GSI report in February 2009 before tender was given had indicated faults in right bank that needed additional investigation
The narrative in the Punatsangchu-I project so far has been that the sinking right side of the dam was a ‘geological surprise’ that became a major problem only from July 2013 onwards.
However, a Joint Audit Report conducted by the Royal Audit Authority (RAA) of Bhutan and the Comptroller General Audit of India (CAG) shows that the Punatsangchu Hydroelectric Project Authority (PHPA) project management, Water and Power Consultancy Services (WAPCOS) and Central Water Commission (CWC) knew that that were geological weaknesses at the area but still went ahead and approved the tendering of the dam on the same site.
A geo technical appraisal report prepared by the Geological Survey of India (GSI) saying GSI had identified some weak geological features at the dam site was deliberated by officials from GSI, CWC and WAPCOS on 10th February 2009. The report pointed out that this may entail additional cost.
The GSI report also said that additional investigations were required for the exact delineation of the weak geological features.
However, instead of conducting further investigations in what was both a cavalier and procedurally questionable manner, WAPCOS, on behalf of GSI, issued a clearance for the project dam bids to be opened on 16th February 2009.
Finally work was awarded to the dam contractor Larsen and Toubro on 27th March 2009.
However, an investigation report conducted between 29th April 2009 and 17th September 2009 by GSI showed serious problems in the current right bank of the project.
The GSI report said, “Examination of cores of the bore hill drilled on the right bank reveals the presence of a number of shear, fracture, faults zones represented by Nil to very poor core recovery with occasional clay gouge. As a result it can be concluded that the right bank is riddled with a number of shears and fractures.”
The report also said, “Adverse geological conditions are expected in the dam site. Hence proper remedial measures for strengthening the foundation and to control the water seepage through the dam sat and abutments should be taken to make the rock mass monolithic.”
The RAA report pointed out that the 3rd Authority meeting held on 8th August 2008 had resolved that “Bidding process be continued and price bids be opened only after receipt of confirmation by GSI.”
The Audit report says it is of the opinion that despite concluding the presence of weak geological features and envisioned geological surprises in the GSI report- the issuance of clearance for opening the bids, completion of the bidding process and handing over of the site to the contractor and that too by WAPCOS instead of GSI was not in line with the decisions of the third authority meeting.
The PHPA in its reply pointed out that Chief Engineer of Designs CWC on 10th February 2009 had said, “The only additional information is about the presence of shears and faults in the left and right abutment. These faults can be satisfactorily addressed technically but may entail additional cost. Thus the dam location and layout of various project components remain as shown in the tender drawings and no review thereof is warranted on geological considerations.”
The RAA report in a counter response quoted from the GSI report issued on January 2009 (before opening of the bid in 16th February 2009). The RAA pointed out that the initial GSI report showed that detailed investigation had not been done prior to the opening of bids, which had necessitated further investigations in order to ascertain the fault zones.
The RAA says that in view of the November 2009 report that confirmed the multiple faults it could not understand why WAPCOS had issued a clearance on behalf of GSI, when the initial study was not done comprehensively. It says that this clearly indicated that there was a gap in the study concluded and the clearance issued by WAPCOS on behalf of GSI.
PHPA Managing Director R.N Khazanchi said that the dam location had not been decided by the PHPA but by the two governments and all technical parameters had been review by expert Indian agencies like CWC, WAPCOS, Central Electricity Authority (CEA) and GSI.
The audit report is titled ‘Joint Audit Report on the Accounts and Operations of the P-I Hydro electric Project Authority’ and covers the period from April 2012 to March 2013.
The project’s original completion date was November 2016 but with repeated delays especially with regard to the sliding area the latest completion date is now April 2019.
The remedial measures which has delayed the project by more than a year, is still ongoing and will cost Nu 3.5 bn pushing up the total project cost from an Nu 94 bn to Nu 97.5 bn.