山西省中部引黄取水条件及引沙状况分析

山西省中部引黄工程存在引水必引沙的问题,为充分认识黄河泥沙对山西省中部引黄工程的影响,笔者采用实测资料分析方法,通过对天桥库区入库水沙条件和取水口附近水流流态及含沙量分布情况分析得出,黄河泥沙会给取水工程带来两方面的影响:一是取水口附近河道局部淤积,滩面抬升影响取水;二是取水隧洞及长距离输水干支线隧洞泥沙淤积。建议山西省中部引黄工程设计及工程运行要对引黄泥沙问题给予高度重视,采取必要的防淤措施,以确保引水工程的正常运行。     

河流泥沙吸附磷的研究现状与展望

输送水流泥沙和营养物质是河流的主要功能之一。大坝等水利工程拦截泥沙的同时,改变了河流营养物质的迁移和转化。从国内外近20 a泥沙吸附磷的相关研究文献可以看出:泥沙对磷的吸附与泥沙颗粒的理化性质、水体初始磷浓度、含沙量以及环境因子等相关,即颗粒越细,表面吸附位越多,更有利于磷的吸附;水体初始磷浓度越高,吸附量越多;含沙量越大,总吸附量越大,单位质量泥沙吸附量越少;泥沙吸附磷的机理模型主要有热力学模型和动力学模型两类,Langmuir模型和Freundlich模型在等温吸附中应用较广;二级动力学模型对泥沙吸附磷的全过程拟合程度更高;在河流生态系统中,泥沙吸附的磷以颗粒态磷的形式作为生物可利用磷的储备,间接影响水生生物的生长。颗粒态磷与水生生物的生长关系、吸附量与含沙量等多因子的动力学模型在今后有待进一步研究。     

海南海花岛内海围堤工程及其影响数值模拟研究

采用潮流泥沙数学模型的方法,对海花岛围堤工程实施后周围海域动力变化、地形变化及其影响进行了研究。结果显示:流速、流向、潮位过程及含沙量过程与实测数据符合良好,模型能够较好地复演了工程建设后海域流场、含沙量场变化;围堤工程实施后,海花岛内海水域呈弱流形势,各个方案流速分布差异不大;围堤工程对附近海域流速影响仅局限于海花岛周围局部区域,对洋浦深槽和洋浦港水域基本没有影响;内海水域呈现为弱淤积状态,正常天气下,内海水域年淤积厚度在0.05 m~0.15 m。     

某水电站库区流态数值计算及沉沙分析

含沙量较高的河流会存在因发电引流导致库内整体流速过高和泥沙沉淀时间被缩短的情况,水流将裹挟大量泥沙进入引水发电系统,对水轮机组产生不利影响。采用流体计算软件Fluent对某水电站库区流态进行了三维数值计算,分析流态对沉沙效果的影响。结果表明:在水库最高运行水位和正常发电引用流量工况下,进水口处流速较大但流速梯度延伸范围较小,对库内流态影响很小,水库上游及水库中心整体流速较低,满足沉沙条件。     

絮凝对三峡水库泥沙沉降的影响

现场与室内实测的泥沙级配差异证实了三峡水库中存在泥沙絮凝现象,絮凝会加速水库泥沙淤积速率。为了确定絮凝对泥沙沉降速率的影响,现场采集了三峡水库原样泥沙,基于三峡水库水体环境,采用室内静水沉降试验对三峡水库中泥沙絮凝沉降规律进行了研究。研究结果表明,当试验采用的初始含沙量大于0.3 kg/m3时,部分单颗粒泥沙会聚集形成絮团,且泥沙絮凝程度以及沉速增加的幅度与水体中含沙量呈正比。参与絮团形成的单颗粒泥沙粒径均位于0.022 mm以下,小于临界粒径的泥沙占全沙的83%;采用絮凝因数和物质沉降通量因数分别表征絮凝对泥沙沉降的影响程度,这两种因数都随含沙量增加而增加,含沙量在1.5 kg/m3以下时其最大值分别为5.03和1.66,表明絮凝对三峡库区汛期的泥沙淤积有可能造成较大影响。     

五指山市毛阳桥工程对毛阳河河道行洪影响的数值模拟

为对比分析不同方案下毛阳桥工程建设对河道行洪影响,构建工程所在河段局部二维水动力模型,采用基于三角形网格的有限体积法求解该模型,模拟毛阳桥工程所在河段的水位和流速流向变化情形。结果表明:原设计方案对水位雍高和流速流态均有较大影响,水位最大雍高值0.593 m,流速最大增加值1.909 m/s;改进方案明显减少了对水位和流速流态的不利影响,水位最大雍高值0.088 m,流速最大增加值0.635 m/s,两者的变化幅度均较小,影响范围局限于工程附近,基本不会对河道行洪安全构成威胁。     

小砾山引水枢纽钱塘江河段含沙量分布的数值模拟分析

根据萧山引水工程附近钱塘江河段的泥沙资料,采用水流泥沙数学模型,模拟引水工程河段近域的流场和泥沙场,进而分析引水口附近水域含沙量的分布特征,得出引水工程所在钱塘江河段典型断面潮位、流速及含沙量的关系,为解决从钱塘江引水后萧山区内河河道泥沙淤积问题提供了技术参考。     

莆田港东吴港区1~#、2~#码头潮流数学模型和泥沙冲淤分析

该文通过潮流数学模型,分析工程实施后湄州湾内纳潮量变化情况,工程区附近流速、流向、流态的变化情况及对泥沙冲淤和船舶靠泊的影响,为工程方案的实施提供科学依据。     

电厂取水口淤积试验研究

在现场实测资料及模型试验成果基础上,研究电厂取水工程附近水域水力条件及其流态,结合仪器数值分析及河床演变理论,分析来水条件对泥沙沉降和淤积的影响,计算取水口附近泥沙淤积量。试验结果表明,河床淤积形态存在区域的差异性,取水口淤积受泥沙浓度、来水流量及来水流速影响较大。     

基于MIKE21的取水泵房二维水动力学模拟研究

为优化巢湖市长江供水工程取水泵房型式及评价建成后对长江行洪的影响,基于 MIKE 21 软件建立了东梁山至石跋河河口江段二维水动力学模型,选用非结构化三角网格进行水流数值模拟。经分析,圆形取水泵房周边水流过渡较长方形取水泵房更平稳;泵房建成后对长江行洪影响甚微,泵房周边水位、流速、流态均会产生一定变化,但总体变化值较小,仅限于泵房附近小范围江域。     

Sediment Flushing of Reservoirs under Environmental Considerations

Freshwater reservoirs are under threat because of huge amounts of sediments deposited annually. Sediment flushing seems to be effective to preserve reservoir storage, but it may have negative environmental impacts on downstream ecosystems such as fish mortality. Therefore, providing a suitable flushing strategy that could be compatible with the river ecosystem downstream is of great importance. Two numerical models were developed in this paper to predict the suspended sediment concentration (SSC) on the reservoir-river system and effects of different flushing scenarios on aquatic life. Developed models were applied to the Dez Resevoir system in the southwest of Iran which has suffered from the sediment problems in two last decades. The suitable values for flushing time, concentration limits, and flushing discharge have been recommended in this research by use of the existing information and previous flushing records, as well as field measurement and modeling. Based on social, environmental and technical limitations, March is the appropriate time for flushing. After hydraulic simulation of different flushing scenarios and sediment routing along the river, flushing with 1275 and 800 cubic meter per second with 30 and 20 g per lit concentration in dry and wet season respectively are feasible and have minimum environmental impacts.     

A simplified water temperature model for the Colorado River below Glen Canyon Dam

Glen Canyon Dam, located on the Colorado River in northern Arizona, has affected the physical, biological and cultural resources of the river downstream in Grand Canyon. One of the impacts to the downstream physical environment that has important implications for the aquatic ecosystem is the transformation of the thermal regime from highly variable seasonally to relatively constant year‐round, owing to hypolimnetic releases from the upstream reservoir, Lake Powell. Because of the perceived impacts on the downstream aquatic ecosystem and native fish communities, the Glen Canyon Dam Adaptive Management Program has considered modifications to flow releases and release temperatures designed to increase downstream temperatures. Here, we present a new model of monthly average water temperatures below Glen Canyon Dam designed for first‐order, relatively simple evaluation of various alternative dam operations. The model is based on a simplified heat‐exchange equation, and model parameters are estimated empirically. The model predicts monthly average temperatures at locations up to 421 km downstream from the dam with average absolute errors less than 0.5°C for the dataset considered. The modelling approach used here may also prove useful for other systems, particularly below large dams where release temperatures are substantially out of equilibrium with meteorological conditions. We also present some examples of how the model can be used to evaluate scenarios for the operation of Glen Canyon Dam. Published in 2008 by John Wiley & Sons, Ltd.     

河流上下游控制断面非点源污染特征的分析

为了深入研究河流上下游断面非点源污染的特征及其变化,以及同一断面不同年份的非点源污染特征,以渭河的支流沣河上游大峪口断面和中游秦渡镇断面为研究对象,根据两控制断面2009-2011三年的非点源污染水质水量同步实测资料,运用平均浓度法估算非点源污染负荷,并结合河流断面控制流域的土地情况、人类活动等情况,分析了河流上下游控制断面的非点源污染特征。结果表明:非点源污染是沣河的主要污染源,河流上游区域非点源污染负荷所占比重大于下游区域;河流上下游断面非点源浓度基本相当,下游点源浓度大于上游;下游COD、TP和NO2—N的非点源负荷量是上游的10~20倍;人类活动所产生的点源排放对中下游河流水质影响更大。     

基于个体模型模拟的鱼类对上游水库运行的生态响应分析

建立了一维全河流和二维局部河段的水环境模型,并与基于个体的鱼类模型耦合,从鱼类种群动态角度研究水库运行对下游河流水生态系统的作用。文中选取了漓江下游的一段复式河道,以优势种草鱼和鲫鱼为研究对象,模拟了自然条件和水库调节作用下河道的水环境条件,以及相应的鱼类生长和分布的变化。通过模拟结果的对比分析,发现如果仅考虑水库运行造成的下游水流变化的作用,枯水期水库向河道补水对草鱼有一定的正面影响,对鲫鱼有轻微的负面影响;而在4—5月,水库运行对两种鱼类都存在比较明显的负面影响。本文建立的模型方法可为河流优化管理及水库生态友好运行提供支持。     

The effect of Keepit Dam on the temperature regime of the Namoi River,Australia

Modifications to water temperature caused by the release of hypolimnetic water from thermally stratified reservoirs pose a major threat to the aquatic biota of lowland rivers in Australia's Murray–Darling basin. Keepit Dam is earmarked as one of several deep‐release structures in the basin causing ecologically significant temperature modification over a large length of river. This study utilized discrete and continuously monitored historical water temperature data from stream gauging stations, together with reservoir thermal profile data, to assess the impacts of Keepit Dam on the thermal regime of the Namoi River. Modifications to selected components of the river's annual temperature cycle were quantified in relation to a pre‐dam temperature regime estimated from statistical models incorporating catchment, hydrological and sample attributes. Keepit Dam has modified the thermal regime of the Namoi River. The effect was greatest immediately downstream from the dam where the annual maximum daily temperature was approximately 5.0 °C lower and occurred three weeks later than the pre‐dam condition. This change was sufficient to disrupt thermal spawning cues for selected Australian native fish species. The magnitude of disturbance progressively diminished with distance from the dam. Key aspects of the river's annual temperature cycle were largely restored to the pre‐dam condition within 100 river km downstream from the dam, which is closer than previous estimates. However, there was marked inter‐annual variation in the magnitude of thermal modification and ecological impact as a result of year to year changes in tributary flow and reservoir behaviour. Copyright © 2002 John Wiley & Sons, Ltd.     

粤北大宝山矿废水中锌的环境地球化学

粤北大宝山铁多金属矿床的开发给周围环境带来了严重的危害。采选产生的酸性废水携带浸滤出的重金属离子流入横石河,严重影响矿区及其下游的生态环境。从尾砂、水体、河流底泥、土壤以及食用蔬菜探讨整个环境系统对锌的环境响应。结果表明,河流水中高锌含量直接源于尾砂,并受水体pH值的显著影响;河流底泥能够大量聚集水体中的锌,在pH值高时,相对稳定存在,当水体pH值降低时,锌会被再次从河流底泥中释放出来,形成河流二次污染;土壤中锌含量和土壤pH值有良好正相关关系;食用蔬菜中锌的高含量受土壤的锌总量决定,并受土壤pH值的影响,通过改善农业用灌溉水质,可以降低蔬菜重金属含量。     

基于卫星遥感技术的赣江尾闾河势演变分析

赣江尾闾地区是包括南昌市在内的江西省经济发展的核心区域,赣江作为江西省内第一大河,其尾闾地区河势变化对其周边地区的经济、防洪、环境等有着巨大的影响。运用卫星遥感技术,对1991—2010年赣江尾闾地区赣江的河道进行了河势演变的研究分析,得出了以下结论:(1)研究区域水域面积1991年约为121 km~2、2001年约为111 km~2、2010年约为132 km~2,经历了先减小后增加的变化过程。(2)历年来尾闾地区的变化主要集中在赣江主干、西支、北支,主干变化最为显著,而南支相对最为稳定。(3)主干的变化主要表现为河道扩张、江心洲面积大幅减小或者消失,其中在南昌市附近河道变化最为明显。推测这些变化主要是由人为影响包括有关工程建设、河砂开采等引起。(4)西支变化较为复杂,其上游段主要表现为河道展宽、水域面积变大,而下游段河道有所束窄;北支历年来均表现为河道束窄、江心洲面积明显增大;中支有所变化,但并不明显。     

自动蒸发水面高度测量检查和评定方法探讨

为探明赣江流域水库沉积物的重金属污染水平,分析测定了流域内7座中型水库沉积物中Cu、Cr、Zn、Pb、Cd、As、Hg等重金属含量,并采用地积累指数法、潜在生态风险指数法进行综合评价,同时,收集整理了库水和下游河道沉积物的污染情况进行对比分析。结果表明：流域典型水库沉积物中Cd、Cu为主要污染元素,但水库水体未受污染。地积累指数法评价结果显示,赣江流域水库沉积物Cd、Cu均属轻度污染程度,与流域内表层土壤的污染程度有关。潜在生态风险指数法结果显示,赣江流域水库沉积物重金属潜在生态风险总体处于中等风险。值得注意的是Pb元素的潜在生态风险属较强风险,其中极强风险、较强风险、中等风险的样点分别占14.28%、28.57%、28.57%。     

长江马鞍山段内河水质二维预测计算模型

长江马鞍山段是马鞍山市最重要的水源,而又汇集全市工业废水和生活污水排放,因此建立适合此江段水域的水质评价和预测模型,预报排污对水质的影响就比较重要。本文通过建立适合长江马鞍山段内河水域的二维模拟预测模型,预报排污对水质的影响范围和程度,考察各排口污染物NH_3-N、TP、F~-在本江段的浓度分布。结果表明:姑溪河的影响较明显,但各污染物混合带宽度不超过100m,污染带对下游影响仅有2 000 m范围,水质基本上能达到Ⅱ类水质要求;通过编制二维模拟预测模型计算软件,可应用于污染控制措施、突发污染事件的预测防范以及沿江产业结构、布局调整等。     

Water Quality Assessment of the Santiago River and Attenuation Capacity of Pollutants Downstream Guadalajara City,Mexico

The Santiago River in Mexico has been seriously polluted because of rapid urbanization and industrialization activities, lacking of appropriate planning and contamination monitoring policies. This research characterized the river water quality and recognizes some overall pollution sources, using two different information references: a dataset of 5 years from the Jalisco State Water Commission and a 14‐year dataset from the National Water Commission. Two zones have been identified as the main sources of pollution (hotspots), where the major events of urban and industrial wastewater discharges occur: (i) the urban fringe of Guadalajara city, with special emphasis in its southern area (nearby the so‐called El Ahogado stream) and (ii) downstream of Guadalajara City. Nevertheless, we have recognized some areas along the Santiago River where significant reduction of pollutants concentration takes place, possibly due to dilution by the inflow of tributaries and to the rainfall increasing. In addition, it is likely that hydropower dams are positively influencing the retention of pollutants along the river. In the lower zone, the water concentrations of O₂ are consistently above acceptable levels (up to 5 mg L^?1), and the majority of the pollution indicators parameters are below the maximum permissible values, despite the high pollution in Guadalajara area. This paper attempts to offer a methodological approach for a more accurate assessment of the river water quality and may assist in interpreting the sampling results derived from the regular monitoring, conducted by the state water authorities, while emphasizing the natural attenuation capacity of the Santiago River. Copyright © 2015 John Wiley & Sons, Ltd.