Day Dam - A Flood Diversion and Natural Disaster Mitigation ProjectPanorama of Day Dam Project Project location: Day river in Ha Tay Construction time: Old dam: 1934 -1937 Rehabilitation: 1974 -1975 Project tasks: Diverting flood on Red river to Day river in large flood years. Draining for areas on two sides of Day river in years without Red river flood diversion. Major technical parameters: - Work grade: Special grade - Flood diversion discharge: + Before 1974: 3000 m3/s + After 1974: 5000 m3/s Scale and structure of the project major works: Before 1934, the French selected a design from 33 designs of 8 contractors for construction of Day dam. The selected design has a dam of light structure with 7 roof gates, width of 1 gate is 33.75m. Sill elevation is at +7.00, pier width is 3m, face wall height is 2.30m, elevation of gate bottom is +12.5m. Upstream water level elevation is +14.00. The gates are operated with hydraulic principle. Upstream apron is 83.10m long with 3 protection layers including crushed stone, concrete and coarse stone. Stilling basin is 13m long, constructed of reinforced concrete of 1.5m thick. Downstream apron is 15m long consolidated with pre-casted concrete slabs sized 2.95 x 1.95 x 0.80m. After construction, the dam was put in trial operation 3 times in 1939, 1941, 1942 with low heads, these trial operations were successful. However, in 3 times of official flood diversion (in 1940, 1945, 1947), the project was seriously damaged at the gates No. 1, 3, 6. In 1974, the Ministry of Water Resources (now the Ministry of Agriculture and Rural Development) assigned the Hydraulic Design Institute (the precursor of HEC-1) to rehabilitate and upgrade the existing dam. On 07/12/1974, design of the Institute was approved by the Government with following contents: Replacing the roof gates with electrically operated segment gates. Raising bottom elevation of main beam from +11.50 to +13.30 Rehabilitating energy dissipator apron Raising upstream dike Improving Day river bed Day dam was improved with 6 gates sized 6 x 33.75 x 4.9m, horizontal pressure of 700 tons, the dam was safely operated. The successful improvement of Day dam is an important technical scientific achievement of water resources sector of Vietnam involving research, mechanical fabrication and construction, especially the important role of Hydraulic Design Institute (now Vietnam Hydraulic Engineering Consultants Corporation - JSC.). It was the first time the Institute was assigned to directly manage the construction which was one of two national important constructions in period 1974-1975. With high responsibility spirit and determination of assertion of self ability, the Corporation staffs successfully fulfilled the design and construction of Day dam and were awarded by the State the Labor Order of third class, the first order of the Institute after nearly 20 years of operation from the foundation. Total hits 61 - Last update 17/02/2014 10:44' SA |
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