THE OPERATION MODE OF "STORING THE CLEAR WATER AND DISCHARGING THE MUDDY FLOW" FOR RESERVOIRS BUILT ON HEAVILY SILT-LADEN RIVERS--A CASE STUDY OF THE SANMENXIA RESERVOIR     

Wenxue LI  Yuanfeng ZHANG  Cuiping ZHANG 《国际泥沙研究》2005,20(2)

Observation of the operation of the Sanmenxia Reservoir on the Yellow River has led to the conclusion that to preserve a certain effective storage volume for reservoirs built on heavily silt-laden rivers is feasible if the reservoir is operated according to the principle known as "storing the clear water and discharging the muddy flow". The relative stability of the bed elevation at the end of the backwater and the reservoir's erosion and deposition equilibrium depend on the compatibility of the pool level maintained in non-flood seasons with the conditions of flow and sediment load during flood seasons. Operating the reservoir to regulate the flood and sediment load during flood seasons can reduce the rate of aggradation in the Lower Yellow River. The basic condition for applying the operation mode of "storing the clear water and discharging the muddy flow" is that a sufficient amount of water should be used for discharging sediment during flood seasons. Under the condition of extremely low flow years, reservoir sedimentation cannot be avoided even if this operation mode is adopted.  相似文献   

山区牧民对极端气候事件的感知与适应——基于祁连山区少数民族乡的调查     

朱国锋  秦大河  任贾文  郑丽敏  刘原峰  梁峰  杨玲  李佳芳  胡鹏飞 《气候变化研究进展》2015,11(5):371-378

为明确山区牧民对气候变化趋势和极端气候事件的感知与适应现状,对青海省祁连县野牛沟乡、甘肃省肃南县大河乡、天祝县祁连乡的418户牧民家庭进行入户走访和问卷调查。结果表明：牧民对当地近20年气温升高感知度较高,对降水量变化的感知程度较低,对近期牧业影响较大的极端气候事件感知度较高。牧民针对感受到的不同的极端气候事件采取了有差别的应对措施。储备草料、修建圈舍和暖棚、处理牲畜和外出打工是主要的适应措施。牧业服务、贷款支持和更完善的社会保障体系对提高牧民适应气候变化能力有积极的作用。  相似文献   

Healthy Yellow River’s essence and indicators     

LIU Xiaoyan  ZHANG Yuanfeng  ZHANG Jianzhong 《地理学报(英文版)》2006,(3)

For thousands of years, people have been trying to promote benefit and abolish harm to the Yellow River by means of various activities such as flood control and water abstraction. However, after the last decade of the 20th century, it was noticed that the…  相似文献   

水文地球化学和地下水同位素特征在确立地下水系统中的应用——以浙江金华盆地红层地下水系为例   总被引：1，自引：0，他引：1  

朱远峰 《中国岩溶》1984,3(1):47-51

<正> 金华盆地位于浙江省中部,是浙江境内最大的内陆盆地——金衢盆地的一部分。但其本身仍是一封闭的向斜盆地。盆地南、北部边界主要为上侏罗统的火山碎屑岩构成的中低山;东西外延邻接鞋塘,白龙桥向斜。金华江横贯盆地中部,除沿金华江及主要支流乌义江等陆续有厚度小于10米的第四系松散层分布外,盆地内主要分布呈梳状丘岗的裸露红色碎屑岩。   相似文献   

太湖梅梁湾水华微囊藻基因型组成和产毒微囊藻丰度的变化   总被引：5，自引：1，他引：4  

施丽梅  蔡元锋  杨华林  李朋富  孔繁翔  孔令东 《湖泊科学》2009,21(6):801-805

采用基于ITS序列的PCR-DGGE方法分析了太湖梅粱湾水华暴发过程中(6-11月)微囊藻的不同基因型组成的变化,同时利用针对微囊藻毒素合成酶基因mcyA和微囊藻特异性的16S rDNA部分核苷酸序列的引物,应用实时荧光定量PCR方法(qRT-PCR)分析水华样品中产毒微囊藻与总微囊藻的量.通过两者的比值反映产毒微囊藻丰度.结果表明,在发生水华的不同时期,微囊藻的基因型组成发生了变化,其中以8月末、9月和10月的基因型最多,基因型M5和M10存在于整个水华发展过程中.共检测到12种主要的基因型,每个基因型在水华的不同时期所占的比例互不相同.实时荧光定量PCR结果显示从6月到10月,产毒微囊藻的丰度呈增大的趋势,从0.750%增加到32.16%,而11月产毒微囊藻的丰度显著下降.  相似文献   

黄河健康生命的指标体系   总被引：12，自引：0，他引：12  

刘晓燕  张建中  张原锋 《地理学报》2006,61(5):451-460

河流健康是人们对河流生命存在状态的描述,是人类对河流向其提供服务的认可程度。通过分析人类和河流生态系统的生存需求,认为连续的河川径流、通畅安全的水沙通道、良好的水质、良性运行的河流生态系统和一定的供水能力是健康黄河的标志,提出用低限流量、河道最大排洪能力、平滩流量、滩地横比降、水质类别、湿地规模、水生生物、供水能力等8项定量指标作为健康黄河的标志,并根据相关的历史水文资料和1956~2004年的实测数据分析,确定了相应的健康指标量值。  相似文献   

Genetic algorithm for seismic topology optimization of lifeline network systems     

Jie Li  Wei Liu  Yuanfeng Bao 《地震工程与结构动力学》2008,37(11):1295-1312

Lifeline systems, such as water distribution and gas supply networks, usually cover large areas. For these systems, seismic design is always a difficult problem because of the complexity of large‐scale networks. In this paper, a topology optimization technology for lifeline networks is established. Firstly, in order to speed up the convergence of optimization process, an element investment importance analysis is carried out to evaluate the importance of components to the lifeline network. Then a topology optimization model is established. The aim of the model is to find the least‐cost network topology while the seismic reliability between the sources and each terminal satisfies prescribed reliability constraints. For this optimization problem, a genetic algorithm, which takes network topologies as the individuals of its population, is used to search for the optimal solutions by suitable operators, including selection, crossover and mutation operators. The capacity of the proposed algorithm is illustrated by its applications to a simple example network consisting of 10 nodes and an actual network with 391 nodes located in a large city of China. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

与微囊藻胞外多糖降解相关的微生物菌群分析   总被引：2，自引：2，他引：0  

蔡元锋  施丽梅  李朋富  邢鹏  于洋  孔繁翔 《湖泊科学》2009,21(3):369-374

从铜绿微囊藻培养液中提取胞外多糖,化学分析显示其为含8.3%蛋白质的酸性杂多糖.以胞外多糖为碳源接种自然水体的菌群进行富集培养,分析胞外多糖的微生物降解过程及降解菌的组成.结果表明,接种太湖水华期微生物富集菌群后,多糖立即开始被降解,大约在18d后多糖降解过程显著减慢,37d后仍有一部分多糖未能被降解.这些结果说明在自然界中微囊藻胞外多糖是可以被微生物降解的.比较不同水体的菌群对多糖的降解能力后显示,降解菌群只存在于微囊藻水华暴发的阶段.变性梯度凝胶电泳(DGGE)结果显示在整个降解过程中,降解菌群的组成未发生显著变化.对DGGE条带中的DNA片段进行序列分析和系统发育分析表明降解菌群包含以下几类:鞘氨醇单胞菌属(Sphingomonas)3个,褐螺菌属(Phaeospirillum)1个,假单胞菌属(Pseudomonas)1个,红环菌科(Rhodoeyclaceae)1个,Hylemonella(无译名)1个,分枝杆菌属(Mycobacterium)1个.  相似文献   

黄河上游干支流交汇区沙坝淤堵形成条件   总被引：1，自引：0，他引：1       下载免费PDF全文

张原锋  王平  侯素珍  吴保生 《水科学进展》2013,24(3):333-339

针对黄河上游干、支流交汇区形成的沙坝淤堵事件,利用野外观测资料,分析了支流高含沙洪水特性及交汇区沙坝淤堵特点,探讨了汇流比(支流流量与干流流量之比)、支流洪水水量、支流洪水沙量等因素对沙坝淤堵形成的影响;根据动量原理建立了交汇区形成沙坝淤堵的判别关系,结合黄河上游干、支流洪水输移特性,得出了基于汇流比与支流洪水水量关系及支流洪水沙量与支流洪水水量关系的沙坝淤堵判别条件。由此,可根据汇流比、支流洪水水量及沙量判断交汇区能否形成沙坝淤堵,可为暴雨洪水期黄河上游交汇区形成沙坝淤堵灾害的预报及防治提供参考。  相似文献   

Estimation of Undrained Bearing Capacity for Offshore Soft Foundations with Cyclic Load   总被引：3，自引：0，他引：3  

WANG Jianhua  LIU Yuanfeng  XING Yan  Di Huimin Professor  Geotechnical Engrg 《中国海洋工程》1998,(2)

The degradation strength of soils under cyclic loading is studied and a method for deter-mining the cyclic degradation strength with cyclic triaxial tests is given in the paper.Furthermore,a dum-my static method for estimating the undrained bearing capacity for offshore soft foundation under waveloads is developed.It can consider the effect of the difference of cyclic stress for different parts of the foun-dation on both the degradation strength of the foundation soil and the bearing capacity so that the esti-mated result can better reflect the real condition of foundation under cyclic loading.The method can be ap-plied to plane and space problem.  相似文献