气候变化和人类活动对黄河上游径流变化的差异性影响

气候变化和人类活动对径流的影响随地理区位、气候背景和时间尺度的不同而不同,如何量化其差异性影响具有重要的现实意义。以黄河兰州站以上流域为研究区,利用SWAT模型研究了气候变化和人类活动不同时空尺度下径流变化的差异性影响及其主导因素,探究了不同区段径流变化的主导驱动因素及其贡献率。结果表明5个水文站的评价指标R²和NSE都达到0.8以上;研究时段内,源区径流变化总体不显著,下游径流下降趋势较上游出现得早和明显;中段地区1986—2005年的径流变化受气候变化和人类活动共同影响,2005年后人类活动为径流减少的主导因素;下段地区1986—1995年的径流变化受气候变化和人类活动共同影响,之后逐渐加强的人类活动为径流变化的主要原因。工农业和城市群快速发展以及水电站陆续修建,导致了径流变化由基准期的"气候控制"向"气候变化和人类活动共同控制"再向"人类活动主导"的差异性驱动特征转变。     

气候变化与人类活动影响下大清河流域上游河流径流响应研究

河北雄安新区的设立,引起了各界对雄安新区所在的大清河流域的广泛关注,特别是其水资源的变化特征与影响因素是了解雄安新区水资源情势的重要参考。研究解析了人类活动和气候变化对大清河流域上游径流过程的相对影响,采用SWAT模型模拟了大清河流域上游径流过程,并结合弹性系数法验证比对,分离了人类活动与气候变化对大清河流域上游径流过程的贡献率。结果表明,1981-2015年,大清河流域上游山区倒马关站及紫荆关站径流量均呈减少趋势,倒马关站及紫荆关站年径流量递减速率分别为0.10m3/s及0.07m3/s。人类活动为影响径流的主导因子,其贡献率为53.4%～60.8%;气候变化较人类活动影响径流稍小,其贡献率为39.2%～46.6%。研究结果可为支撑未来雄安新区建设区域水资源规划和管理提供依据。     

变化环境下子牙河流域水文过程影响要素分析

构建添加水库及取用水模块的SWAT模型，在考虑人类活动影响的基础上，分析土地利用类型及气候变化对子牙河流域水文要素的影响，并利用统合还原法计算人类活动及气候变化对研究区的径流变化的贡献率。结果表明：1980—2020年草地、耕地及水域面积呈减少趋势，建设用地呈增加趋势，其他土地利用类型变化趋势不明显；土地利用类型变化使得流域地表产流增加3.5 mm,地下水补给和蒸散发分别减少0.15 mm和2.93 mm; 1980—2020年研究区年降水量呈不显著上升趋势，年气温呈显著上升趋势，气候变化使得流域地表产流、地下水补给及蒸散发有不同程度的增加；人类活动和气候变化对流域径流减少的贡献率分别为66.36%和33.64%,人类活动占据相对主导的地位。     

近47年来降水变化和人类活动对滦河流域年径流量的影响

近47年来,随着流域降水量的减少,以及水利工程的修建、林草地的减少等土地利用方式的改变,在气候变化和人类活动双重因素的作用下,滦河流域年径流量呈现出显著的减少趋势。现基于降水-径流经验统计模型的构建,定量评估了滦河流域降水变化和人类活动对该地区年径流量的影响程度。结果表明:①1983年以前,滦河流域年径流量受环境变化影响较小,1983年以后,年径流量受到气候变化和人类活动影响较为显著;②1984年-2006年期间,受人类活动影响所产生的年均减水量为11.97亿m3,占该时段减水量的84.42%,受降水变化所产生的年均减水量为2.21亿m3,占该时段减水量的15.58%,人类活动的贡献率远大于降水变化。     

气候变化和人类活动对汉江上游径流变化影响的定量研究

以汉江上游为例,基于弹性系数法和水文模拟法定量估算气候变化和人类活动对流域径流的影响,探讨了变化环境下流域径流对气候变化和人类活动的响应特征。研究结果表明:1961年-2013年汉江上游流域径流呈明显下降趋势,并在1985年前后发生了突变;降水及潜在蒸散发在同时期内也逐渐降低,但变化趋势不显著。气候变化对径流变化的贡献率为42.8%~43.5%,人类活动对径流变化的贡献率为56.5%~57.2%,相比人类活动对汉江上游径流的影响稍大,且其对径流变化的影响呈现增长的趋势。     

黄淮海流域径流量变化及其对降水变化的响应

采用统计分析方法研究了黄淮海流域实测径流量的变化及其对降水变化的响应关系。结果表明:黄淮海流域气温呈现显著性升高趋势,平均线性变化趋势率为0.19℃/10 a;黄河中下游及海河流域降水为非显著性减少趋势,淮河和黄河源区降水量为略增加趋势。受气候变化和人类活动的影响,黄淮海流域10个重点水文站实测径流量均呈现不同程度的减少趋势,其中黄河中下游和海河流域实测年径流量减少趋势显著。降水是河川径流变化的主导因素,黄河中下游及海河流域不同阶段降水径流关系差异明显,淮河流域不同阶段的降水径流关系差异相对较小,人类活动通过改变降水径流之间的响应关系对河川径流产生重要影响。     

滦河流域近59年径流变化分析研究

滦河是渤海的入海河流之一。采用1953-2011年的长期水文气象资料,利用非参数Mann-kendall检验、pettit检验和累积距平方法,研究滦河流域水文气象变量的变化趋势和特点。研究结果表明,在过去的59年里,年平均径流量和季节平均径流量均呈明显的下降趋势;月平均径流量在1,2和5月份呈上升趋势,而在其他季节则呈下降趋势;径流的突变点发生在1964、1984和1998年。基准期或自然期(1953-1964年)的高径流量(Q_5)、低径流量(Q_(95))和中径流量(Q_(50))高于两次人类活动影响的时期(1965-1984和1999-2011年)。人类活动对径流变化的贡献率为56. 6%,远远大于气候变化的贡献率为43. 4%,因此人类活动是影响滦河流域径流变化的主要因素。     

基于Budyko假设的滦河流域上游径流变化归因识别

近50年来,气候变化和人类活动在不同程度上对滦河流域水文过程产生了影响,为了识别径流变化的主要原因,以滦河流域上游地区为研究区,利用Mann-Kendall检验法等分析研究区1966-2015年气象及水文要素变化趋势,同时建立基于Budyko假设的水热耦合平衡方程,运用弹性系数法对研究区径流变化的影响因素进行敏感性分析,并对各要素对径流变化的贡献进行定量评估。结果表明,1966-2015年间滦河流域上游地区年径流深呈显著减少趋势,年降水与年潜在蒸散发均无显著变化趋势。同基准期(1966-1979年)相比,下垫面变化是径流减少的主要影响因素,1980-1997年(影响Ⅰ期)与1998-2015年(影响Ⅱ期)下垫面变化对径流变化的贡献率分别为52.68%、88.12%。在气候要素中,降水对径流变化的影响大于潜在蒸散发的影响。     

土地利用变化和气候变化对温榆河上游流域径流变化的影响

土地利用和气候是直接影响流域水文水资源的两个主要因素,其影响分离的研究对流域的土地利用规划和水资源管理具有重要意义。以温榆河上游流域为研究对象,在统计分析1980-2014年流域气象因子、土地利用变化趋势的基础上,通过SWAT模型模拟与情景设计相结合的方法,评估了气候变化和土地利用变化对温榆河上游径流变化的影响。结果表明,SWAT模型在温榆河上游流域模拟效果良好,率定期和验证期的决定系数R2分别为0.80、0.77,纳什系数Ens分别为0.79、0.74。流域降雨量和气温呈递增趋势,林地和耕地减少,城乡及工矿和居民用地增加,草地在1995年到2005年间增加,这些变化综合影响了流域的径流变化,使得径流先增加后减少。其中气候变化的贡献率为100.46%,土地利用变化的贡献率为2.09%,气候变化的影响远远大于土地利用变化的影响。因此,如何应对气候变化在温榆河上游流域水资源管理工作中值得重视。     

基于新安江模型的老挝南俄河流域径流变化贡献率分析

为分析20世纪60年代以来气候变化和人类活动对老挝南俄河流域径流变化的贡献率,基于流域内地面站点实测降水数据,对广泛应用于湄公河流域的APHRODITE和MSWEP两种卫星降水产品日降水数据进行了偏差校正,采用经校正的基准期卫星日降水和白冠洪、欣赫普两站点实测日径流资料构建了新安江模型,模拟还原了流域水库影响期的天然日径流过程,定量分析了气候变化和人类活动对径流变化的贡献率。结果表明:南俄河流域年径流总体呈下降趋势;白冠洪站两个水库影响期气候变化对径流变化的贡献率分别为-429%和-399%,欣赫普站水库影响期气候变化对径流变化的贡献率为-380%,而对应的人类活动贡献率分别为529%、499%和480%,人类活动是流域径流变化的主要原因;以水库运行为主的人类活动对径流年内分配影响显著,丰水期人类活动影响量的绝对值超过气候变化影响量绝对值的2倍。     

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.     

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.