基于SWAT模型的金华江上游土地利用变化对径流影响的研究

流域内土地利用变化对水文循环有着重要影响。本文通过在金华江上游建立SWAT模型,模拟了不同土地利用情景下流域径流的变化特点,结果表明:SWAT模型模拟精度高,其中验证期Ens=0.85,R2=0.85,Re=0.07,可以模拟及分析流域水文对土地利用变化的响应;在该流域内,林地有减少径流量的作用而草地和耕地相反;保护耕地使流域内农业产量增加但也使径流量增加,且增加量集中在雨季。     

基于SWAT模型的宝库河流域日径流模拟

根据西宁市宝库河流域土地利用、土壤类型及气候特征建立了适合于该区的SWAT分布式流域水文模型,并参考月过程的参数率定结果对日过程进行模型校准和验证。结果表明:基于SWAT模型的日径流模拟在该流域得到了成功运用,其中模拟的相对误差R e为16.9%,Nash-Suttclife系数E ns为0.76,相关系数r2为0.72,为后续模拟该流域鱼类产卵期的流量脉冲过程提供了数据支撑。     

基于ReNuMa模型的长春石头口门水库流域非点源污染负荷模拟

应用区域营养盐管理模型ReNuMa,以长春市饮马河石头口门水库流域为研究对象开展研究,通过对流域总氮非点源污染的调查和模拟,定量计算和分析了总氮非点源污染时空分布规律.结果表明:该模型在研究区域适用性较好(月径流校准期R2=0.7884,Ens=0.7816;验证期R2=0.7602,Ens=0.7092;月负荷校准期R2=0.7429,Ens=0.7008;验证期R2=0.7066,Ens=0.6618).时间尺度上,雨季期总氮非点源污染负荷占总量的69％.空间尺度上,饮马河上游流域对非点源污染负荷比例最大,不同土地利用类型的总氮非点源污染负荷不同,耕地贡献比例最大,其次是农村居民点.     

基于SUFI-2算法的SWAT模型在抚河临水流域径流模拟中的应用

以抚河临水流域为研究区域,整合流域下垫面与气象数据资料,基于GIS平台构建了SWAT分布式水文模型;采用SUFI-2算法进行模型参数敏感性分析、率定及不确定性分析,并对抚河临水流域径流过程进行模拟。结果表明:率定期和验证期的模拟值和实测流量拟合程度较好,决定系数(R2)和纳什效率系数(Ens)均在0.80左右,模拟结果较理想,有很好的适用性。     

SWAT模型在碾盘河流域的应用研究

本文以碾盘河耿王庄水文站以上流域作为研究区域,基于SWAT模型,模拟了碾盘河流域流量、水质指标氨氮的变化过程。研究结果表明:率定期和验证期模拟结果的相关系数R~2和Ens均满足对模型的评判要求,流量和氨氮含量的模拟值与实测值的变化特征基本相符,同时汛期的模拟结果优于非汛期的模拟结果。构建的SWAT模型可用于碾盘河流域的流量、水质模拟与预测,可为研究区域水文测报、水资源管理等工作的开展提供借鉴与参考。     

SWAT模型在缺资料地区的应用——以高明河为例

将SWAT分布式水文模型应用于珠江三角洲地区的佛山市高明河流域,利用GIS强大的空间分析与数据处理能力,对流域流量、气象、DEM、土地利用、土壤等水文气象和下垫面资料进行分析处理,率定模型参数,研究SWAT模型在降雨资料系列短、无长系列实测的河道水位流量数据、缺少有效的水文预报方案等缺资料的中小流域或区域的适用性,并分析误差原因。采用相对误差、相关系数以及Nash-Sutcliffe效率系数三项指标对模型进行评价检验,率定期和验证期的相对误差均在0.2以下,相关系数均在0.6以上,Nash-Sutcliffe效率系数均在0.5以上。结果表明,SWAT分布式水文模型能够对高明河流域日时间尺度水文过程进行准确模拟,达到GB/T 22482—2008《水文情报预报规范》中精度评定的丙级,在缺资料的珠三角中小流域具有较好的适用性。     

甘肃梨园河流域SWAT径流模拟与预报

以甘肃梨园河流域为研究对象,收集相关资料组织数据库,建立SWAT分布式流域水文模型,并模拟1990-1999年月地表径流过程。通过比较模拟值与实测值得相对误差Re小于10%,相关系数R2和Nash-Sutcliffe系数Ens均大于0.80,模拟效果较好,认为SWAT模型可适用于梨园河流域的地表径流模拟。而后结合自回归模型和时域法预测的气象数据,加载到已率定的SWAT模型中预测2009-2018年地表径流。结果表明:预测期径流深呈下降趋势,分析径流对气候变化的水文响应,认为径流对气温的水文响应的敏感性较径流对降水的敏感性高。     

SWAT模型在金沙江上游小流域径流模拟中的应用

为探讨SWAT分布式水文模型在金沙江上游小流域水文过程模拟中的适用性,选择金沙江一级支流冲江河流域为研究区,利用该小流域控制站来远桥水文站1961~2012年月径流量数据进行模型参数率定与模型验证研究。结果表明：SWAT模型对金沙江上游山区小流域径流模拟精度较高,冲江河流域率定期和验证期月径流模拟值与实测值的相关系数分别达0.97和0.81,平均相对误差分别为16%和20%,纳什系数Ens分别为0.84和0.82。     

SWAT模型在赣江流域的适用性及参数敏感性

为评估和管理赣江流域水资源,基于ArcGIS10.2构建了SWAT模型对赣江外州站以上流域进行了模拟。模型中涉及的模型验证、参数率定和敏感性分析,采用了SUFI算法来处理。并基于月尺度、年尺度对研究区域选取近50 a的径流进行模拟。为了评价模型的可行性和拟合程度,计算了拟合系数R~2和纳什系数Ens。结果表明,实测过程线与月尺度和年尺度的径流接近吻合,拟合程度也非常良好,年尺度径流模拟甚至在两个不同时期下得出相同结果。达到了预期期望,事实证明选用的SWAT模型在赣江外州站以上流域模拟具有良好的效果。     

土地利用变化对东江流域产流过程影响的定量评估

基于SWAT(soil and water assessment tool)模型,对东江流域的水文过程进行了模拟,并分别采用1990年、2000年、2009年土地利用数据驱动模型,定量评价东江流域1990—2009年土地利用变化对流域水文过程产生的影响。结果表明:(1)流域出口月径流模拟率定期确定性系数R2为0.89,Nash-Sutcliffe效率系数ENS为0.87;验证期R2为0.88,ENS为0.87,东江流域SWAT模型径流模拟精度较高;近年来流域林地、草地面积减少,园地、城镇用地、水域面积增加。(2)在此影响下,东江流域单位面积侧向流降低了9.66 mm、基流降低了4.86 mm,地表径流增加了8.26 mm、实际蒸发增加了6.40 mm、潜在蒸发增加了4.40 mm;径流总量共减少了6.38 mm。(3)地表径流、侧向流对土地利用变化的响应在雨季更为敏感,实际蒸发、潜在蒸发及径流总量对土地利用变化的响应在旱季更为敏感。     

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。     

Serial discontinuities in a Rocky mountain river. I. Distribution and abundance of plecoptera

Samples were taken year-round at eleven sites along the altitudinal profile (2900-1400 m a.s.l.) of the Gunnison River, a 329 km tributary of the Colorado River, to document the distribution of the Plecoptera and to evaluate responses to hypolimnial-release dams in the headwaters and middle reaches. Twenty-two species were present, with the greatest species richness occurring in an unregulated segment upstream of the middle reach dams; average nymphal biomass over the study period (175 organisms, 395 mg dry mass m^?2) was also greatest in this segment. Only four species (58 organisms, 48 mg m^?2) were present in the tailwaters of the headwater dam and values were greatly reduced (nine species; 35 organisms, 180 mg m^?2) below the middle reach dams. The stonefly community recovered ca. 80 km downstream from the last dam (15 species; 244 organisms, 250 mg m^?2), apparently in response to natural resetting of environmental conditions corresponding to those above the middle reach dams. At the most downstream site (11) only four species (four organisms, 16 mg m^?2) were present. The observed distributional pattern is a classic serial discontinuity in response to hypolimnial stream regulation in a temperate latitude river.     

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。     

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.     

浙江省水域调查录入系统的设计和应用

浙江省水域调查录入系统将调查数据与电子地图相整合,对分类水域数据进行统计计算,并对输入数据进行合理性和完整性检查,得到调查范围内现有水域的详细数据,实现了水域调查数据输入、计算、统计和查询的数字化管理,提高了工作效率和工作质量,为各地下阶段水域保护规划编制和水域管理工作提供了数据支持。对该系统的设计原则、功能和技术设计等作了介绍。     

基于CT-连续加荷水泥乳化沥青混凝土细观损伤规律研究

利用CT技术对水泥乳化沥青混凝土的细观损伤过程进行实时扫描观测,获得了混凝土试件在连续加荷下的CT图像。通过采用直观分析法、CT数分析法、CT数与损伤变量关系3种方法分析表明,水泥乳化沥青混凝土的破坏过程可分为压密、扩容、裂纹扩展、破坏4个阶段,同时混凝土在受压过程中具有韧性,在极限荷载之前各断面处于压密和微扩容的强化阶段,极限荷载之后混凝土从损伤到破坏发展比较平稳。     

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.