机载LiDAR与船载单波束协同的水上水下一体化测绘模型融合实现

为助力河湖管理、防旱减灾等国家新型基础测绘事业,基于机载Li DAR与无人船搭载单波束实现了水上地面点云与单波束水下点云的获取,对水下点云数据采用克里金法进行空间插值以增强水下地形分辨率,而后基于GEOPAK实现水上水下点云数据的无缝接边与融合,构建水上水下一体化TIN网,最终实现水上水下地形一体化建立。利用随机均匀分布的水上水下检核点对构建后的一体化DEM进行精度验证,结果表明,本次试验构建的水上水下一体化模型效果良好,精度远超规范要求。提出的基于机载Li DAR与船载单波束实现协同作业、构建水上水下一体化模型的作业流程对相关水上水下地形研究具有重要的参考价值。     

基于miniLiDAR的山地大比例尺地形图测绘应用研究

无人机载mini Li DAR测绘使得三维激光扫描测图在降低成本的同时提高了精度,进一步降低了三维激光扫描测图的门槛。通过采用旋翼无人机搭载mini Li DAR和CCD相机分别采集某山地库区点云数据和影像数据,制作生成1∶1000地形图以及DEM,结果表明该库区测图高程中误差为0.07m,完全满足1∶1000山地测图高程精度要求,有应用到更大比例尺地形图测绘的可能性。     

联合机载激光测深波形和点云的水陆识别方法研究

水陆识别在河口海岸带水陆资源管理和科学研究中具有重要作用。利用机载激光测深(Airborne LiDAR bathymetry, ALB)回波波形和点云信息可实现水陆交界区域高精度和高分辨率水陆识别。但在复杂海陆环境区域,采用ALB波形特征或三维点云高程特征的传统识别方法具有各自不足。针对复杂海陆环境区域高精度水陆识别问题,提出了联合ALB波形和三维点云特征的水陆识别方法。首先,利用红外激光获取的三维点云高程,基于K-means聚类方法进行海陆识别。然后,利用红外和绿激光波形信息识别陆地中的内陆水域。将该方法应用于实际Optech CZMIL水陆识别。结果表明:相比传统点云聚类和波形聚类水陆识别方法,该方法将ALB水陆识别精度提高了3.6%～5.5%。     

Arc Hydro模型在流域水文特征提取中的应用——以蓟县沙河流域为例

详细介绍了基于ArcGIS9.3平台的Arc Hydro模型的结构及使用方法,包括从原始高程数据提取河网的步骤。研究区域选取天津市蓟县的沙河流域,采用90 m分辨率的DEM作为基本地形数据,对沙河流域水文特征的提取,共生成28个子流域。分析结果表明:与实际河流水系特征基本吻合,因此应用Arc Hydro工具集划分的流域结果是合理的。     

基于离散点的河道地形外包边界自动生成方法

河道地形外包边界是生成河道地形DEM数据的重要约束参数,对基于地形法的水文泥沙分析计算具有重要影响。为了提高河道复杂地形边界的圈定效率,提出了一种基于平面离散点的外包边界搜索自动生成方法。该方法提取河道地形实测点数据,通过格网划分快速确定边界格子闭环,搜索并扫描相邻边界格子内的离散点,遍历生成河道地形外包边界。采用该方法,在GeoHydrology软件中实现了不同比例尺的长江河道地形外包边界的自动搜索,并在此基础上完成了河道地形的DEM生成、槽蓄量计算、冲淤厚度图绘制等工作。结果表明:该方法对于复杂河道地形能够快速提供较为准确的边界约束,具有适应性强、生成速度快、贴合河道实际形态的优点,提高了长江水文泥沙信息管理和分析的时效性和准确性。     

一种航空影像密集匹配点云的迭代中值滤波算法

为有效解决基于航空影像密集匹配生成的点云中含有大量的冗余点和噪声信息,影响表面模型(DSM)的质量和后续数字正射影像(DOM)生成效果的问题,提出了一种航空影像密集匹配点云的迭代中值滤波算法。通过引入邻域法向量求和的思想定义空间圆柱体,并以此作为点云剔除的约束准则,判断空间圆柱体内是否需要获取中值点,并结合距离统计分析的方法剔除少量离群点,迭代直至相邻两次输出点云数量差异少于设定阈值。采用具有重叠区域的两类点云数据进行对比实验,结果表明:提出的方法能够有效剔除摄影测量密集匹配点云的噪声,对于存在厚度的冗余点云进行光顺平滑,能够保留完整的边缘特征。     

基于法向量区域聚类分割的检测坑点云提取

利用三维激光扫描技术获取堆石坝检测坑表面点云，可以快速计算检测坑体积和堆石坝压实质量，但此技术的关键是从扫描点云数据中准确分割出目标检测坑。提出了一种基于法向量区域聚类分割的检测坑表面点云提取方法：首先通过局部密度法检测得到碾压面外部点P,剩余点则为内部点Q;然后以最小二乘法拟合外部点平面，得到拟合平面法向量与内部点法向量的夹角θ;最后以外部点P作为种子点，逐步扩大搜索区域，直至区域内存在θ大于阈值θ′,即可确定碾压面和检测坑表面的交界，精确提取出检测坑表面点云。利用MATLAB编程实现了检测坑表面点云数据的快速提取，并通过采集3类坝料的检测坑点云数据开展试验，验证了此方法的可行性。研究成果可为类似形状目标点云提取和堆石坝压实质量快速检测提供参考。     

机载激光雷达技术在乌龙山抽水蓄能电站工程测量中的应用

基于水利工程测量中采用传统航空摄影测量存在像控点布设困难、影像间不易匹配、项目周期长等问题,针对水利水电常见的作业环境和激光点云数据自身的特点,结合乌龙山抽水蓄能电站工程测量项目,介绍了机载激光雷达技术结合传统摄影测量技术在高密度植被覆盖区域的地形测绘应用情况,重点介绍了机载激光雷达点云数据的分类方法,从数据获取、预处理,点云滤波分类、空三加密到成图的每一个环节,实现高密度植被覆盖区域地表信息的提取和测绘成图。通过数据精度的分析,证明机载激光雷达技术相比传统摄影测量与人工测量等测绘手段在复杂植被等困难区域测量方面有较大的优势,在未来水利水电工程测绘领域具有广阔的应用前景。     

基于DEM的流域数字河网提取算法研究

以GIS为平台,介绍了基于地表径流漫流模型的流域河网提取算法与流程.根据DEM数据特点,通过洼地的识别和填充、平地的抬升、水流方向的确定、水流累积矩阵的确定、河流栅格网络的生成、河网水系的生成以及子流域的分割等过程,实现了流域河网特征的提取,得到了数字流域矢量图.以西安市浐灞河流域为研究对象,采用NASA提供的90m分辨率的SRTM-DEM为基本的地形数据,进行流域特征信息的提取.经计算得到的研究区域河网特征以及流域信息与实际河流水系特征及流域信息基本吻合,认为基于地表漫流模型的流域数字河网提取算法,结果合理可信,能够满足科学研究和实际工程的应用.     

机载LiDAR数据的电力塔建模方法研究

电力塔作为电力传输中的重要设备,以及电力设备检测和管理的重要支持,其提取与可视化建模具有巨大的实际应用价值。在此方面,传统的量测与制作手段存在周期长、人力和财力耗费大的不足。机载LiDAR系统作为一种主动式的测量传感器在近十几年来取了快速的发展,其获取的高精度、高密度的三维点云使得快速高效的电力塔建模成为可能。提出了一种基于机载LiDAR点云数据的电力塔建模方法,其通过检测电力线对的连接点定位和提取电力塔,通过建立三维空间格网、利用二值图像轮廓跟踪的方法跟踪三维线结构,并由三维空间线特征建成电力塔三维模型。实验证明：此方法所建立的模型完整度高,能够保留点云所描述的三维空间位置以及拓扑特征,是可行和有效的。该成果可以有效地应用于电力设备管理与监测以及数字城市等可视化系统。     

SPATIAL AND TEMPORAL WATER QUALITY VARIABILITY IN AQUATIC HABITATS OF A CULTIVATED FLOODPLAIN

The floodplains of lowland rivers contain diverse aquatic habitats that provide valuable ecosystem services but are perturbed when intensively cultivated. Hydrologic, water chemistry and biological (fish) conditions in five aquatic habitats along the Coldwater River, Mississippi, were measured for more than 4 years: the river, two severed meanders that functioned as backwaters, a managed wetland and an ephemeral channel draining cultivated fields. Off‐channel habitats were connected to downstream regions 0.10% to 32% of the dry season and 24% to 67% of the wet season. The median temperatures for the five monitored sites ranged from 18°C to 23°C, the median total solids concentration for all sites was 135 mg L^?1, the median total phosphorus was 0.29 mg L^?1 and the median total nitrogen was 1.56 mg L^?1. Chemical and physical water quality displayed strong seasonal differences between the wet winter/spring and the dry summer/fall periods so that temporal variation consisted of gradual seasonal trends superimposed on strong diurnal variations. All off‐channel habitats exhibited periods of hypoxia and temperatures >30°C during the dry season. Between‐site gradients of water and habitat quality were strongly coupled to water depth and runoff loading. The rehabilitation of one backwater by increasing water depth and diverting agricultural runoff was associated with improved water quality and fish species richness relative to an adjacent untreated backwater. The diversion of polluted runoff and the use of water control structures to maintain greater water depth were observed to be effective management tools, but the former reduces the water supply to habitats that tend to dry up and the latter reduces connectivity. Published in 2011 by John Wiley & Sons, Ltd.     

Spatio‐temporal variation of gross CO2 and CH4 diffusive emissions from Australian reservoirs and natural aquatic ecosystems,and estimation of net reservoir emissions

Carbon dioxide (CO₂) and methane (CH₄) diffusive emissions were measured during two field surveys in Queensland and Tasmania, Australia, using the floating chamber method. Bubbling and degassing emissions in 2010 were estimated in Koombooloomba Dam reservoir using only inverted funnels and gas concentrations, respectively. A total of 14 reservoirs and 16 rivers and lakes were sampled from 2006 to 2010. Spatial variation was substantial within each water body, as well as between them. The main drivers of diffusive emission variation were physiographic region and climate, with a clear demarcation being observed between diffusive emissions from tropical Queensland and temperate Tasmania, and between the humid West Coast Range (Tasmania) and dry Central Plateau (Tasmania). Higher CO₂ and CH₄ diffusive emissions were observed during the dry season, when long water residence times would promote organic matter degradation. Estimated total gross emissions, including diffusive, bubbling and degassing emissions, for Koombooloomba Dam reservoir were about 1.5 × 10⁶ t CO₂eq km² per year, or 24 × 10⁶ t CO₂eq per year. This corresponds to a plant emission factor of 3.18 kg CO₂eq MWh^?1. Using an estimate of terrestrial emissions derived from literature data for the Tully River catchment area, rough estimated net emissions from the catchment area are about 44 kt CO₂eq per year, or 5.83 kg CO₂eq MWh^?1, which is in the lower range of the studied reservoirs.     

Call for Papers

正As the eldest and most distributed professional journal of water industry,Water Wastewater Engineering(W WE)gained very wide acceptance from the colleagues working in this field in this country since start publication in 1964.Now it is administrated by the Ministry of Construction of the People’s Republic of China and sponsored by the China Civil Engineering Society etc.     

Serial discontinuities in a Rocky mountain river. II. Distribution and abundance of trichoptera

River regulation in the headwaters and middle reaches of the Gunnison River, Colorado, significantly altered distributions and abundances of Trichoptera fauna. Twenty-five species were collected from mainstream samples, with the greatest species richness occurring at an unregulated, rhithron segment above the central reach dams. At sites immediately below the three hypolimnial-release dams and a reregulation dam, species richness was reduced 35–90 per cent and abundance > 95 per cent. Net-spinning caddisflies were the dominant trichopterans at unregulated sites; Arctopsyche grandis in the upper reaches (218 organisms, 586 mg dry mass m^?2) and Hydropsyche cockerelli, H. occidentalis and Cheumatopsyche pettiti in the lower river (9041 total organisms, 6621 mg m^?2), downstream from the last dam. The observed distributional pattern of low trichopteran densities in dam tailwaters and high hydropsychid densities at sites 60–80 km below the central reach dams is a classic expression of continuum resets and adjustments in response to stream regulation as predicted by the Serial Discontinuity Concept.     

Surveying for Water Resources

Abstract

A professional Land Surveyor (Geomatician) describes the Hydrogeologists' survey requirements of a major water resources assessment for the government of The Sultanate of Oman (1992 to 1996). The need for objective specifications is stated. Specialist terms like geoid, spheroid, Mean Sea Level are explained and how to relate spheroidal levels to the geoid. Methods like traditional survey, satellite survey, and photogrammetry are introduced. The paper encourages coordinated working for the benefit of water resource assessment and recommends employment of the professional land surveyor for major studies.     

库水波动下库岸边坡地下水浸润线解析解及误差分析

解析法是库岸边坡地下水浸润线计算中便于实际应用的方法,但该方法须基于若干假定并对潜水运动基本方程线性化后才能求解。针对各假定和线性化过程建立不同的地下水渗流数学模型,用解析法和有限元法解答上述数学模型,分析各误差大小及其规律。结果表明：库岸垂直处理带来的误差要小于方程线性化处理和不考虑非饱和渗流带来的误差,而且它们都随渗透系数变大而减小;在三峡库区库水调度情况下,假定库水位等速变化带来的误差对大多岸坡而言可以忽略;计算库岸边坡地下水浸润线时,解析法只适用于水位变化幅度相比含水层厚度较小,且几何边界规则、岩土结构简单、岩土体渗透性较好时的情况。     

Changes in Summer Irrigated Crop Area and Water Use in Southeastern Turkey from 1993 to 2002: Implications for Current and Future Water Resources

Changes in summer irrigated cropland acreage and related water use are estimated from satellite remote sensing and ancillary data in semi-arid Southeastern Turkey where traditionally dry agricultural lands are being rapidly transformed into irrigated fields with the help of water from the Euphrates-Tigris Rivers. An image classification methodology based on thresholding of Landsat NDVI images from the peak summer period reveals that the total area of summer irrigated crops has increased three-fold (from 35,000 ha to over 100,000) in the Harran Plain between 1993 and 2002. Coupled analysis of annual irrigated crop area from remote sensing and potential evapotranspiration based estimates of irrigation water requirements for cotton indicate a corresponding increase in agricultural water use from about 370 million cubic meters to over one billion cubic meters, a volume in accordance with the state estimates. These estimates have important implications for understanding the rapid changes in current agricultural withdrawals in Southeastern Turkey and form a quantitative basis for exploring the changes in future water demands in the region. For example, expansion of irrigated lands have led to a steady decrease in potential evaporation due to increased roughness and decreased humidity deficit in the Harran Plain. Assuming that the changes in future evaporation conditions will be of similar nature, water use for irrigation is expected to decrease over 40 percent in future irrigation sites. Incorporating this decrease in overall planning of the irrigation projects currently under construction should lead to improved management, and by extension, sustainability of water resources in the region.     

The Impact of Economic Development on Water Pollution: Trends and Policy Actions in Malaysia

The paper examines the impact of development activities on water pollution in Malaysia. Hence, the main objective of this paper is not just to examine the trends of development-induced water pollution around the region of the country but to know where the problems are and the policy measures taken by the government. It evaluates the probable causative relationship between problems introduced due to technology employed in water pollution control and governmental policy measures. It examines the relationship between development indicators as sources of pollution and polluted rivers over a period of 12 years. The findings of the paper have shown that despite the policy enforcement actions against the identified sources of water pollution, all the three development indicators (chosen based on those identified sources) still accounted for high percentage of river pollution in Malaysia. The findings of the paper were used to identify the central fact of the location of the problem. Some crucial conclusions of where the problems likely to be, as reflected in the findings, are: (a) the issue of interactive-effects between pollutants that many policy-makers are not aware of. This is when policy measures concentrate only on one source of water pollution; (b) the enforcement strength and/or effectiveness of policy measures themselves; (c) financial constraints to invest in appropriate technology especially sewerage systems for controlling human source of water pollution in the country; as well as those confronting small polluting industries (d) finally, lack of cooperation between government and private business firms to comply with regulatory policies for water pollution control.     

浅淡溢洪道改扩建方案与选择

溢洪道改扩建和进行溢洪道方案布置，要择优选取溢洪道进口型式、防冲消能工，以使其工程量省、施工快、运行管理方便     

Intangible Flood Damage Quantification

Flooding is a natural disaster that may cause tremendous tangibleand intangible damage to the national economy. The tangible damage assessment, i.e. the monetary value of all direct and indirect physical damages, has already been studied, whileintangible damages have not yet been taken into account. Thisarticle, therefore, is the first systematic attempt to assess bothtangible and intangible damages. The new proposed Anxiety-Productivity and Income Interrelationgship Approach (API) has been developed to quantify the intangible damage in monetary terms. The Bangkok area has been selected as the research area because several severe flood events have occurredthere over the last two decades. The 1983 Bangkok flood caused 6600 million baht in damage, according to estimates by the National Statistical Office (NSO). This article examines the totalflood damage (including the intangible damage) at different flood magnitudes. Case studies with and without flood mitigation projects are studied and compared. Furthermore, thisarticle also discusses the improvements over the conventional approach offered by the new API methodology.