基于现代高新信息技术的小流域山洪预报系统建设

小流域山洪灾害严重,监测预警预报难,进一步精准小流域山洪监测预警预报将有助于提升小流域山洪灾害综合防御能力。该文分析目前我国小流域山洪灾害特点及监测预警预报技术现状,提出基于无人机航测及倾斜摄影技术和水文-水动力学模型技术的小流域山洪预报系统,并应用于泉州梅溪小流域山洪预报系统建设中,以期为当前全国小流域山洪监测预警预报系统建设和山洪灾害防治提供参考。     

中国山洪灾害防御关键技术

结合我国山洪灾害防治所面临的自然社会双重胁迫因素和存在的关键技术问题,在总结中国水利水电科学研究院建院以来围绕小流域暴雨洪水规律、分析计算方法、防洪减灾监测预警技术等方面所完成的创新成果基础上,阐述我国山洪灾害防治的总体思路、理论技术体系和防御模式。重点论述小流域下垫面特征及产汇流特性、缺资料地区小流域暴雨洪水规律、新一代缺资料小流域产汇流模型及分布式水文模型、预警指标体系和风险评价理论、小流域山洪灾害动态预报预警技术、全国山洪灾害小流域预报预警系统建设等方面的技术突破和取得的创新性成果。     

山洪灾害监测预警技术研究及发展趋势综述

山区城市化进程加快、生态环境恶化、极端水文事件增加造成山洪灾害日益严重,已成为制约山丘区社会经济发展的重要因素。针对当前山洪灾害监测预警技术研究现状,综述了山区暴雨洪水过程模拟、山洪灾害监测预警技术研发和防灾减灾模式构建的最近进展。在综述国内外研究现状的基础上,提出了山洪灾害监测预警技术研究的发展趋势,包括从机理研究、技术研发、模式构建和应用示范等方面开展监测预警关键技术攻关;充分发挥物联网技术在山洪灾害防治领域的作用;采用"自然-社会"二元山洪灾害防治范式。研究成果可为山洪灾害防治体系升级改造提供科技支撑。     

基于中国山洪水文模型的山洪灾害预警指标实时动态分析

山洪灾害具有突发性强、成灾快、破坏力大、人员伤亡多等特点,被公认为是世界上危害最大的自然灾害之一。为提高山洪灾害预报预警精度,综合考虑小流域暴雨洪水特征、前期降雨、上游产汇流过程以及土壤湿度动态变化等因素的影响,基于中国山洪水文模型(CNFF)模型分析法和设计暴雨洪水实时反算法,提出了基于中国山洪水文模型的小流域防灾对象预警指标实时动态分析方法,分析了防灾对象不同土湿和典型预警时段长的临界雨量动态变化过程。以江西省东河流域为例,评估了动态预警指标的精度。研究表明：(1)中国山洪水文模型在研究区具有较好的适用性,率定期和验证期的平均径流深相对误差和洪峰流量相对误差均在15%以内,平均峰现时间误差在1.5 h以内,平均Nash-Sutcliffe效率系数分别为0.76和0.8,场次雨洪模拟合格率在90%以上。(2)以东河流域南泊村典型灾害事件为例评估了动态预警指标应用效果,基于动态雨量预警指标的实时动态分析结果相比原山洪灾害调查评价中静态预警指标结果提前1~2 h预警,有效延长了预警预见期。研究成果可为小流域山洪灾害预警提供理论支撑和技术支持。     

山洪预警预报技术研究与应用

受特殊的气候和地形地质条件影响,特别是近年来极端天气事件增多,我国山洪灾害频繁发生,损失严重,已成为洪涝灾害损失的主体,日益引起政府和社会各界的广泛关注。加强山洪监测预警预报,全力提升山洪灾害综合防御能力,是山区建设、社会经济可持续发展的必须保证。分析了我国山洪特性及预警预报特点,介绍了国内外常用的山洪预警预报技术方法,提出了我国山洪预警预报模型与方法选择的原则和步骤,展示了基于动态临界雨量的山洪预警方法和基于分布式水文模型的山洪预报方法在江西遂川江流域的应用案例,以期为当前所开展的全国山洪灾害防治县级非工程措施建设和中小河流水文监测系统建设等工作提供参考。     

国家山洪灾害监测预报预警平台建设

正2010年以来,全国开展了大规模山洪灾害防治项目建设,初步建立了自动监测预警系统与群测群防互补的监测预警体系,有效增强了基层山洪灾害防御能力。中国水利水电科学研究院在项目实施中,采用大数据和云计算理念,基于分布式水文模拟技术建设了国家山洪灾害监测预报预警平台,有助于实现山洪灾害监测预警向精     

积极推进小流域山洪灾害预警系统建设

该文分析了小流域山洪灾害的主要特点,指出防治山洪灾害的指导思想。针对小流域山洪灾害防治技术现状,提出以现有气象水文理论与遥测通信手段为支撑,构建小流域山洪灾害预警系统,以满足当前需要,减少灾害损失。     

基于中国山洪水文模型的动态临界雨量研究及应用

以中国山洪水文模型为基础,综合考虑前期影响雨量、累积雨量、降雨强度及雨型分布、地形地貌等因素的影响,提出了基于分布式水文模型的小流域动态临界雨量预警指标分析方法。以四川省不同水文分区3个典型小流域(赶场、西宁和新生流域)为例,评估了该指标用于小流域山洪预警的精度。研究表明:(1)中国山洪水文模型在研究区内具有较好的适用性,3个小流域率定期和验证期的山洪模拟合格率均在90%以上;(2)以1h、3h和6h为预警时段,赶场、西宁和新生流域的临界雨量分别为20～250mm、12～160mm、6～140mm;(3)不同预警时段下,3个小流域山洪预警的合格率达到80%以上。研究成果可为小流域山洪预警提供理论支持和技术支撑。     

水文气象预警技术在山洪灾害防治中的应用

我国江河众多,地形复杂,降雨时空分布不均,灾害发生频繁.近年灾害损失统计表明,山洪灾害造成的危害愈来愈重,已成为当前防洪减灾中的一个突出问题.主要针对作为防治山洪灾害的主要非工程措施的水文气象测报、预报、警报技术应用及研究,重点从山洪灾害暴雨天气形势和气候特征、区域水文和气象站网布设及针对山洪灾害防治的临界雨量(强)分析计算方法、致灾强降雨综合预报方法、高分辨数值天气预报模型应用、山洪灾害预警信息发布技术与方式等进行研究,提出相应的应用原则或指导性对策.     

山洪灾害监测预报预警云平台及应用

以延长山洪预警预见期、提高预警精度为目标,综合应用并行云计算、大数据、人工智能和移动互联网技术,设计开发了省级山洪灾害预报预警云平台.省级云平台集成了流域分布式水文模型和实测降雨、预报降雨信息,实时驱动流域内各河段山洪水文模拟,实现基于小流域的洪水预报和基于流量指标的山洪灾害预警.结合山洪灾害气象预警和基于雨量/水位监...     

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。     

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。     

Fish assemblage response to recent mitigation of a channelized warmwater stream

Various designs of low‐head dams are used to rehabilitate streams or forestall upstream channel incision after channelization. We report on the efficacy of using notched sills and grade control structures (GCS) to restore the fish assemblage in Luxapallila Creek, Mississippi. We tested the null hypotheses that habitat variables and species richness, evenness, and assemblage structure would not differ among: (1) a channelized segment with no modifications; (2) a channelized segment mitigated by the installation of sills and GCS; (3) a segment upstream of the installations and undergoing channel incision; and (4) an unaltered segment. Although habitat variables changed, neither species richness, evenness, nor fish assemblage structure differed between mitigated and channelized segments with both exhibiting less richness and different assemblage structures than the unaltered segment. Lack of differences in species richness between the incised and unaltered segments suggest that the GCS may have halted the negative effects of upstream channel incision before species were extirpated. Conspicuous habitat differences between the altered (channelized and mitigated) and unaltered segments were lack of backwaters and canopy coverage and finer substrates in the altered segments. Our results suggest a more comprehensive rehabilitation strategy is required in Luxapallila Creek. Published in 2003 by John Wiley & Sons, Ltd.     

NUMERICAL STUDY OF WAVE EFFECTS ON SURFACE WIND STRESS AND SURFACE MIXING LENGTH BY THREE-DIMENSIONAL CIRCULATION MODELING

1. INTRODUCTION Coastal and continental shelf regions are characterized by intensive interaction between wave and current. These regions are of great economic significance to mankind. Therefore, the modeling of wave and current as well as their mutual int…