黄河流域典型沙质河段冲淤量预估方法及应用

Prediction method for erosion and deposition on typical sandy bed sections of the Yellow River and its applications

为扭转宁蒙河段水沙失衡趋势,合理分配输沙用水,提高河道排洪输沙效率,本文根据黄河流域典型沙质河段实测资料,依照河流动力学原理,通过引入水流挟沙力,建立了不同水沙条件下典型河段冲淤量预估方法。实测资料检验表明,该方法能够简便快速地根据进口断面洪水实测水沙因子,较好地预估下游河段的冲淤量。通过分析不同条件下预估冲淤量可以得出,在经历多年淤积而致主槽严重萎缩的情况下,内蒙古巴彦高勒-头道拐段以1 500 m3/s流量级冲刷河槽效率最高,建议在水库调节初期采用小流量多阶段冲刷的方式,达到重塑河槽的效果。根据不同的进口条件快捷估算河段冲淤量,能够为河流水沙过程调控以及河道整治规划提供技术支撑。

To reverse the unbalance of water and sediment in the Ningxia-Inner Mongolia reach of the Yel-low River, a method was proposed to predict the volume of silting sediment according to various observedsediment load and discharge data from some typical sandy bed sections. The method is able to optimize theallocation of water requirement for sediment transport and to improve its sediment transporting capacitybased on the principle of river dynamics. The measured test data shows that the method can assess easilyand quickly the sediment factors with the runoff flow,thus giving a better estimation of the silting sedi-ment volume in the reaches downstream. Analysis of the predicted volumes of silting sediment under differ-ent conditions has shown that the section starting from Inner Mongolia Bayangaole to Toudaoguai possessedthe highest efficiency of riverbed scour with a speed of 1500m3/s under the current situation,thus recom-mends the approach of low flow multi-stage flush to reshape the river channel in the initial adjustment. Inaddition, according to the amount of quickly estimated sediment under different import conditions, suchmethod can provide technical support for the process control of the river sand and river channel regulationplanning.