鄱阳湖洪水水位变化趋势的计算与分析

根据鄱阳湖洪水成因与影响机制，建立一个包括历年入湖流量过程的还原、湖泊容积的改变、出湖流量的变化等可变因素在内的洪水水位过程计算模型；利用该模型计算鄱阳湖1952-2000年历次洪水在不同年代水文环境下的最高水位；对不同年代年最高水位系列进行频率分析，得到不同年代鄱阳湖洪水水位变化的特征值；对比表明，鄱阳湖洪水的水位呈显著抬高趋势；从不同角度探讨鄱阳湖洪水水位抬高的原因在和估计退田还湖对洪水水位的影响。     

洪泽湖近50 a特征水位变化规律及影响因素

根据1967—2016年蒋坝、尚咀、高良涧和老子山4个水位站逐日数据,运用Mann-Kendall检验、有序聚类分析、BFAST算法和小波分析,揭示了洪泽湖特征水位年际、年内变化规律;并通过分别构建各特征水位与同期各入湖、出湖流量及降水量、蒸发量之间的多元回归关系,揭示了驱动洪泽湖特征水位变化的主导因素。研究表明:3类特征水位(平均水位、最高水位、最低水位)显著突变时期均在1982—1985年之间,1986年后洪泽湖特征水位呈显著上升趋势,最低水位变化响应时间最早,最高水位响应时间最晚;各特征水位均存在36、17、9 a的第1、第2、第3主周期;在蓄水期(Stage1)小柳巷入湖流量是影响平均水位和最低水位变化的主要因素,分别达到36%和33%,三河闸出湖流量是影响最高水位变化的主要因素,达36%;泄水期(Stage2)双沟入湖流量对最低水位影响更加明显,达到47%;涨水期(Stage3)小柳巷入湖流量在平均水位变化中起主要作用,达到29%。研究结果对于进一步认识洪泽湖水位变化规律具有重要意义,可为洪泽湖水位及上下游径流调控提供科学依据。     

鄱阳湖水龄时空特征和影响因素分析

换水能力是表征湖泊水动力和污染物输移扩散的关键指标,鄱阳湖水文情势波动显著,换水能力时空特征和影响因素复杂。本文选取水龄描述鄱阳湖换水能力,建立鄱阳湖水龄模型,研究了鄱阳湖水龄的时空特征和影响因素,分析了水龄对鄱阳湖江湖关系演变的响应规律。结果表明:(1)鄱阳湖水龄具有显著的时空异质性。夏季和秋季水龄明显大于冬季和春季,碟形湖和湖湾区域水龄明显大于主河道和滩地。(2)湖口水位和流域入流是影响鄱阳湖水龄的主要因素。湖口水位对鄱阳湖水龄的影响大于流域入流;湖口水位越高则鄱阳湖水龄越大,流域入流与之相反;鄱阳湖水龄年内显著波动的主要原因是湖口水位的年内显著变化。(3)2003年后,随着江湖关系的演变,鄱阳湖水龄有所减小,其中秋季减小最为明显。研究成果能为鄱阳湖水资源保护提供科学支撑,也可为其他大型湖泊换水能力研究提供参考。     

1954-2018年东平湖水位变化特征及驱动因素分析

依据东平湖1954-2018年水位资料,采用Mann-Kendall突变检验、小波分析等方法,分析了1958-2018年东平湖的水位变化特征,探讨了其变化的自然和人为因素。研究结果表明:1958-2018年东平湖水位年际变化幅度较大,总体呈现中-低-高的变化特征;年际水位周期变化具有28a和40a的时间尺度特征。人类活动影响下的入湖径流量变化是东平湖水位变化的主要因素,气候因素也起到一定程度的作用。1958年之前,东平湖与黄河自然联通,水位变化受黄河和大汶河来水影响较大; 1958年以后,东平湖与黄河水文系统被人为控制,水位变化主要受大汶河入湖径流量变化的影响; 1970年以后,气候变暖加剧,降水量增加影响了水位的变化; 2013年南水北调东线工程实施后,人为因素的影响进一步加大。     

鄱阳湖近60年天然入出湖径流特征分析

依据鄱阳湖流域“五河”7个入湖控制水文站及出湖湖口站观测资料,对其中人类活动影响较大的李家渡、柘林站进行径流还原,得到7个入湖站和出湖站1953～2011 年天然径流序列。综合采用多种方法对各站径流序列进行了分析。结果表明：李家渡站年径流量比以往研究结果增加25%左右,且枯水期增加更明显,与上游站点天然径流演变规律更具有一致性;“五河”各站天然径流量的年际变化和年内分配总体上具有相似性;入、出湖各站径流年内分配极不均匀;1953～2000年,入、出湖各站径流均呈现小幅度上升趋势,但21世纪以来各站径流量处于下降趋势;各站年径流序列存在33~35 a的变化主周期,与流域年降水量变化主周期基本一致。研究结果可为鄱阳湖流域水资源的合理开发和科学管理提供参考依据。     

西苕溪流域2012年“海葵”台风洪水分析

文中利用西苕溪流域2012年“海葵”洪水水文资料,统计了西苕溪“海葵”台风与另外两场台风洪水的场次、起涨时间、峰现时间（控制站点水位最高）、起涨水位、峰现水位、降水量、水位涨幅等因素,并完成了台风型洪水水位涨幅与降雨量的关系分析.通过与历史上“罗莎”、“莫拉克”两场超强台风暴雨洪水的比较,对三场台风型洪水进行评述,归纳问题与看法以供参考.     

对1995年长江中下游洪水的认识

１９９５年６、７月间长江中下游干流及洞庭，鄱阳两湖地区发生了较大洪水，加上河湖槽蓄量的变化，中下游干流个别站和两湖的一些支流控制站出现了超历史最高洪水位，作者从峰现时间，洪水组成，洪水位和各河段分布洪量，洪水水面线，水位流量关系等方面对１９９５年长江中下游洪水的特性进行了分析，认为１９９５年长江洪水属于中下游型洪水，大通站最大洪水流量为建国以来仅次于１９５４的较大洪水流量。     

鄱阳湖区水资源安全问题分析

本文分析了鄱阳湖流水资源及湖区水位的特征及其演变规律,研究了鄱阳湖区存在的水资源安全问题,计算了三峡水库初期运行和正常对鄱阳湖区水资源开发利用的影响,得出了鄱阳湖流域天然水资源情势未发生趋势性变化、湖区“高水湖相,低水河相”特征造成枯水季节湖区用水困难和三峡水库蓄水期间鄱阳湖出湖流量增加使用水困难加剧等认识。     

基于小波变换的开都河径流量多时间尺度分析

以开都河大山口站1956—2006年的年径流量资料为例,利用Morlet小波变换对其水文序列的多时间尺度演变特性进行了分析,并预测了开都河2006年以后的年径流量变化趋势。结果表明:开都河存在6 a、10 a、15 a和38 a等4个主周期,其中38 a和10 a分别为第一和第二主周期;2006年后的未来几年内开都河将处于偏枯期。     

江都水利枢纽下游潮水位变化规律及影响分析

为了探究江都水利枢纽下游潮水位变化规律及其影响,根据输水口门三江营站逐日资料, 应用趋势分析和周期分析的方法,分析1957—2019年长系列的特征潮位、潮差、潮历时、周期等典型要素的变化规律以及对工程运用的影响。结果表明:多年潮位呈显著增大变化,涨落潮最大潮差呈不显著增大趋势、涨落潮最大历时呈不显著减小趋势,但最大潮差和潮历时在夏季呈现与年趋势相反、在枯水期呈现与年趋势相同的变化。特征潮位、潮差、潮历时均呈周期性变化,特征潮位和最大潮差主周期均约为28 a,涨落潮最大历时主周期约为22 a;根据主周期特征时间长度,特征潮位、潮差、潮历时目前均处于增大阶段,将于2020—2021年进入为期约7~9 a的减小期。该研究对南水北调东线源头充分调引长江水源以及淮河洪水安全下泄具有重要的现实意义,也为更好地掌握长江河口潮流界末端潮流的运动规律提供参考。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

地下厂房施工过程的三维非线性数值模拟分析

根据冗各电站地下厂房开挖支护的施工顺序,以隐式杆单元模拟锚杆,以壳单元模拟混凝土喷层,采用三维非线性有限元技术,对洞室群的开挖支护动态过程进行了模拟计算。通过三维非线性有限元计算分析得到:洞室群动态开挖过程中围岩应力变形的分布规律,围岩塑性区的发展规律,锚杆受力变化情况。计算结果表明:整个开挖过程中,洞周围岩位移变化规律正常,量值较小,塑性区主要分布在洞室周边,围岩稳定性较好;但在洞室交叉口处围岩的变形较大,出现较大范围的塑性区,在此基础上提出了支护措施优化方案,并对优化方案的效果进行了评价。     

Evaluation of freshwater mussel relocation as a conservation and management strategy

The relocation of unionacean mussels is commonly used as a conservation and management tool in large rivers and streams. Relocation has been used to recolonize areas where mussel populations have been eliminated by prior pollution events, to remove mussels from construction zones and to re-establish populations of endangered species. More recently, relocation has been used to protect native freshwater mussels from colonization by the exotic zebra mussel Dreissena polymorpha. We conducted a literature review of mussel relocations and evaluated their relative success as a conservation and management strategy. We found that 43% of all relocations were conducted because of construction projects that were forced to comply with the Endangered Species Act 1973 and that only 16% were monitored for five or more consecutive years. Most (43%) relocation projects were conducted from July to September, presumably a period when reproductive stress is relatively low for most species and the metabolic rate is sufficient for reburrowing in the substrate. The mortality of relocated mussels was unreported in 27% of projects; reported mortality varied widely among projects and species and was difficult to assess. The mean mortality of relocated mussels was 49% based on an average recovery rate of 43%. There is little guidance on the methods for relocation or for monitoring the subsequent long-term status of relocated mussels. Based on this evaluation, research is needed to develop criteria for selecting a suitable relocation site and to establish appropriate methods and guidelines for conducting relocation projects.     

基于模型试验的河床砂砾石层基本特性研究

为了经济可靠地确定深厚覆盖层的基本特性参数,以大渡河双江口水电站坝基河床砂砾石层基本特性研究为工程背景,进行大尺寸模型试验,研究河床砂砾石层的旁压模量和动探击数随密度、级配以及上覆压力的变化规律。根据室内模型试验结果,结合现场旁压试验及钻孔试验成果,推断出坝址区河床砂砾石相关层位的密度,并依此进行砂砾石室内力学试验,获得设计所需力学参数。研究成果可为深厚覆盖层基本特性测试提供新的方法。     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered. __________ Translated from élektricheskie Stantsii, No. 2, pp. 26–30 (2008).     

The flood pulse advantage and the restoration of river-floodplain systems

The ‘flood pulse advantage’ is the amount by which fish yield per unit mean water area is increased by a natural, predictable flood pulse. Evidence for this increase is presented from tropical and temperate fisheries. It is argued that increasing multispecies fish yield by restoring the natural hydrological regime is consistent with increasing production of other trophic levels and with restoration from ecological and aesthetic viewpoints. When applied to a river-floodplain system, this restoration would provide a large, self-sustaining potential for recreation, commercial exploitation, and flood control. An interim ‘natural flood pulse’ restoration approach is proposed for systems modified for navigation. This approach approximates the natural hydrological regime in a river reach and is intended as a first step in the long process of restoring the watershed.