塔里木河下游应急输水植被恢复响应及生态修复研究

在干旱地区内陆河流域,由于水资源不合理的开发利用,流域生态系统退化已成为一种普遍现象.向断流的河道和生态退化区域实施输水工程,补偿地下水和改善水环境是河流生态系统恢复的基本行为和必然过程.为了抢救塔里木河下游生态环境,国家在2000～2003年向断流30余年的塔里木河下游500余km的天然河道实施了五次应急输水.以五次应急输水监测资料为基础,以河道水量沿程消耗-地下水位动态变化-植被恢复响应为主线,应用河道水力学、地下水动力学、植被生态学、大系统优化理论等多学科交叉研究方法,提出了下游生态修复的整体方案,为今后创建和完善干旱区受损生态系统输水、恢复与重建的评价体系奠定了理论和实践基础.     

浅析塔里木河下游绿色走廊输水后生态与环境的变化

由于多种原因,塔里木河下游大西海子水库以下350km河道断流近30年,地下水位下降,植被衰败,塔里木河下游绿色走廊生态恶化趋势严重.为了遏制生态劣变的趋势,保证在必要的工程实施完成前维持和保护现有植被,从2000年4月开始至2004年7月,由塔里木河流域管理局与巴州、农二师共同组织6次向塔里木河下游生态应急输水.输水后塔里木河下游绿色走廊生态与环境发生了一系列动态变化,结合实测数据进行初步分析,认为塔里木河干流上中游林草植被得到有效保护和恢复,下游生态与环境得到初步改善.     

塔里木河下游气候变化与生态输水之间的关系分析

研究利用塔里木河下游各水文断面径流、气象资料,分析塔里木河下游的气候变化与生态输水的关系.结果表明生态输水实施后,即2000—2018年下游整体呈湿润化发展,而干旱化的区域主要分布于喀尔达依及阿拉干区间内及台特玛湖湖区南侧.该研究确定了生态输水对塔里木河下游气候变化的影响,为今后下游水资源合理分配提供指导.     

从塔里木河河岸地下水与植被覆盖看尾闾湖维持面积

实施塔里木河下游生态输水工程（简称生态输水工程）是塔里木河下游“绿色走廊”保护的重要举措。以塔里木河下游（含湖区）为研究对象,采用密集时序遥感技术对自2000年生态输水工程实施以来的生态输水过程中河岸带与湖区植被面积和植被覆盖度的变化特征进行定量分析,结果表明：生态输水对河道两岸地下水水位的影响范围局限在1～2 km内,越往尾闾方向影响范围越窄;植被面积与植被覆盖度增长趋势显著的区域中,湖区占比较大,主要体现在尾闾湖区。为提高生态水利用效率,建议优化目前的生态输水方式。     

塔河下游河道生态输水对气候变化的影响探讨

以塔里木河下游河道断流、生态恶化和持续性生态输水为背景,以所取得的尉犁国家级气象站1960年～2020年气温和降水资料为依据,从下游气温及降水变化、降水蒸散指数变化及干旱指数变化等方面探讨塔河下游河道生态输水对气候变化影响的进行分析.结果 表明,生态输水是恢复河道下游水生态环境、改善区域小气候的有效措施,从大西海子水库...     

塔里木河下游河道疏浚工程输水线路选择

针对塔里木河下游河道断流和生态环境恶化问题,为保护下游绿色走廊,对塔里木河下游大西海子水库下游河道疏浚工程,通过投资、占地、施工、管理、防洪等综合比较,在可供选择的3种输水方案中,建议选择在大西海子水库主坝上新建1座放水闸方案.分析结果表明,实施塔里木河下游河道疏浚工程具有良好的生态效益和社会效益.     

塔里木河干流治理综述

受气候干旱、水资源无序开发和低效利用等的影响,塔里木河流域生态环境日渐恶化,已成为制约流域经济发展、社会稳定等的主要问题。塔里木河干流治理的主要任务是在干流修建输水堤、生态闸和河道护岸工程,防止洪水漫溢,变无序用水为控制用水,提高该河段水资源的利用率,其作用是在满足上中游两岸生态用水和农业灌溉用水的同时,增大向下游的输水量,到2005年实现向大西海子以下河道输水3．5亿m^3的目标。根据分析计算,治理工程实施后可基本达到向下游输水5．08亿m^3的目标,堤防工程的修建可增大河道输沙量,减少泥沙淤积。同时,工程布局以及河道护岸工程建设如何根据未来河势的变化进行调整和完善,还需要进行深入的研究。     

塔里木河下游环境监测与生态修复研究

塔里木河下游357km河道断流近30年后，经输水使其生态产生了恢复迹象，是世界范围内流域退化生态系统恢复与重建的稀有案例。本文以此为背景，在生态环境本底状况调查的基础上，通过大量的监测资料，应用河道水力学、地下水动力学、植被生态学以及系统分析与优化方法，对五次应急输水植被生态响应效应，进行了全面系统地评价。科学地确定了合理的生态修复目标和下游河道输水与区间水量优化配置方案。为创建和完善干旱区受损生态系统输水、修复与重建的评价体系奠定了理论和实践基础，也为塔里木河流域综合治理提供了重要的技术支撑。     

塔里木河下游输水对地下水位和生态恢复的影响

地下水及天然植被对保持水土、维护物种多样性有着不可或缺的作用。以塔里木河为对象,通过对比塔里木河生态输水前后地下水水位线与植物群落的分布特征发现：塔里木河流域地下水位的变化与河道生态输水有直接关系,输水次数越多、量越大,水位抬升越明显;下游植物群落及生态问题在河道输水前后优势物种会产生改变,且在输水后丰富度会有所上升;河道横向方向由于随着地下水高度的逐渐降低生态植被的密度、盖度分布会急剧降低。     

简讯

塔里木河综合治理工程初现成效塔里木河综合治理工程第四次生态应急输水，已在塔河尾闾台特玛湖东北面形成超过１０km２的水面，水位和水面都大于去年的第三次输水．第四次生态应急输水，已通过孔雀河，从博斯滕湖向大西海子以下输水２．８亿m３，超过了原计划向大西海子以下输水２．４５亿m３的水量．２０００年至２００１年，新疆水利部门先后三次从博斯腾湖向塔河输送生态水１３．５亿m３，累计向塔河下游泄水７亿m３，水头到达塔里木河尾闾———台特玛湖，从而结束了塔河下游３００多km河道近３０年滴水未见的历史．经过这三次应急输水…     

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。     

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.     

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。