The crucial question to be answered is:
What if Mullaperiyar dam breaks, in spite of all the strengthening done so far, with the dam burst resulting from torrential rains or earthquakes or due to structural weaknesses of the aging 116 year old dam?
The dam holds 15 tmc of water (at its full capacity) at an elevation of approx 3000 ft from msl. The water level has a height of 155 feet at its maximum level and length of 1200 feet at the top and 139 feet at the base.
If the dam breaks, what is the rate of flow of water downstream? What will be the height of the column of water and the force with which it will strike Idukki Dam, 45 kms downstream?
Even if Idukki Dam is able to hold the 15 tmc of water, will it sustain the force of the gushing waters and the waves formed in the Idukki reservoir?
How much time will it take to traverse the 244 km course of Periyar River to reach Arabian Sea?
Considering the topography of the mountain range through which the gushing waters have to pass through, where are the possibilities of new ribs or new rivers (flow channels) being formed? Which areas in Kerala will be most affected by this scenario?
What will be the impact on 11 other dams downstream and the waters held by them?
Assume the spillways are able to divert some of the water.
Consider the main dam and baby dam also breaking.
-Joseph Ponnoly
What if Mullaperiyar dam breaks, in spite of all the strengthening done so far, with the dam burst resulting from torrential rains or earthquakes or due to structural weaknesses of the aging 116 year old dam?
The dam holds 15 tmc of water (at its full capacity) at an elevation of approx 3000 ft from msl. The water level has a height of 155 feet at its maximum level and length of 1200 feet at the top and 139 feet at the base.
If the dam breaks, what is the rate of flow of water downstream? What will be the height of the column of water and the force with which it will strike Idukki Dam, 45 kms downstream?
Even if Idukki Dam is able to hold the 15 tmc of water, will it sustain the force of the gushing waters and the waves formed in the Idukki reservoir?
How much time will it take to traverse the 244 km course of Periyar River to reach Arabian Sea?
Considering the topography of the mountain range through which the gushing waters have to pass through, where are the possibilities of new ribs or new rivers (flow channels) being formed? Which areas in Kerala will be most affected by this scenario?
What will be the impact on 11 other dams downstream and the waters held by them?
Assume the spillways are able to divert some of the water.
Consider the main dam and baby dam also breaking.
-Joseph Ponnoly
5 comments:
http://www.thehindu.com/news/states/kerala/article2694363.ece (The Hindu, Dec 2 2011)
According to M.Sasidhar, Retired Chief Engineer and Member of the Inter-State Water Authority Committee, in case Melluperiyar dam collapses, the Cheruthoni and Kulamavu dams could fail first. The Mullaperiyar waters would rush down at 50 to 60 kms an hour through a 10 km gorge downstream and then through a 15 km slope down to the Idukki reservoir 1200 feet below in elevation. The water column could be 20 to 30 feet high and could wipe out everything on its way. The force of water could move away hills.
“The huge volume of 12 TMCft of water spread out in an area of 4668 acres when gushed through an opening of the present Mullaperiyar dam, the height of water that will rise along its path to Idukki is unimaginable. The enormous force that is created by the surging water when it reaches the Idukki reservoir will create huge waves, just like tsunami waves, in Idukki reservoir.
“The nature and magnitude of such waves could be very high, and it can generate great forces on the Idukki dam structures, especially Kulamavu masonry dam structure first, as the dam was constructed with rubble masonry. This could happen even if the water level in the reservoir is low.”
He added that apart from generating high stress on the three dams holding Idukki reservoir, the surging waves could overtop all the three dams.
The team from IIT Roorkee has started the 'dam break' impact analysis:
http://www.thehindu.com/news/states/kerala/article2760988.ece
Here is the report of the dam break analysis in full.
http://expert-eyes.org/mullaperiyar/
Here is the report of the dam break analysis in full.
http://expert-eyes.org/mullaperiyar/
Here is the dam break analysis report in full:
http://expert-eyes.org/mullaperiyar/
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