河漫滩湿地淹没柔性植物水流涡量场研究

含植物水流的涡量场构成了河漫滩湿地水生动物生境的物理基础，形成水、营养物质的循环以及能量的分配过程。本文通过玻璃水槽试验用二维标准PIV测量研究了含淹没柔性植物二维垂直涡量场的分布。得出流速梯度是形成含植物水流涡量的关键因素，植物冠层附近对水流的干扰大，因而流速梯度大；涡量最大值出现在淹没柔性植物冠层以下约50%处；植物冠层处，涡量绝对值大，拟熵大，能量耗散率也高。植物冠层是造成水流紊动耗散的主要原因。     

河漫滩湿地淹没柔性植物水流涡量场研究

含植物水流的涡量场构成了河漫滩湿地水生物生境的物理基础,形成水、营养物质的循环以及能量的分配过程。本文通过玻璃水槽试验用二维标准PIV测量研究了含淹没柔性植物二维垂直涡量场的分布。研究表明:流速梯度是形成含植物水流涡量的关键因素,水流过植物冠层附近受到的干扰大,因而流速梯度大;涡量最大值出现在淹没柔性植物冠层以下约50%处;植物冠层处,涡量绝对值大,拟熵大,能量耗散率也高。植物冠层是造成水流紊动耗散的主要原因。     

植被群落之间水流紊动强度垂向分布规律探讨

以生态特征参数不同的植被群落为研究对象,在室内水槽中种植灌木、芦苇和灌木-草本植被混合群落,利用多普勒流速仪沿程测量各测点瞬时流速,基于河流动力学和紊流力学理论,将水流紊动强度表达为植被直径、水流绕流阻力因数、植被直径梯度和水流绕流阻力因数梯度的函数,比较不同类型植被群落之间水流紊动强度垂向分布规律的差异。结果表明,灌木完全淹没时,紊动强度在垂向上最大值位于灌木冠层顶端区域,极小值位于茎杆向冠层过渡区域。植被群落水流紊动强度垂向分布曲线上存在三个拐点,即茎杆向冠层过渡处、植被偏转点和植被冠层顶端。     

SPAC系统中的水热CO2通量与光合作用的综合模型(Ⅰ)模型建立

本文建立了模拟农田SPAC(Soil-Plant-Atmosphere Continuum)系统中土壤水分动态，蒸发蒸腾、CO2通量和光合作用的模型。模型包括土壤水流子模型，根系吸水子模型，蒸发蒸腾子模型，冠层阻力-光合作用-CO2通量子模型几个组成部分。土壤水流子模型采用土壤水流的连续方程来描述；根系吸水子模型采用了根据Feddes模型改进得到的模型；蒸发蒸腾子模型采用Shuttleworth-Wallace公式；采用叶片水平的气孔阻力-光合作用模型，并将其扩展到冠层尺度来确定冠层阻力、光合作用速度以及叶片气孔下腔的CO2浓度，并进而确定冠层的CO2通量。本模型的特点是尽可能采用简便的处理方法来描述SPAC系统中的水、热、CO2传输过程与光合作用过程，同时各个子模型又具有较强的机理性。     

SPAC系统中的水热CO_2通量与光合作用的综合模型(Ⅰ)模型建立

本文建立了模拟农田SPAC (Soil Plant AtmosphereContinuum)系统中土壤水分动态 ,蒸发蒸腾、CO2 通量和光合作用的模型 .模型包括土壤水流子模型 ,根系吸水子模型 ,蒸发蒸腾子模型 ,冠层阻力 -光合作用 -CO2 通量子模型几个组成部分 .土壤水流子模型采用土壤水流的连续方程来描述 ;根系吸水子模型采用了根据Feddes模型改进得到的模型 ;蒸发蒸腾子模型采用Shuttleworth Wallace公式 ;采用叶片水平的气孔阻力 光合作用模型 ,并将其扩展到冠层尺度来确定冠层阻力、光合作用速度以及叶片气孔下腔的CO2 浓度 ,并进而确定冠层的CO2 通量 .本模型的特点是尽可能采用简便的处理方法来描述SPAC系统中的水、热、CO2 传输过程与光合作用过程 ,同时各个子模型又具有较强的机理性 .     

含苦草水流紊流结构典型剖面的象限分析

该文以含苦草水流的实验室水槽实验数据为基础,选取典型流速剖面,利用象限分析法,从紊流质点的角度分析了含苦草水流的动量传输特征。分析发现,苦草冠层顶部附近水流紊动掺混剧烈,雷诺应力在冠顶处达到最大值,且水流在冠顶以上及以下区域分别以"喷射"与"下扫"流态为主;冠层内部,水流紊动掺混明显减弱,雷诺应力较小,受时均流速逆梯度的影响,雷诺应力出现负值及局部最大值,且水流在雷诺应力局部最大值出现位置以上及以下区域分别以"外向交互"与"内向交互"流态为主。冠顶附近水流强烈的紊动掺混决定了整个剖面紊流的动量传输特征,且苦草冠顶以下所形成的下扫流有利于水体中黏性泥沙的沉积,降低水体浊度。     

柔性植物消浪及沿程阻流特性试验研究

采用聚乙烯仿真绿色植物模拟柔性植物,通过物理模型试验研究了柔性植物对波高和断面流速分布的影响,结果表明:波高消减系数大小与水流速度大小无明显关系;植物出水0.5倍波高时消浪效果最好,水深越大波浪消减效果越差;柔性植物使断面流速在植被上部冠层区域减小,特别是植被带中和植被带下游边缘处,冠层区域流速减小显著;水流通过植被带以后,在植被带下游断面流速垂向分布逐渐恢复至与上游断面一致,但大流速情况下流速恢复较慢;波流共同作用下断面流速的垂向分布与纯流速作用下基本一致,但在波浪作用下断面流速减小区域有下移趋势。     

SPAC系统中的水热CO2通量与光合作用的综合模型（I）模型建立

本文建立了模拟农田SPAC（Soil-Plant-Atomosphere Contiuum)系统中土壤水分动态，蒸发蒸腾，CO2通量和光合作用的模型，模型包括土壤流水力子模型，根系蒸腾子模型，冠层阻力－光合作用－CO2通量子模型几个组成部分，土壤水流子模型采用土壤水充的连续议程来描述，根系吸水子模型采用了根据Feddes模型改进得模型，蒸发蒸腾子模型采用Shuttleworth-Wallace公式，采用叶片水平的气孔阻力－光合作用模型，并将其扩展到冠层尺度来确定冠层阻力，光合作用速度以及叶敢也下腔的CO2浓度，并进而确定冠层的CO2通量，本模型的特点是尺可能采用简便的处理方法来描述SPAC系统中的水，热，CO2传输过程与光合作用过程，同时各个子模型又具有较强的机理性。     

弯道植被水流中Monami现象及湍流特性试验研究

自然河流中生长的水生植物是生态系统的重要组成部分，植物的形态变化会影响水流的流动特性及污染物的输运。该文利用U型折叠弯道水槽进行试验，设置半侧分布的柔性植被，分析在弯道水流下不同流量及柔性植被配置对Monami现象的影响。试验结果表明：不同流量下的柔性植被形态存在差异，进而影响流速分布，当流量较大时，弯道中会出现Monami现象。在不同流量下，植被形态在弯道入口处呈现Monami现象、倾斜倒伏或直立；而在弯道后半程呈现Monami现象或无组织性轻微摆动。通过功率谱频率分析的高相关性证明Monami现象由K-H涡的不稳定性产生，且在弯道中，Monami频率减小。植被叶片的摆动使得湍流应力更深入植被冠层，而Monami现象的出现降低了植被冠层边界动量传输效率。此外，弯道会扩大植被冠层内扫掠主导区域的影响范围，改变无植被区的湍流活动类型。     

河道漫滩及湿地上淹没柔性植物水流的紊流特性

植物在河流生态的修复中起重要作用,因此对含植物明渠水流的紊流机理的研究显得非常重要。将河漫滩及湿地中含淹没柔性植物的水流视为充分发展了的紊流,在实验室中用特定材料模拟柔性植物,通过水槽试验用三维ADV对淹没柔性植物段紊流特性进行了测量研究,对试验结果计算分析表明含淹没柔性植物的垂向流速分布不再符合指数分布;其紊流具有明显的各向异性特性;植物冠层交界处,水流紊动交换强烈,该处紊流强度及雷诺应力出现最大值。     

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。