Dechen Dolkar  

The detailed project report (DPR) for the construction of a barrage at the 1,200MW Punatsangchhu Hydroelectric Project I (PI) has been delayed and is now expected to complete by the end of this month.

It was supposed to be complete by February end.

Druk Green Power Corporation’s (DGPC) Managing Director (MD), Dasho Chhewang Rinzin said that when the core drilling works were about to complete, there was lockdown in the Punatsangchhu projects’ areas after workers tested positive for Covid-19.

He said that the Wangdue Covid-19 Task Force eventually facilitated the movement of the camps of the core drilling team, the geotechnical expert and the DGPC support team. They were moved to the opposite left bank of the Punatsangchhu and core drilling works restarted.

“The core drilling and the collection of samples could finally be completed under the bubble mode at the end of February 2022,” Dasho Chhewang Rinzin said.

The DPR for the barrage for the PI project is being prepared by a company from Switzerland, Stucky.

The data from the geotechnical investigations have already been made available to Stucky.

He said that the test results from the last core samples that were sent to India should become available within a week.

“After incorporating the findings on site from the core drilling and the test results, Stucky will finalise the DPR for the barrage option,” the managing director said, adding that the DPR is almost ready. Only the final incorporation of the results of the geotechnical investigations is left.

Investigations and the test results of the samples need to be incorporated into the geotechnical modelling and 3D structural analysis for ascertaining the most optimal and cost-effective barrage option.

“Stucky is putting in all efforts to complete and submit the draft DPR within March 2022,” Dasho Chhewang Rinzin said.

After review and comments, if any, from the government of Bhutan side, the final DPR is expected to be submitted by mid-April 2022.

The consultants from Stucky have been ‘very confident’ that the barrage option at the selected location is feasible based on which they are in the final stages of submitting the DPR.

He said, “Both governments are interested in finding a way forward with the project.” The stability and safety risks with the dam have been deliberated at the Authority. The government has conveyed its views on the dam to the government of India.

“Until recently, consultant Centre Water Commission (CWC) of India was in direct contact with Stucky in respect of the ongoing preparation of the DPR for the barrage option,” he said.

When the DPR for the barrage option is submitted, the two governments are expected to consider a way forward with the PI project.

If the barrage option is adopted, the barrage and the 2.5km of connecting tunnels to the already constructed desilting arrangement would replace the dam. All other features of the project remain the same as has already been constructed.

Due to differences in operational parameters of the barrage option, it is estimated that the generation loss could be about 1.5 percent of the design generation with the dam.

However, the cost of the barrage is expected to be lower which would make it cost-effective compared to other alternatives if any.