Delayed drainage of aquitard in response to sudden change in groundwater level in adjacent confined aquifer: Analytical and experimental studies

The problem of the groundwater dynamics and water balance of a confined aquifer in the aquifer system has been solved in previous studies, whereas that in the aquitard adjacent to the confined aquifer has seldom been considered. In reality, the groundwater dynamics of the aquitard are closely related to the exploitation of groundwater resources, groundwater contamination, underground storage utilization and land subsidence. In this paper, an analytical solution is derived to describe the drawdown variation in the aquitard when the head in the adjacent confined aquifer declines by a constant value. The characteristics of groundwater dynamics and water balance of the aquitard are analyzed using a dimensionless analytical solution. There is obvious delayed behavior in the response of groundwater dynamics in the aquitard, which is characterized by the delay index t0. The delayed behavior in the response of groundwater dynamics is not only dependent on the properties of the aquitard, but also proportional to the square of the thickness of the aquitard. The law of the delayed release of water is described in terms of the ratio of the delayed release of water. A water balance equation for the aquitard is established. Three stages of the water balance and the corresponding characteristics are presented with the water balance curves of the aquitard. The analytical solution is given to analyze the flux per unit horizontal area of the aquitard. The hydrogeological parameters of the aquitard, namely the hydraulic conductivity, specific storativity and hydraulic diffusivity, are estimated according to type-curve fitting between the analytical solution and observed flux. The parameters are identified and validated in an experiment.     

Dynamics of total culturable bacteria and its relationship with methylmercury in the soils of the water level fluctuation zone of the Three Gorges Reservoir

Field investigations were conducted to study the temporal and spatial distribution characteristics of total culturable bacteria(TCB)and its relationship with methylmercury(MeHg)in the soils of the water level fluctuation zone of the Three Gorges Reservoir.Different altitudes(170–180,170–175,165–170 and 160–165 m)in Zhenxi(Site 1),Shibaozhai(Site 2)and Tujing(Site 3),Chongqing,China were chosen as sampling sites.Results indicated that TCB did not have significant difference in the top(0–10 cm)and sub(10–20 cm)soil of the non-inundated area(175–180 m),but showing a significant difference in the water level fluctuation zone(\175 m,suggesting that water level fluctuation had an important effect on TCB.Moreover,TCB in soils of various altitudes of Site 1 and 2had significant difference,while for Site 3,this difference was not significant.And the difference of TCB in Site 2was much greater than that in Site 1.These results suggested that there were significant differences for TCB in soils of mainstream and tributaries.In addition,TCB in soils of 10–20 cm had significant or highly significant positive correlations with MeHg level(r C 0.762,P B 0.048),thus we assumed that there may be some aerobic microorganisms playing dominant roles in mercury methylation.     

三峡库区地下水双酚A运移数值模拟

双酚A（BPA）是一种能够对人类及动物产生重大威胁的环境雌激素。以BPA为目标污染物,以三峡库区重庆市茶园新区为例,利用VSAFT2软件建立地下水水质模型并分析库水位变化、地层非均质条件和土壤吸附作用因素对BPA在地下水环境中运移规律的影响。研究中通过假设茶园新区渗透系数分布特点,以变异系数为非均质划分标准,模拟了变异系数分别为0.237、0.529和0.748条件下,BPA在地下水中的运移过程。结果表明：BPA运移速率和运移量随水头边界值的增加而增加,运移能力与地下水水力梯度值呈现正相关;非均质性越强,BPA运移速度越慢;土壤吸附作用在一定程度上会阻滞BPA在地下水的运移过程,对流与弥散均发生延迟;经参数敏感度分析,饱和渗透系数对模拟结果的影响较大。     

三峡船闸水力学数值实验室的研制及应用

阐述数值实验室的组成和结构,拓宽数值模拟的内涵,介绍相关的计算机图形及可视化技术在水利工程界的应用现状．将数值模拟技术和计算机图形处理及可视化技术紧密结合,研制了三峡工程永久船闸输水系统水力特性数值实验室．利用该数值实验室可以对三峡工程永久船闸输水系统任意运行工况进行实时数值试验,并以图形、图像、表格、动画等多种可视化方式给出数值试验成果．该成果表达形象直观,应用方便快捷．系统友好的界面使其能直接为工程设计和施工部门服务．     

云南开远深井水位异常与地震

首先对开远深井地下水位近30年资料中,大震前异常变化特征进行了分析研究;同时,利用相关数学分析方法对资料进行了滤波处理,对云南及近场区中强以上地震前中长期、短期异常指标进行了进一步的提取;最后对该井地下水位在震前的微动态变化特征进行了探讨.     

弘扬三峡传统文化精华构建三峡当代人文精神--对三峡民间传说的深层透视

三峡民间传说以三峡风景传说为主,其本质意义是三峡人民附加在三峡自然景观之上的一种地域文化活动形态.作为以三峡人民为主体在漫长岁月中所创造并以口耳相传方式而流播的三峡文化的一个特殊分支,它集中反映了三峡人民的精神意志、心理情感、价值取向、理想追求和乡土情结.发掘三峡先民留给我们的这片地域文化富矿,对深入研究三峡文化与文学、弘扬三峡传统文化精华,构建三峡当代人文精神均有重要作用.     

三峡库区水位变动下推移式滑坡监测变形分析

三峡水库蓄水诱发了多处推移式滑坡变形加剧,为了加强对该类滑坡在三峡水库水位调节下变形特征的认识和灾害的预防,以三峡库区典型推移式滑坡——云阳凉水井滑坡地质条件和变形特征为例,制定监测方案;通过对滑坡地表位移、地表裂缝、深部位移、地表水位、降雨量及宏观巡查等方面的监测,分析监测指标的变化规律及相互关系,研究降雨及库水位升降对滑坡变形影响,分析了降雨、库水位变化时滑坡体变形和变形速度的规律;结合条块自身稳定系数变化量,揭示了推移式滑坡在降雨和库水位两种不同作用机制下的变形规律：降雨对后部变形影响大,库水对前部变形影响大,水位越高影响越强烈;降水时动水压力对滑体变形影响较大;同时受降雨和降水作用时滑体变形最大。其变形规律为该类滑坡防灾减灾提供了科学依据。     

宜昌地区第四纪沉积物重矿物特征及其与三峡贯通的关系

水系的变化导致物源区的变化,反映在相关沉积盆地中表现为沉积物中矿物组合的改变,以及特征矿物的出现.通过对三峡出口处宜昌地区第四纪沉积物中重矿物特征的研究,结合区域地质资料、野外沉积特征研究和样品EsR测年资料,认为0.73 Ma以前的冲积扇一扇三角洲沉积中重矿物特征明显不同于之后的阶地沉积及现代河床沉积物.这种重矿物组合的不同反映了0.7 Ma前后物源区的改变,同时也指示长江三峡贯通的时间.     

长江三峡库区水渗漏引起的地下水污染问题讨论

为明确三峡库区渗漏水对长江下游地区的影响,根据长江径流量的时空分布变化、三峡库区的地质构造、区域水量平衡等,分析长江下游地区地下水的污染源头。结果表明:三峡库区存在深部断裂和暗河系统,库区渗漏水可能通过深部循环通道向长江下游和流域外排泄;长江下游的地下水污染源头不仅包括源区污染、采矿业污染、农业污染、城市生活和工业固废污染,还包括通过深部循环通道的上游污水排泄;上游的水源保护对下游的地下水污染治理至关重要。     

三峡库区外迁移民的心态及对策分析

分析三峡外迁移民的各种心态及其影响因素对移民安置的影响，从而提出解决移民各种消极心态的建议和措施，这对确保移民工作的顺利开展，具有重要的意义和作用。     

与时俱进,建好用好三峡工程

长江三峡水利枢纽是迄今为止世界上最大的水利水电工程。三峡工程研究论证了数十年,最终才在1992年七届人大五次大会上表决通过。该工程1994年正式开工,2003年实现初期蓄水、通航、发电三大目标,目前正顺利进行三期工程,预期2008年全部机组可以投产,可望提前1年竣工,发挥设计预定效益。经过十多年艰苦卓绝的奋战,克服了难以想象的困难,三峡工程已取得巨大成就,工程建设呈现出质量优、进度快、造价低、环境美诸多特点;尤其是工程质量,一期比一期提高,三期工程数百万立方米的大坝混凝土中未出现一条裂缝,创造了世界大坝建设的新记录和奇迹,成…     

组合灰色神经网络法在地下水动态预测中应用

为了更好的预测地下水水位,在对现有的地下水动态预测的方法深入分析的基础上,利用某地区地下水位监测数据,采用灰色动态模型与人工神经网络相结合的方法,对该地区地下水水位进行了建模预测分析,并对未来可能的变化进行预测.预测结果与实测结果吻合较好,达到了较高精度,该方法对于地下水的动态预报具有一定的实用价值.     

华北平原典型区不同砂层井灌中水位水量变化差异特征—以滹沱河冲洪积扇藁城段为例

井灌作为地下水超采区治理中应用的一种重要回灌方式,具有占地面积小回灌效率高的优势,但不同砂层中回灌水入渗特征不同。基于华北平原典型区砂层特征,通过研发井灌仿真扇体砂箱模型,开展粗中细3种砂层中不同定水位、定流量条件下的室内井灌实验,综合对比分析井灌过程中水量与水位的时空变化数据。结果表明：定水位稳定井灌条件下,沿水流方向粗中细砂介质中的水位均呈降低趋势,粗砂中降幅最小,细砂中最大;粗中细砂介质中的水位降低过程均可分为快速和慢速两段,分界点距井壁越来越近。定流量井灌条件下,随井内水位增长,粗中砂介质中回灌流量呈二次方增长,细砂介质中呈线性增长,粗砂中回灌流量大小对水位变化的响应最明显。井灌过程包含井周边储水、向远处扩散然后趋于稳定的过程,粗中砂介质中储水和扩散过程较快,达到稳定回灌用时约600 s;细砂介质中储水和扩散过程较慢,达到稳定回灌用时约9 500 s。研究对开展地下水人工回灌工程选址、回灌砂层优选及回灌井布局优化具有一定的指导意义。     

三峡文化的影视传播及审美价值

三峡文化历史悠久,内涵丰富,为影视艺术提供了资源和动力.影视艺术既是三峡文化的载体,又是三峡文化的重要组成部分.自然三峡的影视传播形成复制式、背景式和意象式三种形态,人文三峡的影视传播探讨人的性格特征、人的情感状态和民俗风情.三峡工程的影视传播主要包括三峡工程的建设和三峡移民两个层面.三峡文化和影视传播同质同构、兼容互渗.     

分形块体理论及其在三峡高边坡工程中的应用

把分形几何与块体理论相结合提出了分形块体理论，建立了分形块体赤平解析法，并将其应用于三峡永久船闸高边坡稳定性分析中，初步结果表明；分形体理论符合工程实际，是分析裂隙岩体工程稳定性行之有效且可靠的方法，。相信在三峡高边坡岩体稳定分析中将具有很好的应用前景。     

论摄影对三峡旅游的助推作用

当代中国摄影事业蓬勃发展,旅游产业方兴未艾。文章以长江三峡地区资深摄影家长期跟踪拍摄著名旅游景观＂巫山云雨＂推动三峡旅游发展为例,提出摄影与旅游是一对＂姻亲＂关系,摄影通过记录再现、阅读传播等途径助推旅游,而旅游产业也为摄影的多元化发展提供了广阔的实践空间,二者的亲密互助,前途光明。     

Physiological response of natural plants to the change of groundwater level in the lower reaches of Tarim River, Xinjiang

Based on the analysis of the three-year (2000-2002) monitoring data of the four times intermittent stream water conveyance to the lower reaches of Tarim River where the stream flow was dried up for more than 30 years and the measurement of PRO, SOD and POD in plants collected from 24 vegetation plots, it is concluded that the stream water conveyance plays an important role in lifting groundwater level. The groundwater nearby the watercourse was raised from 5～8 m in depth before the stream water conveyance to 2.5～5 m after stream water conveyance. The physiological response of Phragmites communis, Tamarix spp. And Populus euphratica to the change of groundwater is sensitive and represents a grads change obviously. The growth of the plants in the lower reaches of Tarim River is stressed by drought to various degrees. Lengthways, the drought stress exposed to the plants increases with groundwater depth from the upper sections to the lower sections; and breadthwise, the drought stress exposed to the plants is increased with the increase of distance away from the river channel of stream intermittent water releases and of the groundwater depth. Combining the field investigation and the analysis of the plots, it is considered that the stress groundwater depths for the Phragmites communis, Tamarix spp. And Populus euphratica are 3.5 m, 5 m and 4.5 m respectively.     

Magnetism parameters characteristics of drilling deposits in Jianghan Plain and indication for forming of the Yangtze River Three Gorges

The forming time of the Yangtze River Three Gorges is considered as one of keys in the research on the Yangtze River, also is one of the most disputed hotspots. In order to solve the difficult problem, the authors adopt the internationally recognized thoughts and methods of substance tracing from source to sink. The lithologic characteristics, magnetic parameters and magnetic mineral characteristics of deposits in 2 bores are analyzed, which are both sampled from the sedimentary center of the Jianghan Plain. The results are as follows： At about 110 m depth of the core, the contents of coarse materials and stable magnetic mineral both increase significantly. Meanwhile, the magnetic susceptibility of sediment, saturation isothermal remanent magnetization and magnetic susceptibility values of anhysteretic remanent magnetism increase suddenly, which all reflect that at about 110 m depth, the important adjustment has appeared in water system of the Jianghan Plain, and the sedimentary environment and material composition have changed greatly. And it may be the horizon where the Yangtze River Three Gorges formed, its forming time reflected by the paleomagnetic dating is between 1.17 and 1.12Ma B.P.     

长江三峡阶地的年代对比法及其意义

长江三峡的成因是一悬而未决的难题,而阶地的划分对比又是解决三峡贯通问题的切入点.作者在详细研究的基础上提出在阶地对比中的年代对比法.利用对比结果,结合在三峡出口处记录水系演化历史的宜昌地区第四纪早期沉积特征、物源分析及ESR测年等方面的研究结果,认为贯通三峡的长江在宜昌地区出现的时间晚于湖相沉积结束的时间(0.75±0.08) Ma,而长江三峡段的阶地最多可以划分为5级,其中最老一级阶地的年龄为0.7～0.73 Ma.由此证实了长江三峡是形成于中更新世早期的相对年轻的河谷.