POLAVARAM DAM DESIGN - ENGINEERS MISTAKES

PART-1

 

AP ENGINEERS FOR MISLEAD CHIEF MINISTERS AND THE CENTRAL WATER COMMISSION ON GODAVARI FLOODS

 

AP State Engineers misled AP Chief Minister to enter into impracticable and illegal Interstate agreement with Madhya Pradesh and Orissa during August and December 1978 ( extract of para 100 and 102 of Bachawat Tribunal report of 1979:

 

Clause VIII(E) of the Agreement dated the 7th August, 1978 between Andhra Pradesh, Madhya Pradesh and Maharashtra provides—

“(E) The state of Madhya Pradesh agrees subject to the State of Orissa agreeing for the construction of Polavaram project of the State of Andhra Pradesh  so that the maximum submergence in Madhya Pradesh territory at Konta does not exceed R.L.+150ft due to all effects including backwater effect.  The Polavaram project shall be designed for the maximum probable flood in consultation with the Central Water Commission so as not to exceed the limit of submergence mentioned above.”

Clause-II(I) of the Agreement between the states of Andhra Pradesh and Orissa dated the 15th December, 1978 provides-

“(I) The States of Orissa and Andhra Pradesh agree for the construction of Polavaram Project of the State of Andhra Pradesh, so that the maximum submersion in the State of Orissa territory at Motu/Konta does not exceed RL +150ft due to all effects including backwater effect.  The Polavaram Project shall be designed for the maximum probable flood in consultation with the Central Water Commission so as not to exceed the limit of submergence mentioned above”.

The Central Water Commission sent letter No.6/125/78-T.E/25, 12-2514, dated the 3rd July, 1979 to Andhra Pradesh Government, the material portion of which is as follows:

“It  is seen from the project report that the State Government of Andhra Pradesh have proposed the Polavaram project for an FRL /MWL of +150ft.  Therefore, prima facie, with MWL at Polavaram at RL +150ft. submergence due to all effects including that of backwater effect will always be more than RL +150ft. upstream and also at Konta.  The State Government will no doubt be working out the backwater effects at Konta/Motu considering advance releases from Polavaram Dam.  It is however seen that during the year, 1966 CWC had observed that a flood level at Konta had reached an RL 46.595m (RL +150ft).  This is an observed flood whose frequency is expected to be high.  For a flood at Konta corresponding to frequency the flood adopted for the Polavaram Dam (which will be between 1 in 500 years to 1 in 1000 years), the natural flood level at Konta should be expected to be substantially higher than RL +45.72m (RL +150ft.)  It would thus be seen that the stipulation that a flood level at Konta/Motu should not rise above RL +150ft will not be practicable and that the agreements entered into by the States may have to be suitably modified.  Perhaps this situation about observed flood level at Konta might not have been known to you and other states when this agreement was concluded.”

PART-2

AP STATE ENGINEERS DESIGNATED POLAVARAM AS A BARRAGE AND THEREBY MISLEAD CENTRAL WATER COMMISSION TO ACCEPT PEAK FLOOD OF 36 LAKH CUSECS FOR THE DESIGN OF THE POLAVARAM PROEJCT  (E-MAIL DT.11-12-2009)

 

Central Water Commission

Hydrology (South) Directorate

Letter dt.13-2-2008

In the earlier suties, the project authorities proposed a design flood of 80,000 cumecs (36 lakh cusecs).  These studies were based on flood frequency approach and the observed data for the period 1981-1995 was used to obtain flood of 500-year return period.  Central Water Commission accepted this estimated flood of 80,000 cumecs in 1979.  From the records, it is found that this flood was accepted when the structure proposed at the project location was a barrage.  In the revised reports submitted earlier, same design flood i.e.80,000 cumecs has been recommended and no revised studied were carried out.


 
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