南水北调中线北京段输水系统数字三维视景仿真

为直观形象的展示南水北调中线北京段输水系统，运用视景仿真技术，建立了包括北京段管涵、水工建筑物和周围景观在内的数字三维虚拟场景，并实现了整个系统的虚拟漫游。     

VRML在河道地形景观制作中的应用

应用基于3DWeb的虚拟现实建模语言和数字高程模型的格网插值算法，论述了从数据采集、数据模型建立以及VRML文件的设计等开发河道三维地形景观实现方法。通过在水利工程信息化管理中应用河道三维景观，达到了直观、形象，便于分析、决策的目的。     

大范围地形及城市三维快速建模与漫游

大范围地形及城市三维建模,不仅包括地表高程网格构建,还包括场景中各种地物如河流、建筑物、湖泊、森林等的建模,所需的数据量比较大,涉及到的数据种类和格式较多。用传统的方法实现整个大范围城市场景的三维浏览功能时,建模的工作量很大,一般无法实现快速建模。介绍了Terra Vista在地形建模方面的强大特性以及OSG开源图形库在三维渲染方面的独特品质,结合一个城市大范围地形三维漫游系统,具体说明了如何准备数据并利用Terra Vista的强大地形建模能力,以及OSG的三渲染功能实现大范围城市三维系统的快速建模及流畅漫游。     

基于BIM和WebGL技术的异步场景漫游方法

随着页面渲染技术的快速发展,云端BIM应用不断涌现,由于浏览器处理能力和计算资源的限制,为处理大体量BIM模型的流畅浏览与操作提出了新的挑战。为了解决对大型BIM模型的顺畅浏览和操作问题,通过WebGL技术,提出了一种BIM模型异步加载模式下进行场景路径漫游的方法,实现了在网页端三维轻量化BIM模型的异步加载,提高了模型帧率;同时,通过样条曲线算法,使用关键点指定漫游路径,提高了创建漫游路径操作的交互性;最后,通过视点的动态剔除、遮挡剔除等算法,保证渲染漫游动画的流畅性。验证表明,该方法可有效提高了大体量BIM模型路径漫游的流畅性与稳定性。     

杭州城市河道现状及其整治策略

河道及其组成的水域生态系统和滨水区域在杭州整个城市生态与景观系统中发挥着重要作用。基于杭州城市河道的基本概况,从驳岸样式及其处理、景观多样性及其精致度、河道的监督与管理等三大方面,详细阐述了杭州城市河道现状及存在的问题,并从采用灵活的驳岸处理方式、营造差异性的城市河流景观以及做好河道监管工作等方面,提出了杭州城市河道整治的若干策略。     

基于河道生态护坡的施工技术研究

生态护坡具有较强的景观、防洪和生态功能,能够促进水域生态系统良性循环、河道及其周边植物覆盖率的增加。文章详细探究了生态护坡的基本概念、设计原则以及生态功能,并提出植生型、自然原型、土工材料固土、三维植被网等护坡技术,其中有效结合土工网与植被护坡技术的三维植被网护坡能够显著提升河道防洪能力,并保证土工网护坡优势的发挥和植被护坡效果的实现。生态护坡工程要全面考虑各类因素,合理选择根系庞大、生命力顽强的植物类型。     

IMAGIS在校园三维可视化中的应用

以数字地图为基础,利用三维地理信息系统软件IMAGIS,通过地图预处理、三维建模、纹理映射及三维漫游,建立了东华理工学院校园三维景观;并就其在三维可视化中的应用进行了展望。     

鄱阳湖水利信息三维展示可视化系统设计与实现

三维可视化技术已在大坝安全监测、水利工程质量检测、水资源配置等领域得到广泛应用。借鉴其它领域的应用成果,利用三维可视化等技术构建了鄱阳湖水利信息三维展示与查询系统,实现了鄱阳湖在不同水位下的三维地形信息展示,再现了鄱阳湖水利信息虚拟场景;此外,还利用Java进行二次开发,构建了鄱阳湖区空间数据库和多媒体数据库,实现了湖区三维场景的直观清晰浏览与展示,以及专题水利热点数据的动态查询和漫游等功能。该系统的建立可方便用户全面了解鄱阳湖区不同水位下淹没区域、自然保护区和风景区的水资源、水生态、水环境和水利工程等水利信息,有助于提高鄱阳湖管理者的科学决策水平。     

海陆空大数据测绘系统的构建与应用

利用多波束测深系统、三维激光扫描系统和无人机航摄系统,结合4S技术和云计算平台构建了海陆空大数据测绘系统,实现了海陆空三位一体化测量和大数据的快速处理、分析和管理。结果表明:海陆空大数据测绘系统在数据采集、处理、分析和管理方面具有传统测绘系统无法比拟的优势,提高了测绘效率,实现了陆地水下地形三维一体化无缝拼接和陆地水下三维一体化漫游,真实地再现了陆地水下的三维虚拟场景,拓宽了应用领域,生成了多样化的地理信息成果;实现了测绘产品的再利用,通过研究分析测区的地形变化情况,可及时掌握陆地水土流失的趋势和河道冲淤变化程度,更好地为测区水土保持、河道管理提供基础性的依据,掌握了系统的数据处理和基于4S技术的河道地形演变分析方法。     

黄河口三维GIS设计与实现

利用ArcScene和ArcGlobe来组织三维场景数据,把ArcGIS Engine作为二次开发平台,在VS.NET 2005集成环境下,采用C#语言进行黄河口三维GIS的设计与开发.黄河口三维GIS具有场景配置、图层管理、三维查询、动态模拟、飞行漫游、书签管理等六大功能,实现了三维地形场景的组织和对黄河三角洲的三维浏览与信息查询,可对海岸线、等深线、断面等多年历史数据进行管理,能完成对海岸线变迁和冲淤演变的动态模拟与演示等.     

Die unbekannte dritte Dimension: Geländehöhen,Gewässertiefen und Dynamik österreichischer Donaulandschaften vor der Regulierung

River landscapes are multidimensional ecosystems characterized by diverse spatio-temporal interrelations. Longitudinal interactions along the river continuum and lateral exchange processes between river and floodplain are common focal points in river restoration projects. Vertical interactions, such as between aquatic habitats and river bottom (hyporheic interstitial) or between groundwater and terrestrial habitats, are often only addressed in planning schemes, if the impairments of ecological functions and human uses are already evident. This partly reflects the dearth of well-founded basic data on the configuration of river landscapes prior to regulation in the vertical dimension. Consequently, only few reference data are available for designing adapted restoration measures.     

Was? Wie? Warum? Jugendliche erforschen Flusslandschaften – Förderung des Systemverständnisses als Basis für gelebte Partizipation im Flussgebietsmanagement

River landscape planning and management to promote the positive long-term development of river landscapes must adhere to the principle of sustainability. In this context, the goal is to initiate a development process for river landscapes that successfully reconciles the requirements of nature and water conservation with social and economic aspects, and which actively involves affected citizens in the decision-making process. A systems-based understanding and the opportunity to make ecologically relevant decisions are essential prerequisites for participative processes.     

POTENTIAL FOR VEGETATION‐BASED RIVER MANAGEMENT IN DRYLAND,SALINE CATCHMENTS

The approaches used to manage rivers have been developed and adapted to many different problems and settings. Because of their relatively low cost, vegetation‐based approaches implemented at the reach, landholder and catchment scales have become the foundation for river management in most landscapes. In many dryland agricultural catchments, secondary (anthropogenic) salinity caused by clearing native vegetation has resulted in rising saline groundwater, streamflow salinity values that exceed seawater and severe the degradation of riparian vegetation communities. The potential effectiveness of vegetation‐based strategies in these landscapes remains largely unknown, yet these strategies are still widely pursued. This study initially investigated the patterns of vegetation recovery and recolonization following a large flood in a saline river that disturbed the system. A conceptual model was developed to describe spatial patterns of where different vegetation types had regrown and recovered in relation to controls exerted by streamflow salinity, surface texture characteristics, topography and reach morphology. Using this model, vegetation‐based river management options for different reaches were developed, and their potential effectiveness in stabilizing reaches was investigated using a 1‐D hydraulic modelling approach. This study finds that in a dryland catchment with high stream salinity (20 000–93 000 mg L^?1), there is still a strong potential for successful vegetation‐based management, but only in selected reaches. Results showed that changes in stream power and channel velocity were not associated with the areas of most severe vegetation degradation. Rather, there is a complex interplay between channel morphology, channel slope and places of potential vegetation growth within a reach. This paper outlines an approach to evaluate the potential success of vegetation‐based river management in saline landscapes. It identifies the need to prioritize investment based on the following: an understanding of factors controlling revegetation potential, the likely impact of revegetation in mitigating adverse channel changes and the proximity of reaches to high‐value infrastructure and biodiversity assets. Copyright © 2011 John Wiley & Sons, Ltd.     

Influence of surrounding land cover on marsh-breeding birds: Implications for wetland restoration and conservation planning

Marsh-breeding birds are valuable components of healthy ecosystems and are useful indicators of successful wetland restorations. The occurrence of these species, however, is influenced by the surrounding landscape. To aid decision-makers, we used data from the Great Lakes Marsh Monitoring Program of Birds Canada at 521 sites across four time periods (2000–2001, 2005–2006, 2010–2011, 2015–2016) throughout southern Ontario, Canada, to quantify how initial occupancy and subsequent local extinction or colonization of 13 marsh-breeding bird indicator species (or species groups) was influenced by the composition of, and concurrent changes in, surrounding remotely-sensed land cover within 200–6,400 m. For six species (46 %) initial occupancy was higher or extinction was lower where surrounding wetland/open water land cover was higher. By contrast, initial occupancy was lower, extinction was higher, and/or colonization was lower: 1) where surrounding anthropogenic (predominantly urban) land cover was higher (four species, 31 %), 2) in Great Lakes coastal compared to inland landscapes (five species, 38 %), and 3) where loss of surrounding wetland/open water land cover increased, depending on whether surrounding wetland/open water land cover was initially low or high (seven species, 54 %). We recommend that decision-makers consider the influence of the surrounding landscape during conservation planning and when measuring success of wetland restorations based on marsh-breeding bird indicator species, particularly in Great Lakes coastal landscapes and landscapes with high urban land cover and/or low wetland/open water land cover.     

Simulation of Non-Point Pollutants Evolution in Coastal Plain Island-A Case Study of Chongming Island

The coastal plain region usually shows the agricultural dominated industry mode, so more and more attention is paid to non-point pollutants discharge. In this study, the method for assessing the influence of non-point pollutants discharge on river water quality is probed which is concluded as follows： （1） Considering the costal plain island is characterized as nearly even elevation, the conventional gravitational runoff confluence method based on eight-point gravitational flowing directions （DS） is unable to compute the runoff confluence received by the surrounding rivers, so a new method of triangular confluence based on three-points of grid center and the river segments is presented. Further the equations of non-point pollutants loads estimation and non-point pollutants confluence on rivers are presented. （2） The integration mode of non-point pollutants model and river water quality model is presented so as to further assess the non-point pollutants contribution to river water quality. （3） With the Chongming Island, the third largest island in China, as an example, the above-mentioned equations are specified. For this island, the non-point pollutants loads are estimated and linked to the developed water quality model of the river network in the island, and further the non-point pollution evolution in river network is simulated. In this scenario, the non-point pollution contribution to river water quality over the whole island is clearly displayed, and the area where the river water quality is seriously influenced by non-point pollutants discharge is distinctly depicted. This scenario also shows the water quality contribution ratio of non-point pollution to point pollution can be in the range of 55.5% to 44.5% which proves the importance of non-point pollution control in costal plain islands.     

南水北调西线工程建坝取水对坝下沼泽湿地水文影响初步研究

根据南水北调西线工程建坝取水后坝下径流量及水位变化情况,确定了坝下减水河段范围.在GIS、RS支持下,分为雅砻江、大渡河两个流域生成了工程重点影响区域,利用1985年、2000年、2005年3期Landsat TM影像分别提取出区内沼泽湿地景观.根据湿地景现的动态演变过程,将其划分为活动区、变动区和稳定区3部分.最后以活动区内沼泽湿地为研究对象,根据其与减水河段的关系,分层次设置了以下3种情境.结果表明,按照黄河水利委员会提供的调水方案,建坝取水对坝下游沼泽湿地的水文情势基本没有影响.     

Hydrostatic versus nonhydrostatic hydrodynamic modelling of secondary flow in a tortuously meandering river: Application of Delft3D

Given the importance of pressure gradients in driving secondary flow, it is worth studying how the modelled flow structures in a natural river bend can be impacted by the assumption of hydrodynamic pressure. In this paper, the performance of hydrostatic versus nonhydrostatic pressure assumption in the three‐dimensional (3D) hydrodynamic modelling of a tortuously meandering river is studied. Both hydrostatic and nonhydrostatic numerical models were developed using Delft3D‐Flow to predict the 3D flow field in a reach of Stillwater Creek in Ottawa, Canada. An acoustic Doppler velocimeter was employed to measure the 3D flow field at a section in a sharp bend of the simulated river at two flow stages. The results of the Delft3D hydrostatic model agreed well with the acoustic Doppler velocimeter measurements: The hydrostatic model predicted reasonably accurately both the streamwise velocity distribution across the section and the magnitude and location of the primary secondary flow cell. The results of the Delft3D nonhydrostatic approximation showed that the model was not conservative and could not accurately generate either the secondary flow or the streamwise velocity distribution. This study illustrated the superior performance of the hydrostatic over nonhydrostatic 3D modelling of the secondary flow using Delft3D. Several possible reasons for unfavourable performance of the nonhydrostatic version of Delft3D are discussed, including the pressure correction technique employed in Delft3D. Considering the uncertainties that may arise in both modelling and field measurements, the 3D hydrostatic Delft3D model was capable of reasonably predicting the river bend flow structures in the studied meandering creek.     

三维泥沙动力数值模型的高效应用——准三维模型“轻装”效应

近年来泥沙动力和河床冲淤三维计算模型(SB3D)取得了快速的发展,然而由于SB3D基于全三维水动力模型,计算量过大将会降低SB3D的工程实用性。从模型结构、模型求解与程序代码编译三个角度,探讨准三维水动力模型和SB3D联用的合理性和实用性,并采用实验室模拟和工程应用予以证明。结果表明:准三维模型多数条件下可以为SB3D提供合理的三维水流速度;全三维水动力模型和程序模块可以方便的由准三维模型和模块替换;准三维水动力模型极大的提高了模型计算效率,具有理想的"轻装"效应,可以提高SB3D的工程实用性。