1975－2015年洪泽湖水沙变化趋势及成因分析

淮河流域洪涝灾害频繁,洪泽湖对其防洪除涝起关键性作用。掌握洪泽湖水沙变化趋势及突变点对流域水资源管理、水沙调节有重要的现实意义。利用入、出洪泽湖各支流代表水文站1975-2015年实测年径流量和年输沙量数据,分析入、出洪泽湖水量和沙量分布特征。通过Mann-Kendall(M-K)秩相关检验法和Pettitt突变点识别法研究入湖、出湖水沙量年际变化趋势和突变点。在此基础上,从流域降雨、水资源开发利用和水库滞沙三个方面分析了洪泽湖水沙变化的主要影响因素。研究表明:洪泽湖入湖、出湖水量年际变化趋势一致,无明显减小趋势,且无显著突变点。入湖沙量有小幅减小趋势,出湖沙量M-K统计值超过95%显著性水平,有明显减小趋势。入湖、出湖沙量发生突变的年份为1991年。对影响因素的分析得到:降雨量变化是水量变化的重要影响因素。1993-2015年,入湖水量呈不明显减小趋势则与流域用水量明显增加、水资源开发利用程度不断提高有关。上游水库建设是导致洪泽湖沙量有明显减小趋势的主要原因,1991年治淮工程的实施,水库复建和水土保持等措施是沙量突变的主要原因。     

Compensation flows in the UK: A hydrological review

A survey of United Kingdom reservoirs identified the development of compensation flow policy from the early 19th Century to the present day. Details on the level and pattern of releases below 261 impounding reservoirs provided the basis for assessing the spatial and temporal variation in compensation flows and the impact of impoundment on downstream flow regimes. By standardizing compensation releases by the natural pre-impoundment mean discharge, release patterns from reservoirs with a wide range of both catchment area and climate could be compared. Analysis of the change in flood and low flow frequency following impoundment enabled the impact of reservoir regulation to be evaluated at the regional scale. For individual reservoirs the natural downstream increase in river flow provides a basis for determining the length of river reach which is sensitive to regime changes. The majority of present day compensation discharges were set to satisfy river interests which no longer apply or were based on inadequate hydrological or biological information. This has led to a wide range of release patterns and it is therefore recommended that the re-evaluation of existing water resource schemes should include an assessment of the suitability of current release patterns for present day downstream demands and water resource requirements.     

Analysis of Flow Behavior as Influenced by Reservoir with Flow Regularization

Understanding the behavior of reservoirs with flow regularization formed by hydroelectric power plants is essential for assessing water availability. The operationalization of reservoirs can be influenced both by climatic characteristics and by the consequences resulting from human actions in the basin. The objective of this study was to evaluate the existing relationships between the inflows and outflows of a reservoir, as well as with the conventional streamflow gauge stations downstream of the dam. Also evaluated were trends in the behavior of minimum, average and maximum flows, in the post-operation period, considering the characteristics of rainfall and irrigation in the region. The results indicated that reservoir operationalization is strongly related to the behavior of inflows. Moreover, a reduction was also verified in all the variables analyzed related to inflows and outflows, as well as in the stations downstream of the dam, except for the maximum flow in the station farthest from the reservoir, which showed a stationary behavior. The reductions in the flows may be related to the almost three-fold increase in the area irrigated by the center pivot in the basin; however, the same cannot be said in relation to the annual rainfall regime of the region, since it showed a stationary behavior for most of the stations evaluated. The work demonstrates the importance of trend analysis of flows over the years in order to identify possible factors responsible for their variability and assist in decision making regarding measures for the recovery and preservation of water resources.

     

The Role of Reservoirs in Shaping The Dominant Cyclicity And Energy Of Mountain River Flows

The main objective of the paper is to determine the role of mountain reservoirs in shaping the dominant cyclicity and energy of river flows. The paper compares a large complex composed of two reservoirs (Czorsztyn–Sromowce Wy?ne) with a smaller reservoir (Besko). These reservoirs are located in the Polish Carpathians and are characterised by very different parameters and functions. Moreover, they operate on rivers (the Dunajec and the Wis?ok) with different hydrologic regimes. Using Fourier spectral analysis of daily inflows, outflows and water levels in reservoirs for the period 1998–2012, it has been possible to identify the dominant frequencies of the considered time series with a percentage of spectral energy for these frequencies. Moreover, for signals created by river flow rates, changes in signal energy are associated with adequate changes in river energy. Therefore, by calculating the energy of the signal in the time domain, changes in signal energy can be observed before and after the water passes through the reservoir. Data on cyclicity of water levels in these reservoirs forms the background to the analysis of reservoir‐induced changes in cyclicity of river flows. The conducted analysis revealed that reservoirs strengthen the regularity of the annual periodicity of stream flow in the studied rivers. Besides, these reservoirs significantly reduce the energy of water flowing out of them compared to the energy of inflow. Copyright © 2015 John Wiley & Sons, Ltd.     

The increasing damming of the Paraná basin and its effects on the lower reaches

The development of large impoundments along the Paraná river, particularly on the Superior section, with fifteen large dams having a capacity over 25000 MW, has had important hydrological and ecological impacts on the lower reaches. The important retention of the suspended solids by the dams has caused a significant reduction of P concentrations. With river impoundment and water eutrophication, cyanophiceae currently dominate during spring and summer, with brief but dense blooms of Anabaena spiriodes and Microcystis aeruginosa. Many fishes of the Superior Paraná have been dispersed downstream as the Itaipú reservoir covered the Guayra falls, the natural barrier for these fishes. The most important effects of Superior Paraná dams are related to the changed hydrological regime in the alluvial Middle and Lower reaches. This floodplain plays an important role in the bioproductivity of the river. Fisheries production depends to a high degree on the relationship of the river and its alluvial valley, where the alevines and small fishes of migratory species develop after spawning. During falling river levels the waters carry large quantities of organic matter, floating vegetation, important amounts of plankton and fishes from the alluvial plain to the river. Before the dams, the river defined two subsystems which were joined for about six months during the flood season and effectively isolated during low water periods. Since the commencement of river impoundment and flow regulation, the river ecology has begun a sequence of changes especially within the alluvial reaches.     

溪洛渡、向家坝水库与三峡水库联合蓄水调度研究

由于溪洛渡、向家坝水库与三峡水库蓄水时间上的同步性,使三峡水库蓄水难度进一步加大,进而影响其综合效益的发挥。为满足下游地区在蓄水期对上游梯级水库下泄流量的新要求,研究金沙江溪洛渡、向家坝水库与三峡水库联合蓄水调度方案,优化梯级水库蓄水过程。在综合分析防洪、泥沙、库区、发电及供水等指标基础上,推荐梯级水库蓄水调度方案。防洪、库区淹没及泥沙淤积的影响分析表明,所提方案可进一步缓解下游地区的供水压力,对金沙江梯级水库联合蓄水调度一定实践指导意义。     

基于图论的韩江流域水库群生态调度

采用水文学方法计算了韩江流域干支流重要控制断面的生态流量目标;基于图论原理,根据流域内干支流水系特征、重要水利工程和控制断面分布情况构建了韩江流域河网图模型;考虑河段区间来水、河道外取水、引调水等边界条件以及流域水库群水量调蓄作用,开展了河网水量平衡计算,确定了河网节点流量。通过计算水库坝址所在断面的天然生态基流,提出了耦合最小生态下泄流量要求的水库常规调度规则;借鉴大系统聚合-分解思想,提出了韩江流域河网图模型迭代优化求解思路;通过选取不同典型年来水过程,评估了常规调度情况下控制断面生态流量保障程度,并在此基础上进行优化调度,分析流域水库群生态调度保障潜力。结果显示,耦合最小生态下泄流量要求的水库常规调度规则能够让水库在独立运行的情况下,基本保障不同来水条件下的控制断面生态流量需求;韩江流域水库群可通过开展联合优化调度满足控制断面生态流量需求;基于图论方法开展流域水库群生态调度具有可行性和实用性。     

水库除险加固后做好蓄水安全工作的思考

水库除险加固后初期蓄水,水库主管部门(或业主)应负责所属水库运行管理工作,明确水库管理单位或管护人员职责;建立健全水库安全运行管理规章制度;组织委托相应资质的技术单位编制及上报初期蓄水方案、工程运行调度方案、度汛方案以及大坝安全管理应急预案;对大中型水库应筹措经费,委托相应资质的技术单位,开展蓄水安全鉴定评价工作;督促并监督水库管理单位或管护人员履行职责。水库管理单位或管护人员应严格执行水库安全运行管理规章制度、初期蓄水方案、运行调度方案,认真实施水库蓄水调度运用工作;进行大坝巡视检查和大坝观测;开展水库工程日常维修养护;报告大坝安全情况。     

Understanding the Thermal Regime of Rivers Influenced by Small and Medium Size Dams in Eastern Canada

Although small and medium‐size dams are prevalent in North America, few studies have described their year‐round impacts on the thermal regime of rivers. The objective of this study was to quantify the impacts of two types of dams (run‐of‐river, storage with shallow reservoirs) on the thermal regime of rivers in eastern Canada. Thermal impacts of dams were assessed (i) for the open water period by evaluating their influence on the annual cycle in daily mean water temperature and residual variability and (ii) for the ice‐covered winter period by evaluating their influence on water temperature duration curves. Overall, results showed that the run‐of‐river dam (with limited storage capacity) did not have a significant effect on the thermal regime of the regulated river. At the two rivers regulated by storage dams with shallow reservoirs (mean depth < 6 m), the annual cycle in daily mean water temperature was significantly modified which led to warmer water temperatures in summer and autumn. From August to October, the monthly mean water temperature at rivers regulated by storage dams was 1.4 to 3.9°C warmer than at their respective reference sites. During the open water period, the two storage dams also reduced water temperature variability at a daily timescale while increased variability was observed in regulated rivers during the winter. Storage dams also had a warming effect during the winter and the winter median water temperature ranged between 1.0 and 2.1°C downstream of the two storage dams whereas water temperature remained stable and close to 0°C in unregulated rivers. The biological implications of the altered thermal regimes at rivers regulated by storage dams are discussed, in particular for salmonids. Copyright © 2016 John Wiley & Sons, Ltd.     

我国库坝建设对河流生态系统服务功能的影响与战略对策

客观地分析了我国库坝建设对河流生态系统社会经济服务功能和自然生态服务功能正负两方面的影响。库坝建设大大提高了河流生态系统的社会经济服务功能,而降低了自然生态服务功能。由于调蓄洪水、供水、水力发电、减少温室气体排放和发展低碳经济等的需要,继续建设水库和大坝是我国未来一定时期的必然选择。提出了提高我国河流生态服务功能的战略对策。     

高坝水库放空要求及设施设计研究

高坝水库调节能力强,在流域梯级开发和防灾减灾中发挥重要作用,但其面临的风险也客观存在,一旦失事后果不堪设想。水库放空或降水位能力是经济社会发展新阶段对大坝风险防控和应急管理提出的新要求。本文给出水库放空的定义、目的及分类,系统阐述了放空水头比、放空库容比、库水位降速等水库放空能力评价指标,梳理了国内外对水库放空的要求,选取我国25座典型高坝水库进行放空能力分析。结果表明：高坝水库放空水头比介于17.5%～71.8%,均值为42.7%;放空库容比介于47.2%～99.2%,均值为81.7%;放空时间介于7.2～123 d,均值为42.7 d;库水降速介于0.71～9.03 m/d,均值为3.0 m/d。从实践来看,高坝水库放空能力受总库容、放空水位、坝型等工程特性参数影响,也受河流形态、河谷形状和库盆特点等因素影响。据此对水库放空设施设计中的入库流量、放空指标、启动条件和分级决策模式等关键问题进行了分析,对我国水利水电工程行业水库放空设施设计和应急管理有一定参考意义。     

水库多目标生态调度

分析了现行水库调度方法的不足,指出应在实现社会经济多种目标的前提下,兼顾河流生态系统需求,实行水库的多目标生态调度。文中讨论了水库多目标生态调度的方法,包括建立相应法规体系;保证维持下游河道基本生态功能的需水量;模拟自然水文情势的水库泄流方式;进行水库泥沙调控及水库富营养化控制;减轻水体温度分层影响;进行防污调度以及增强水系连通性等方面的调度技术。     

Reservoir Inflow Monitoring for Improved Management of Treated Water Quality—A South Australian Experience

Large tributary inflows into water supply reservoirs caused by heavy catchment rain may be of concern due to problems associated with high levels of natural organic matter (NOM) present in the inflows. The movement of these inflows within a reservoir is dependent on its relative density to the receiving waters. For example, if the inflow is denser (colder) than the recipient water it will travel along the base of the reservoir as an underflow and can penetrate as far as the dam wall water off-take to a water treatment plant (WTP). Field studies were conducted to track the passage of underflows through two South Australian reservoirs, Little Para and Myponga. Samples were collected before and during storm event inflows and analyses undertaken to determine NOM concentration, alum demand, disinfection by-product formation potential, and quality of the water. We demonstrate that by monitoring the movement of inflows into reservoirs, combined with changes in reservoir off-take levels, that the risk of NOM entering a water treatment plant can be reduced which in turn will lower water treatment costs by reducing alum dosing levels and lessen the risk to human health by reducing disinfection by-product formation.     

资水中下游特大洪灾成因及减灾对策

由于柘溪水库共库容不足，泄量大，资水河道逐年淤积，行洪能力减弱，沿岸防洪设施标准不高，非工程措施滞后等致使资水中下游常遭遇特大洪灾。通过对江民因分析，提出了减轻水害的对策与措施；加强水土保持治理、保护、监督区建设；兴建溪口水库，进一步优化柘溪水库洪水调度；继续加高加固堤防的同时，注重疏浚整治河道；加强蓄洪垸安全建设与运行管理。     

The Isotope Hydrology of a Large River System Regulated for Hydropower

Impoundments, regulation and inter‐basin transfers associated with large hydropower developments affect runoff regimes, water residence times and stream water quality. We used stable isotopes to understand these effects on the river Tay system in Scotland, examining their spatial and temporal variation in surface waters at 22 sites. Spatial patterns of isotopes in stream water were consistent with those of precipitation, being more depleted in streams draining higher, colder northern headwaters and enriched in the milder western headwaters. To a lesser extent, spatial patterns also reflected effects of inter‐basin and intra‐basin water transfers at some sites. Temporal dynamics reflected precipitation inputs modulated by landscape properties, the presence of lakes and reservoirs, and regulation operations. Isotopic variability was highest in headwater tributaries with responsive soils and lowest downstream of lakes and reservoirs. Variability of isotopes in lower river sites was also damped as they integrate contributions from the rest of the catchment. Importantly, regulation from both reservoirs and inter‐basin transfers can distort simple input–output relationships for stable isotopes and affect catchment transit times with implications for water quality and in‐stream ecology. On the one hand, reservoirs and extension of natural lakes have created additional storage, potentially slowing flows; on the other, transfers have increased the volume and rates of water throughput in many of these water bodies, reducing hydraulic turnover times. Such effects tend to be quite localized and are not apparent at the larger catchment scale. Copyright © 2014 John Wiley & Sons, Ltd.     

东江梯级开发现状及存在问题浅析

简述了东江流域新丰江、枫树坝和白盆珠三大水库及干流梯级开发现状,分析了三大水库现状防洪调度不能满足社会经济发展的防洪要求、以发电为主的枯水期调度难以满足流域内外供水需求,以及干流梯级群调度存在的问题和梯级开发对水生态和水环境的影响等问题,并针对上述问题提出了几点建议。     

Assessing sediment inputs to small reservoirs in Upper East Region,Ghana

Many small dams and dugouts have been constructed in the Upper East Region of Ghana to address the problem of regional water scarcity. The reservoirs were constructed primarily as water supplies for agricultural irrigation and livestock watering, aquaculture and domestic use. However, many of the reservoirs dry up during the dry season, affecting the livelihoods of their basin inhabitants. A major cause for the dried reservoirs is siltation, which reduces the reservoir’s storage capacities. The goal of this study is to quantify the annual siltation rate of four study reservoirs, using a bathymetric survey and reservoir soil sampling. The sediment yield and its relation to catchment area also were assessed. The results of this study indicate that the annual siltation rates are 1272, 3518, 2764 and 6135 t year^?1 for Doba, Dua, Zebilla and Kumpalgogo reservoirs, respectively. Analyses of the sediment yield and catchment areas illustrated that the sediment yields decreased with increasing catchment area. All the study reservoirs have lost their dead storage capacity, which was meant to store sediment until the end of their anticipated design lives. The decreasing storage capacity because of siltation will affect the livelihoods of the local basin inhabitants, as the reservoirs will not be able to achieve all their intended purposes. The results of this study indicate that, because siltation is not the only factor threatening the benefits gained from the reservoirs, the integrated assessment of all relevant factors is required.     

新时期三门峡水库的地位和功能

三门峡水库投入运用以来，在确保黄河下游防洪、防凌安全等方面发挥了巨大的作用，在水库调度、机组抗磨蚀等方面取得了丰硕成果，为多泥沙河流水库如何长期保持有效库容探索出了一条成功之路。小浪底水库修建后，根据黄河治理开发规划及黄河下游洪水处理调度和水资源综合利用的要求，三门峡水库仍须承担相当繁重的任务：①按照小浪底水库设计要求，只有当小浪底、三门峡、故县、陆浑4座水库联合调度时，黄河下游才能达到千年一遇防洪标准。小浪底水库死库容淤积完后，需要三门峡水库配合运用的防洪库容将更大。②当黄河下游发生严重凌情时，小浪底正常运用后的库容不能满足下游防凌的要求，仍需要三门峡与小浪底两水库联合控制。③随着黄河流域经济的快速发展，三门峡水库将在未来的供水体系中占有十分重要的位置。④三门峡、小浪底和西霞院3座水利枢纽将组成梯级水库群，小浪底水库承上启下，发挥中心枢纽的作用，但小浪底水库库容也是有限的，一些问题仍需要三门峡水库配合才能得到解决。此外，三门峡水库建库初期，破坏了当地的自然环境，而投入运用40多年来，非汛期蓄水，汛期降低水位，经过自然的修复和人工的建设，在库区形成了独特的生态系统和自然环境，在库周形成了依托水库发展的社会经济模式，因此三门峡水库不仅承担着流域治理开发而赋予的任务，而且对库区自身的发展起着重要作用：①保护和改善库区湿地生态环境。②为库区沿岸工农业用水提供保障。③改善库区水质。④支撑三门峡市的发展。