流域可视化是数字流域建设的关键，目前空间信息的二维表达方式在某些层面上已经不能满足信息化管理的需要。如何利用地形三维可视化技术表达流域内的各类信息，并将其与水体分析模型进行集成分析流域内的水体变化情况是现阶段急需解决的问题。本文以三峡库区流域为研究区域，对流域三维地形场景的构建和流域内水体模型进行了研究，着重对水体的流场模拟和基于流场的点源污染扩散问题进行了探讨，建立了三峡库区流域三维可视化系统。首先基于多分辨LOD模型，对地形和影像数据进行分层分块组织，构建地形和影像的瓦片金字塔，应用四叉树数据结构对地形块进行动态的调度和渲染，构建了一个高效的流域三维地形场景。在此基础之上，根据河道的断面点，提取河道的边界；水体的数学模型是流域可视化研究的重点，现有的商业软件存在难以集成应用，难以扩展等缺点，而一些算法不能满足实时性或精度的要求，影响了模拟的准确性和科学性，针对这些问题，本文应用流体力学原理计算河道内的流场，并给出了流场的两种绘制模式，直观地表达了河道内水体的流动细节，解决了水体流场数值可视化的问题；近年来水污染事件时有发生，直接威胁到河道沿岸城乡供水系统和水生态环境。为了使水污染事故造成的环境灾害减小到最低程度，有必要对水污染事故造成的污染水体的迁移进行时空预测与模拟分析。本文应用元胞自动机模型，并把流场作为影响因子，模拟了点源污染扩散的过程；另外本文还对洪水淹没和流动水面仿真进行了探讨，并将其应用到了三峡库区流域三维可视化系统当中。基于多分辨率LOD的流域三维可视化在三峡库区流域中的应用表明：多分辨率LOD是解决大场景三维可视化的关键，流场的实时计算提高了水体模型和污染扩散模型计算的准确性和科学性，对流域洪水资源利用和污染控制有实际意义。

Watershed Visualization is the key to the construction of the digital watershed, two-dimensional expression of the spatial information at some level can no longer meet the needs of information management. How to use 3D terrain visualization technology to express all kinds of information within the basin, and to integrate with water analysis model for analysis of the basin's water body changes need to be resolved at this stage. The main study area is Three Gorges Reservoir Area watershed, the research of the watershed three-dimensional terrain scenes construction and basin water model are dealt, the water body flow field simulation and the spread of point source pollution problems based on the flow field are discuss emphatically, the Three Gorges Reservoir Area 3D visualization system is constructed. First, the Tile Pyramid of the terrain and image is built through the organization of blocks, an effective watershed three-dimensional terrain scenes is constructed with the application of the quad tree data structure for dynamic scheduling and rendering of terrain blocks. On this basis, the boundaries of the river are extracted according to the cross-section point of the river; The mathematical model of the water body is the focus of the study of watershed visualization, there are shortcoming of difficult to integrate and to expand with the existing commercial software, and some algorithms can’t meet the requirements of real-time or accuracy, affect the simulation of accurate and scientific. In this paper, To solve these problems, principles of fluid mechanics are used to calculate the flow field within the river and two drawing modes of the flow field are given, the details of the flow of the water are expressed visually in the river , and the problem of water flowing numerical visualization is solved ;Water pollution incidents have occurred some times in recent years, and posed a threat to the urban and rural water supply systems and water ecology along the coast of river. In order to make the environmental disaster caused by water pollution accident reduce to the minimum ,it is necessary to predict and analyze the migration of polluting water bodies caused by pollution accidents temporally and spatially. In this paper, cellular automata model is used to simulate the diffusion process of point source pollution, and the flow field as the impact factor; This article also discussed the simulation of flood and flow of the water, and this is applied to 3D visualization system of the Three Gorges Reservoir watershed. Application of three-dimensional visualization of multi-resolution LOD in the Three Gorges Reservoir watershed basin shows that: Multi-resolution LOD is the key to solve the three-dimensional visualization of large scenes, real-time calculation of the flow field improve the accuracy and scientificity of calculation in the water model and pollution dispersion model, it is meaningful to the use of flood resource and pollution control.