule curve refers to the water level or empty space that is to be maintained in a reservoir at different points in a year.
Speaking to TNM, KSEB Director (Generation - Civil) Bibin Joseph said hydroelectric dams operate based on the rule curve. “We will increase the hydropower generation in June, which will reduce the water level. If the water level increases above the rule curve, we will release the water from these dams,” he said.
According to KSEB Chief engineer (Dam Safety and DRIP) Supriya S, the present water level in the hydroelectric dams has not gone above the rule curve.
“In all circumstances, we will inform the district disaster management committee before opening the shutters of dams in each district. KSEB has already fixed an action plan to open hydroelectric dams at various water levels,” said Supriya.
The action plan for monsoon preparedness this year has already been prepared. “The earlier action plan was modified after the 2018 flood,” added Bibin.
Sekhar L Kuriakose, Member Secretary, Kerala State Disaster Management Authority (KSDMA), told TNM, “We follow a standard operating model every year. An executive committee presided over by the state chief secretary, has already issued some directions to the district collectors in the state. Additionally, the Disaster Management State Relief Commissioner will convene a meeting before May 15 to assess the preparations by each department.”
Sekhar added that unlike in 2018, where dams were opened overnight and caught people in low-lying areas unaware, the shutters will not be opened between 6 pm and 6 am.