系统工程在甘肃梯田建设中的应用

梯田工程是一项以梯田建设系统为对象的系统工程,它具有系统科学所必备的最基本的特征。甘肃将系统工程技术应用于梯田建设,采用适度规模治理,路、林、渠、池与田配套,优化设计,规范化施工,建立服务网络,进行制度化管理等综合集成技术,取得了显著的经济效益、社会效益、生态效益。     

坡耕地六角形砖生态景观梯田设计与效果分析

为探讨梯田建设新技术与方法,以水土保持学和景观生态学理论为基础,遵循水土保持与生态园林景观工程相融合的原则,坚持人与自然和谐发展的生态梯田设计理念,将六角形砖与植草(或栽植灌木)技术进行耦合集成应用于坡耕地梯田建设,建成六角形砖生态景观梯田工程,以期为加速坡耕地水土流失治理提供技术支撑。     

卷首

构建人与自然和谐的社会主义和谐社会是实现中华民族伟大复兴的必然选择。人与水和谐是人与自然和谐的必然要求。华夏几千年文明与治水实践密不可分。在我国几千年的治水历程中兴建的众多水利工程，以追求工程与自然和社会的和谐为目标，成为推进社会文明进步和经济发展、促进人水和谐的重要动力。许多工程蕴含着中华民族特有的思维方式、科学精神和人文内涵，形成了中华民族特有的水文化符号。     

周至县小型农田水利设施现状调查及解决对策

本文通过对周至县小型农田水利设施现状的调查与分析,找出了小型农田水利中存在的农田水利设施配套不到位、工程设施老化以及设施配套不完善等主要问题,并提出解决对策,以便加快解决群众灌溉难的问题,促进县域经济、社会的全面发展.     

坡地集流梯田工程蓄水效果试验研究

为了探索在小流域土壤侵蚀治理基础上的雨水集蓄利用模式和技术,以丘陵半干旱区国家重点治理小流域为试验区,遵循坡地水量平衡和雨水叠加利用理论,将小流域综合治理与雨水集蓄利用技术有机集成,研究确定了坡地集流梯田工程的集流潜力、集流效果及其断面参数;并对该工程集蓄径流提高土壤水分和增产增收效果进行了研究.结果表明,该地区坡耕地适宜修建1∶1平坡比的集流梯田工程;与坡耕地相比,集流梯田土壤含水量提高1.96～3.12个百分点,特别是7,8,9三个月的差异更大,比坡耕地平均提高3.62个百分点,集流梯田产量提高58.28%～76.02%;产值增加70.98%～114.30%.     

南水北调三潼宝工程征地移民系统和谐性研究

和谐强调的是事物、事情协调地生存和发展的状态.工程移民系统的和谐分析反映了工程移民系统的整体状况,有利于促进移民工作的开展.现以和谐理论的分析为起点,从社会系统、经济系统、环境系统和资源系统4个方面建立了评价移民系统的综合指标体系,建立移民系统和谐度的计算模型,并以南水北调三潼宝工程的移民工作状况为例,计算分析了三潼宝工程移民系统的和谐度.     

水资源工程和谐的涵义与层次

水资源工程在综合利用水资源方面发挥着巨大的效益,水资源工程的建设将对经济社会、生态环境都产生较大影响.本文从人水和谐的观点出发,运用和谐理论,对水资源工程系统的和谐进行了系统分析,界定了水资源工程和谐的涵义,系统地对水资源工程和谐的内容进行了研究,初步构建水资源工程和谐框架,为进一步研究水资源工程和谐的相关问题提供了基础.     

水资源工程和谐的涵义与层次

从人水和谐的观点出发，运用和谐理论，对水资源工程系统的和谐进行了分析，界定了水资源工程和谐的涵义．对水资源工程和谐的内容进行了研究，初步构建水资源工程和谐框架，为进一步研究水资源工程和谐的相关问题提供了基础。结论指出，水资源工程项目开发应坚持以科学发展观为指导，遵循人与自然和谐相处的理念，按照生态持续、社会持续、经济持续的顺序进行规划设计和运营管理。     

探索山区田间工程新路完善灌溉排洪排渍网络

松柏水库灌区治理是联合国粮援组织WFP3779项目工程。本文针对山区梯田多这一特点，对山区田间渠系灌排网络配套实施，达到灌排自如，兼顾了输水与排涝，对冷浸渍害田治理、改变土壤理论结构现状、促进作物生长发育，探索出了一条提高山区梯田产量的新路子。     

南水北调东线三阳河潼河宝应站工程征地移民系统和谐性研究

移民工程后评价可以检验移民安置规划的落实效果,科学系统地评价移民安置工作情况和移民工程在打破了原有的和谐状态后,要使新建的系统恢复甚至超过原来的和谐状态.结合南水北调江苏省三阳河、潼河段工程开工一年多来征地移民工作,根据和谐性原理,探索移民在搬迁到安置区后是否能够与整个安置区和谐发展.     

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。     

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.     

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.