摘要
牛栏江滇池补水工程自2013年通水以来对改善滇池水质发挥了重要作用,但实际运行中存在汛期水体浑浊的现象,对瀑布公园、盘龙江河道景观及城市供水等造成了影响.根据多次现场考察与观测结果,本文研究了水源地德泽水库中取水口及其上游牛栏江和左岸支流干河的水沙运动规律及汛期水体泥沙含量偏高的成因机制,认为造成取水口含沙量偏高的主要原因,一是入库泥沙较细,沉降速度较小,水库回水长度难以满足细颗粒泥沙沉降距离的要求;二是取水口以上河段存在表层、中层和底层异重流,频繁出现的中、底层异重流常会导致取水口所在高程处的含沙量显著增加,不利于泵站取水;三是取水口断面距离交汇口较近,干、支流交互作用会扰动取水口附近的含沙量分布,且支流含沙量较大的洪水汇入干流时会造成取水口断面含沙量的升高.研究结果深化了对细颗粒泥沙在水库变动回水区运动特点的认识,可为牛栏江滇池补水工程汛期泥沙问题的治理提供参考.
The Niulan River-Dian Lake Water Diversion Project(NRDLWDP)has greatly improved the water quality of the Dian Lake since its start of operation in 2013.However,the turbid water in flood seasons from the Deze Reservoir,which was the water source of the NRDLWDP,had an adverse impact on the Kunming Waterfall Park,Panlong River and municipal water supplies.Field observations were carried out in the Deze Reservoir to study the characteristics of flow and sediment movement along the Niulan River and its tributary,the Gan River,and analyze the cause of high suspended sediment concentration(SSC)at the intake in flood seasons.Analyses indicated that there were three main causes for the high SSC at the intake.Firstly,the very fine incoming sediments with a low settling velocity had a long settling distance that was longer than the backwater length of the reservoir.Secondly,three different types of density currents,including overflows,interflows and underflows,occurred in the upper reaches of the intake.Frequently occurring of interflows and underflows resulted in the rise of SSC at the intake,which caused the pumping station to get the turbid diversion water.Thirdly,due to the short distance between the intake and the confluence,the strong interaction between the mainstream and the tributary disturbed the vertical distribution of SSC near the intake.Moreover,tributary floods with high SSC also caused the increase of SSC at the intake when flowing into the mainstream.This study deepens the understanding of the movement characteristics of the very fine sediments in the fluctuating backwater zone of the reservoir,and provides support for solving the sediment problems in flood seasons of the NRDLWDP.
作者
章若茵
吴保生
刘绍川
ZHANG Ruoyin;WU Baosheng;LIU Shaochuan(State Key Laboratory of Hydroscience and Engineering,Tsinghua University,Beijing 100084,China;PowerChina Kunming Engineering Corporation Limited,Kunming 650051,China)
出处
《应用基础与工程科学学报》
EI
CSCD
北大核心
2020年第1期1-17,共17页
Journal of Basic Science and Engineering
基金
国家重点研发计划项目(2017YFC0405202,2016YFC0402406)
国家自然科学基金项目(51639005).
关键词
德泽水库
取水口
异重流
细颗粒泥沙
含沙量
水温
Deze Reservoir
intake
density current
fine sediment
suspended sediment concen-tration
water temperature
