镇江内江沉水植物恢复的环境效应

建立了镇江内江水流、水质、悬沙及叶绿素a多因子耦合数学模型,对内江沉水植物恢复后产生的环境效应进行了定量评估了模型参数根据前期研究成果确定.研究结果表明:内江沉水植物恢复后,夏秋季节与冬春季节水体平均含沙量分别比天然条件下降低了约11.1%、11.5%;由于沉水植物对水体的净化作用,在夏秋季,内江TN,TP平均浓度分别降低为0.659mg/L、0.137mg/L,较恢复前分别降低了32.2%、30.8%;在冬春季,恢复后的内江TN、TP浓度较恢复前分别降低了29.5%、27.3%;沉水植物的克藻作用亦使内江叶绿素a的平均浓度降低了37.2%,可能暴发水华的面积减少了49.3%;同时,夏秋季及冬春季平均水体透明度分别提高了7.9%和14.0%.     

Interactions between vegetation,water flow and sediment transport: A review

The vegetation, as one of the most important components, plays a key role in the aquatic environment. This paper reviews recent progress on the complex interaction between the vegetation and the water flow. Meanwhile, the relationships between the vegetation and the sediment transport are discussed. The vegetation characteristics, such as the shape, the flexibility and the height, have significant effects on the flow structures. The density and the arrangement of the vegetation influence the flow velocity in varying degrees and the flow resistance increases with the increase of the plant density. In turns, the growth of aquatic plants is influenced by the water flow via the direct effect(stretching, breakage, uprooting, etc.) and the indirect effect(changes in gas exchange, bed material distribution, sediment resuspension etc.). Numerical models were developed and widely used for the flow through vegetated waterways, and the results could be applied to solve engineering problems in practice. The sediment is essential for the survival of most vegetation. The existence of the vegetation helps to resist the deformation and the erosion of the bed sediment, to maintain the bed stability and to improve the water quality by removing suspended particles. Additionally, the effects of the sediment transport on the growth of the vegetation mainly consist of the reduction of their photosynthetic capacity by decreasing the water transparency and hindering the exchange of gas and nutrients between plants and water by attaching particles to plant leaves. Therefore, the interaction between the vegetation and the sediment transport is great and complicated. In order to establish a healthy aquatic ecosystem, it is important to study the relationships between the vegetation, the water flow and the sediment transport.     

大通河天王沟水电站泥沙设计重点问题探讨

天王沟水库坝前水深和库容都较小,且入库沙量相对较多,库沙比仅为0.8,所以水库很快淤积平衡,库区泥沙问题较为严重。天王沟水电站工程泥沙问题主要是研究水库回水与上游铁城电站尾水合理衔接以及保持进水口前＂门前清＂,通过对入库水沙分析提出的水库泥沙调度运行方式及防排沙措施,基本解决了电站的主要工程泥沙问题。     

关于浅水湖泊沉水植物覆盖度设计依据的探讨

沉水植物是维持浅水湖泊清水态的关键因子,其覆盖度是水生态修复工程中植物措施的重要参数。从沉水植物作用机理出发,通过收集天然浅水湖泊沉水植物变迁情况,分析国内外相关学者和工程的研究成果,得出在浅水湖泊沉水植物覆盖度设计时可在50%~70%范围内取值;对于污染负荷小的湖泊,可以取相对较低的值;对于水塘,其取值可按约30%考虑;当营养盐浓度超过阈值时,覆盖度应处于较高的水平。根据工程经验,在污染源恒定的情况下,覆盖度越高,对水质可起到越好的维持效果。同时,针对影响沉水植物覆盖度的有关因素,例如底泥污染、水体透明度以及季节变化等作了思考并给出了相关建议。研究结果为今后浅水湖泊沉水植物恢复的相关工作提供一定的经验和借鉴。     

浅水湖泊底栖动物栖息地模拟

为研究白洋淀水生生物栖息地适宜度,分别于2016年春、夏、秋3季进行了实地考察和采样,结合野外观测和实验室测量得到环境和生物信息。基于14个采样点的数据,通过构建广义可加模型(GAMs)模拟和预测底栖动物的分布。使用Margalef指数作为响应变量,采用向前逐步回归筛选解释环境因子,通过评价剩余偏差来判断模型的表现。水深、水温、底泥氨氮、底泥有机质和沉水植物生物量被用于建立最终优化的广义可加模型。Margalef指数对环境因子的响应曲线表明该指数与水深和底泥氨氮浓度成线性负相关,与水温和底泥有机质浓度成线性正相关,而与沉水植物生物量是单峰关系。结果表明,预测值与实测值呈现显著的强相关性(Pearson R~2=0.847,P0.001),均方误差较小(MSE=0.013),模型性能表现良好。     

天门市中小河流水生态环境评价与保护

为了掌握湖北省天门市水环境质量状况,制定水生态环境恢复和保护规划,选择该市主要河湖典型断面进行了水质监测分析。分析结果表明,天门市城区河流、湖泊、沟渠的水质均为劣Ⅴ类,水生态系统遭受破坏,水体的污染已经成为制约当地社会经济发展的制约因素。根据对该市水环境状况的分析,制定了水污染控制规划、城市生态水网规划、城市水体生态修复与滨水景观规划、河道综合整治规划以及水生态管理保障体系建设规划。     

Reach‐scale interactions between aquatic plants and physical habitat: River Frome,Dorset

Substrate and flow velocity are two key physical factors influencing the distribution of aquatic plants. These two controls are closely related and reflect interactions between flow regime, quantity and calibre of sediment supplied to and bounding river channels, and channel dimensions. Seasonal growth of aquatic plants has important impacts upon flow resistance, flow velocities and sediment dynamics. This paper focuses upon the reach scale and the aggregate impact of the seasonal growth of aquatic plants on the meso‐habitat characteristics of chalk rivers. It provides a contribution to the broader literature by illustrating how submerged and emergent macrophytes interact with one another at the reach scale to control flow patterns and the retention of fine sediment. The research was conducted within the River Frome, Dorset, UK. Four sets of observations from 2004 of the seasonal growth of aquatic plants, flow velocity behaviour and the storage of fine sediment are presented. Aggregate velocity behaviour over the four observation periods is classified using agglomerative, hierarchical cluster analysis. The spatial arrangement of patches exhibiting different aggregate velocity behaviour are explored and the degree to which velocity behaviour can be attributed to physical characteristics of patches and the growth of aquatic plants is discussed. Conclusions include: (i) patterns of aggregate velocity behaviour within reaches are strongly influenced by macrophyte growth; (ii) average fine sediment deposition is higher around emergents such as Sparganium erectum than submerged plants such as Ranunculus penicillatus subsp. pseudofluitans; (iii) complementary flow patterns evolve across the river channel as aquatic macrophytes grow and it appears that this allows marginal emergents to scavenge fine sediment from faster flow velocity threads that become diverted towards the channel edges. (iv) These processes are important for mesohabitat evolution and maintenance, and they also contribute to patterns of bank erosion and aggradation. Copyright © 2006 John Wiley & Sons, Ltd.     

基于EFDC模型的尾水回用于城市景观水体优化计算

以昆山市内蓬朗污水处理厂深度处理后的尾水回用于城市景观水体夏驾河为例,以环境流体动力学模型(environmental fluid dynamic code,EFDC)构建的夏驾河三维非稳态水量模型为基础,考虑经济、社会、环境等多方面的效益,构建目标函数,研究6种设计情景下尾水回用的综合效益,确定污水处理厂尾水回用的最佳运行方案。结果表明,从经济、社会、环境效益最大化的角度出发,昆山市夏架河尾水回用最优方案为:出水口选为距太仓塘4.5 km处,排水方向为吴淞江,回用流量为3.4万m3/d。尾水回用于景观水体可以有效改善水体交换,蓬朗污水处理厂尾水入河位置及回用量流量直接影响夏驾河换水周期以及夏驾河水质的好坏。     

上海市吴淞口水质在线自动监测技术改进分析

针对吴淞口水质在线自动监测系统位于感潮河道黄浦江河口,河水含沙量高,粒径小,极易导致设备管路泥沙沉积,藻类繁殖,影响系统的正常运行的情况,改进了水质在线自动检测技术。改进后的系统防止了底质淤泥对采样水质的影响,水样预处理采用2级沉降技术,系统管路和过滤设备增加了自动除沙、清洗和除藻功能,水样处理后能保持原来理化性质,具有良好的可比性,保证了自动监测数据准确可靠。     

武汉大东湖水网构建工程对生物多样性影响研究

由于江湖通道隔截,武汉大东湖各湖泊变得相对“孤立”,水质污染严重,生物多样性明显下降,为此,武汉市实施了大东湖水网构建工程,将长江与大东湖各湖泊连通起来。根据大东湖目前的污染现状、工程引水规划以及长江和东湖的水质和水生生物情况,分析了工程实施对湖泊生境、水生生物、鱼类及鸟类的影响。工程的实施,将增强水体的流动性、提高湖泊的水体置换能力、减少死水区、扩大湖泊环境容量,为水生生物多样性的恢复创造适宜的生境。     

Three-dimensional Water Quality and SAV Modeling of a Large Shallow Lake

This study presents the Lake Okeechobee Environment Model (LOEM), a three-dimensional (3D) hydrodynamic, sediment, water quality, and submerged aquatic vegetation (SAV) model of Lake Okeechobee, Florida. The LOEM is developed under the framework of the EFDC model (Hamrick 1992). Lake Okeechobee is the largest subtropical lake in North America (1,730 km²), it is very shallow (mean depth 2.7 m), and it includes a littoral habitat that makes up 20% of its area. The LOEM is calibrated, verified, and validated to 3 years of water quality and SAV data. The water quality results are consistent with observed data from 25 locations in the lake. The model is capable of reproducing key water quality characteristics of the lake without having to resort to extensive, site-specific parameter manipulations. The SAV model is calibrated using measured SAV data in the lake. The SAV model is capable of representing the spatial and temporal variations of SAV variations in the lake well. The LOEM is applied to study water quality and SAV processes in the lake. The model results are consistent with observed data indicating that algal growth in the lake is primarily nitrogen limited in the summer and nitrogen and light co-limited in the winter. Lower water elevation generally leads to larger SAV area. SAV can have positive impact on the lake water quality by reducing algae concentration. The calibrated, verified, and validated LOEM model serves as a useful tool to support lake management.     

Quantifying and characterizing contemporary riparian sedimentation

Fluvial processes of erosion, sediment transport and deposition determine the changing form and sedimentary structure of naturally adjusting riparian zones. Riparian sediment storage has both scientific and management importance in relation to: (i) the quantities of sediment that are involved; (ii) the quality of the sediment; and (iii) the dispersal of biological materials, notably the vegetation propagules that are transported and deposited in association with the sediment. After discussing the significance of riparian sedimentation processes, this paper reviews methods for quantifying contemporary sediment deposition within water bodies and their margins. Methods for investigating contemporary riparian sedimentation are given particular emphasis, and the extent to which different methods provide comparable estimates and have been used to support the analysis of different physical and chemical properties of the sediment are outlined. The importance of the following are stressed: (i) selecting a sampling method that is suited to the sedimentation environment; (ii) incorporating careful cross‐calibration if measurements from different methods are to be combined; and (iii) replicating measurements to give more robust estimates if small traps are employed. It is concluded that artificial turf mats provide a useful design of sediment trap across a range of environmental conditions because: (i) their surface roughness reduces problems of sediment removal by flood waters or rainfall; (ii) their pliability permits installation on irregular surfaces; (iii) they can be securely attached to the ground with metal pins to resist high shear stresses from river flows; (iv) they are robust and light and so easily manipulated in the field and laboratory; (v) it is possible to fully recover the deposited sediment to accurately determine the amount of sediment deposited and to support a range of other analyses. Results are presented to illustrate how artificial turf mats can be used to estimate the quantity and quality of deposited sediment and to explore the associated deposition of viable seeds. This provides one example of the important hydroecological role of riparian sedimentation processes and of the potential for the development of innovative, interdisciplinary research on riparian sediment dynamics. Copyright © 2003 John Wiley & Sons, Ltd.     

泥沙污染水质模型研究综述

对现有的泥沙污染水质模型进行分类,总结了国内外泥沙污染基本问题及泥沙污染水质模型研究的成果,指出模型发展方面应加强泥沙与污染物相互作用机理研究,进一步揭示污染物在水体、悬浮泥沙、底泥之间迁移转化的机理,模型的建立应综合考虑污染物的沉降再悬浮、以及吸附解吸、底泥释放等动态过程。     

向家坝水电站泥沙淤积计算

为了研究上游为两个水库共同调度的情况下水库泥沙的淤积特性,选取了金沙江干流向家坝水电站作为研究对象.采用自主开发的一维非恒定流泥沙冲淤计算数学模型对向家坝水电站水库泥沙淤积进行了计算,具体对水库库区泥沙淤积、水库河床纵剖面变化、水库库容损失、水库排沙比、库区坝前泥沙淤积厚度作了计算,进一步分析泥沙淤积形态、泥沙淤积速度、库容损失以及排沙比的变化特点,得出了以下结论:由于上游水库的调度作用,使库区来水来沙较天然大不相同,导致库区泥沙淤积呈现带状淤积为主;前期泥沙淤积速度较慢,以后逐年加快,接近平衡时,淤积速度才又减慢;库容损失逐年增加;排沙比较大,水库运行前期排沙比较大但逐年减小,以后又逐年增大至水库淤积平衡.此外,还简要介绍了向家坝、溪洛渡以及雅砻江上的二滩电站的联合运行的综合拦沙效应.     

碳中和愿景下城市供水面临的挑战、安全保障对策与技术研究进展

随着我国人口逐渐增多、经济迅猛发展、生活水平不断提高、城市化进程逐渐加速,城市面积扩大并发展成城市群,对水资源的需求持续增加.与此同时,工业、农业生产、人类活动等途径进入环境中的各类污染物总量也在增加、成分更加复杂,这些污染物最终进入城市水体.为满足水质要求,城市供水系统能源消耗逐渐增加,产生较多的碳足迹.一些城市群为...     

白洋淀底栖动物群落影响因子研究

基于2016年春、夏、秋3季的调查采样,采用典范对应分析(canonical correspondence analysis,CCA)研究底栖动物群落结构和分布对水环境因子和底泥环境因子的响应,识别影响底栖动物群落分布的关键环境因子。CCA结果显示,水环境因子中透明度、叶绿素a、水深、水温、溶解氧、氨氮、硝氮和氧化还原电位是影响底栖动物分布的主要因子;底泥环境因子中底质中值粒径、沉水植物生物量和氨氮含量是影响底栖群落分布的主要因子。优势物种摇蚊科和颤蚓科对高污染物浓度环境适应性更好。水体中氮、磷对底栖动物影响显著,而底泥中氮、磷的影响较小,可以通过氮磷的吸附转移降低水体污染对底栖动物的胁迫。     

太湖梅梁湾水源地通过生态修复净化水质的试验

通过在太湖实施的试验研究,发现富营养化水体营养盐浓度的增加会导致附着在水生植物上的附着生物增加,对水生植物(主要是沉水植物)的光合作用造成胁迫,从而说明草型湖泊生态系统的恢复,首先必须降低营养盐浓度,因此,通过恢复水生植物来净化水质是不现实的。与营养盐浓度相比,风浪、光照、鱼的牧食等都不是根本的影响因素。根据调查,示范区夏季盛行偏南风,吹程长,风浪较大,导致沉积物悬浮,影响水环境质量,而蓝藻水华易于在此堆积,这些都是影响该水域水质的主要因素。为此,在生态净化方面,以恢复漂浮植物和浮叶植物为主来净化水质,在工程净化措施方面,提出了消浪和控藻等工程措施,以及布设人工介质(渔网)富集附着生物来净化水质等措施。经过3年的实施,示范区的水质改善已经取得初步成效。     

2-D NUMERICAL SIMULATION OF RADIONUCLIDE TRANSPORT IN THE LOWER YANGTZE RIVER

The assessment of the radiological impact of the liquid discharges from nuclear power plants is a major issue for the environmental protection. In this study, a numerical model for the radionuclide transport in the aquatic environment is built, based on the hydrodynamic equations, including the complete set of Saint-Venant equations, the sediment transport equations, with consideration of several different particle sizes and the deposition and erosion of the suspended sediments, and the radionuclide transport equations. The exchanges of radionuclides between water, suspended matter and bed sediments are described in terms of kinetic transfer coefficients. The model is used to simulate the transport of the radionuclides discharged from a planned nuclear power plant project to be sited along the lower Yangtze River. From the model results, one may see the detailed temporal-spatial evolution of the radionuclide contamination in the solution, in the suspended matter and in the bed sediments. The model can be used as a basic tool for studying the environmental impacts of the liquid discharges from nuclear facilities on a river system.     

侧向引水工程导流墙体型对取水口防沙效果影响

多沙河流取水口泥沙淤积问题一直困扰着引水枢纽工程的安全运行。以我国西北地区某火电厂引水工程为例,针对导流墙体型参数对取水口前冲沙效果的影响,进行了水工实体模型试验研究。试验研究过程中采用了潜没式、露顶式以及复合式3种不同型式的导流墙,观测了不同型式导流墙在多种流量下的冲沙效果,在理论分析的基础上,提出了关于取水口防沙方面的导流墙体型选择建议。     

百龙滩水电站库区泥沙淤积现状及预测分析

百龙滩水电站是红水河流域十个梯级水电站的第七级。通过百龙滩水电站不同运行期库区来水来沙的变化,分析百龙滩库区泥沙淤积现状情况,提出了采用典型水沙年来分析库区泥沙淤积的方法,并采用数学模型预测了不同水沙条件下库区泥沙淤积情况。