伶仃洋沉积动力特点及其水沙治导问题

按系统论的观点结合河口界面理论,以实际观测数据和数学模型作为实证,分析伶仃洋的沉积动力特点,在此基础上从伶仃洋的动力结构、水利排洪、港口航道建设和河口生态方面探讨了伶仃洋西北三口门的水沙治导问题,为珠江口伶仃洋水沙治导指明了方向.     

伶仃洋滩槽演变趋势预测研究

近年来伶仃洋高强度开发和建设改变河口形态和边界,必然对滩槽冲淤和演变产生影响,其累积和长期效应是河口开发治理需高度关注的问题。采用泥沙数学模型作为技术手段,通过设计出代表珠江河口长期的径潮特征动力的水沙系列计算河床冲淤变形,在对伶仃洋水沙运动和冲淤发展进行验证的基础上,对伶仃洋河口区的滩槽演变趋势进行了预测,并分析伶仃洋近期的滩槽演变趋势。     

伶仃洋河口湾的形态研究

珠江河口、三角洲河网和口外海域是一个互动的大系统,伶仃洋的河口湾形态变化对三角洲防洪及伶仃洋沉积动力都将产生一定的影响.根据伶仃洋的自然发展趋势和人类活动特点,设计了3个方案,其中一个方案为原治导线方案,利用珠江口一、二维水沙数学模型的计算结果,分析了伶仃洋喇叭形河口湾缩小后对三角洲的防洪水位以及伶仃洋动力影响.     

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。     

潮汐通道理论在伶仃洋淤积研究上的应用

一、前言伶仃洋是珠江流域八门入海中东四门的总汇,洋面辽阔,是一个南北向漏斗状海湾。湾内外有几列东西向的大小岛屿束窄洋面,使伶仃洋成为潮汐通道。它是广州港和黄埔港的出海水道。珠江流域上中游带来的河流输沙量逐步充填在河口内外,伶仃洋的淤积研究也就联系到珠江河口治理问题。笔者根据《人民珠江》的资料以及1978、1979年珠江河口伶仃洋水文调查工作的成果,在输沙淤积问题上,提出下列三点商榷意见:     

珠江河口治理

针对珠江流域存在的河口淤积、河口区水道冲淤严重、浅海区淤积和水质污染等问题，根据地理环境和水沙条件，分为三部分即东部的伶仃洋及东四口门、中部的磨刀门和西部的黄茅海及啼门开展了不治理规划工作。经过近２０年系统的规划妆显成效，取得了增强河口防洪、防潮能力，改善航运条件，滩余资源综合利用，加强珠江河口整治和资源开发等效益。为了进一步实施珠江河口防洪、防潮能力，改善划、充分发挥河口的综合功能，近期的工作主     

珠江河口水沙情势变化及响应对策研究

利用珠江三角洲主要控制站历年水沙观测资料对珠江河口水沙情势进行深入分析研究。结果表明,珠江河口洪水水情主要变化是洪水归槽显著、腹部水位异常壅高;珠江三角洲年径流量无明显的增加或减小趋势,年输沙量呈下降趋势。根据水沙变化特点,在工程措施和非工程措施两方面提出响应对策,为珠江河口综合治理提供技术依据和有益参考。     

议新情势下珠江河口的治理问题

近年来,在自然演变的背景下,区域日益加剧的人类活动,使得珠江河口水沙动力格局及水生态环境发生一系列演化和响应。该文从珠江河口自然属性和社会属性的视角,分析珠江河口水沙动力格局特征以及当前面临的新情势、新问题,以新发展理念为指引,以构建河口文明为总目标,思考河口治理的总体思路及宏观布局,提出了维护水沙动力格局稳定、完善区域防洪排涝体系、构建区域水资源配置格局、加强河口湾形态保护及生态保育等近期治理对策措施,旨在将珠江河口综合治理推上新台阶。     

伶仃洋河口环流特征及其动力机制分析

基于FVCOM模型,该文建立了珠江河口三维水动力数值模式,模式覆盖了上游三角洲河网区域、八大口门区域以及伶仃洋等近岸海域。该模式的水位、流速和流向验证结果表明模式能较为准确地反映伶仃洋的潮汐潮流变化过程。对珠江河口枯季水动力特性进行了数值模拟,并基于模拟结果分析了伶仃洋余流的时空变化特征及动力成因。结果表明,伶仃洋深槽中存在表层余流向海、底层余流向陆的河口环流特征,且河口环流特征随大小潮发生明显变化:小潮期间河口环流特征较为明显,小潮后的中潮期间最为显著,大潮时河口环流特征减弱,大潮后的中潮期间表底层余流几乎均为向海,河口环流特征趋于消失。这种纵向上的余流变化特征主要是与河口斜压作用有关。此外受东北风作用,伶仃洋横向上存在一个表层余流向西,底层余流向东的横向风生环流。     

从"05·6"洪水看珠江河口水沙输移

研究河口水沙输移规律,尤其是近年来河口水沙输移变化趋势,对于河口综合治理有着重要意义。根据近年来两次洪水期的水沙观测资料,分析了"05·6"洪水期珠江河口水沙输移及在各口门的分配,点绘了各口门流量与输沙率关系曲线,并与"99·7"洪水期水沙输移进行了对比,在此基础上对河口输沙率变化的原因进行了简要分析。     

山西省地下水资源开发利用中存在的问题及对策

山西省水资源严重短缺 ,地下水超采严重。分析了地下水资源量及可开采量、地下水开发利用历史和现状 ,以及超采产生的环境地质问题。在此基础上 ,提出了缓解地下水超采、有效合理开发利用地下水的一些措施意见 ,为加强地下水保护和管理提供了科学依据。     

2003年兰考、东明洪水漫滩落淤情况调查

通过对2003年秋汛期间兰考北滩、东明南滩两处漫滩情况进行调查与分析，得出的结论为：滩区共滞蓄水量6亿～9亿m^3，漫滩落淤范围为7．5km^2，顺漫滩水流方向的落淤距离约3km。在这种水沙条件下，泥沙不能被输送至较远的堤河。经分析计算，本次泥沙落淤量为900万～1350万t，且距口门1．0km范围内落淤泥沙中的82％为粒径大于0．05mm的粗沙。由此得到的主要认识有：①靠自然落淤解决“二级悬河”问题非常困难，甚至会增大“二级悬河”程度；②给漫滩水预留出路是降低淹没损失的关键；③落淤的粗沙使土地产生了十分严重的沙化现象，并且使当地环境趋于恶化。     

雷州半岛地区2015年防旱抗旱工作对策与启示

2015年,广东省雷州半岛地区出现大范围干旱,该文总结了干旱特点,分析了干旱成因,采取了水资源统筹调配、引导调整种植结构及播种时机、人工增雨、筹措资金应急补助等抗旱措施,效果较好。此外,提出该地区今后打造"扩库硬渠上井群"升级版、推进农业结构调整、改善生态环境推动绿色发展的防旱工作对策。     

Operation and Maintenance Performance and Conflicts in Flood-control Projects in Bangladesh

Many embankments failed in severe floods in Bangladesh in 1987 and 1988, and concern grew over ways to improve flood-control projects. Maintenance was poor due to reliance on periodic rehabilitation, but few failures were due to poor construction or maintenance. Embankments mostly failed where they were eroded or were deliberately cut. They were cut by people living outside who believed they were made more flood-prone, and by people living inside because of internal drainage congestion. This reflected inadequate hydrological modelling, lack of consultation and failure to resolve conflicts between affected groups. Resources for maintenance are not generated locally and could be used more efficiently. Participatory planning could reduce conflicts, encourage a sense of project ownership and facilitate contributions to maintenance.     

南京市2016年暴雨洪水分析与思考

2016年汛期,南京市发生了建国以来的大洪水,降雨量和主要河湖水位均超历史.在对2016年暴雨、水情、洪水特点分析的基础上,提出加强南京市防洪工程体系的建议.     

Domestic Water and Sanitation in Cyclones and Floods in Bangladesh and a Proposed Research Agenda

ABSTRACT

Water is one of the top priority item s i relief activities but the appropriateness and effectiveness of this activity may be questioned. Water and sanitation (WS) are inseparable and together they play major roles in the transmission of the pathogen of diarrhoeal disease. Thousands of people die or suffer from WS-related diseases during postdisaster periods. Here we present WS-related experiences gained after Bangladesh's 1991 cyclone and the views of participants in a regional and a national (local) workshop on this matter held in Bangladesh. About 63 per cent of the water purifying tablets (WPTs) distributed after the 1991 cyclone were found to have lost potency Relief personnel lack basic knowledge about WS practices and the management of WS provision. Participants in the two workshops documented serious problems i this field at both regional and national levels. Major issues for research may include: an appropriate environmental preparedness plan; appropriate waste disposal technologies; appropriate water treatment methods; self- help activities during vulnerable periods; and health education related to WS in disaster situations.     

我国灌区建设及管理技术发展成就与展望

新中国成立70年来,我国灌区建设与管理取得了举世瞩目的成就,农田灌溉面积由1949年的1593万hm2发展到2016年的6714万hm2,位列世界第一,保障了我国粮食安全供给和社会经济发展。我国灌区建设与管理已经历了三个大的发展阶段,依靠科技进步解决了发展过程中出现的各种问题,使我国灌区建设与管理水平逐步得以提升。今后的30年将是我国实现灌区现代化的时期。本文较系统介绍了我国灌区发展概况、灌区建设与管理技术进展和成就、灌区面临的主要问题和挑战、以及灌区现代化发展展望。     

Distribution and removal of Giardia and Cryptosporidium in water supplies in Germany

This study has been conducted, to estimate the distribution of Giardia and Cryptosporidium in German water supplies and the removal efficiency of surface water treatment plants for Giardia and Cryptosporidium by conventional treatment. Water samples from six surface water treatment plants in different parts of Germany were simoultaneously examined for Giardia and Cryptosporidium. Investigations for both parasites were carried out in the period from July 1993 until December 1995. The results confirmed the occurrence of Giardia and Cryptosporidium in surface and raw water, to intermediate steps after treatment, in back wash water, in the first filtrate and in final water. Giardia or Cryptosporidium or both have been found in 76.2% of the investigated raw water sources. The average number of the detected Giardia cysts was 88.2/100 1 (max.1314/100 I), and the average number of Cryptosporidium oocysts was 116/100 I (max. 1081/1001). In the intermediate steps (including flocculation and several steps of filtration), Giardia or Cryptosporidium or both have been found in 33.3% (50/150) of the samples. 14.9% of drinking water samples (7/47) were positive for Giardia (max. 16.8 /1001) and 29.8% (14/47) were positive for Cryptosporidium (max. 20.8/100 I). Overall, Giardia and Cryptosporidium, or both were detected in 38.3% of the drinking water samples. The parasites have been found in nearly all of the investigated backwash water samples. The filtrate of a rapid sand filter was analysed immediately after filter backwashing during the ripening period of the filter. Good elimination results were obtained by optimizing relevant water treatment process, but a low flocculant dose following sudden variation in the raw water quality, causes a breakthrough of Cryptosporidium into the treated water. Although water treatment technologies are effective to remove Giardia and Cryptosporidium, the results clearly show that Giardia and Cryptosporidium evade the filter harries m the absence of visible treatment deficiencies and low turbitidy level, and contaminate final water.     

衡水市地下水开发利用存在的问题及对策

通过对衡水市地下水开发中存在问题的客观分析,提出了今后开发、利用和保护地下水的措施.