P-1 likely to take off with proposal for a Dam but with due mitigation measures on right bank

The much delayed 1,200 MW Punatsangchu-I hydro project is finally on the verge of taking off after a recent meeting of the Technical Coordination Committee (TCC) in Delhi.

In the TCC meeting in Delhi both the Bhutanese side and Indian side made their presentations and are putting up a proposal on which the final decision is to be taken by the Project Authority.

Earlier, after the rock samples were drilled from the right bank to check its stability there were two reports with the Bhutanese report pointing to deep seated fractures and shear zones and asking for major mitigation measures.

The Indian report while acknowledging the fractures did not see it as big a problem and wanted to go ahead with the dam.

The two sides had meetings to reconcile their reports and are finally coming around to a common understanding.

According to a source, initially the Indian side did not agree to it being very serious but they have now agreed to the need for mitigation measures and so the authority meeting will decide the final mitigation measures and the way ahead.

It has been learnt that the talks are progressing positively and TCC may jointly agree to the dam provided that due mitigation measures are presented and taken on the right-bank side.

The mitigation measures on the right-bank side will go into whether the muck overhead needs to be removed or not, possibly concreting the whole right bank and other measures.

The authority will decide on this and the consultants may be asked to come up or design detailed mitigation measures on the right bank to address the Bhutanese concerns.

Then based on the Bhutanese demand being agreed to the authority is also likely to agree to the dam, but with mitigation measures in place first.

The earlier Bhutanese proposal to build a barrage instead of a dam is likely to be given a quiet burial.

The authority meeting will most probably be after the National Assembly session which ends on 3rd July 2024.

A major concern for the Bhutanese side was the long-term safety of the dam and this is why there was initially no agreement between both the sides, and the Bhutanese side only budged after major mitigation measures are being agreed to.

The PHPA Authority is comprised of Lyonpo Gem Tshering, , Ministry of Energy and Natural Resources (MoENR) as the Chairman, Karma Tshering, Secretary, MoENR,  Leki Wangmo, Secretary, Ministry of Finance, Dzongdag, Wangduephodrang, Tshering Wangmo, Director, Department of Immigration, Anurag Agarwal, Additional Secretary & Financial Advisor, Ministry of External Affairs., Ajay Tewari, Addition Secretary, Ministry of Power and Anurag Srivastava, Joint Secretary (North), Ministry of External Affairs with

 Mr. Sanjeev Kumar Yadav, MD of PHPA-1 as a member Secretary. 

The permanent invitees to the board are Ambassador of India to Bhutan, Ambassador of Bhutan to India. (D&R), Central Water Commission, (Hydro), Central Electricity Authority, Dy. Advisor (Energy), NITI Aayog, MD DGPC, Director DHPS, CEO BPC, JMD PHPA-1, Director (Technical), PHPA-I and Director (Finance), PHPA-1.

Last year Bhutan and India agreed to drill multiple rock samples into the right bank area to check for its stability to see if a dam is feasible or not.

The rocks show fractures along the whole right bank in lots of places where boreholes have been done.

On the Bhutanese side the main focus was on the need for a thorough mitigation and right bank stability before the dam could even be brought up.

The Bhutanese side wanted mitigation measures before going ahead with the dam and this is what is likely to have been agreed to before the dam is agreed to

Background

In 2008 the then PHPA MD R.N Khazanchi proposed to change the original dam site to generate more power which was agreed to by the then cabinet.

A Joint Audit Report of the two countries said the PHPA, its main consultant WAPCOS and CWC knew that there were geological weaknesses at the right bank area but still went ahead with the tendering of the dam.

The problem made itself known with a major slide on the right bank in July 2013 which at the time WAPCOS and the civil consultant CWC said could be fixed with Nu 3.5 bn of mitigation measures. However, despite the measures another major slide happened in August 2016 and again despite additional mitigation measures the same area slid on 22nd January 2019. A total of Nu 4.85 bn spent on mitigation measures had failed.

After this, the government in the 21st PHPA Authority meeting in January 2019 insisted to the Indian consultants to come up with a comprehensive solution.

The report was submitted by CWC on 1st October 2019 and detailed drawings later in December of the same year.

One suggestion of the CWC was that the dam on the right bank side be constructed over 288 concrete piles driven into the ground to avoid excavating the shear zone below the right bank side

The Bhutanese side not very convinced with the idea of concrete piles under the dam for the long term and feeling the need for an overall review of CWC’s proposal called for a review in the TCC meeting

The National Hydro Power Corporation (NHPC) was then called upon to do a third-party review of the WAPCOS and CWC proposal.

The NHPC in mid 2020 presented its review of the CWC report as a third party and disagreed with the CWC assessment and said it is not safe enough to build a dam.

The NHPC instead recommended to build a smaller structure in the form of a barrage 820 meters upstream of the current site.

The project authority asked the two companies with different findings to reconcile their contradictory findings. The two companies came back giving a factor of safety of 1.4 safe enough for a dam.

However, this called into question how the NHPC drastically changed its own stance and data to fit in with the CWC.

The government through DGPC hired a foreign company Stucky to do a review of the review which also showed the current site to be unsafe with a recommendation for a barrage.

With no agreement, a joint expert committee was set up by Bhutan and the Government of India (GoI) but they were unable to agree on the future course of the 1,200 MW Punatsangchu-I, with the Bhutanese side insisting on a barrage due to safety concerns over the dam site, and the Indian side insisting that the dam can be done at the dam site.

The Bhutanese side softened its stance in 2023 and has agreed to do a set of geo technical investigations on the right bank area and the dam site near it. The findings were to look at the geological conditions.

If the dam was abandoned of the Nu 23 bn spent on it around half of the cost in other structures like the 4 large de-silting chambers and around 11 km of tunnels could have been reused for the barrage.

Nu 83 bn has been spent on the project so far as of last year.

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