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1.
Retrogressive erosion, a widespread phenomenon of sediment transport in reservoirs, often impacts on both the reservoir capacity and the sedimentation in the downstream river channel. Based on field data from the Sanmenxia Reservoir and the Lower Yellow River over the past decades, three courses of ret-rogressive erosion with distinctive features were analyzed. The results indicate that retrogressive erosion, especially caused by rapid reduction in the water level till the reservoir is empty, often results in the serious siltation of the lower Yellow River and threatens the safety of the flood control in the Lower Yellow River. Unreasonable operation of the reservoir and incoming hyperconcentrated floods accom-panied by retrogressive erosion also aggravate the siltation of the main channel of the river. However, a reasonable operation mode of the reservoir so named"storing the clear (low sediment concentration) water in the non–flood season, and sluicing the muddy(high sediment concentration) water in the flood season" was found, which might mitigate the deposition in both the reservoir and the Lower Yellow River. This operation mode provides important experience for the design and operation of large reser-voirs in other large rivers carrying huge amounts of sediment. 相似文献
2.
JueyiSUI ChengLIU DaxianFANG JunWANG 《国际泥沙研究》2005,20(2):89-101
Based on long-term measurements at three gauging stations, Toudaoguai, Fugu and Hequ, and one meteorological station, this article discusses the features of discharge (Q) and sediment concentration (Cs) of a river reach of the Yellow River with a reservoir located in the Loess Plateau. The impacts of the local sub-watershed between Toudaoguai and Fugu gauging stations on sediment budget to the Yellow River have been analyzed. In addition, the deposition processes in the Tianqiao Reservoir have been investigated. Results show over 80% of the precipitation that falls in the local subwatershed is unable to contribute to the Yellow River runoff process. It is found that the annualmaximum sediment concentration is usually less than 30 kg/m^3 during flood seasons at Toudaoguai Gauging Station, but the sediment concentration varies dramatically at Fugu Gauging Station. About 35% of the sediment eroded in the sub-watersheds between Toudaoguai and Fugu gauging stationswas produced from the Huangfuchuan sub-watershed which has a drainage area accounting only for 10% of the drainage area between Toudaoguai and Fugu gauging stations. The Tianqiao Reservoir generally has deposition during the summer flood season, and scouring during the non-flood season.On average, over 85% of deposited sediment in the reservoir occurs in the 12 km long lower reservoir reach. The volume of annual deposition in the reservoir mainly depends on the volume of water from the local region between Hequ and Fugu gauging stations. 相似文献
3.
HUANG Jincbi China Institute of Water Resources Hydroelectric Power Research Fuxinglu A- Beijing China. E-Mail: HJC@IWHR.COM 《国际泥沙研究》2001,16(2)
1 INTRODUCTIONBed aggradation and degradation haPpen to be the most imPOrtant aspects of the alluvial processes instreams if the equilibrium conditions among water discharge, sediment flow, and channel shaPe areclistuIbed by natural or man-made factOfs, e.g., the constrUchon of a dam, change in the sediment suPplyrate, or base level changing. Reliable and quanhtative estimation of the bed aggradation or degradation isimPortant in rivertalning engineering and water management projects. … 相似文献
4.
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
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6.
Estuarine environments are influenced by both river flows and oceanic tidal movement of water, sediment, and nutrients, often forming ecosystems that are rich in resources and biodiversity. The Yellow River once carried the world’s largest sediment load, but artificial structures have transformed its hydrodynamic processes. An annual Water-Sediment Regulation Scheme(WSRS) was introduced to flush accumulated sediment from the Xiaolangdi Reservoir, which provides flood control and water storage.Ho... 相似文献
7.
Instream flows are essential determinants of channel morphology, riparian and aquatic flora and fauna, water quality estuarine inflow and stream load transport. The ecological and environmental instream flow requirements (EEIFR) should be estimated to make the exploitation and utilization of water resources in a highly efficient and sustainable way and maintain the river ecosystem good health. As the largest tributary of the Yellow River, the Wei River is the ‘Mother River’ of Guanzhong region in Shaanxi province. It plays a great role in the development of West China and the health of the ecosystem of the Yellow River. The objective of this study is to estimate the EEIFR for improving the Wei River's ecological and environmental condition and develop the river healthily. Concerning the main ecological and environmental functions of the Wei River in Shaanxi Province, the EEIFR for each section of the Wei River including minimum instream flow requirements (IFR) for aquicolous biotopes maintenance, IFR for channel seepage, channel evaporation, stream self‐purification and sediment transportation were estimated in this paper. The methods to estimate the instream flow requirements for stream self‐purification and instream flow requirements for sediment transportation were proposed. The temporal scale of typical years include the year with the probability 25% of occurrence (high‐flow year), the year with the probability 50% (normal‐flow year) and the year with the probability 75% (low‐flow year). The results show that the EEIFR for the Wei River mainly include instream flow requirements for self‐purification and sediment transportation in each typical year. From high‐flow year to low‐flow year, the annual EEIFR for each reach decrease, except those for the reach from Linjiacun to Weijiabao, and from Linjiacun at the upper reaches to Huaxian at the lower reaches, and the annual reach EEIFR decrease in a sequence. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
8.
三峡水库与诱发地震 总被引：4，自引：0，他引：4
三峡水利枢纽规模宏大,举世瞩目,具有巨大的防洪、发电、航运等综合效益,是开发治理长江的骨干工程。三峡工程已于2003年6月15日蓄水至135m,永久船闸通航,7月第一批机组发电;2006年5月20日大坝185m高程全线贯通,10月27日蓄水至156m;2009年全部工程竣工投产。三峡水库已初步形成,随着蓄水位上升,库容加大,诱发水库地震的可能性也将加大。根据最大历史地震震级并适当加权,确定库区最大可信地震为6级左右。在仙女山和九湾溪断裂一带(距坝址为18km)存在诱发地震的可能,震级MS=5.0～5.8级。对坝址所受影响烈度为Ⅵ度,不会对按烈度Ⅶ度设防的枢纽主要建筑物构成直接威胁。必须加强对三峡水库诱发地震的监测及预报,预防地震及地质灾害,确保工程建设及运行安全,构建和谐社会,确保长治久安。本文根据国内外及三峡水库有关地震监测及预测预报资料,对三峡水库诱发地震进行初步探讨,供参阅指正。 相似文献
9.
This paper summarizes the latest developments, future prospects, and proposed countermeasures of reservoir sedimentation and channel scour downstream of the Three Gorges Reservoir (TGR) on the Yangtze River in China. Three key results have been found.(1) The incoming sediment load to the TGR has been significantly lower than expected.(2) The accumulated volume of sediment deposition in the TGR is smaller than expected because the overall sediment delivery ratio is relatively low, and the deposition in the near-dam area of the TGR is still developing.(3) River bed scour in the river reaches downstream of the Gezhouba Dam is still occurring and channel scour has extended to reaches as far downstream as the Hukou reach. Significantly, sedimentation of the TGR is less problematic than expected since the start of operation of the TGR on the one hand;on the other hand, the possible increases in sediment risks from dependence on upstream sediment control, deposition in the reservoir, and scour along middle Yangtze River should be paid more attention.(1) Sediment trapped by dams built along the upper Yangtze River and billion tons of loose materials on unstable slopes produced by the Wenchuan Earthquake could be new sediment sources for the upper Yangtze River. More seriously, possible release of this sediment into the upper Yangtze River due to new earthquakes or extreme climate events could overwhelm the river system, and produce catastrophic consequences.(2) Increasing sediment deposition in the TGR is harmful to the safety and efficiency of project operation and navigation.(3) The drastic scour along the middle Yangtze River has intensified the down-cutting of the riverbed and erosion of revetment, it has already led to increasing risk to flood control structures and ecological safety. It is suggested to continue the Field Observation Program, to initiate research programs and to focus on risks of sedimentation. 相似文献
10.
Water is a critical natural resource upon which all social and economic activities and ecosystem functions depend. With a surprising social and economic development in the past decades, water has become an important constraint for China’s sustainable development, and a matter concerning economic security, ecological security and national security of the country. Understanding the changes of water resources is greatly helpful in analyzing the impacts of climatic change, formulating plans for utilization and protection of water resources, and making water resource decisions. Based on China’s national water resources assessment, the Mann-Kendall’s test, and Morlet wavelet, we analyzed the changing trends and periods of China’s renewable water resources during 1956–2010. The results as following: (1) There is no significant change trend of water resources on the countrywide scale during the period 1956–2010, the total water resources show a slight increasing trend, and the national annual average water resources during the period 1991–2010 increased by 1% relative to that of the period 1961–1990. (2) The changes of water resources in different level-I water resource regions vary significantly. Annual average water resources of the Haihe River and Yellow River regions in the northern China decreased 19% and 17% respectively in the past 20 years. Water resource increased in Southern and Northwestern rivers regions, particularly in the Northwest rivers region, with the increasing amplitude by nearly 10% in the past 20 years. (3) The inter-annual variation of national water resource became larger in the past 20 years, as compared with that of the period 1961–1990. The coefficients of water resource variation increased in Northwestern and Southwestern rivers regions, while the inter-annual variation tended to decrease in the Haihe and the Yellow River regions where significant decline of water resources happened. (4) A 14-year quasi-periodicity of the national water resource variation was detected, overlapping with various periodicities of water resources of different level-I water resource regions. Remarkable uniformity exists between the first or secondary primary periodicity of water resource variation in adjacent level-I water resource regions. 相似文献
11.
中国水库生态学研究的回顾与展望 总被引：40，自引：7，他引：33
水库是通过人工筑坝形成的水体,其早期功能主要是防洪、发电、灌溉和航运等,但随着全球水资源供需矛盾的加剧,水库供水成为缓解供水压力的最主要途径.水坝是人类影响地球表面水体最重要的工程建筑,筑坝修建水库利用水资源对全球水环境系统产生了巨大的影响.中国是水资源短缺的国家,水库供水在国民经济发展中发挥着重要作用,大量水库的建成也对我国水环境系统产生了多方面的影响.刘建康先生在1955年发表了我国水库生态学研究的第一篇论文,揭开了我国水库生态学研究的序幕.我国水库生态学大致分为三个阶段,1955-1975年的起步阶段、1976-2000年以水库渔业生产为目标的研究阶段和2001年至今以水库水质管理为目标的研究阶段.当前,水质、水质模拟、富营养化、环境容量和生态调度等已成水库生态学研究中的关键词.我国水库研究主要集中在珠江流域和长江流域,以大型供水水库为对象.在水利学科领域,有大量有关水库水文、水动力学和调度的研究论文,这些工作还未能被以生物和化学为研究基础的生态或环境科学的学者所重视.多数以水库为对象的生态学研究还没有很好地体现水库作为人工湖泊的特殊性.近10年来,中国水库生态学经历了从任务导向到学科导向的生态学研究过渡,有不断增加学科交流的趋势.有理由相信,作为水库大国,中国水库生态学和湖沼学今后将会有一很大的发展,并对我国淡水生态学和湖沼学作出重要的贡献. 相似文献
12.
Wenxue LI Jixiang LIU Zhanwei WAN 《国际泥沙研究》2007,22(2):103-113
Small runoff, large sediment load, and incompatible relationship of flow and sediment load are very important characteristics of the Yellow River. They are also the crux of the most prominent problems of the Yellow River. To solve these problems, the regimes of flow and sediment load have to be improved by increasing water, reducing sediment load, and by using reservoirs to regulate flow and sediment load. The results of experiments for regulating the flow and sediment load in the last three years by the Xiaolangdi Reservoir have indicated that this measure is a realistic and effective way to mitigate the prominent problems in flood control of the Lower Yellow River at present and in the near future. However, the regulation system is still imperfect. It is advisable to speed up the pace of research and construction of the system for regulating flow and sediment load. 相似文献
13.
Xiaoya Tang Sichen Tong Guoxian Huang Guangxiang Xu Xinghua Li Kun Lei Shiming Yao 《国际泥沙研究》2021,36(2):177-189
Construction of large dams is attractive because of their great benefits in flood control,hydropower generation,water resources utilization,navigation improvement,etc.However,dam construction may bring some negative impacts on sediment transport and channel dynamics adjustments.Due to the effects of recent water and soil conservation projects,sediment retention in the newly constructed large upstream reservoirs,and other factors,the sedimentation in the Three Gorges Reservoir(TGR)is quite different from the amount previously predicted in the demonstration stage.Consequently,based on the measured data,characteristics of sedimentation and the related channel deformation in the TGR were analyzed.The results imply that sediment transport tended to be reduced after the Three Gorges Project(TGP).Sedimentation slowed dramatically after 2013 and indicated obvious seasonal characteristics.Due to the rising water level in the TGR in the flood season,the yearly sediment export ratio(Eratio)was prone to decrease.The water level near the dam site should be reasonably regulated according to the flow discharge to improve the sediment delivery capacity and reduce sedimentation in the TGR,and to try to avoid situations where the flood retention time is close to 444 h.The depositional belt was discontinuous in the TGR and was mainly distributed in the broad reaches,and only slight erosion or deposition occurred in the gorge reaches.Sedimentation in the broad and gorge reaches accounted for 93.8% and 6.2% of the total sedimentation,respectively.The estuarine reach located in the fluctuating backwater area experienced alternate erosion-deposition,with a slight accumulative deposition in the curved reach.Sedimentation mainly occurred in the perennial backwater area.The insight gained in this study can be conducive to directly understanding of large reservoir sedimentation and mechanism of channel adjustment in the reservoir region in the main channel of large river. 相似文献
14.
Abstract The planning of water resources depends on the type and size of projects, the ecological factors involved, etc. Emphasis is placed on presenting an overview of water resources through meteorological, hydrological, ecological and economic data. Economic data include all costs and benefits, specifically those hitherto under estimated, environmental social costs and benefits. This study was carried out on the Bedthi and Aghnashini rivers in the Uttara Kannada district of the Western Ghats region, Karnataka State, India. It is estimated that 720 and 510 million kWh of electricity can be generated in Bedthi and Aghnashini River basins, respectively, if all the streams are harnessed. Focusing on land submergence impact, a model is proposed to minimize submergence and maximize net energy in a region with seasonal power generation, reservoir storage capacity (to meet the region's demand during all seasons) and installed generation capacity as the decision variables. Net energy analyses incorporating biomass energy lost in submergence show that maximization in net energy at a site is possible if the hydroelectric generation capacity is adjusted according to the seasonal variations in the river's water discharge. A Decision Support System (DSS) used for optimal design of hydroelectric projects in Uttara Kannada district is discussed. 相似文献
15.
本文对黄河三角洲Z07孔沉积物进行了系统的磁性地层学和环境磁学研究.通过结合沉积速率和古地磁长期变化数据,我们为该孔建立了较为精确可信的年代框架(1999-03—2006-06A.D.).环境磁学结果表明黄河三角洲沉积物与中国黄土的磁学特征相似,主要载磁矿物为单畴(SD)磁铁矿,超顺磁颗粒(SP)含量也较高.整体上,该孔沉积物磁学参数的变化主要受粒度和含量控制.岩芯磁性参数在2003年前后发生了系统变化.我们认为,黄河自2002年起进行调水调沙工程,黄河下游河道冲刷加剧,形成新的物质来源,河流输入的沉积物粒度变粗,输沙量增加,这一新的物质来源是造成Z07钻孔磁性参数发生显著变化的主因. 相似文献
16.
Planting structure influences the economic, social, and ecological benefits of crop farming as well as the use efficiency of water and arable land resources, and so crop planning (CP) benefits for agricultural sustainable development and soil resources utilization. The projection pursuit evaluation (PPE) model is put forward to solve the problem of selecting an optimizing scheme for CP by considering the indices of water‐saving and economic, social, and ecological benefits. The real‐coding‐based accelerating genetic algorithm (RAGA) is introduced to accelerate the calculation process. The model can translate multi‐indices into a single index by transforming high‐dimensional data to low‐dimensional space, which helps evaluate CP optimizing schemes. For example, the model is used to evaluate and select an optimal scheme of CP in the middle reaches of the Heihe mainstream basin in the arid area of northwest China. According to four criteria (high efficiency of resources use, economic rationality, social equity, and ecological security) 19 indices were chosen to evaluate 12 optimizing schemes of four kinds (economic‐benefit, food‐security, ecological‐benefit, and water‐saving programs) in 2006, 2020, and 2030. The result shows that, in the 3 years, the water‐saving program is always the optimized scheme in an arid region with water deficiency and fragile ecology. The evaluated results match up to the developmental conditions of crop farming in recent years. Moreover, the direction of the optimal projection could reflect the weight and orientation of indices objectively and accurately. 相似文献
17.
金沙江下游4个梯级水电站总装机容量相当于两座三峡水库,是“西电东送”中部地区的源头工程,工程效益发挥对经济社会发展意义重大。2012年以来,向家坝、溪洛渡、乌东德和白鹤滩电站等陆续蓄水运行,层层拦截金沙江的泥沙,2013—2020年向家坝出库年输沙量均值下降至152万t,减幅超过99%。大量泥沙淤积在梯级水库内,同时向家坝以下河道发生长距离冲刷。本文以自金沙江下游工程筹建以来的观测资料为基础,针对梯级水库的泥沙淤积和坝下游河道冲刷规律开展研究,结果表明:金沙江下游四个梯级电站自建成运行至2020年底,累计淤积泥沙约5.98亿m3,其中溪洛渡库区淤积量占比达92.5%,2013-2020年溪洛渡和向家坝水库排沙比分别为2.64%和22.2%,其水库泥沙主要淤积在常年回水区的干流河道内,以死库容内淤积为主,侵占有效库容的比例小于1.3%。金沙江下游库区干流河道的峡谷特征明显,淤积多表现为主河槽的平铺式淤高。溪洛渡和向家坝库区淤积的泥沙沿程分选特征明显,越靠近坝前,中数粒径减小、细颗粒泥沙沙量百分数增加,极细颗粒泥沙会在库区一定范围内大量沉积。向家坝下游河床普遍冲刷,但... 相似文献
18.
Environmental and ecological issues caused by water resources crisis have brought enormous challenges to the sustainable development of water-deficient area. Water resources allocation management balancing the relationship between the social-economic development and the ecological environment has become a hot topic in recent years. In this paper, an inexact fuzzy chance-constrained programming (IFCCP) approach is proposed for regional water resource allocation optimization with the aim of promoting the harmonious development of the social economic and the ecological environment, improving water utilization efficiency, and realizing water resources consumption control under uncertainties. The method is incorporated with interval parameter programming, fuzzy programming, and chance-constrained programming, for handling system uncertainties and balancing the optimal objectives with the risk of violating system constraints. Under this framework, an IFCCP model for water resources allocation management was successfully formulated and applied to a typical water-deficit area, Tianjin, China, for obtaining a better water resources plan among multiple users under resources and environmental limitation. Different total water consumption control policies are designed for assessing regional water allocation schemes. The results indicated that the gap of supply and demand will only be solved by foreign water, the transferred water from Luan River and Changjiang River would still be the main supplier in planning horizon. Moreover, the strict total water consumption control policy would guarantee the water requirement of ecological environment, lead to changes in the structure of water supply, actively guide on water conservation, and promote the large-scale utilization of desalted water and recycle water. 相似文献
19.
The impact of silt trapping in large reservoirs on downstream morphology: the Yangtze River 总被引：2，自引：0，他引：2
The sediment load of the Yangtze River (China) is decreasing because of construction of dams, of which the Three Gorges Dam (TGD) is the best known example. The rate of the decline in sediment load is well known, but changes in the sediment grain size distribution have not been given much attention. The TGD mostly traps sand and silt while clay is flushed through the reservoir. A large amount of sand is available in the Yangtze River downstream of the reservoir, and therefore the pre-dam sand concentration is not substantially reduced. The availability of silt on the Yangtze River bed is limited, and it is expected that most silt will be removed from the riverbed within one to two decades. In order to evaluate the impact of the change in grain size distribution on the tidal flats of the Yangtze Estuary, a highly schematized tidal flat model is setup. This model broadly reveals that the observed deposition rates are exceptionally large because of the high sediment concentration, the abundance of silt, the seasonal dominance of waves (shaping a concave profile), and the offshore tidal asymmetry. The model further suggests that deposition rates will be limitedly influenced by reductions in clay or fine silt but strongly impacted by reductions in median to coarse silt. The response of the downstream morphology to reservoir sedimentation therefore strongly depends on the type of trapped sediment. As a consequence, silt-dominated rivers, such as the Yangtze River and the Yellow River may be more strongly impacted than sand-dominated systems. 相似文献
20.
This paper proposes a new methodological approach to silted reservoir management and defence, which combines the reservoir rehabilitation process and the utilization of the recovered water volumes and sediments. This approach, strategic from both the economical and environmental points of view, is here defined as Economic Environmental Defence (EED) of a reservoir. The EED approach is applied to the case study of Guardialfiera reservoir, where the available experimental data allowed the estimation of silta-tion up to date, the analysis of the distribution of sediment particle size along the reservoir bottom and the possibility to propose a feasible utilization of water and sediments resulting from the reservoir rehabilitation. 相似文献