集对多粒度水体富营养化评价模型构建与验证

为了满足用户进行水体富营养化评价时的不同需求,针对水体富营养化评价中各评价指标的多样性和不确定性,综合考虑指标的多粒度特性,运用集对信息粒计算方法构建多粒度水体富营养化评价模型。首先,分级别建立样本各个指标的集对关联度,根据正同度最大和负反度最小的等级,计算评价确定度;其次,计算各个指标的信息熵,根据熵的大小确定评价指标的重要度,分析不同指标子集下不同粒度的评价确定度,构建多粒度的水体富营养化评价模型;最后,以我国12个代表性湖库为实例对模型进行了验证,并与Gamma-云方法、改进粗-云方法、模糊可变集法、单一指标法、神经网络法以及投影寻踪法的评价结果进行了对比,结果表明该模型可以客观反映水体的实际状况,适用性更强。     

基于改进云模型的堤坝除险加固效益后评价研究

针对堤坝除险加固效益后评价,从经济、社会、生态环境效益3方面构建效益评价指标体系,该体系包括防洪增量效益、灌溉增量效益、经济内部收益率、水环境影响等15项指标,确定效益极佳、较好、一般、较差、极差5个评价等级及相应标准,提出改进云模型进行综合评价。该模型将投影寻踪法和熵权法计算得到的客观权重与云模型计算的初始权重相耦合,利用组合评价法计算指标权重,根据指标等级与标准计算云模型的3个特征值(期望Ex,熵En,超熵He),采用条件云发生器计算各指标的隶属度,进行综合评价。将上述方法应用于湖北省黑湾水库堤坝除险加固效益后评价,验证了改进云模型评价方法的有效性和适用性。     

基于组合赋权模糊云理论的高边坡稳定性评价

针对高边坡稳定性评价中指标赋权及其模糊隶属度等不确定问题,提出了一种基于组合赋权模糊云理论的高边坡稳定性评价方法。通过构建多因素协同驱动的高边坡稳定性评价指标体系及其等级划分标准,综合利用梯层指标的主客观组合赋权方法,并考虑到评价中的模糊性和随机性特点,引入模糊熵和云理论,建立了适应于高边坡稳定性多维评价梯级云模型。最后应用于锦屏Ⅰ级水电站左岸边坡的稳定性评价,对比分析了不同评价方法的计算结果,从而佐证了文中提出方法的有效性。     

基于Critic-Cloud模型的东江干流水质评价

将云模型引入到水质评价研究中,选用CODMn、NH3-N和TP等9个指标构建云模型的特征数,利用Critic法推求各因子客观权重后采取最大确定度来判定水质的综合评价等级,对2004-2010年东江干流水质进行了综合评价,并选取东岸断面评价结果与由模糊综合评价法得出结果进行对比。结果表明：基于云模型的东江干流水质综合评价多为Ⅰ～Ⅱ级,这与实际水质相符,同模糊综合评价法评价结果吻合程度为96.6％,表明基于云模型的地表水体水质评价方法合理可行,且能更为直观的表述水质评价中的模糊性和随机性。     

熵权法-正态云模型在云南省水生态承载力评价中的应用

为科学衡量水生态承载力评价过程中的随机性与模糊性,将正态云模型引入水生态承载力评价,建立熵权法-正态云模型对云南省2006-2016年和2020年水生态承载力进行评价。从水资源系统、水环境系统、经济系统和社会系统遴选19个指标构建水生态承载力评价指标体系和分级标准,采用云模型正向发生器计算水生态承载力分级评价指标的隶属度,利用熵权法求出各指标权重,再根据隶属度矩阵和权重矩阵给出水生态承载力分级确定度并进行评价,将评价结果与模糊综合评价法、投影寻踪法的评价结果进行比较。结果表明:2006-2009年云南省水生态承载力评价为基本可承载,2010-2016年评价为可承载,2020年评价为绝对可承载;评价结果与模糊综合评价法、投影寻踪法的评价结果基本一致;该模型兼具模糊性和随机性,用于水生态承载力评价是可行的,可作为一种新的水生态承载力评价模型。     

基于熵权法-正态云模型的辽宁省水生态承载力评价

将正态云模型引入水生态承载力评价中能够科学衡量其随机性和模糊性特征,对辽宁省2025年、2008—2018年水生态承载力运用熵权法-正态云模型进行评价。从社会、经济、水环境和水资源子系统中选择19项指标,结合相关资料构建分级标准和指标体系,然后运用云模型正向发生器、熵权法计算分级评价指标的隶属度及其权重,其中水生态承载力分级确定度依据权重矩阵与隶属度矩阵计算。为进一步验证模型的可靠性,对比分析了投影寻踪法、模糊综合法和熵权法-正态云模型评价结果。研究表明:辽宁省2008—2011年、2012—2018年、2025年分别处于基本可承载、可承载和绝对可承载状态;投影寻踪法、模糊综合法和该评价结果保持较好的一致性;该模型具有随机性和模糊性,可为水生态承载力评价提供一种新的思路。     

基于组合赋权-正态云的大坝安全评价模型

针对大坝安全评价问题,提出了一种基于组合赋权和正态云耦合的安全评价模型。选取变形、渗流、环境因素为大坝安全评价指标体系,根据既定评价指标体系确定大坝安全评价标准,在此基础上确定云模型的特征参数和各评价指标的综合权重,由云模型正向发生器给出评价指标在各评价等级下的隶属度,最后由各评价指标的综合权重矩阵和对应评价等级下的隶属度矩阵得出大坝安全评价结果。运用该模型对某大坝进行了安全评价,结果表明,该方法可以得出准确的结果。     

关门山水库除险加固效益后评价

从生态环境、经济、社会3个方面选择15项要素构建效益后评价体系,然后以关山水库为例提出改进云模型综合评价法,结合当地经济发展和工程建设实际情况将后评价等级划分为5个等级。改进云模型评价法可将熵权法与投影寻踪法相耦合,运用组合赋权法求解各参评因子权重,其中云模型超熵He、熵En、期望Ex三个特征值利用评价等级与标准计算,对各参评要素隶属度采用条件云发生器求解,以实例验证了模型的适用性和有效性。     

基于区间直觉模糊TOPSIS法的水资源空间均衡评价

为更好体现指标值的模糊性以及评价结果的客观性,将区间直觉模糊集引入水资源空间均衡评价,构建包含水资源禀赋和水资源利用两个子系统的评价指标体系。采用改进的区间直觉模糊TOPSIS法计算相似度、区间直觉模糊熵法确定权重,构造不均衡系数,建立基于改进区间直觉模糊TOPSIS法的水资源空间均衡评价模型。将模型应用于山西省2015—2019年水资源空间均衡评价,结果表明：山西省水资源空间均衡等级总体为中部均衡、北部较均衡、南部较不均衡,其中太原市为水资源空间不均衡等级;该模型能够反映各地级市水资源空间均衡程度并揭示其空间不均衡的原因,有效评价水资源空间均衡。     

基于复合云模型的太湖流域水环境质量风险评价

针对太湖流域水环境质量风险评价问题,提出了评价指标体系。根据2011—2015年7个断面的实测数据对现有指标进行筛选,计算各指标的属性重要度,并选取较为重要的4个水质指标和富营养化指数;对实测水质数据和地表水环境质量标准等级,采用Shannon熵和云模型相结合的方法,利用最大隶属度原则得到太湖流域各年水环境质量风险评价的结果。结果表明该流域水环境质量处于中等风险水平,需要采取相应措施降低发生水污染事件的风险。评价结果可以为太湖流域的水质改善提供一定的科学依据。     

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.     

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。     

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.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

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.     

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.     

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.