Troubleshooting at Ban Ang Hydropower Plant

(Baonghean) - On February 23, Nghe An Newspaper published an article about Ban Ang Hydropower Plant blocking the flow, National Highway 7 seriously eroded, reflecting on the "Ban Ang Hydropower Project" which had just blocked the flow for a load test run for nearly 2 months, but now many sections of the hydropower reservoir along National Highway 7 have shown signs of erosion. Immediately after that, Nam Mo and Nam Non Hydropower Joint Stock Company coordinated with relevant agencies to come up with a solution.

Mr. Tran Duc Thanh - Head of Planning Department of Nam Mo, Nam Non Hydropower Joint Stock Company (project investor) said: After receiving feedback from some newspapers on the media, Nam Mo, Nam Non Hydropower Joint Stock Company coordinated with the local road management agency, Cua Rao Road Management Department, to check the contents according to the feedback raised by the press agency to take remedial measures.

Mr. Tran Duc Thanh added: After conducting the water storage test, the investor coordinated with the Road Management Department II to inspect the site, review the documents and make some specific assessments as follows: When Ban Ang hydroelectric reservoir stores water for a long time, some sections of National Highway 7 running close to the reservoir are often flooded with talus, which has a potential risk of affecting the roadbed at Km165+025 -:- Km165+075; Km165+425 -:- Km165+625.

The cross-culvert at Km 165+570 was flooded, changing the flow regime and requiring recalculation to determine the flow through the culvert according to the flooded flow regime. Apart from the above-mentioned notable points, other locations on National Highway 7 (adjacent to the Ban Ang hydroelectric reservoir) have not shown any signs of being affected.

After conducting the assessment, the investor hired a consultant to conduct a survey, make a specific assessment, and propose a solution to completely handle and ensure long-term safety for National Highway 7. The parties have agreed on a solution. Specifically: For points with potential risk of slope landslides during the water immersion process, the negative slope will be covered with concrete trays + stone for roofing. For the horizontal culvert at Km165+570, a box culvert with a 3m x 3m aperture will be added next to the old culvert to ensure drainage during the flood season, while raising the roadbed and changing the road structure of this section with cement concrete.

Ban Ang Hydropower Project. Photo: Van Truong

After agreeing on the treatment plan, the investor requested the consultant to design in detail. According to the plan, the design work will be completed in February 2017, construction will begin in early March 2017 and will be completed before the 2017 flood season.

Mr. Thanh said: “Although the treatment will incur a large additional cost for the investor, we are still ready. Currently, we have selected a unit with a lot of experience to be able to proceed with the treatment immediately after the design is available and the Road Management Department II agrees.”

Mr. Dao Duy Tan - Chairman of the Board of Directors of Nam Mo Hydropower Joint Stock Company, Nam Non shared more: Ban Ang Hydropower is a small hydropower project with low water column. The total capacity of Ban Ang Hydropower Reservoir accounts for 2.977 million m3, of which the useful capacity (used for power generation) accounts for 0.865 million m3. The structure of the project is simple, the project only has a spillway, no dam. The entire water flow discharged through the project is carried out through generators and through 6 sets of flat valves measuring 15m x 10m. In addition, the project also has a sand discharge sluice measuring 4m x 4m, in case of necessity, the entire amount of water in the lake can be discharged to return the lake bed to its natural flow.

The Ban Ang Hydropower Project, invested by Nam Non and Nam Mo Hydropower Joint Stock Company with a capacity of 17MW and a total cost of over VND520 billion, started construction in April 2015 by Song Da 4 Joint Stock Company. After completion, it will be put into operation to supply electricity to the national grid with about 70 million kWh/year. The investment in the construction of the Ban Ang Hydropower Project is expected to contribute to restructuring and accelerating economic development for localities along National Highway 7. It is expected to contribute to the local budget about VND12-13 billion in VAT, water resource tax and forest environmental fee, creating jobs for 30-40 workers with stable wages.

Van Truong