Dechen Dolkar
A joint technical assessment is underway for the 1,200 MW Punatsangchhu-I Hydropower Project (PHPA-I) dam, with technical teams from Bhutan and India evaluating stabilisation measures for the right bank slide.
Both countries have agreed to proceed with the construction of the dam, integrating necessary stabilisation measures to address the issue.
An official from the Ministry of Energy and Natural Resources (MoENR) said that technical deliberations are being conducted during Technical Coordination Committee meetings.
“Geo-technical investigations have commenced at the site following joint visits and discussions,” the official added.
The first phase of borehole drilling has been completed, and the findings are currently under analysis. This will be followed by further technical deliberations as the teams evaluate design parameters, modeling, slope stability, and other critical factors.
The timeline for commencing and completing the stabilisation measures will be determined only after these measures are finalised, according to the MOENR official.
The finalised measures will define the scope and complexity of the work required.
“In a mega project like the PHPA-I, which has experienced significant delays due to unprecedented geo-technical challenges, during the implementation of stabilization measures until the dam construction is complete,” the official said.
While contingency plans and scenario analyses are being developed, the project timeline remains uncertain.
The design and construction of the Punatsangchhu-I dam and its associated structures will proceed once the stabilisation measures are implemented.
However, the additional cost estimate for these measures will only be finalised once the final decision is made.
The project’s cost efficiency will largely depend on the tariff rates at the time of commissioning. Efforts are underway to minimise costs, including rationalsing the workforce to reduce overhead expenses.
The timeline for the resumption and eventual commissioning of the project can only be determined once the stabilisation measures are finalized. The project is expected to take at least five more years to complete.
The construction of the PHPA-I dam was halted following a major landslide on the right bank of the site, causing an indefinite delay. Multiple rounds of geo-technical studies were conducted, and two potential solutions were proposed: constructing either a dam or a barrage to salvage the project.
The first major landslide occurred in 2013, leading to rectification measures. However, these measures failed in 2016 and again in 2019, causing further delays.
The government of Bhutan proposed the construction of a barrage as a viable alternative to a dam. A detailed project report (DPR) prepared by Swiss company Stucky, at a cost of Nu 150 million, found the barrage to be feasible at a location 2.6 km upstream from the current dam site. However, Indian officials raised safety concerns and expressed reservations about the barrage proposal.
The cost overrun for PHPA-I has surged to a staggering Nu 100 billion, up from the initial project cost of Nu 35 billion. So far, around Nu 86 billion has been spent.
The Punatsangchhu-I project is being executed under a mutually beneficial bilateral agreement between the governments of Bhutan and India. The construction of project began in November 2008.