Analysis of the Effectiveness of Prototype Test for Lowering Tongguan Elevation by Utilizing and Optimizing Spring Flood in 2007

摘要

the paper has introduced the processes and results of the prototype test for lowering Tongguan elevation by utilizing and optimizing spring flood in 2007.Some achievements were gotten,such as the water level of Tongguan (6) at the discharge of1,000 m3/s decreased for 0.05 m,about 3.47 × 106 t sediment in Xiaobeiganliu reach was scoured,about t4.45 × l06 t sediment in Wanjiazhai Reservoir was scoured,the topset bed of the delta war scoured and pushed forward for 5.5 kin.Comparative analysis against the scouring effects of Tongguan elevation in 2007 with that in 2006 has been made in three aspects include the water level of Tongguan(6) at the discharge of 1,000 m3/s,the average bed elevation and the area of cross section.The results show that the test in2007 gets good effectness.The causes for slight lowering of Tongguan elevation in 2007include great increasing of roughness factor in Tongguan reach,great reduction of discharge and slight lowering of water level by backwater produced.It also points out that the siltation changes in Tongguan,with the water level at the discharge of 1,000 m3/s in Tongguan (6) as one of the representations for Tongguan elevation,sometimes cannot thoroughly reflect the variation in bed siltation.