西江干流敏感生态需水量研究

西江干流是珠江流域内最重要的鱼类产卵场分布区和鱼类洄游通道,其敏感生态需水可由控制断面的鱼类繁殖期适宜生态流量来确定。针对西江干流河道实际情况,选取迁江站和梧州站作为控制断面,依据西江鱼类产卵繁殖所需流速,采用生境模拟法估算西江干流迁江站、梧州站断面生态敏感期的适宜生态流量分别为1 722 m3/s、5 213 m3/s,敏感生态需水量分别为183亿m3、575亿m3,并利用Tennant法对计算结果进行了分析评价。该研究结果为西江干流的鱼类生境保护及水资源配置提供了技术依据。     

云南海峰湿地生态需水分析

云南省海峰湿地结构完整、功能齐全,是云南最具代表性的典型喀斯特湿地景观,具有较高的科研、科考价值。近年由于连年干旱,湿地水位逐年下降,为防止生态环境恶化、湿地面积减小、生物多样性遭到破坏等生态问题发生,需要分析确定海峰湿地适宜的生态水位和生态需水量。依据海峰湿地水域、水位实测成果,结合湿地保护区降水、蒸发及鱼类调查资料,采取鱼类生境法和湿地形态法分析了维持湿地生态系统所需的适宜生态水位和生态需水量。分析结果为,海峰湿地适宜生态水位为1 955.2 m,生态需水年均为0.539 m~3/s,各月生态需水量为0.467~0.597 m~3/s。分析结果可供海峰湿地保护区和类似地区管理参考。     

生态流速—临界水深法及在杜柯河中的应用

在归纳国内外河道内生态需水方法的基础上,提出了一种同时考虑河道信息和维持河道生态功能所需河流流速的生态需水计算方法（下简称生态流速—临界水深法）,并建立相应的流量与水深、流速的函数关系,重点推导了抛物线型过水断面下流量与水深、流速与水深之间的关系。以绰斯甲河支流杜柯河河道内生态需水为例,给出了计算过程,同时用Tennant法作为对比。结果表明：生态流速—临界水深法计算杜柯河壤塘站河道内适宜生态流量处于Tennant法所计算的适宜和最佳生态需水量之间,计算得出的最小生态需水量比Tennant法计算的最小生态需水量少0.06 m3/s。由于该方法考虑了生态流速（保护目标鱼类产卵所需流速）和临界水深(维持生境最低水深),以临界水深确定了最小生态需水量,以生态流速界定了适宜生态需水量范围,故所得的结果更接近实际状况。     

闽江流域山溪性河流生态需水量计算

根据闽江流域生态现状,在综合国内外生态需水研究方法及适用范围的基础上,分非汛期、鱼类产卵期、汛期3个时段进行流域生态需水满足程度的分析。从水生生物保护及河床稳定的要求出发,构建了识别性生态需水计算模型,并选取流域典型站点及各河道代表物种,进行生态需水量计算。结果显示,流域非汛期、鱼类产卵期、汛期的生态需水范围分别为多年平均径流量的10%、26.3%～46.6%、28.3%～37.7%。研究结果可以为流域水资源和水环境的综合治理提供参考。     

基于鱼类栖息地需求的雅鲁藏布江中游环境流量计算

针对水利工程影响下,河道下游天然水文情势改变造成鱼类产卵场面积减小和质量降低等潜在生态问题,通过数值模拟与统计建立拉萨裸裂尻鱼产卵期栖息地适宜度模型,采用栖息地模拟法计算了雅鲁藏布江中游藏木水电站坝下米林—尼洋河汇口处38.9 km河段的环境流量。结果表明:拉萨裸裂尻鱼产卵期适宜水深为0.7～1.0 m,适宜流速为0.4～0.6 m/s;研究河段内拉萨裸裂尻鱼产卵期环境流量为432 m~3/s。     

基于生态水力半径法的瑞丽江河道内生态需水量估算

从保护瑞丽江流域特有珍稀、濒危鱼类的角度出发,根据瑞丽江流域的水资源特性,采用生态水力半径法对瑞丽江进行河流生态需水量研究：利用戛中水文站的实测流量资料,建立Q～R关系,计算了瑞丽江河道内生态需水量,枯期最小生态需水量20.1m³/s;汛期最小生态需水量63.2m³/s。从而推求出龙江水电枢纽工程汛期下泄流量不应小于47m³/s;枯期下泄流量不应小于15m³/s,以满足水生生物生存繁衍所需的基本生态需水量。     

随机流量历时曲线及其在生态流量计算中的应用

河流生态流量是生态水文研究的重要部分,其相关理论和计算方法一直是当前国内外学者研究的热点。尝试基于随机流量历时曲线计算河流系统的生态流量,给出了维持河流生态系统健康各等级流量的历时或频率,并进而估算生态需水,为流域水资源的合理配置提供参考。以松花江干流8个断面为例,研究结果表明,在随机流量历时曲线上基于Q97,10估算得到的最小生态需水量与7Q10法所得到的需水量数值接近且相关性好,而基于保证率P=75%的随机流量历时曲线可求得河道的适宜生态需水量。研究区内嫩江流域大赉断面以上河段最小生态需水量、适宜生态需水量分别为4.6亿m3和99.1亿m3,约占总水资源量的2.6%和56.2%;松花江下游佳木斯控制断面以上河道最小生态需水量、适宜生态需水量分别为79.1亿m3和388.9亿m3,约占总水资源量的13.4%和65.7%。     

赣江下游河道适宜生态需水量计算

受气候变化及人类活动的影响,赣江下游河道生产生活与生态用水的矛盾日益增加。本研究采用Tennant法和生态流量阈值法分别计算外洲断面生态需水量,并采用基于四大家鱼为生态保护目标的湿周法进行筛选比对,确定赣江下游适宜和较适宜的生态需水过程。结果表明：Tennant法和生态流量阈值法计算得到的年均适宜生态需水量分别为845.44m³/s、1 041.30m³/s,占外洲断面多年平均径流的40%左右;年均较适宜生态需水量为626.60m³/s、561.16m³/s,占外洲断面多年平均径流的27%左右,为赣江下游适宜生态需水量的预留提供依据。     

考虑鱼类产卵场健康的生态需水核算 ——以西江东塔产卵场为例

产卵场是鱼类栖息地中敏感场所,具有特殊的水文水动力特征,对鱼类自然繁殖有重要的生态学意义。为有效缓解家鱼资源衰退趋势,开展针对四大家鱼自然繁殖的生态需水核算研究,保障家鱼繁殖的用水需求是一种有效的方法。首次以西江段东塔产卵场为研究区域、四大家鱼为目标物种,构建研究区水动力特征指标适宜性曲线,采用二维河流水动力学模型River2D,模拟不同流量下流速和水深等因素对鱼类产卵场的影响,建立流量与四大家鱼栖息地权重可用面积变化的关系,从而确定研究区生态需水量。研究结果表明:基于20种流量工况(1 000～20 000 m~3/s)模拟结果显示,东塔产卵场最大权重可用面积为101 935.48 m~2,适宜权重可用面积对应的生态需水量为10 277.54～12 546.61 m~3/s,该值可作为四大家鱼产卵期的生态需水峰值。基于历史月平均流量工况模拟结果显示,东塔产卵场1—12月可利用加权面积最小值对应的流量分别为:1 339.67、1 256.53、1 361.93、2 126.09、4 057.10、6 202.66、6 734.19、5 316.12、3 092.66、1 680.32、1 234.40、1 168.32 m~3/s,该系列值可作为维持东塔产卵场功能的最小生态需水量。利用维持四大家鱼产卵场健康确定河道生态需水量有利于鱼类种质资源的提高,在维持生物多样性乃至对整个生态系统具有重要的生态学意义。     

长江上游地区生态需水量变化研究

生态需水是生态用水控制和区域生态环境恢复的基本依据和关键。为了确保流域生态系统健康发展,实现水资源合理配置,基于GIS技术与水文气象实测数据等,采用Tennant法计算研究区河流生态需水和Penman-Monteith法计算植被生态需水。结果表明:长江上游地区河流生态需水量为1 022亿m~3,植被生态需水量为4 668.43亿m~3。研究区1981—2007年年均生态需水量呈下降趋势;水资源二级区中,金沙江石鼓以下生态需水总量最大,为1 349.90亿m~3,乌江生态需水总量最小,为562.73亿m~3。各植被类型需水量由大到小依次为水田(1 564.62亿m~3)、林地(1 460.30亿m~3)、灌丛(1 231.91亿m~3)、草地(397.22亿m~3)、旱地(14.64亿m~3)。研究区植被生态需水主要集中在5—8月,占植被整个生长季全部需水的63.78%,河流生态需水主要集中在6—10月,占河流全年总需水量的74.50%。研究结果可为内陆河区域的生态需水量的合理配置提供科学依据,为流域生态环境保护提供理论支撑。     

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.