Sudden release of water from Idamalayar, Idukki dams caused Kerala floods: Tamil Nadu government

Tamil Nadu refuted allegation by Kerala government that water from Mullaiperiyar Dam created a deluge.
Water being released from the Idukki dam through the Cheruthony reservoir. (Photo | File/EPS)
Water being released from the Idukki dam through the Cheruthony reservoir. (Photo | File/EPS)

CHENNAI: Refuting Kerala’s allegation that sudden release of water from Mullaiperiyar dam on August 15 was one of the causes of the deluge, Tamil Nadu on Friday said indeed sudden releases from Idukki and Idamalayar dams had resulted in floods. Around 36 tmc of water was released from both these dams between August 14 and 19 whereas only 1.24 tmc was released from  Mullaiperiyar dam on August 15  and 2.02 tmc on August 16.

To substantiate this, Tamil Nadu government submitted data regarding rainfall, spillage from dams etc., during the days when Kerala faced floods. In the rejoinder submitted before the SC, the government made a point by point clarification on issues raised by Kerala, in its affidavit filed on Thursday to a petition filed by Russel Joy  from Idukki seeking to reduce storage level of Mullaiperiyar dam.

Tamil Nadu said Kerala had received torrential rain since the beginning of July and rainfall recorded for Idukki as per Meteorological Centre, Thiruvananthapuram between June 1 and  August 22 was of the order of 3,555.5 mm, which was almost double the normal rainfall and occurred during a period of about two-and-a-half months.

The water level in the Idukki dam on August 14 was 2,399 ft against the Full Reservoir Level of 2,403 ft and the quantity spilled was 1.634 tmc. But on August 15, the level was 2,401 ft and the quantity spilled was 13.791 tmc, which is evident from data available in KSEB website. Thus, it can be seen that Kerala suddenly increased the releases from 46.26 Mm3 on August 14 to 390.51 Mm3 on August 15. Similarly, water released from the Idamalayar dam flows into the lower part of Periyar river. The release was 117.72 Mm3 on August 16 while the release from the dam was nil on August 14 and 15, and thus, the release was sudden.

Asserting that Tamil Nadu government was fully committed and concerned with the safety of the people living in the downstream of Mullaiperiyar dam, the State informed the SC that the officials of the two States were exchanging information and all possible steps were taken to safeguard the interest of both the States.

“In any event, the Maximum Water Level (MWL) of the dam is 155 ft and the flood cushion available for Full Reservoir Level (FRL) 142 ft. is 13 ft and that the dam is designed for a Possible Maximum Flood (PMF) of 2,12,000 cusecs and peak outflow of 1,43,000 cusecs could be passed through the spill gates,” Tamil Nadu pointed out.

Rejecting the averment of Kerala that Mullaiperiyar dam was exceptionally vulnerable as it has a large catchment, Tamil Nadu recalled that the construction of Mullaiperiyar dam commenced in 1886 and completed in 1895.

“The Mullaiperiyar dam, which is above the Idukki reservoir has a catchment of 612 sq. kms, with an effective storage of 7.66 tmc and a gross capacity of 12.758 tmc at the presently permitted storage level of 142 ft. Taking exception to the suggestion of Kerala on the need for ‘flexibility of operation of reservoirs’, Tamil Nadu government pointed out that the same was not a subject matter of dispute either in the first Mullaiperiyar case or the second case decided by the Constitution Bench.

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