The Bhutanese Leading the way.
So far, the delays and failures in the 1,200 MW Punatsangchu I and 1,020 MW Punatsagnchu II projects have all been laid at the floor of ‘Geological Surprises,’ which basically means that whatever happened was not known in advance and so it could not be prevented.
The P I project is still stuck in limbo as while a dam has been agreed to in principle, both Bhutanese and Indian sides are unable to agree on the extent of the protection measures to be done on the right bank.
The Bhutanese side wants much deeper level of protection works as they believe the problem is deep within, while the Indian side wants a lesser amount of work done.
The 1020 MW P II project was delayed for few years when the cavern of the Downstream Surge Gallery (DSG) collapsed killing six workers.
Though complete, P II is unable to produce power or revenue due to water seepage from the powerhouse ceiling being the latest challenge.
Now the former Director Technical of the P-I and P-II project from 2010-2017, former Central Water Commission (CWC) member as Ex-officio Additional Secretary rank to Government of India, Yoginder Sharma, has come out in the open and squarely put the blame for the condition of both the projects on the overall project consultant Water and Power Consultancy Services (WAPCOS) and the civil works consultant and expert CWC.
Yoginder Sharma has not been secretive about his views, and he has presented papers on the matter, taken part in YouTube presentations and discussions with other experts and has written detailed technical articles on how WAPCOS and CWC are to blame for the issues in P I and P II and even published them in online publications.
He has written saying, “Harping on the geological surprises was only a scapegoat for the lack of proper geological investigations and inappropriate design done by the Consultants.”
Punatsangchu I
Yoginder in his articles, slides and videos essentially says that the P I dam site was shifted 1.5 km upstream as it was thought that it would generate 105 MW more power and the dam depth below the river would be a lesser 45 meters.
He said in 2009 WAPCOS and CWC did tender stage investigations with Bore holes and drift and came up with drawings and it indicated no shear zone.
Yoginder says the consultants had failed to detect and delineate the shear zone in the geological investigations forming the basis of selection of the present dam site in 2009.
A Joint Audit Report of the two countries main Audit bodies earlier had said WAPCOS and CWC in 2009 knew that there were geological weaknesses at the right bank area but still went ahead with the tendering of the dam. This is well known and has been reported by this paper in the past.
However, what is not well known and essentially exposed by Yoginder is that in in 2010-11 the Consultant WAPCOS carried out a geological investigation for excavation of the dam pit.
Yoginder says that shear rock mass were found in multiple drillings at this time, but the consultants did not do any analysis or do additional drillings to see if this was part of one big shear zone. This was the second miss, according to Yoginder.
He says a third miss happened when the senior resident geologist of the project in 2011 gave a report to WAPCOS and CWC saying there is a 15 meter thick fractured rock mass present all along the foundations of dam blocks 7,8,9,10,11 and 12, with shear seems dipping in to the valley, having the potential of sliding .
The report also informed of the 1.5 meter thick shear zone dipping in to the hill which would be getting exposed in excavation of dam blocks 11 and 12 .
The report further warned that the layered rocks with softer beds or shear zones confined between harder beds are always prone to shear stress problems or sliding.
The geologist’s report said such bands are prone to slide under forces and hence require proper treatment during excavation.
The report specifically asked to provide adequate support and treatment, which was not designed as per the needs.
In short the report of the geologist was indicating a shear zone and this too was ignored by WAPCOS. CWC only designed 7.5 meter long rock anchors for the right bank which was not sufficient.
Excavation continued with only minimal protection measures until the first major slide happened in 10 July 2013.
The slide saw 500 meter height area of the right bank of 40 to 50 meter thickness move 2.5 meter downwards and 5 meters towards the front.
After the slide a lot of drilling was undertaken to find out the size of the shear zone and here Yoginder says during many instances of drilling, undertaken for installation of micro piles, the drill rod used to drop for one to two meters depth, by itself without requiring any drilling effort, thereby indicating that the entire hill mass in the Right bank has been rendered geologically weak and porous resulting from the massive movement of the hill mass.
Given the above fact Yoginder has questioned if the right bank will make a safe and water-tight abutment to a dam.
Yoginder is not alone in his critical assessments.
In a YouTube discussion where Yoginder made a presentation to eminent experts in India, people shared their views.
Dr Yash Pal Shardha a retired and senior Engineering Geologist from the Geological Survey of India said, “This project is the best example of deceit and dishonesty by project people. A very good investigative Detailed Project Report at one place was done but the project was shifted to another place without conducting any investigation and whatever investigations were done were cooked up data knowing fully well we are going to face problems and we went for the tender stage and drilled a few holes and the project started for construction and now see fate of the project and will it ever be completed.”
A.K Mishra the former MD of the MHPA project said that once the dam is filled and the right abutment becomes charged with water then there is a chance of water bypassing the right bank and coming out on the other end.
After the first slide in July 2013, WAPCOS and CWC had come up with a series of rectification measures that cost a total of 4.85 bn but they failed in August 2016 and January 2019.
Some may wonder why all off the above is relevant today, but it is relevant as the cause of the problems, WAPCOS and CWC, in essence are still driving discussions on rectification measures that can affect the P I dam.
The CWC in October 2019 proposed to build the dam on the right bank side over 288 concrete pylons.
The Indian experts in the YouTube discussion all pointed out that the only dam built on concrete pylons is a 30 meter dam and P I is a 136 meter high dam with a weak right bank.
The former CMD of National Hydro Power Corporation (NHPC) Balraj Joshi in the same talk pointed out his worry about the plunge pool downstream where the force of the water coming out of the dam hits the riverbed in light of the shear zone.
Punatsangchu II
The other area where Yoginder Sharma says WAPCOS and CWC failed is in the 1,020 MW P II project in terms of the Downstream Surge Gallery (DSG) collapse.
The P II powerhouse was originally supposed to be on the surface but the issue was the amount of muck that would be displaced as well as the need to build huge retention walls.
It was then agreed that it would be an underground one on the right bank.
Here Yoginder says that the change of the Power house complex to the underground site selected by the consultants was based on limited exploration through one proper borehole only as the additional borehole was driven by the consultants at a different far away location to that was suggested by their own geology consultants and the hole did not even penetrate through the level of crown (roof) of DSG and ended much above it.
Thus the rock mass and type in the DSG crown was not explored at the particular specific location suggested by the geology consultant.
Yoginder writes that the geology consultant to WAPCOS in-fact had reported, in 2010, saying less information about the DSG is available for the selected location of power house complex of P II.
Even though only one proper hole had been drilled the geologist based on the available samples warned WAPCOS and CWC that a shear or highly fractured zones may be encountered in the Downstream Surge Gallery cavern and so to minimize the size of the DSG as far as possible.
Since minimal geological exploration had been done by WAPCOS the location of the DSG was found to be grossly wrong.
In reality a minimum of 4 deep boreholes needed to be dug with two criss-crossing each other so that every aspect of the geology was explored.
Instead WAPCOS and CWC instead of reducing the size of the DSG planned it to be made even bigger. Works were awarded by mid 2011 for the overall powerhouse complex.
In 2013 as digging was going on a major shear zone was encountered that went across the DSG, Transformer Hall and the Power House. The project management proposed shifting the powerhouse and the transformer hall to avoid the shear, which the consultants agreed to do by 18 and 36 meters respectively.
The consultants (WAPCOS and CWC), however, rejected the advice of the project management to not build a big DSG but to shift it away from the shear zone and have a set of smaller chambers, which shall be interconnected by a network of tunnels to be the DSG.
The consultants came up with protection measures for the DSG but it was not enough.
The project management’s proposals for stronger protection measures for the DSG as they dug down was not accepted and as a result on 3rd March 2016 there was a major cavern collapse that happened killing 6 workers leading to the formation of a huge cavity of 91m height, 45m width and 70m length above the crown or roof of the DSG Cavern.
This would delay the project by 4 years and lead to additional costs.
Ultimately, after this, the consultants WAPCOS and CWC had to follow the original project management suggestion of building a smaller network instead of one big DSG.
Yoginder said that while excavating the shear zones it led to seepage of water.
He also wrote that a Tomography study indicates that a bigger zone surrounding the profile of the cavity is disturbed.
Yoginder in his articles and presentations said a proper 3D Numerical Analysis was done by the National Institute of Rock Mechanics (NIRM) but only in 2018 when they were brought in too late. The NIRM analysis does indicate that there was an affected zone around DSG cavern which had tensile stresses present and it followed the profile of shearzone in the DSG.
He pointed out that if the 3D Analysis incorporating regularly given information of geology encountered and readings of instruments were done by the Consultants at various stage of excavation between 2013 to 2016, the failure could have been foreseen.
In fact an analysis done by civil contractor provided to Consultants in 2014 did indicate such apprehension of big failure in DSG by the consultants ignored it.
Going through the articles of Yoginder it seems plausible that the current seepage affecting the P II project could be due to the multiple shear seams present in the crown or roof of the three caverns of the larger power house complex.
The shear seems had been grouted by pouring in liquid cement to make it fool proof against seepage but the continued seepage shows it has not worked.
Yoginder says that WAPCOS and CWC in their DPR report also failed to detect a major shear zone present under the dam site of P II which contributed to the delay of P II by one more year as well and raises safety questions as well.
When construction was well under way the project management found a major shear zone under the dam foundation with the width of 30 meters and depth of 13 meters running across 4 blocks of the dam.
Yoginder says damage control was done with shear zone treatment , but at a great cost both in terms of the big time delay of more than one year and extra cost of Nu 387 million, put to the project in exploring the shear zone and treating it. He said, the success of the shear zone treatment would be tested with time.
Yoginder says that one very vital requirement from the Consultants remain unfulfilled by them, that is the consultants have never submitted any Design Document to the Project Management.
Design Documents are a must to be in custody of the Project Management to evaluate integrity of any project’s features in any eventuality occuring anytime over project’s lifetime spanning over 100 years or so.
Conflict of Interest
The issue is not only the competence of WAPCOS and CWC in the P I and P II projects as pointed out by Yoginder and other experts from India, but also the inherent conflict of interest of the role of the consultants in the two projects.
In a slide presentation online Yoginder does not spell it out, but indicates this.
An organization chart or project implementation structure shown by him shows that CWC is there as the supervisor of the project construction at level 4 along with WAPCOS.
The CWC and WAPCOS are on level 3 as the consultants doing the DPR, cost and work, investigation and designs for construction.
The again CWC and WAPCOS are also part of the Technical Coordination Committee at level 2 as part of the technical decision making authority.
CWC is also there at level 1 in the PHPA Authority itself as the technical permanent invitee to the body that approves the DPR and cost of the project.
This structure is inherently flawed with a lot of conflict of interest where WAPCOS and CWC are the consultants on the ground but they are also the regulators over themselves, technical experts over themselves and ultimately in the highest decision making body over themselves.
This is like a contractor in Bhutan becoming the site engineer, member of the procurement committee and member of the ministry’s top agency to decide on the construction work.
This conflicted structure ensures that WAPCOS and CWC will have a strong conflicted interest to never admit their fault and also keep deciding the way forward in the absence of other experts in a way that does not expose them.
The 720 MW Mangdechu project also had its fair share of challenges but since the NHPC was the main consultant it was checked by the CWC ensuring no conflict of interest.
