基于GIS的DEM和分布式水文模型的应用比较

本文采用GIS地形分布技术和栅格技术，对TOPMODEL和新安江水文预报模型进行基于GIS的技术改造，构建了基于DEM栅格的TOPMODEL水文模型和基于GIS的TOPMODEL和新安江分布式水文模型，并将3个模型应用于黄河支流——洛河卢氏以上流域的水文模型的参数率定和模拟比较，以探讨 GIS技术的应用和模型的适应性。结果表明在该研究流域上，3个模型都能很好地进行水文过程模拟，其中基于DEM栅格的TOPMODEL模型可取得更好的效果。     

基于DEM栅格的水文模型在沂河流域的应用

本文结合GIS技术和数字高程模型,运用基于DEM栅格流域信息提取技术,对传统的新安江模型及TOPMODEL进行改进,构建基于栅格的分布式新安江模型、基于栅格的TOPMODEL水文模型。并将模型应用于沂河临沂以上流域。通过流域信息提取、模型参数率定和流域典型洪水模拟,以探讨GIS技术与数字高程技术的应用和水文模型的适应性。应用结果表明,4个水文模型在该流域上的水文过程模拟效果良好,其中,基于栅格的新安江模型与基于栅格的TOPMODEL的模拟效果更好。     

多种水文模型在潘家口水库流域中的应用比较研究

由于传统水文预报模型的局限性,分别采用新安江模型、TOPMODEL模型及降雨径流相关图,对位于半湿润半干旱地区的潘家口水库流域进行洪水模拟计算并进行适用性分析。结果表明,采用蓄满产流机制的新安江模型及基于地理信息系统的TOPMODEL模型均适用于该流域,在潘家口水库洪水预报中预报精度较高,为海河流域洪水预报方案的建立提供了新的思路和模式,具有一定的理论基础和借鉴意义。     

湿润地区山区小流域水文模型应用与比较

将新安江模型、萨克拉门托模型及TOPMODEL应用在3个不同的湿润地区山区小流域,将洪峰相对误差及峰现时间误差作为预报精度主要评价指标,分析不同水文模型在各流域的精度及适用性。结果表明:在南阳河流域,新安江模型略优于另外两种模型,但3种模型总体精度均不高;在雾渡河流域,新安江模型精度较高,萨克拉门托模型次之,TOPMODEL精度最低;茅坪河流域资料匮乏,仅有的6场洪水全部用于模型率定,3种模型均能达到预报精度要求。综合比较后发现,新安江模型在3个研究流域预报精度最高。     

西枝江流域水文预报技术及应用

随着社会经济的发展,城市化带来的防洪问题越来越突出。安墩水流域是西枝江上游受人类活动影响相对较小的流域,选择此流域进行模拟研究TOPMODEL和新安江模型在西枝江流域水文预报的适用性。从TOPMODEL和新安江模型模拟结果可以看出模拟径流的精度较高,而且参数变化范围较小,2个模型在此流域是合适的,为TOPMODEL和新安江模型在整个西枝江流域的模拟奠定基础。     

基于网格新安江模型的汇流方法研究

为使网格新安江模型更好应用于无资料地区洪水模拟及预报,文章采用网格水滴汇流方法构建网格新安江模型的汇流部分,以湿润地区屯溪流域为研究流域,将网格水滴模型与扩散波汇流模型及马斯京根汇流模型对比验证其模拟精度,并将网格水滴模型应用于半湿润半干旱地区东湾流域验证其适用性。结果表明,采用网格水滴汇流方法的洪水模拟过程在屯溪流域的模拟精度与其他2种方法基本相当,均可以达到甲级预报精度;同时在半湿润半干旱地区东湾流域的应用达到乙级预报精度。网格水滴汇流方法具有一定适用性。     

新安江NAM和TOPMODEL模型在安阳河流域比较应用研究

海河流域作为我国的政治文化中心,流域内人口密度大,水循环过程受到强烈的人为干扰,导致流域的水文水资源特征改变。因此,为了探讨海河流域河流的产流机制,本研究以安阳河流域为例,分别采用新安江模型、NAM模型和TOPMODEL模型进行日径流过程模拟和次洪模拟计算,结果表明在海河流域三个模型模拟效果均良好。三种水文模型模拟的结果为:在日径流模拟方面,NAM模型与新安江和TOPMODEL模型相比,在率定期其确定性系数较其它模型相对较高,在验证期其率定系数也相对较高,且径流深相对误差较小;在次洪模拟方面,NAM模型与新安江和TOPMODEL模型相比,2场洪水的确定性系数有所提高;2场洪水的径流深相对误差都较小;2场洪水的洪峰相对误差较小,峰现时差有了明显的提高。因此,NAM模型在安阳河流域的应用效果最佳。     

基于DEM的汉中流域水文过程分布式模拟

选择汉江上游的汉中流域为研究对象,在基于栅格DEM流域水文特征的获取和降雨空间插值的基础上,建立了基于TOPMODEL的松散耦合型结构的分布式水文模型.应用该模型对汉中流域的水文过程进行模拟,结果表明:该模型的模拟精度与集总式TOPMODEL和集总式三水源新安江模型基本相当,而且能够得到流域内部产汇流的分布状况等信息,基本上能够满足流域水资源规划与管理的需求.     

新安江模型、TOPMODEL和萨克拉门托模型的应用比较

通过ArcView软件对英那河流域进行了流域信息的提取．并利用VB编程提取出该流域的地形指数与河网等流时线,使之成为TOPMODEL的客观参数。为了客观表示流域的初始状态,还建立了初始土壤缺水量与地形指数之间的关系式：并选用TOPMODEL、萨克托门托模型和新安江模型对英那河上史家堡流域和英那河水库流域的产汇流规律及洪水预报进行了应用研究,对三个模型在研究区域应用的结果进行了比较分析。     

新安江模模型、TOPMODEL和萨克拉门托模型的应用比较

通过ArcView软件对英那河流域进行了流域信息的提取,并利用VB编程提取出该流域的地形指数与河网等流时线,使之成为TOPMODEL的客观参数.为了客观表示流域的初始状态,还建立了初始土壤缺水量与地形指数之间的关系式:并选用TOPMODEL、萨克拉门托模型和新安江模型对英那河上史家堡流域和英那河水库流域的产汇流规律及洪水预报进行了应用研究,对三个模型在研究区域应用的结果进行了比较分析.     

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.