北大港水库分库后的水质咸化风险研究

对北大港水库水环境、库区底泥及土壤盐分分布、释放强度及规律、水文地质条件等方面进行实验分析,通过模型对水库分库蓄水后水质变化进行预测,提出北大港水库分库后作为南水北调东线及引黄济津工程调蓄水库的咸化风险以及为防止咸化采取的水质、水位控制方案和对策措施。     

北大港水库水质咸化规律与影响因素分析

天津滨海平原水库普遍存在的水质咸化问题,以北大港水库为研究对象,采用野外调查和取样分析方法,识别了北大港水库不同季节水质咸化垂直分布规律,同时分析了水库水质咸化机理及其影响因素。研究结果表明:从电导率、氯离子和总溶解性固体(TDS)等代表性咸化指标来看,相对于引黄水,水库水各站点均存在咸化现象,并且出库口水质咸化程度明显高于进水口;不同站点电导率、氯离子浓度和总溶解性固体(TDS)值分别为867.5μS/cm、0.41g/L和1.46g/L,水体呈弱碱性;北大港水库水质咸化程度有季节性变化,为夏季略高于春季;水库各站点氯离子浓度和TDS值垂向上均随深度的增加而降低,但不明显;而电导率则随着深度的增加而增加,且变化明显。研究还发现,水库水质咸化受土壤含盐量、温度和混合作用的影响:从各站点水平分布来看,越靠近海岸线土壤含盐量越高,水质咸化现象越严重;温度的升高会影响底泥盐分的释放,温度越高,底泥中Cl-越容易释放;引黄水进入水库后,水库水体垂向发生了混合作用,导致氯离子和TDS垂向方向变化很小。     

碧流河水库下游河道生态需水分析及应对措施研究

天津滨海平原水库普遍存在的水质咸化问题,以北大港水库为研究对象,采用野外调查和取样分析方法,识别了北大港水库不同季节水质咸化垂直分布规律,同时分析了水库水质咸化机理及其影响因素。研究结果表明:从电导率、氯离子和总溶解性固体(TDS)等代表性咸化指标来看,相对于引黄水,水库水各站点均存在咸化现象,并且出库口水质咸化程度明显高于进水口;不同站点电导率、氯离子浓度和总溶解性固体(TDS)值分别为867.5μS/cm、0.41g/L和1.46g/L,水体呈弱碱性;北大港水库水质咸化程度有季节性变化,为夏季略高于春季;水库各站点氯离子浓度和TDS值垂向上均随深度的增加而降低,但不明显;而电导率则随着深度的增加而增加,且变化明显。研究还发现,水库水质咸化受土壤含盐量、温度和混合作用的影响:从各站点水平分布来看,越靠近海岸线土壤含盐量越高,水质咸化现象越严重;温度的升高会影响底泥盐分的释放,温度越高,底泥中Cl-越容易释放;引黄水进入水库后,水库水体垂向发生了混合作用,导致氯离子和TDS垂向方向变化很小。     

北大港水库分库前后水质安全数值模拟

为探索北大港水库分库的可行性,假定北大港水库在维持水库现状、分库不挖深及分库挖深1 m三种工况条件下均调蓄3亿m3"引黄水"时,运用零维水质模型对其水量水质的变化进行模拟,以此对比探究水库分库前后水质安全。结果表明:水库分库时较不分库时具有水质咸化风险低、不超标天数多及可供水量大等优点,即水库分库较不分库水质安全,同时水库分库时不挖深较挖深好。     

北大港水库水质咸化特征与沉积物盐分释放

选择天津滨海地区北大港水库为研究对象，采用野外调查和数据分析相结合的方法，于夏季对水库不同位 置取样，分析水体 pH 值和主要咸化指标溶解性总固体（TDS）及 Cl ?质量浓度，研究北大港水库不同位置水质咸化 的变化规律，对水库咸化机理进行探讨。研究发现：沿着水流方向自西向东，TDS 和 Cl ?质量浓度呈现“水库上游 闸＞水库下游闸”的分布特征，而 pH 值正好相反，沿着水流方向水体咸化呈现逐渐减弱的趋势；北大港水库水体 各指标在垂向分布上可分为两种类型：“混合型”水体，多分布在水库水流上游西侧进水闸口（南岸进水闸、赵连 庄闸、马圈进水闸、大港农场闸和刘岗庄闸），水库东南部的沙井子闸以及东北部的出水闸（十号调节闸和排咸 闸）；“分层型”水体，TDS 和 Cl ?质量浓度在垂向上均随着深度的增加而增加，其中三号泄水闸最具代表性。沉积 物盐分释放对水库咸化有影响。     

北大港水库微生物群落的空间分布特征

天津北大港水库水质存在咸化问题，水质咸化可能会导致微生物群落组成和多样性发生显著变化。为探究 水质咸化条件下水库微生物群落组成的空间分布特征，于 2021 年 12 月在北大港水库采集表层、中层和底层的水 样，利用高通量测序技术，对北大港水库不同深度及上下游的微生物群落组成及多样性进行分析，并探究溶解性 总固体与微生物群落的关系。结果表明：北大港水库的溶解性总固体（total?dissolved?solids,?TDS）质量浓度在表层、 中层和底层存在差异，下游高于上游。微生物的主要优势菌门为变形菌门、拟杆菌门和放线菌门，变形菌门的相 对丰度均超过 50%。优势菌属是 Clade_III 未定属（相对丰度 1.10％～72.72?％）和黄杆菌属（Flavobacterium?相对丰 度 0.32％～20.09?％），Clade_III 未定属的相对丰度上游高于下游，黄杆菌属的相对丰度表层高于中层和底层。上 游水体表层的微生物群落组成与中层、底层的微生物群落组成存在显著差异，下游在不同深度微生物群落组成差 异不显著，中层和底层的微生物群落组成存在相似性。Chao1 和 Shannon 指数表现出表层<中层<底层，下游略高 于上游，微生物 Alpha 多样性指数随 TDS 质量浓度的增大而减小。在科水平上，Clade_Ⅲ能够耐受较高的盐度，但 当 TDS 质量浓度>3?000?mg/L 时其丰度降低。     

天津滨海地区水库水质咸化问题及机理分析

天津滨海地区的北大港水库和其他水库存在水质咸化问题.根据传质理论,结合滨海地区的自然地理和气候特点,全面地分析了滨海地区水库水质咸化机理,主要机理有盐碱土和地下水的传质作用、蒸发量大于降雨量的蒸发浓缩作用、风的搅拌加速传质作用和加速蒸发浓缩作用等.     

风对北大港水库水质咸化影响的理论分析与实验研究

从理论上分析了风加快北大港水库水体水质咸化速度的原因，一是由于风对水体的扰动作用，加快了盐份从底部土壤向整个水体的扩散速度，二是风可加快水体的蒸发速度，加速了水体的蒸发浓缩作用，并通过有风、无风的对比实验定性地证明了此结论。     

从引黄济津工程看南水北调东线工程水环境保护

通过对引黄济津工程调水水质变化情况的分析,类比分析了南水北调东线工程水质变化情况及其水环境保护效果,并提出了保护意见。     

引黄输水工程水质变化特征分析及污染控制对策

随着城镇化进程的加快,华北地区缺水问题愈加凸显,河北省从1972年开始实施了引黄输水工程,旨在缓解华北地区水资源的紧缺状况。通过对典型年引黄济津输水水质时空变化特征分析,探讨引黄输水沿线水质变化程度及其影响因素,并结合实施过程中的水污染具体问题,提出了引黄输水工程中水资源质量的保障措施。     

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。     

基于BP神经网络-马尔科夫链模型的隧道围岩位移预测

在隧道工程施工中,围岩位移预测起着很重要的作用。将BP神经网络-马尔科夫链模型引入到隧道围岩位移预测中来,通过对训练样本的学习,利用BP神经网络实现了对位移时间序列的滚动预测,同时得到了实测值与预测值的相对误差;在此基础上利用马尔科夫链对相对误差进行修正,有效地提高了预测结果的精度。并将该模型应用于某公路隧道拱顶下沉位移时序预测中,结果表明该模型具有精度高、科学可靠的特点,为隧道围岩变形的预测提供了新的途径。     

Short communication. Pipelines as a refuge for freshwater snails

In the lower River Murray, Australia, populations of gastropods have declined markedly over the past 40 years. Of the native fauna of about 18 species, only the ancylid Ferrissia petterdi remains common (but in patches), and another five species feature in sporadic local resurgences. Until recently the viviparid Notopala was thought to be extinct. The introduced physid Physa acuta is widespread, but in low numbers. The decline probably is associated with flow regulation, high turbidity and the introduction of common carp. Snail populations have persisted, however, in irrigation pipelines fed from the river, where they periodically cause blockages. This paper reports the discovery of the only known populaion of Notopala hanleyi in a pipeline where the inner wall accumulates microbial and other organic matter, providing high quality food for snails. In the Murray before regulation most of the periphytic biomass was probably microbial, as fluctuating water levels would have maintained littoral communities in a highly productive, early state of succession his postulated that, by stabilizing seasonal water levels, regulation has promoted the production of filamentous green algae, an inferior food source, and so displaced snail populations from the open aquatic environment.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

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.     

浅谈天湖水电站水轮机运行故障及处理措施

简述天湖水电站投运以来各种故障的表现形式，分析其原因，提出了相应的处理方法及措施，并对合理利用国内外设备提出建议。