分布式水文模型EasyDHM模型

介绍了自主开发的分布式水文模型EasyDHM的空间单元离散方式、主要理论模块及相应的模型软件系统MWEasyDHM。EasyDHM模型的空间离散采用自主开发的通用子流域划分算法,很大程度上扩展了分布式水文模型的通用性,支持多种产汇流算法,支持用户对主要产汇流参数的敏感性分析和参数优化,以优化模型模拟效果,开发了专门的洪水预报模块,支持洪水实时校正及多模型组合预报技术并在嫩江流域使用EasyDHM模型进行了应用验证。     

分布式水文模型EasyDHM在海河阜平流域的应用

目前很多分布式水文模型还主要应用在科研领域,缺乏在实际的水管理业务中的应用。分布式水文模型EasyDHM的开发则以实用为目的,着重关注模拟效果及建模效率。模型具有友好的操作界面,适用于各种时空尺度的流域水文模拟,并且模型易于扩展,可进行水资源评价。以海河流域阜平水文站以上流域为研究对象,应用EasyDHM模型进行流域水文模拟,通过对模型参数进行敏感性分析及率定,使阜平流域率定期及验证期Nash效率系数达到0．96。分析表明,EasyDHM模型在阜平流域具有很好的适用性。     

分布式水文模型EasyDHM(Ⅰ):理论方法

介绍了自主开发的分布式水文模型EasyDHM的空间单元离散方式、主要理论模块以及相应的模型软件系统MWEasyDHM。EasyDHM的空间离散采用通用子流域划分算法,很大程度上扩展了分布式水文模型的通用性。同时,它支持多种产汇流算法,还支持用户对主要产汇流参数的敏感性分析和参数优化,以优化模型模拟效果。     

分布式水文模型软件系统MWEasyDHM 简介

本文介绍了分布式水文模型EasyDHM模型的软件系统MWEasyDHM,主要由4个部分组成：（1）面向水文分析的通用GIS软件;（2）前处理模块;（3）模拟模块;（4）后处理模块。其中面向水文分析的通用GIS软件以开源GIS软件MapWindow为基础开发,并包括了其他模块所涉及的基本GIS功能;前处理模块包括基于DEM的水文分析组件,模型参数推求模块和降水量、气象数据插值模块;模拟模块提供了实时计算功能,能实时查看模拟结果;模型后处理模块包括了模型参数自动识别、运算结果统计分析及以表格、图表等方式对模拟结果的展示。MWEasyDHM的开发解决了分布式水文模型快速建模及率定的难题,并为将来升级开发及大范围推广应用奠定了基础。     

分布式水文模型EasyDHM模型（II）应用实例

本文介绍了分布式水文模型EasyDHM在汉江上游流域的应用实例。作者通过采用EasyDHM模型中的改进WetSpa产流模型、马斯京干汇流模型、LH-OAT敏感性分析方法、SCE-UA参数优化方法等，对汉江上游流域进行了水文模拟及参数率定。由参数敏感性及参数优化结果知，各产汇流参数敏感性随空间分布的不同有一定差异，而随着时间系列的延长其变化并不大，这不仅说明了按水文站进行参数分区的必要性，也说明在长系列水文模拟中，可仅对指定校正期进行参数优化。而参数优化后能较大程度提高水文模型模拟精度，则证实了参数优化的必要性以及本模型所选取参数优化算法的合理性。     

EasyDHM模型在诺敏河流域的应用

文章介绍了分布式水文模型EasyDEM的原理及构建流程,以诺敏河流域为研究对象,应用EasyDHM模型进行流域水文模拟,结果表明,EasyDHM模型在诺敏河流域具有较好的适应性。     

分布式水文模型EasyDHM （Ⅱ） ：应用实例

本文介绍了分布式水文模型EasyDHM在汉江上游流域的应用实例。通过采用EasyDHM中的EasyDHM产流模型、马斯京干汇流模型、LH-OAT敏感性分析方法和SCE-UA参数优化方法等,对汉江上游流域进行了水文模拟及参数率定。由参数敏感性及参数优化结果可知,各产汇流参数敏感性随空间分布的不同有一定差异,而随着时间系列的延长其变化并不大,这不仅说明了按水文站进行参数分区的必要性,也说明了在长系列水文模拟中,可仅对指定校正期进行参数优化。而参数优化后能较大程度提高水文模型模拟精度,则证实了参数优化的必要性以及本模型所选取参数优化算法的合理性。     

分布式水文模型EasyDHM在玛纳斯河流域径流模拟中的应用

玛纳斯河流域作为新疆干旱区典型的内陆河流域,其年径流量主要来源于高山区融雪径流。掌握该流域的径流变化规律,对探讨该地区气候、水文及水资源、生态环境之间的联系以及预测未来山区径流的变化规律具有重要意义。以玛纳斯河流域作为研究对象,基于分布式水文模型EasyDHM(Easy Distributed Hydrological Model),利用DEM、实测河网、土壤、土地利用及水文气象数据构建玛纳斯河流域分布式水文模型研究该流域径流过程。通过模型参数率定及验证发现,该模型精度较高,验证期内各站点纳什效率系数均在0.75以上,说明EasyDHM分布式水文模型的泛化能力较好,可应用于该流域的水雨情势分析,为预防和减轻春季融雪型洪水灾害提供了理论依据。     

分布式水文模型研究与应用进展

分布式水文模型是探索和认识复杂水文循环过程和机理的有效手段，也是解决许多水文实际问题的有效工具。当前水多（洪水）、水少（干旱）、水脏（水质污染）、水浑（土壤侵蚀）的现状，以及全球气候变化和数字水文学的兴起，为分布式水文模型的研究、开发和应用带来了巨大的挑战。本文从当前水文水资源研究的热点问题出发，系统总结了分布式水文模型在解决水文学面临的重要问题中研究与应用的现状以及主要进展与不足，探讨了分布式水文模型的发展趋势，并讨论了建模中存在的难点问题和关键技术。     

分布式水文模型研究与应用进展

分布式水文模型是探索和认识复杂水文循环过程和机理的有效手段,也是解决许多水文实际问题的有效工具。本文从当前水文水资源科学研究的热点问题出发,系统总结了分布式水文模型在解决水文学面临的重要问题中研究与应用的现状、进展与不足,讨论了建模中存在的难点问题和关键技术,并探讨了分布式水文模型的发展趋势。     

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。     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

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。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

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。     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

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.     

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.