珠江河口生境演变与生物变化趋势

珠江河口地处粤港澳大湾区的核心区域,是世界上生境结构最为复杂的河口区域之一,其生态系统具备高度的开放性、敏感性、脆弱性和较低的稳定性。随着粤港澳大湾区城市化进程和海洋经济的持续发展,人类活动对珠江河口生态系统的干扰日益加剧,河口生境结构和水生生物群落发生了巨大的变化。概述了珠江河口形态结构、水环境的变化,分析了人类活动和气候变化对珠江河口的影响,提出了珠江河口水生态系统保护建议,为珠江河口生态安全和粤港澳大湾区高质量发展提供战略参考。     

第三届长江论坛“河口治理与生态保护”分论坛

“河口治理与生态保护”分论坛由上海市水务局主办、长江水利委员会长江勘测规划设计研究院协办、上海市水利工程设计研究院承办。分论坛共吸引了来自中国、美国、英国、荷兰、葡萄牙等国家25家机构的66名专家学者参会。围绕“河口研究与治理”及“河口资源与环境”两个议题，参会代表就河口研究与治理的新理论、新方法、新工艺，     

浅析长江河口的界定

在介绍河口分类的基础上，分析了长江河口的形态特征、潮汐特性和水特点，根据《中华人民共和国法律大百科全书》中国际法对河口界线的阐述，结合《奥本海国际法》对河口问题的论述，按照我国现有法规的有关规定，针对长江河口的实际情况，对长江河口末端位置提出建设性的界定方案。     

珠江河口规划与治理

概述珠江河口基本情况，简要回顾珠江河口规划工作，并叙述河口治理现状，指出珠江河口目前存在的主要问题，一是洪、涝、潮、风灾害突出，二是河口区的水文及水生态发生较大变化，三是河口规划与研究工作滞后，四是河口管理方面还存在薄弱环节。建议尽快编制《珠江河口综合治理规划》，重视并加强治理规划的基础和研究工作，完善投入机制，加大投入力度，加强河口的水行政管理。     

对海河河口生态进行恢复的可行性分析

通过对海河河口生态的各项制约因素的分析,提出由于海河河口生境自然条件不可逆转的改变进行历史生态系统原貌的恢复已不可能,建议对该类地区进行生态重建.     

认真贯彻三河口管理办法依法加强河口管理

《海河独流减河永定新河河口管理办法》将于2009年7月1日正式施行。分析了全面理解和深刻认识《办法》颁布实施的必要性和重要意义,指出了当前要抓好《办法》的学习和宣传工作,提出了抓好《办法》的贯彻实施工作、推进三河口管理法治化进程的观点。     

人类活动对长江河口的影响与对策

目前,长江河口地区已成为长江流域经济社会最具战略发展优势的区域,但其资源环境承载能力有限,生境条件脆弱。归纳分析了气候环境变化,特别是人类活动对长江河口的影响,如随着流域用水量增加,导致河口地区水质性缺水,加重了咸潮入侵的影响程度;沿江废污水排放量增加,导致河口水体污染加剧,赤潮发生频率升高;上游水库的拦沙和清水下泄作用,使河口地区河岸、滩涂受到侵蚀,以及河口地区的开发活动所带来的一系列负面影响。阐述了加快河口治理与保护的总体思路以及需要处理好的关系。提出了做好统一调配流域水量,强化水生态、湿地生态和水环境保护,加强对河口影响重大问题的科学研究和统一管理等指导性对策措施,并根据不断发展与变化的河口情势寻求因应之策,以期实现长江河口的可持续利用。     

依法行政开创河口管理工作新局面

《海河独流减河永定新河河口管理办法》将于2009年7月1日正式施行。《办法》的出台是加强河口管理的客观要求，为强化河口管理提供了法律支撑。在简要介绍《办法》主要内容基础上，提出了依法行政、开创河口管理工作新局面的对策。     

国务院批准珠江河口综合治理规划

为加强珠江河口综合整治开发和保护,维护珠江河口的泄洪纳潮功能,统筹协调流域和区域防洪、防潮、供水、岸线及滩涂保护与利用、航运、采砂、水生态和环境保护等各方面的关系,支撑珠江河口地区经济社会的可持续发展,依据《中华人民共和国防洪法》,水利部组织编制了《珠江河口综合治理规划》（以下简称《规划》）。日前,《规划》得到国务院批准。     

龙河口水库发展旅游之管见

龙河口水库又名万佛湖,坐落在安徽省舒城县中部,距县城25公里,水库总库容8.2亿立方米,是淠史杭灌区五大水库之一。水库拥有丰富的自然资源和人文景观,是不可多得的旅游胜地,先后接待过国内及港澳台、美国、俄罗斯、日本等十几个国家和地区的游客。龙河口水库发展旅游,经历了十几年的创业历程。游乐项目从初始阶段的游泳、野餐,发展到现在的大型、惊险的现代水上运动;湖内现有大小游艇20多艘,年接待游客十多万人次,年收人从几千元增加到今天的50万元。这样一个艰苦创业的历程,为水利行业开展多种经营提供了一个成功的范例。然而,从深度和广度来说,该水库的旅游业还没有形成规模,潜力还没有得到充分的开发和利用,在硬件和软件的配套建设上,还没能适应社会主义市场经济的要求。因此,笔者认为,龙河口水库发展     

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。     

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.     

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。     

Desiccation and recolonization of phytobenthos in a regulated desert river: Colorado River at Lees Ferry,Arizona, USA

We tested the recolonization of the phytobenthic community in the tailwaters of Glen Canyon Dam following long- and short-term experimentally induced desiccation. The response of Cladophora glomerata, Oscillatoria spp., miscellaneous phytobenthos species and periphyton was studied over 18 weeks using three treatments: (1) undisturbed control cobbles from the submerged zone; (2) cobbles desiccated and replaced into the submerged zone; and (3) cobbles desiccated and replaced into the varial zone. Periphyton density and compositional response resulting from these treatments were also examined. Desiccation treatments were significantly different in biomass from controls throughout the study. The biomass of desiccated and replaced river cobbles averaged <30% of the controls for C. glomerata and periphyton during the 18-week recolonization period. In contrast, the biomass of the control Oscillatoria and miscellaneous phytobenthos species averaged only 3 and 50% of that in the desiccation treatments, respectively. Cladophora, the dominant alga, comprised 77% of the phytobenthic biomass. A significant positive relationship between discharge, Cladophora and periphyton biomass was present in all treatments, while there was a negative relationship with discharge for Oscillatoria and miscellaneous phytobenthos species. There was a significant inverse correlation, as well as a pattern of separate biomass dominance, between C. glomerata and Oscillatoria. Cladophora was the dominant phytobenthos species on cobbles below the baseflow and Oscillatoria was dominant on cobbles in the varial zone. In general, the Cladophora biomass decreased under intermittent drying conditions, while Oscillatoria declined under permanently wet conditions. Diatom composition was not significantly different between treatments; however, their density was lower on desiccated cobbles. Diatom density on desiccated cobbles in the submerged and varial zones averaged 69 and 42% of that of the controls, respectively. Recovery and maintenance of benthic resources are hindered by fluctuating flow regimes driven by electricity and irrigation requirements. Repeated desiccation of the phytobenthos has major effects on the bottom-up interactions in the Colorado River ecosystem. © 1998 John Wiley & Sons, Ltd.