Inundation analysis of the effectiveness of an estuarygate in Hori River

Storm surges and floods around bays in Japan frequently result in water disasters. Both dikes and estuary gates can be constructed in urban areas near bays as counter measures. Estuary gates at the mouth of a river are intended to protect the upstream areas from storm surges and tsunamis. The sewer systems in urban areas also decrease the inundation. In this study, a numerical simulation is carried out to examine the effectiveness of the estuary gate and performance of the sewer system. A synthetic analysis model of inundation phenomena is developed and applied to the behavior of water in the urban area near the Nagoya Port and the estuary region of the Hori River. The developed model consists of models for the sea, river, sewer, overland flood flow, and typhoon. The inundation analysis model is validated by a comparison of analytical and observed results. The features of the inundations in the urban area caused by various conditions are discussed.     

基于通量收支分析的珠江口冲淡水扩展规律研究

本文基于南海北部陆架模型对珠江口外海淡水通量进行收支分析,研究珠江口冲淡水的扩展规律.首先建立了一个南海北部陆架模型,然后对穿过珠江口外海三个断面的水量通量和淡水通量(盐度≤34.6 psu)进行了统计分析.结果表明:冬季,穿过粤东断面和粤西断面的水体通量和淡水通量均沿陆架自东北向西南输运,且穿过粤东断面的淡水通量约为穿过粤西断面淡水通量的60％;夏季,穿过粤东断面和粤西断面的水量通量和淡水通量均向东输运,且穿过粤东断面的淡水通量是穿过粤西断面淡水通量的4.3倍多;对于珠江口外海断面,冬季和夏季跨陆架的水量通量和淡水通量均由外海向近岸输运,但二者夏季远大于冬季.由此可知,珠江口冲淡水的扩展方向与沿岸流方向基本一致,冬季主要向粤西方向扩展,而夏季则主要向粤东方向扩展,珠江口冲淡水的扩展具有明显的季节变化.     

南水北调工程对长江河口生态环境的影响

对南水北调工程受水区和水源区的特点和现状作了综合评述 ,指出缺水区黄淮海流域的缺水特点。虽然调水水源区长江径流丰沛 ,但长江三角洲地区由于人口密集、工农业发达 ,缺水现象时有发生。通过长江口生态环境现状分析 ,对如何尽可能地减少南水北调工程对长江口生态环境的负面影响 ,提出了一些意见和建议。     

黄浦江河口建闸研究40年回顾与展望

在简要阐述黄浦江历史演变、水文特性和历年风暴潮灾害的基础上,回顾了黄浦江河口建闸研究历程及相关成果,并提出了下一步主要研究方向。前期研究结果表明：黄浦江河口建闸是黄浦江防洪能力提升总体方案的重要组成部分,是解决上海永久防洪(潮)问题的必然选择;挡潮闸的基本功能是挡风暴潮、适应通航,合理调度挡潮闸对洪、潮共同作用引起的流域超标准高水位具有较大控制作用;挡潮闸设防标准建议为100年使用期末可防御千年一遇潮位,且闸孔单孔总净宽超过300 m,对行洪、航运、河势影响较小且能控制闸室淤积。下一步研究重点为弯道建闸对河势、航运的影响,关闸时机和频次对挡潮效果、航运的影响,挡潮闸闸型对功能、关闸时长、河道淤积的适应性以及突破跨度对受力的影响等。鉴于河口建闸并不能完全解决中上游堤防的防洪能力提标,建议同步实施中上游堤防加高加固,并在两项工作完成前做好防汛应急预案。     

浅谈PLC控制系统在水闸工程中的应用

在数字化技术的基础上,实行智能化的水闸监控,运用数字化技术进行数据的传递、远程监控和操作,能够节约操作时间与花费.本文基于PLC控制系统上,提出并设计了中央监控站与许多辅助控制站,采用ZigBee智能测控模块进行无线连接,以达到智能化控制水闸的目的.     

2016年长江流域洪涝灾情探析

2016年长江流域入汛早,暴雨频发。受强降雨影响,长江流域多条河流发生超警戒水位以上洪水,部分支流发生超保证乃至超历史洪水。洪涝灾害频繁发生,多地重复受灾,基础设施水毁严重,防汛抗灾形势一度异常复杂、严峻。重点总结了2016年长江流域洪涝灾情,并分析了抗灾应对情况及成效,其相关工作经验将对做好今后长江流域防汛工作提供良好借鉴。     

A modelling study of residence time and exposure time in the Pearl River Estuary,China

This paper presents an investigation into two transport timescales, i.e. the residence time and exposure time, of a conservative matter in the Pearl River Estuary (PRE) using a depth integrated hydrodynamic-dispersion model. The model has been verified against field measured tidal and salinity data in three typical seasons, including the wet, dry and average rainfall seasons. The model predicted distributions of tidal wave amplitude and salinity level agree generally well with the field measurements. The model is then enhanced by including capabilities for calculating the two timescales. The numerical model predictions show that both the freshwater discharge and tidal water elevation affect significantly the values of residence time and exposure time. The return coefficient is found to be about 0.5. Using a regression analysis, an exponential function has beenderived to correlate the timescales to the freshwater discharge. In the dry season the average residence time and exposure time are up to about 6 days and 12 days, while in the wet season these values are reduced to 3 days and 5 days, respectively. Generally, in all three types of seasons, the exposure time is about two times greater than the residence time, which demonstrates that there is a high possibility for water to re-enter the PRE after leaving the estuary. Both the residence time and exposure time decrease as the initial water elevation increases, which indicates that a contaminant will stay in the PRE for a longer time if it is released at a low tide. The effects of monthly averaged wind forcing on the resident time and exposure time are also investigated.     

海宁市辛江塘河道健康诊断及病因分析

以水清、流畅、岸绿、景美为河流健康的标准,建立河流健康现状诊断模型,确定各诊断指标的权重系数,计算河流健康综合指数。从诊断结果可以看出:辛江塘河道各河段的河流健康综合指数都大于0.5,河流处于基本健康状态;辛江塘河道的流畅指数、岸绿指数和景美指数均较高,这主要得益于近几年实施的以植物措施为主的生态河道建设;辛江塘河道的水清指数很低,主要是由于河道的外来污染较严重,严重影响了河道的健康状况。     

恭城河“2015.5”暴雨洪水分析

2015年5月,恭城河流域上游普降暴雨,恭城水文站发生了自1953年有实测水文资料以来的历史第二大洪水。通过对这场暴雨的特点和洪水的特性进行分析,探究恭城河流域暴雨洪水特性,提高洪水预报的及时性和准确性。     

基于HEC-RAS的淮河淮南段洪水漫顶风险分析

淮河淮南段聚集了大量的人口、工厂、农田、建筑物等,一旦发生较大规模的洪水,将对人民生命财产安全造成严重威胁。运用HEC-RAS软件和HEC-GeoRAS模块,在GIS环境中,模拟现有防洪工程条件下淮河淮南段在40年、60年及100年一遇洪水周期下的洪水漫顶淹没情况,得到不同横断面的设计水位线、漫顶淹没的范围、淹没水深等...     

东莞市宏远片区内涝原因分析及整治方案设计

对广东东莞市宏远片区排水系统现状和内涝原因进行分析,提出了内涝整治方案,采用以下具体措施:建立雨水和污水分流制收集系统,其中雨水收集系统根据地势不同,以3.70m(1985高程)划分自排和强排范围,自排区域建设雨水系统,排至运河,原排水管作污水管;强排区域建设污水系统,原排水管作雨水管,排至现状泵站.同时对狭窄街巷敷设雨水边沟,对运河雨水排出口进行优化设计,改善水流条件,减少对河道的影响.     

珠江河口近30年演变趋势分析

总结了珠江河口近30年来的变化过程,通过实测资料分析了河口岸线和河势变化特征,探讨了演变原因,认为近30年来,在上游来沙量逐渐减少的条件下,人为活动与径潮流是塑造珠江河口演变的主要动力,近岸浅滩的围垦,深水航道的疏浚,径潮流作用对拦门沙前缘及其主槽的淤积有控制作用,珠江河口已初步形成了岸线平顺,水沙输移顺畅,淤积幅度大幅减缓的态势,有利于维护伶仃洋、黄茅海滩槽基本稳定格局,这对保持河口的水沙平衡和可持续发展,具有良好效果。     

闸站监控系统在液压设备维修养护中的应用

闸站监控系统是南水北调中线干线工程生产调度关键系统,其建立在通信和计算机网络系统的基础上,采用先进的计算机、自动控制和传感器技术,通过远程方式监测、控制、预警等自动化设施建设,实现对干线参与调度的节制闸、分水口等建筑物信息和运行状态的监测和控制,实行全部闸站的高度自动化日常调度管理。通过调取闸站监控系统中闸门远程指令执行中监控数据,并结合液压启闭机系统中出现的问题进行分析研判,同时针对沿线同类设备共性问题制定整改方案,在增强节制闸设备安全稳定运行的同时提升闸门远程指令执行成功率,为总干渠通水安全运行提供可靠保障。     

Potential impacts of the Sunderban mangrove degradation on future coastal flooding in Bangladesh

The coastal areas of Bangladesh are recognized by the United Nations (UN) as the most vulnerable areas in the world to tropical cyclones and also the sixth most vulnerable country to floods around the world. Cyclone Sidr (2007) was one of the most catastrophic natural disasters in Bangladesh causing nearly 10,000 deaths and $1.7 billion damage. During cyclone Sidr, mangrove forests in coastal areas played a crucial role in the mitigation of these deadly effects. Sunderban mangrove, the world’s largest mangrove ecosystem with 7900 sq. miles, forms the seaward frontier of the bay and is now facing significant degradation. The Sunderban mangrove ecosystem is increasingly being degraded for a variety of purposes such as agriculture, fishing, farming and settlement. In this study, we evaluate the potential impacts from the degradation of the Sunderban mangrove on storm surge flooding. We evaluate two hypothetical and extreme scenarios: 1) the conversion of the entire mangrove land cover to an estuarine forested wetland; and 2) by considering a full degradation scenario where the entire mangrove is converted to grassland. To quantify the benefits of the mangrove forests to attenuate storm surge in this area, we applied a framework combining a spatial characterization of mangroves vegetation with numerical simulations. Storms surge was calculated using a hydrodynamic model (ADCIRC) coupled with wave model (SWAN) under a High Performance Computing environment. An unstructured numerical mesh with 200,000 nodes was developed and validated along with the coupled SWAN + ADCIRC model at six separate locations in the Bangladesh coast using Cyclone Sidr (2007) meteorological inputs. Twenty-seven model simulations were performed considering nine cyclones of different categories to quantify the effects of mangrove degradation on spatial flood inundation and storm surge magnitude. Simulation results showed that, on average, the mangroves degradation to grassland could raise the surge elevation as high as 57% and had a significant impact on increasing the velocity of the flood wave by up to 2730% for category 3 cyclones. In addition, the inundation inland penetration and total flooded area would increase almost 10 km and 18% respectively for low intensity cyclones. Furthermore, these hypothetical scenarios support the importance of the existing Sunderban mangrove in the reduction of surge elevation, velocity, inundation penetration and flooded area. More importantly, it also demonstrates how the continuous degradation of this important ecosystem has the potential to adversely impact the future cyclone induced hazards in the region.     

香港沿岸台风暴潮灾害联合强度概率分析

以香港东部鲗鱼涌和大埔滘两个验潮站的风暴增水数据为基础,以1999-2018年影响香港的台风过程所引发的风暴最大增水为研究对象,利用广义极值分布分别对两站的最大台风增水进行一元拟合,并基于二元Copula函数,构造两站最大台风增水的联合概率分布,根据其联合重现频率进行潮灾的联合强度概率分析。研究结果表明:两站台风暴潮最大增水变量的联合重现频次能够反映台风在香港东部引发的风暴潮的强度,这种联合概率分析较一元分析有更强的地区适用性。     

北江流域突发性水污染事件影响分析

选取北江干流(韶关~思贤窖北滘口)河段作为研究对象,通过资料收集及现场调研,结合历年北江突发性水污染事件发生情况,从水污染事故成灾机理出发,对突发性致灾影响因子、水环境影响因子、受体影响因子以及社会经济影响因子等进行了归纳分析,并得出了北江流域潜在污染源类型及分布,为预警指标的筛选及预警体系的建立提供了参考依据。     

长江口风暴潮流场计算

利用一、二维数学模型，并考虑长江口深水航道治理工程的进展情况，对长江口区风暴潮流场进行了数值模拟计算。计算结果表明，治理工程对风暴潮引起的增长影响不显著，风暴潮增水期间潮位升高，涨、落潮流速及长江口北槽的分流会增大。     

郁江流域水电站大坝灾害监测分析系统构建技术

因近年来灾害性天气对电站输变电设备的影响越来越大,以构建水电站大坝工程灾害监测与分析评估信息系统为目标,立足于大坝生产运营的实际需要,设计了相应的硬件网络结构与软件架构。在此基础上,研究了灾害与水电站大坝的信息接入、灾害评估与可视化展示,提供了水电站大坝灾害监测、智能水电厂一体化管控、水利工程综合管控等已有业务的数据通信接口、集成展示接口,以实施暴雨、台风、高低温、雷电、山火5种类型灾害的监测和评估,实现雨量与气温监测分析、卫星云图与热带气旋监测、气温预报、水电站气象灾害分析等应用功能。该系统具备自动化、智能化、兼容性和扩展性等特点。以郁江流域龙桥水电站为例,进行了灾害监测分析的功能与应用场景描述。该系统对水电站大坝气象灾害监测预警有一定的借鉴意义。     

长江口盐度对氨氮流动分析法检测的影响研究

为了探讨采用流动分析-靛酚蓝分光光度法测定水体中氨氮含量时,水体含盐度对测定结果的影响,根据长江口水体的特征,配置了系列标准海水样本进行了室内分析。分析结果表明,当水体氨氮浓度大于0.5mg/L时,盐度的影响可以忽略;当氨氮浓度≤0.5 mg/L时,盐度影响较大,必须通过模型对检测结果进行校正。根据试验分析获得的氨氮校正值与测定值和盐度之间的关系,建立了非线性回归方程。将所建立的回归模型在长江口现场进行了实际验证,获得了较好的效果。     

清江流域滑坡灾害地形因子敏感性分析

滑坡从孕灾到成灾的演化过程与其所处的地质环境密切相关,其中对地形因子具有较高的敏感性。基于GIS和RS研究技术,以清江流域宣恩县为研究对象,选取坡度、坡向、地形起伏度和平面曲率等4个地形要素作为敏感性分析评价因子,分别采用敏感性系数法和条件概率法进行敏感性分析对比研究。研究结果表明：两种分析方法所获得的敏感性分区面积基本接近,且与地表地质调查的滑坡信息基本相同。可为类似宣恩县这种中小区域滑坡灾害评价和预测提供新的思路和参考,且对中小区域防灾和规划具有一定的宏观决策意义。