THÁI NGUYÊN — The investor of Núi Cốc Lake Dam in the northern province of Thái Nguyên was told yesterday to speed up work of repairing the facility.

In mid-June, the provincial People’s Committee announced a state of emergency due to leaks in the 480 metre-long dam.

At a scientific workshop held yesterday to discuss solutions, Đoàn Văn Tuấn, deputy chairman of Thái Nguyên Province’s People’s Committee, urged Thái Nguyên Irrigation Exploitation One Member Co Ltd to conduct repair work economically, ensuring quality, progress and safety.

He also asked the investor to urgently create a water-proof membrane by jet grouting for the dam’s body while dealing with water drainage system and repairing a roof on the downstream side. These works must be accomplished no later than August 30.

The workshop gathered leading irrigation experts, and the dam’s consultant unit - Việt Nam Hydraulic Engineering Consultants Corporation - proposed two measures to repair the leakage.

The first is to create a water-proof membrane in the dam’s middle core by jet grouting.

The second solution is to make a water-proof membrane in the upstream side by creating a water-proof soil layer consolidated by reinforced concrete. At the heel of the dam the unit will create a water-proof membrane in its foundation by jet grouting or a blanket on the upstream side.

Most participants were in favour of the first solution, agreeing that it is cheaper and enables the repair work without having to let out water. Creating a water-proof membrane by jet grouting in the dam’s body is technically effective and economical. The participants agreed that the second solution is ineffective and impractical, requiring the release of water.

Tuấn asked the consultant unit to obtain proposals, finish research and assessment document and submit a report to the local People’s Committee by Thursday.

A report from the provincial Department of Agriculture and Rural Development showed that the dam was leaking from its shoulder and from a downstream area. Large volumes of water were also leaking from parts of the dam’s left bank, with downstream drainage ditches suffering damage and the upper sloping roof sagging.

Núi Cốc Lake is a man-made lake built in 1973 and has seven dams. It provides 30 million cu.m of water for irrigation per year, 30,000cu.m of water for residents per day and between 30,000 and 150,000cu.m of water for the Yên Bình Clean Water Plant per day. — VNS