三峡水库汛期控制水位及运用条件

随着长江上游梯级水库的陆续建成投运，三峡水库的水文情势和功能需求与设计条件相比发生了显著变化，仍维持固定的汛限水位运行已不能适应新形势需求。本文通过辨析三峡水库设计阶段汛限水位的设置条件，挖掘流域洪水特性和洪水遭遇规律，论证三峡水库汛期运行水位动态控制的可行性。结果表明:①三峡水库设计推求的汛限水位145 m的适用条件是应对流域性大洪水，而流域性洪水发生概率小且特征明显，可以通过水文水情分析提前预判。②根据流域洪水类型、洪水分期和遭遇规律，预判发生区域性大洪水时，三峡水库6月初至梅雨期结束汛限水位按145 m设置，从梅雨期结束后逐渐提高水位，8月20日后过渡到155 m。③在考虑上游水库群联合调度和气象水文预报的配合下，正常年份三峡水库汛期运行水位可在155 m上下浮动，并考虑提前蓄水。④三峡水库汛期运行水位动态控制，不会增加防洪风险和库区淤积风险，对中下游江湖关系和水文情势有利，可显著提高发电、航运、生态保护和供水等综合利用效益。     

三峡水库汛期控制水位及运用条件

随着长江上游梯级水库的陆续建成投运，三峡水库的水文情势和功能需求与设计条件相比发生了显著变化，仍维持固定的汛限水位运行已不能适应新形势需求。本文通过辨析三峡水库设计阶段汛限水位的设置条件，挖掘流域洪水特性和洪水遭遇规律，论证三峡水库汛期运行水位动态控制的可行性。结果表明：① 三峡水库设计推求的汛限水位145 m的适用条件是应对流域性大洪水，而流域性洪水发生概率小且特征明显，可以通过水文水情分析提前预判。② 根据流域洪水类型、洪水分期和遭遇规律，预判发生区域性大洪水时，三峡水库6月初至梅雨期结束汛限水位按145 m设置，从梅雨期结束后逐渐提高水位，8月20日后过渡到155 m。③ 在考虑上游水库群联合调度和气象水文预报的配合下，正常年份三峡水库汛期运行水位可在155 m上下浮动，并考虑提前蓄水。④ 三峡水库汛期运行水位动态控制，不会增加防洪风险和库区淤积风险，对中下游江湖关系和水文情势有利，可显著提高发电、航运、生态保护和供水等综合利用效益。     

Estimating water volume discharge through salt-marsh tidal channels: An aspect of material exchange

Water volume discharge estimates were made at a sample cross-section of the Canary Creek salt marsh (Lewes, Delaware). To account for cross-sectional velocity variations, a dense spatial array of current meters was used. Simultaneous measurements were taken at hourly intervals over three complete tidal cycles. A practical method is presented whereby instantaneous average cross-sectional velocity, instantaneous cross-sectional discharge and tidal cycle discharge can be estimated from a dense current meter array, orideal data set. Based on theseideal estimates, it is shown that a simplified spatial array can be used to estimate water discharges within acceptable error limits. Instantaneous cross-sectional discharges and total tidal cycle discharges were estimated with uncertainties of ±11% and ±7%, respectively. To minimize errors when estimating material exchange between salt marshes and adjacent waters, it is suggested that a comprehensive assessment of cross-sectional lateral current velocity variations be conducted.     

Effects of a photosynthesis inhibitor,atrazine, on the salt-marsh fiddler crab,Uca pugnax (Smith)

Atrazine (2-chloro-4-ethylamino-6-isopropylamine-s-triazine) concentrations of 1,000 ppm either killed or eliminated the escape response (considered to be analogous to death) ofUca pugnax in laboratory experiments in August 1977. Adverse effects were observed at concentrations as low as 100 ppm and the severity was dependent on size and sex of the crab. However, in subsequent experiments, each with a new group of crabs, the effects of atrazine became smaller and smaller until a November experiment when no deleterious effects were observed even when exposed to 1,000 ppm. Experiments in August, 1978 confirmed the data obtained 1 year earlier. Ecological and physiological considerations of this seasonal variation in response are discussed. Crabs fed for 20 days with detritus wetted with 10^?4 M atrazine were not adversely affected. Crabs exposed to a single application of 0, 100, 1,000, and 10,000 ppm atrazine in the field and in microecosystems were adversely affected only by the 10,000-ppm rate. Toxicity of atrazine to the larval stage of the crab was not investigated.     

水库汛限水位调整与运用

基于对水库汛限水位主要影响因素的系统分析,从洪水资源安全利用的角度出发,阐明了水库汛限水位调整综合分析论证所应遵循的原则,提出了风险设计分析论证的框架、定量分析方法和汛限水位合理调整的论证。最后以海河流域潘家口水库为分析实例,从设计洪水、预报预泄、洪水预报调度方式、上下游防洪设计标准、上游移民淹没及土地退赔线、水库长期运行的风险和效益等多个方面分析论证了水库汛限水位的合理调整方案。     

Long-term growth and development of transplants of the salt-marsh grassSpartina alterniflora

Estuaries and Coasts - The effect of transplant spacings (45, 60, and 90 cm) on establishment ofSpartina alterniflora along an eroding shoreline in North Carolina was evaluated and annual biomass...     

岩溶场地地表水体对抗浮水位影响及取值研究

文章针对贵州山区岩溶场地中,近湖泊或水库分布场地、靠河流岸边场地、河湾场地、河流三角地场地等4种不同地表水体场地的抗浮水位取值进行了研究,得到如下结论:①抗浮水位取值可通过:勘察期间场区地下水最高水位（H_kmax）、可能的意外补给造成该层地下水位的变幅值（ΔH₀）、该层地下水相对勘察时的最大变幅值（ΔH_e）三者之和求得;②近湖泊或水库分布场地抗浮水位取值可以利用反推法或经验法获得。通过场地与湖（库）水水力比降反推在洪水期场地的最高地下水位;靠河流岸边场抗浮水位取值应以历史最高洪水位为基础,根据场区岩溶发育程度、建筑物与河流距离及水力比降综合分析确定,抗浮水位应在历史最高洪水位基础上增加0.5~1.0 m为宜;河湾地段场地抗浮水位取值应查明历史最高洪水位、水力坡降和场地岩体完整性、岩溶发育程度及规模,在岩体透水性、岩溶贯通好的场地增加0.5~1.0 m应较为宜;河流三角地段抗浮水位取值应确定地下径流方向、与河流间的水力比降及工程位置的最高水位,在岩体透水性、岩溶贯通好的场地增加0.5~1.0 m应较为适宜。      

水库汛限水位动态控制的实现途径

水库汛限水位动态控制是洪水资源利用的主要方式之一,提高水库洪水预报精度和延长有效预见期是实现水库汛限水位动态控制的关键所在。针对水库实时防洪调度的特点和流程,概述了新一代天气雷达、气象卫星及相关应用系统的技术进展,评价了这一技术进展在水库实时防洪调度中的重要作用,据此提出了综合应用新技术改进水库洪水预报、洪水量级判断和蓄水时机选择的技术途径。在此基础上,以海河流域潘家口水库为例,综合论证了水库汛限水位的动态控制范围,提出了汛期蓄水的控制策略与调控方法。     

Biogeochemistry of Cadmium: Anthropogenic Dispersion,Bioaccumulation, and Ecotoxicity

The article considers biogeochemical features of cadmium as one of the most dangerous elements. Data on its concentrations in waters of small lakes in the European Russia (from the tundra to deserts) and large river systems (Volga, Severnaya Dvina, Pechora) are given. It is shown that, despite the relatively low concentrations of the element in waters, its enrichment factor is hundreds and thousands of units, especially in the northern regions and regions subjected to the influence of non-ferrous metallurgy. Data are presented on the bioaccumulation of cadmium within fish body systems, which is determined by the concentration of the element in waters, as well as by the water pH and the calcium content. It is proved that the highest Cd concentrations are accumulated in kidneys and liver of whitefish and salmon, causing pathological disturbances. Data are reported on the accumulation of cadmium in kidneys and liver of human population of the industrially developed Northern region under impacts of copper–nickel smelters. The similarity in tendencies of the Cd accumulation and pathological disturbances in fish and the population consuming water from contaminated sources makes it possible to recommend fish as a bioindicator of the environmental pollution by cadmium.     

Effects of water table changes on soil CO2, CH4 and N2O fluxes during the growing season in freshwater marsh of Northeast China

A field control experiment was carried out to determine the influence of water table changes on soil CO₂, CH₄, and N₂O emissions in Calamagrostis angustifolia freshwater marsh in Northeast of China. The results showed that the water depth of 5 cm below the ground surface increased soil CO₂ emission, but there was no significant influence of deeper water table on gas emission. CH₄ emission was accelerated by deep standing water and approached the peak in the plant booming time. This suggests that root activity has influence on CH₄ production. The result also demonstrated that both low water table level and inundated environment would inhibit N₂O emission. Comparing the total global warming potential of three gases under different conditions, it can be concluded that maintaining a comparatively steady water table near the soil surface can benefit soil carbon sequestration in the C. angustifolia marsh, and decrease of the greenhouse gases emissions to the atmosphere.     

Tide gauge records,water level rise,and subsidence in the Northern Gulf of Mexico

Long-term water level changes in the northern Gulf of Mexico were examined using tide gauge records for this century. Strong coherence exists between the annual mean water changes at Galveston, Texas, and (1) the relatively geologically-stable west coast of Florida, (2) global mean sea level, and 93) the subsiding Louisiana coast. Water levels at the Galveston gauge, one of the longest records (81 yr), have risen steadily, but not accelerated over the long-term. The apparent acceleration of water rise in the recent two decades is within the historical pattern, and is probably driven by regional or global, but not local climatic factors. Because eustatic sea level has risen steadily this century, the analysis supports the conclusion that regional geologic subsidence has not varied significantly over the tide gauge record (1909–1988). Variations in the estimates of subsidence in the surface layers are generally consistent with the generally accepted understanding of the geology of deltaic processes on this coast.     

云南程海沉积物粒度对水深的指示意义

不同湖泊盆地构造以及流域水文过程的差异导致湖泊沉积物粒度的指示意义有所不同。文章以云南程海表层岩芯为研究对象,分析取自不同水深的表层岩芯沉积物粒度（1 cm、5 cm以及137Cs-峰层位）和碳酸盐含量（2cm、5cm以及137Cs-峰层位）,探讨其与水深的空间相关性;通过对垂直钻孔岩芯粒度的分析,并结合过去50余年来的湖泊水位记录,探讨沉积物"粒度-水深"在时间尺度上的关系。结果表明：1）在空间分布上,沉积物平均粒径和水深呈显著反相关关系,即程海沉积物平均粒径随水深增加（减小）而变细（变粗）,且该"粒度-水深"空间分布模式得到沉积物碳酸盐含量空间分布规律的支持;2）在时间尺度上,水深的时段沉积物粒度细,水浅的时段沉积物粒度粗;与"粒度-水深"的空间关系一致。我们推测上述"粒度-水深"的时空变化关系与湖泊面积变化导致的采样点与岸边/河口的距离有关。在此基础上,进一步分析了程海近千年的沉积物粒度与水位变化关系：中世纪暖期和现代暖期粒度偏粗,程海处于低湖面;小冰期程海沉积物平均粒度偏细,对应于高湖面。上述基于"粒度-水深"关系推导的水位变化与我们前期基于岸边地质证据得出的水位变化,以及历史文献记载的水位变化一致,验证了本文获得的"粒度-水深"关系的可靠性。     

冻融季节苏打盐渍土的水盐变化规律

通过野外定位观测和室内分析,探讨了冻融季节的微域尺度(32 m长的横剖面)苏打盐渍土的水分和盐分的变化规律.结果表明:冻结期大量地下水迁移并储存在盐化草甸土的冻层中,同时地下水位埋深迅速从1.2 m下降到2.5 m以下;苏打盐化草甸土冻结层的含水率明显增加,其中30~40 cm土层的含水率变化最明显(从冻结前的20%增加到50%).苏打碱土冻层的含水率增量不明显,但盐分显著增加,其中白盖苏打碱土表层的盐分增量幅度达80%.盐分变化主要表现为苏打盐渍土表层HCO₃-、CO₃2-、SO₄2-以及Na+的增加,大量盐分表聚使消融期土壤的盐渍化程度不断加重.     

乌伦古湖最低生态水位及生态缺水量

确定乌伦古湖的生态保护目标是流域水资源合理、高效配置的前提和基础.针对乌伦古湖冷水系淡水鱼类的生存繁殖特征,提出了基于干旱区湖泊鱼类～盐度～水量关系的湖泊最低生态水位计算方法,并根据该方法计算得到布伦托海和吉力湖的最低生态水位分别为476.12 m和478.12 m.由水量平衡关系进一步计算了湖泊最小生态需水量和接近9...     

永安井水位记录水震波能力及分析

本文主要在对永安井水位记录的水震波进行统计分析 ,在此基础上 ,择出有代表性震例的水震波进行分析探讨 ,并提出一些假设进行讨论     

Abundance and seasonality of meiofauna,including harpacticoid copepod species,associated with stems of the salt-marsh cord grass,Spartina alterniflora

Ten Spartina alterniflora plants were sampled monthly in a Louisiana estuary to determine the abundance and species composition of stem-dwelling meiofauna and small macrofauna. Most organisms were associated with epiphytic algae found relatively high on standing stems; one harpacticoid copepod, Leptocaris brevicornis, was associated with vascular tissue. Only 15% of the stem fauna was found within 6 cm of the sediment surface. Highest abundance of total meiofauna (>8,000 individuals per 100 cm² stem surface) occurred in July. The overall seasonal average was 1,563 individuals per 100 cm² (about 800 per stem). Nematodes (24% of the total) and harpacticoids (adults and copepodites 19%, and nauplii 15%), were abundant and omnipresent taxa. Rotifers (30%) were limited to the summer months, but were extremely abundant when present, 5,037 individuals per 100 cm² in July. Mites were common (10%) while several groups, for example, amphipods, isopods, polychaetes, and insect larvae, were rare. The stem harpacticoid assemblage was not diverse; four sediment-dwelling and three species reported only from stems were recorded. Overall, abundance was low from December to May, and high from June through November. Winter and spring minima may have resulted from several factors. Estuarine water levels in the Gulf of Mexico are lowered by as much as 25 cm in the winter, and stems likely were desiccated. Highest rhizomatic growth occurs in the spring, and the resulting reduced epiphyte populations may have influenced meiofauna. The density of stem meiofauna above the sediment surface averaged about 225 individuals per 10 cm² sediment surface, but frequently exceeded that in the surrounding sediments.     

福州温泉区地下热水开采与水位动态响应研究

地下热水是一种极其宝贵的资源，然而长时间的过量开采，使资源濒临枯竭，同时还会产生一系列的环境负效应。福州温泉区蕴藏着丰富的地下热水，多年开采，水位不断下降，已使部分泉消失。针对这一状况，笔者对福州温泉区地下双层热储层——第四系孔隙热储层及下伏基岩裂隙热储层中热水的赋存条件，补给与排泄条件，开采的历史与现状，热储层历年地下水位动态变化特征及漏斗展布状况进行了详细的对比分析与研究。研究结果显示第四系孔隙热储层北部抽水漏斗较深，南部补给相对充分而漏斗不明显，经过10a的变化漏斗中心最大变化幅度为7．6m；基岩裂隙热储层出现南北2个漏斗，10a间漏斗中心水位最大变化幅度为12．61m。表明随着开采的进行，地下热水水位在持续性下降，热资源在逐渐流失。指出加强地热资源开采量监控及建立比较完善的地热资源管理系统的迫切性，以实现资源的合理利用和可持续发展。     

The changes in the lower Drava River water level, discharge and suspended sediment regime

Massive construction on the Drava River basin and on the river itself during the last centuries, as well as recent climate change and/or variability, has caused many different and possibly dangerous changes to its hydrological and ecological regime. Since 1975, numerous hydrotechnical works have been carried out on the 60-km long section of the Drava River from the Slovenian–Croatian border to the River Mura mouth. Three hydrotechnical power plants with three reservoirs and three long inlet and outlet canals have been built. Changes in water level, discharge and suspended sediment yield along the Drava River measured in Croatia, downstream of the three Croatian reservoirs, during the last 30–130 years are presented. The investigation focuses on changes that have occurred during the last thirty-odd years, caused by the anthropogenic influences on the Drava River watercourse and its catchment in Croatia and Hungary, and probably by climate change or variability. Methods of rescaled adjusted partial sums, statistical tests, as well as regression and correlation analyses are used to explain changes in water level, discharge and suspended sediment yield. There is evidence in the time series of decreases in the minimum, mean and maximum annual water levels, and minimum and mean discharges on the lower part of the Drava River. One of the main objectives of this study was to examine the effect of dams and reservoirs operation on the changes in the downstream suspended sediment regime. The amount of suspended sediment has been greatly reduced, which can cause serious consequences.     

地下水库特征水位与特征库容的划分及确定研究

参考地表水库调控指标的划分方法,将地下水库的特征水位与特征库容划分为死水位与死库容、正常蓄水位与调蓄库容、腾空库容和已占库容以及总库容,并提出了特征水位确定的一般原则以及承压地下水库的库容计算原理与方法。以大庆市西部地下水位降落漏斗区地下水库为实例,确定地下水库水量调蓄的死水位为115m,正常蓄水位为132m,结合现状地下水位,计算得出相应的死库容为1161.58×108m3,调蓄库容为1.75×108m3,腾空库容为1.57×108m3,总库容为1163.33×108m3。