摘要
丹江口水库蓄水和南水北调中线调水,引起了枢纽下游河段水沙条件复杂变化。依据多年实测水沙资料,统计分析了蓄水后及调水后汉江中游河段水沙条件的复杂变化特点,结果表明:蓄水后,径流过程离散度趋势性减小,中水历时增加,枯水历时减小;调水后径流过程离散度继续减小,但中水历时减小,枯水历时增加,呈现"长低水历时"特点。蓄水后水沙搭配平衡度降低,水流挟沙不饱和度显著升高,汛期水沙搭配平衡度下降更快,且已接近非汛期,调水后继续减小。蓄水后中、枯水流量下水位变化率增加,水位变化率-流量关系曲线拐点右移,漫滩流量呈上升态势,反映出断面主槽向窄深方向发展。径流过程离散度降低、洪枯比减小将有利于降低河道的游荡性。
Complex processes of water flow and sediment transport in the downstream reach of the Danjiangkou Reservoir have been induced by both water impoundment of the Danjiangkou Reservoir and water transfer in the Middle Reach of South-to-North Water Diversion Project. The characteristics of the complex processes of water and sediment conditions in the middle reach of the Hanjiang River are analyzed based on observed data.Results show that the dispersion of discharge hydrographs within a year tends to decrease after water impoundment. The medium flow duration prolonged while the low flow duration shortened. The dispersion of discharge hydrographs continued to decrease after water diversion. However,the medium flow duration shortened while the low flow duration prolonged. After water impoundment,the balance degree of water-sediment collocation is greatly declined,and the unsaturation of sediment carrying capacity increased. The balance degree of watersediment collocation declined faster in the flood period than in the non-flood period,and now it is close to the degree in non-flood period. After water diversion,the balance degree of water-sediment collocation continues to decline. After water impoundment,the rate of water level change of the medium flow and low flow increased.The turning point in the relationship curve between the water level change rate and flow discharge shifts to the right,and the bankfull discharge increased,which indicate that the riverbed is further narrower and deeper.Reductions of both the dispersion of the discharge hydrographs and the ratio of maximum flow to minimum flow tend to reduce river wandering.
作者
陈立
房复康
袁晶
陈烁
CHEN Li;FANG Fu-kang;YUAN Jing;CHEN Shuo(State Key Laboratory of Water Resources and Hydropower Engineering Science,Wuhan University,Wuhan 430072,China;Bureau of Hydrology,Changjiang Water Resource Commission,Wuhan 430010,China)
出处
《泥沙研究》
CSCD
北大核心
2020年第3期15-21,共7页
Journal of Sediment Research
基金
国家重点研发计划项目(2016YFC0402101)
国家自然科学基金项目(11472199)。
关键词
径流过程离散度
南水北调中线工程
水沙搭配平衡度
水位变化率
游荡型河段
Dispersion of discharge hydrographs
Mid-route of South-to-North Water Transfer Project
balance degree of water-sediment collocation
rate of water level change
wandering river
