兴国县塘背河小流域综合治理的生态经济效益

塘背河小流域是南方小流域水土保持综合治理试点之一。从1980年开始,在原有的基础上综合规划,治管并重,通过五年的努力,取得了较好的生态经济效益,为今后开展小流域治理提供了初步经验。一、基本情况塘背河系平江一条小支流,流域面积为16.38平方公里(塘背水库坝址以上),其中,山地面积为1154.67公顷,占70.5％,耕地面积为293公顷,占17.9％,水面65.67公顷,占4％。小流域属丘陵地带,地势西高东低,基岩出震旦系混合花岗岩和燕山早期中粗粒斑状黑云母花岗岩构成,花岗岩中     

水保世行贷款项目带来的综合效益

利用世行贷款进行小流域综合治理开发，成效显著，文中就呼斯太河尔圪壕小流域的综合效益进行了分析评价。     

山东省土地治理现状及预测

采用灰色系统动态模拟GM(1,1)分析方法,对山东省1996-2005年间土地治理中的小流域综合治理面积和盐碱地改良面积进行了相关分析和模拟预测.结果表明:山东省小流域综合治理面积和盐碱地改良面积总体保持增长势头,分别达到了平均每年18.633万hm2和0.706万hm2;但治理面积空间分布不均,其中丘陵和山区水土流失治理成效显著,黄泛平原区盐碱地改良情况良好.利用灰色模型对典型地市2002-2005年的盐碱地改良面积、小流域综合治理面积进行预测,并利用已知的历史数据进行检验,表明模型预测较准确.预测山东省未来几年土地治理的面积仍将呈增长趋势.     

遥感技术在老挝南里河小流域综合治理中的应用

遥感技术具有监测范围大、获取信息快，受环境条件限制少等优势，已成为小流域综合治理中的一种重要手段。从小流域划分、土地利用现状、水土流失现状、小流域综合治理规划设计、小流域综合治理效果评估等方面介绍了遥感技术在老挝南里河小流域综合治理中的应用。研究结果显示，多源时序遥感数据在工程规划设计、工程实施综合效益评估等工作中具有明显优势，较大程度提高了工作效率及成果质量。     

塘背河小流域植被覆盖时空动态变化及水保驱动分析

塘背河小流域位于赣南革命老区和全国第一个水土保持改革试验区腹地,是我国第一批水土保持治理试点小流域,系统、科学评估塘背河小流域水土保持生态修复成效,对赣南水土保持改革试验区建设和水土保持高效治理技术模式提炼具有重要现实意义。利用40a遥感影像数据和水土保持治理数据,基于NDVI阈值分割法,开展了塘背河小流域植被覆盖时空动态变化以及水保驱动分析。结果表明:近40年塘背河小流域植被覆盖度由1975年的22.91%已提升到2014年的86.87%,随时间呈递增趋势;在时间和空间上均有差异性,时间上主要分为植被覆盖迅速增长期(1975-1989年),植被覆盖自我修复完善期(1989-2001年)以及植被覆盖稳固发展期(2001-2014年)3个阶段,空间上分为上游原有植被自我修复区、中游人工半干预植被修复区和下游人工直接干预植被修复区3个分区;植被覆盖与水土保持工程在时间和空间上具有较好的一致性,后期水土保持政策实施以及水土保持新技术、模式的应用大大减少了植被覆盖空间上的差异性,对于植被修复具有重要的推动作用,人类大规模农林开发在植被修复研究方面,不容忽视。     

浅谈小流域的综合治理

小流域的综合治理是一项复杂的系统工程，它汇集了自然生态、社会经济等多方面的内容。小流域综合治理的目的在于防止水土流失，合理利用土地资源，充分发挥小流域体系的经济效益、社会效益和生态效益，以实现环境优美、经济繁荣、社会文明之目标。为此，必须创立一个高效、协调持久优化的小流域生态经济系统。而创立这样一个多因素、多变量、多功能和多效益的复杂系统就需要有好的理论和方法。下面主要介绍一下小流域治理的步骤与方法。     

小流域综合治理效益分析

依照有关规定，以全省50条取得综合治理效益的小流域统计数据为基础，结合浙江省小流域综合治理的实践，探讨了小流域综合治理各项效益的计算方法，并通过对小流域综合治理项目的国民经济评价及效益分析，反映小流域综合治理在国民经济中的作用和地位。     

灰色模型群在水土保持经济效益分析中的应用

水土保持是一项改善山区生产条件和生态环境,促进各业全面发展的综合治理措施,涉及土地资源合理开发利用的各个方面,需要投入大量的人力、物力、财力,治理周期及效益重现期较长。因此,对小流城的水土保持经济效益作一全面分析预测是十分必要的。本文以广东省饶平县九村小流域为例,运用灰色控制系统理论,建立灰色动态GM(1,1)模型群,对当地1987～1992年社会生产总值和人均收入两项指标进行定量分析预测,并展望到2000年的变化发展超势。1 九村小流域的基本情况     

朝阳县木头城子镇满达小流域水土保持综合治理效益评价

通过对朝阳县木头城子镇满达小流域项目区的整体分析,运用层次分析模型评价了其水土流失综合治理效益,并总结了流域治理经验,以期为促进该流域水土流失治理和水土保持规划提供理论支持。文章对比分析了满达小流域在2015-2016年期间的综合治理状况,探讨了水土流失治理措施在社会、经济、生态环境方面的效益,从而反映了流域系统内部收益在综合治理期间的效益变化状况。     

水土保持效益评价

在水土保持规划中，必须用效益预测来确定规划是否可行，在评价小流域综合治理成果时，也要进行效益分析。因此，水土保持效益评价是水土保持工作的一项重要内容。     

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.     

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.     

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。