微观建模在城市给水管网系统中的实践

给水管网系统动态建模是自来水公司实现科学管理、提高效益、提高服务水平的重要手段.以天津市给水管网系统建模为例,详细地阐述了给水管网系统微观建模的理论与方法.     

基于管网可靠性的阀门布局优化设计

阀门作为给水管网的主要附件,其数量和位置的合理设置,对提高管网可靠性具有重要意义。首先以阀门布局对管网可靠性的影响作为切入点,建立管网可靠性分析模型和阀门布局优化设计模型,然后使用模拟退火算法进行了阀门布局优化设计算例分析,通过分析,可以得出符合阀门设置规则和具有较高可靠性保障的阀门布局建议方案。     

微观建模在城市给水管网系统中的实践

给水管网系统动态建模是自来水公司实现科学管理、提高效益、提高服务水平的重要手段。以天津市给水管网系统建模为例 ,详细地阐述了给水管网系统微观建模的理论与方法。     

基于EPANET本地化的给水管网教学软件开发

水力与水质模拟软件的应用已成为大型给水管网分析的主要手段,高等院校专业课程教学中必须适应给水管网技术发展的需求.为缩短给水管网教学软件的开发周期、节约资源投入,在英文软件EPANET基础上,实现了软件本地化(命名为EPANETH).开发内容包括计算器模块、图形用户界面、帮助文件和用户手册的处理,并形成安装程序,在使用中不断完善.该软件能使学生更深入地理解管网设计理论,提高给水管网系统课程的教学质量.     

计算机辅助设计动态给水管网模型

运用计算机建立给水管网动态模型不但能完成静态的数据分析和系统设计 ,还可以实现对给水管网的动态分析和仿真 ,从而实时获取管网系统在不同供水需求以及极端用水条件下的状况。讨论了国内现有的管网模型和应用情况 ,并详细介绍了国外专业软件WaterCAD。     

用节点水龄量度给水管网的水质状况

通过给水管网的水质模型推导得出了节点水龄的计算公式 ,给出了以节点水龄量度的给水管网水质状况曲线 ,并以此为基础 ,针对某大城市给水管网进行了节点水龄实例计算 ,绘制出整个给水管网等水龄线及节点 2 4h水龄变化曲线图 ,从而得出该城市给水管网基于节点水龄的水质状况。管网节点水龄的计算对从理论上分析给水管网的水质以及对提高给水系统的服务水平均具有重要意义。     

港区给水工程管网模拟软件的选择

随着港口经济的高速发展,大规模、综合性的港区工程对给水管网的规划和设计提出了更高更精确合理的要求,而传统的给水管网系统的设计和监控方法逐见弊端.因此,兼具水力计算和系统分析等功能的管网模拟软件逐渐成为管网系统设计和管理的重要手段。文中介绍了对目前世界上市政工程中应用较广的给水管网软件,并比较分析了其优缺点,希望能在港区工程给水管网建设、管理以及模拟软件开发方面提供参考。     

给水管网排水口管径选择的探讨

通过分析温州主城区给水管网排水口的分布现状、存在问题,对现行<给水排水设计手册关于排水口管径确定的方法进行探讨,认为可适当增大排水口管径.并对实践中存在的主要问题进行探讨,提出解决措施.     

深圳市给水管网水质安全管理技术研究

分别研究了出厂水水质稳定性、管网单向冲洗、管网改造模式以及管网水质在线监测系统等技术.提出了适合深圳地区的水质稳定性参数.采用管网单向冲洗后,浊度和细菌总数明显降低,管网水质得到了有效的改善.在小区管网改造方面,将生活给水系统和消防给水系统合理分离,既可以降低消防给水系统对生活给水系统水质污染的风险,又可节省管网改造投资.建设并充分利用管网水质在线监测系统是保障饮用水安全的重要措施.     

给水管网水力计算模型数据库的开发

数据库系统是对数据进行存储、管理、处理和维护的软件系统,是现代计算环境中的一个核心成分.给水管网水力计算模型数据库的建立,可以把给水管网计算、监控、调度、运行、优化设计和绘图有机地结合在一起.它为给水系统现代化管理提供了有利条件.     

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.     

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.     

Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera

River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m^?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m^?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept.     

Surveying for Water Resources

Abstract

A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies.     

The Impact of Economic Development on Water Pollution: Trends and Policy Actions in Malaysia

The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.     

浅淡溢洪道改扩建方案与选择

溢洪道改扩建和进行溢洪道方案布置，要择优选取溢洪道进口型式、防冲消能工，以使其工程量省、施工快、运行管理方便     

Intangible Flood Damage Quantification

Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology.     

Seasonal variation in nutrient retention during inundation of a short‐hydroperiod floodplain

Floodplains are generally considered to be important locations for nutrient retention or inorganic‐to‐organic nutrient conversions in riverine ecosystems. However, little is known about nutrient processing in short‐hydroperiod floodplains or seasonal variation in floodplain nutrient retention. Therefore, we quantified the net uptake, release or transformation of nitrogen (N), phosphorus (P) and suspended sediment species during brief periods (1–2 days) of overbank flooding through a 250‐m floodplain flowpath on the fourth‐order Mattawoman Creek, Maryland U.S.A. Sampling occurred during a winter, two spring and a summer flood in this largely forested watershed with low nutrient and sediment loading. Concentrations of NO increased significantly in surface water flowing over the floodplain in three of the four floods, suggesting the floodplain was a source of NO. The upper portion of the floodplain flowpath consistently exported NH, most likely due to the hyporheic flushing of floodplain soil NH, which was then likely nitrified to NO in floodwaters. The floodplain was a sink for particulate organic P (POP) during two floods and particulate organic N and inorganic suspended sediment (ISS) during one flood. Large releases of all dissolved inorganic N and P species occurred following a snowmelt and subsequent cold winter flood. Although there was little consistency in most patterns of nutrient processing among the different floods, this floodplain, characterized by brief inundation, low residence time and low nutrient loading, behaved oppositely from the conceptual model for most floodplains in that it generally exported inorganic nutrients and imported organic nutrients. Published in 2007 by John Wiley & Sons, Ltd.     

Experience in the Introduction of Steam-Water-Oxygen Cleaning, Passivation, and Preservation at the TÉTs-23 Cogeneration Plant of the Mosénergo Company

Conditions of the process of steam-water-oxygen cleaning, passivation, and conservation (SWOC, P, and C) of internal heating surfaces of the boiler and the high-pressure feed heater (HPFH) piping over the steam side are presented. The process produces partial cleaning of the internal heating surfaces from scale and yields a corrosion-resistant protective film that hinders corrosion processes both in the operation of the boiler and in the idle period.     

钢筋混凝土三点弯曲梁断裂韧度计算模型

基于虚拟裂缝模型,针对钢筋混凝土试件在三点弯曲作用下开裂截面的受力特征,在合理假定的前提下,给出了一种计算钢筋混凝土三点弯曲梁的失稳断裂韧度的解析方法。然后,应用该方法计算了初始缝高比 α₀（初始裂缝长度与试件高度的比值）分别为0.2,0.3,0.4,0.5的三点弯曲试件的最大荷载和临界有效裂缝长度,进而求得了钢筋混凝土三点弯曲梁的失稳断裂韧度。通过对计算结果与试验数据的误差分析,发现失稳断裂韧度最大误差为4.915%,说明这种方法可以较为准确地预测三点弯曲梁的失稳断裂韧度。在此基础上研究了初始缝高比 α₀对失稳断裂韧度的影响,发现失稳断裂韧度基本上不随 α₀ 变化,失稳断裂韧度可以作为材料常数,应用于裂缝扩展状态的判断。