Was the Jan 2019 slide that pushed P-1 project to 2025 preventable
November 2 | The Bhutanese
By Tenzing Lamsang
The right bank of the Punatsangchu I saw a major slide on 22nd January 2019 when the support measures of the August 2016 slide gave way, which has now pushed the completion date to 2025 from the recent completion date of 2024.
With a loan interest rate of Nu 12.6 mn a day the loan interest cost itself will be Nu 4.5 bn for a year not calculating revenue lost. The overall rectification works will also cost around Nu 1.5 bn.
Documents with The Bhutanese now show that the former outgoing management of PHPA-1 in the form of the former MD Amresh Kumar and JMD Dorji Pavo Phunthsok had both decided in September end to remove the August 2013 slide and some preparatory work had commenced in October 2018.
This is because it was earlier observed that the 100 MT capacity cable anchors helping hold the 2013 slide was already bearing a load of 108 MT.
Accordingly, work to move the highway back by 15 meters back from the slide area to allow access to the slide area for removal was started from 3rd October 2018.
However, an internal note by a senior and former PHPA official alleges that the new PHPA MD N.C Bansal and new JMD Karma Tshewang reversed the decision of the previous management and did not remove the slide but continued with excavations below the slide area in the dam pit.
The internal note says that only when more movement was detected then it was finally decided to remove the slide.
The note alleges that instead of excavating the slide and dumping the mud elsewhere it was simply thrown over the same slide, further adding pressure to it.
The note says that this then led to the January 22, 2019 slide where Nu 280 mn worth of earlier support measures were damaged in the form of cable anchors and 2-meter diameter concrete piles.
It says that after the slide there was accelerated movement of the slope and a cable anchor above the highway failed.
The note says that if the remaining excavation of the dam was done with extreme care by first removing the slide slump of August 2016, then the concreting of the dam could have been definitely started after the monsoon of 2019 and the project would have been completed by late 2023 or early 2024.
It says, “With this avoidable failure of August 2016 slide slump, both time and cost of completion of PHPA-1 have again escalated.”
The note also says that the failure of the cable anchors above the highway and the higher than average movement after the January 2019 slide was not included in a briefing made to the MoEA Minister and PHPA Chairman, Secretary of MoEA, MD DGPC and Director of DHPS when they visited the site on April 2, 2019.
The Bhutanese has also accessed the handing over notes of the former JMD and MD who were leaving to take charge of PHPA-II as the PHPA management was bifurcated into two.
The former JMD’s 8th October 2019 handing over note says, “After repeated and much persuasion it has been decided to remove the slide of August 2016 below the highway. Recession of the highway started on October 3, 2018 to enable this work.’
It says, “Scope of removal of overburden and support of the hill slope above EL 1265 (slide area) has varied extensively. With continued observation of creep of the slope and to provide long term stability, it is felt within RGoB that some level of removal of mass and support of slope would be needed above EL 1265 masl. This may kindly be reviewed on a regular basis.”
The former MD’s handing over note on October 23, 2019 says, “With the decision to recess the highway and offload the 2016 slide, the excavation in the pit is disrupted. Ways and means and methodology of work needs to be worked out in order to make possible the commencement of RCC (concreting of dam) from March 2019.”
A source said that there was an opinion of moving the slide even earlier but other stakeholders needed to be brought around.
The source said that the decision of the former MD and JMD was also approved by the main consultant Central Water Commission (CWC) who in turn had also been advised for the same by the Norwegian Geological Institute.
However, in response to the above allegations the current JMD Karma Tshewang said that the notes of the former JMD and MD while being there were not concrete decisions in by themselves as they had not provided detailed drawings and measures to remove the slide.
The source, however, said that the fact that the highway was being moved back already showed detailed action.
The JMD said that the current management had stopped the slide removal plans and went ahead with the excavation in the dam pit below the slide area.
The JMD said that this was in fact done with the approval of the same CWC consultant.
He said that once more movement was detected and then the CWC again advised to remove the slide.
When asked on why the slide muck was dumped on the slide the JMD said that it was done on the advice of the CWC which felt that it would stabilize the slide below.
A point to note is that the same Germany company Bauer who is being hired to do strengthening works on the right bank also saw 13 of its earlier piles or concrete pillars driven into the ground fail under the January 2019 slide.
The German company had been hired to do strengthening works from 2015-2017 as a sub contractor of L&T.
Here the JMD said that an explanation was sought form the company on why their piles failed and the company said that the piles were meant to take vertical load and not horizontal load and so the latest 26 piles of 2-meter diameter and 110-meter length would be strengthened with more and thicker steel inside it to withstand even horizontal slide pressure.
The JMD had also clarified earlier that the right bank slope movement had greatly decreased as per the latest data.
The notes, allegations and defense instead raises more questions on the competency of the CWC which is the lead consultant for civil works.
When the first slide occurred in July 2013 it was CWC that said it has the capacity to deal with the issue and accordingly rectification measures were done but they failed in the August 2016 slide which again failed in the 2019 slide.