Irrigation System Under Repair

摘要

Rehabilitation work has been carried out on the Bai Thoung irrigation project in northern Vietnam to safeguard water supply to the province and bring areas back into irrigated agriculture. Pan Dong explains how a diaphragm cutoff wall played an important part in the rehabilitation works The Bai Thoung project on the Chi river in northern Vietnam was built in the 1920s to supply irrigation water to an area of 50, 000ha, and domestic water for 130,000 people in the city of Thanh Hoa. The project includes a 170m long concrete diversion weir, lined with hand-placed riprap, which has been designed to raise the dry season flow level in the river by 6m. The average discharge of the weir in the dry season is less than 50m-Vsec and its average discharge in the wet season is about 500m~3/sec. In addition, the project also comprises a three-bay scouring sluice; headworks and navigation structure with seven outlet gates; and one lock gate and retaining wall.