澜沧江梯级水库对汞输运的影响

拦河筑坝对河流中汞的输运产生重要影响,但有关高海拔落差河流中汞的来源及输运特征的认识较为匮乏.以澜沧江为研究对象,监测了筑坝河段水体中汞浓度的年时空变化过程（2017—2018）,量化了梯级水库对汞沿程输运的影响.结果表明,澜沧江水体中汞浓度总体与径流的季节分配呈同步变化趋势,但在上下游因土地利用类型的差异而呈现相反的季节性变化特征.因水库的拦截,溶解态汞与总汞的比值沿程呈上升趋势,加之水库泄水量的沿程增加,共同导致了河流汞通量自上游至下游呈非连续累积的趋势,从144 kg·a^-1增加至788 kg·a^-1.相应地,梯级水库对汞的拦截率自上游至下游由88%逐渐降低至65%.该项研究丰富了对梯级水库中汞的补给和输运的认识.     

Effects of artificially induced complete mixing on dissolved organic matter in a stratified source water reservoir

Naturally complete mixing promotes the spontaneous redistribution of dissolved oxygen(DO), representing an ideal state for maintaining good water quality, and conducive to the biomineralization of organic matter. Water lifting aerators(WLAs) can extend the periods of complete mixing and increase the initial mixing temperature. To evaluate the influence of artificial-induced continuously mixing on dissolved organic matter(DOM) removal performance, the variations of DOM concentrations, optical cha...     

Evidence on the causes of the rising levels of CODMn along the middle route of the South-to-North Diversion Project in China: The role of algal dissolved organic matter

As the biggest inter-basin water transfer scheme in the world,the South-to-North Water Diversion Project（SNWD） was designed to alleviate the water crisis in North China.The main channel of the middle route of the SNWD is of great concern in terms of the drinking water quality.In this study,we tested the hypothesis that the dissolved organic matter（DOM） derived from the planktonic algae causes the rising levels of COD_Mn along the middle route by monitoring data on water quality（2015-20...     

滇中高原水库外源污染负荷贡献解析与环境容量核算

为探究高原型水库上游流域的污染负荷来源及其贡献率,并计算水库的水环境容量,以云南高原柴石滩水库为研究对象,应用排污系数法估算了水库上游流域污染来源,运用水文和水质同步监测资料计算入库污染负荷,采用富营养化模型核算了不同水质目标情景下水库TN和TP的最大容量.结果表明：(1)柴石滩水库及其以上流域主要特征污染物为TN和TP;(2)水库上游流域的COD和TP主要来源于农村面源污染,贡献率分别为49.40%和50.11%; NH⁺₄-N和TN主要来源于城镇生活污染,贡献率分别为45.76%和33.77%;农村面源污染贡献中,陆良县COD和TP贡献率最大,分别为34.82%和36.82%;城镇生活污染贡献中,麒麟区COD、 NH⁺₄-N、 TN和TP贡献率最大,均高达65%.(3)COD、 NH⁺₄-N、 TN和TP污染负荷入河量分别为28 050.90、2 465.16、4 680.54和870.93 t·a^-1,TN和TP污染负荷入库量分...     

Upstream Sediment‐Control Dams: Five Decades of Experience in the Rapidly Eroding Dahan River Basin,Taiwan

Sedimentation is emerging as a key issue in sustainable reservoir management. One approach to controlling reservoir sedimentation is to trap sediment in hydraulic structures upstream of the reservoir. In the 1,163‐km² catchment of the Dahan River (Taiwan) over 120 “sabo” dams were built to reduce sediment yield to Shihmen Reservoir. Built in 1963 for water supply, Shihmen has lost over 40% of its 290‐Mm³ storage capacity to sedimentation. Most of these upstream structures were small, but three had capacities >9 Mm³. Field measurements and historical data from the Water Resources Agency show most smaller dams had filled with sediment by 1976. The three largest were full or nearly so by 2007, when one (Barlin Dam) failed, releasing a pulse of 7.5 Mm³, most of its 10.4 Mm³ stored sediment downstream. The Central Range of Taiwan is rapidly eroding (denudation rates 3‐6 mm/yr), so geologically high loads make sediment problems manifest sooner. Even in other environments, however, eventually small dams built upstream of large reservoirs are likely to fill themselves, creating multiple small sediment‐filled reservoirs, some located in sites inaccessible to mechanical removal. Our analysis suggests sabo dams do not offer a long‐term basis for controlling reservoir sedimentation in such a high‐sediment yield environment. Sustainable solutions must somehow pass sediment downstream, as would be accomplished by a sediment bypass around Shihmen Reservoir, as now being studied.     

三峡库区腹地规模农地空间分布规律

山区农业转型对于我国山区耕地可持续利用效率、土地整治方向以及生态建设方向具有一定的指导意义,渝东北生态涵养发展区是重庆市农用地整治项目的主要分区,通过定义作为农业转型产物的"规模农地"相关概念及其判读标准,旨在提出一种新的研究路径对重庆市典型山区地貌的耕地利用现状给予指导和改善意见。首先选取三峡库区腹地5个区县为研究区,并结合研究区实际对"规模农地"进行等级划分,利用Arc GIS10.2等软件通过景观格局指数、核密度测算、空间自相关等方法从斑块特征、数量分布、空间格局三方面对研究区内规模农地的空间分布规律进行探讨。研究表明:(1)不同类型规模农地斑块特征呈现一定的规律性,小规模农地斑块密度最大为6.004,大规模农地平均最近指数MNN值最低为643.401,且农地规模越大,面积加权平均斑块分维数AWMPFD值和聚集度AI值越高;(2)中、大规模农地数量多集中在奉节县,微、小规模则多集中在巫山县,且规模农地自身及其相互之间存在固定的邻接性规律,即同类斑块之间的邻接性与其斑块大小成反比,不同类型斑块之间则与之相反;(3)研究区规模农地整体空间分布主要集中在奉节县中部以及巫溪县东部,沿江流域的平坝地区分布相对密集,且不同类型规模农地在空间上存在明显的自相关性。     

三峡工程建设前后库区城镇发展与环境变化

利用卫星遥感监测，分析三峡工程建设前后库区城镇发展类型、时空过程，揭示库区城镇变化的驱动力，探索了城镇扩展与人口城镇化关系，研究城镇环境变化特征。三峡库区城镇规模发展不均衡，库尾城市规模庞大，库中、东部区县级城市规模较小，而乡镇的比例占城镇面积24%；在过去15 a中，建城区规模扩大172%，高于全国省会城市发展水平72%；三峡库区城镇规模扩大的同时，东西城镇规模差距逐步缩小，三峡工程建设起着重要的推动作用；城镇发展以侵占了优质耕地资源为代价，耕地占城镇变化83%；城镇用地变化与人口城市化发展不平衡，城镇空间发展快于人口城镇化过程，城镇对农村人口的吸引力不及全国省会城市平均水平，在2007年城市化率低于全国水平13%，差距进一步扩大；城市空间结构发展模式受地形和土地资源的限制，城市分维数和坡度分别增加12%和104°，城市向潜山区扩展或搬迁的同时，城市空间的完整性下降     

猛进水库水环境问题研究

猛进水库是五家渠地区的主要水源地,也是乌鲁木齐市重要的淡水鱼供应基地.近年来,猛进水库水质呈不断恶化的趋势,水质为劣V类,为此,猛进水库水质恶化问题已经成为各级政府及公众十分关注的问题.本文选用新疆水环境监测中心多年对猛进水库水质监测及调查的资料,对猛进水库水质现状进行分析评价,运用季节性肯达尔(Kendall)检验等方法,分析了猛进水库水质变化趋势及影响猛进水库水质的主要污染源,提出了进一步保护猛进水库水质的建议,为改善其水环境质量提供依据.     

Spectroscopic Distribution of Dissolved Organic Matter in a Dam Reservoir Impacted by Turbid Storm Runoff

Spectroscopic characteristics of dissolved organic matter (DOM) in a large dam reservoir were determined using ultraviolet absorbance and fluorescence spectroscopy to investigate spatial distribution of DOM composition after turbid storm runoff. Water samples were collected along a longitudinal axis of the reservoir at three to four depths after a severe storm runoff. Vertical profiles of turbidity data showed that a turbid water layer was located at a middle depth of the entire reservoir. The spectroscopic characteristics of DOM samples in the turbid water layer were similar to those of terrestrial DOM, as demonstrated by the higher specific UV absorbance (SUVA) and the lower fluorescence emission intensity ratio (F ₄₅₀/F ₅₀₀) compared to other surrounding DOM samples in the reservoir. Synchronous fluorescence spectroscopy revealed that higher content of humic-like DOM composition was contained in the turbid water. Fluorescence excitation–emission matrix (EEM) showed that lower content of protein-like aromatic amino acids was present in the turbid water DOM. The highest protein-like fluorescence was typically observed at a bottom layer of each sampling location. The bottom water DOM exhibited extremely high protein-like florescence near the dam site. The particular observation was attributed to the low water temperature and the isolation of the local bottom water due to the upper location of the withdrawal outlet near the dam. Our results suggest that the distribution of DOM composition in a dam reservoir is strongly influenced by the outflow operation, such as selective withdrawal, as well as terrestrial-origin DOM inputs from storm runoff.     

长江干支流输沙量减少趋势及其影响因素浅析

通过对长江干支流各主要水文控制站的多年径流量、输沙量、含沙量、中值粒径等水沙基本特征值的统计分析，表明在过去的近50年时间内，长江干支流的年径流量中心趋势不存在具有显著统计意义的变化，而输沙量、含沙量、中值粒径值均有明显的下降态势。以水库建设和水土保持为主的人类活动是长江干支流泥沙输移量减少趋势的重要影响因素，在20世纪90年代以前长江输沙量的减少主要是水库建设的影响，之后随着“长治”工程的展开则兼具了水库建设和水土保持的影响，未来水土保持工作对长江保水减沙的长期效益将更为显著。