平原河网区非点源污染过程的分布式模拟研究

The transportation and diffusion process of non-point source pullution in plain river network areas is one of major issues of water pollution management.In this project the western Taihu Lake Basin is selected as a typical study area,where has many artificially hydrological structures and consists of many lakes and polders, and intersected stream networks, etc. By using of remote sensing images and multi-source spatial thematic data, the spatial structure of the regional hydrology is extracted. The proposed study designs a raster-based data model and will develop a novel method for modeling the distributed spatial discretization of the plain river network area based on the digital river and lake network system to solve the existing problems while the cuurent methods are not suitable to extract the lakes, reservoirs, parallel channel, discontinuous rivers and the definition error of the catchment area. The SWAT model is improved to simulate the water exchange process in-and-out the polder areas according to the scheduled rules of the polder areas, and regulate the dynamic river water deployment by defining the ring and crossed-river network topology. Through the improvement of the modeling methods and models, the distributed simulation of the non-point source pollution processes in the western area of Taihu Basin is conducted, which is appropriate for China's situation as well as for regional features, in terms of exploring the relavant theories and key technologies regarding the distributed simulation process of the nitrogen, phosphorus transportation in the plain river network areas. this study is aimed to lay the foundation to improve the understanding the process mechanism of non-point source pollution, and farther optimizing the water pollution management decision for the plain river network areas in the southeast of China.

平原河网区非点源污染的扩散和传输过程是水体污染治理决策中重要科学问题之一。本项目以太湖湖西区为典型区，针对平原河网区地势平坦、湖泊水体众多、圩区、交叉河网相互嵌套水文结构特征，利用遥感和多源辅助数据，提取该区域的水文空间结构，研究基于数字河、湖网络系统的平原河网区栅格数据模型以及分布式空间离散建模的方法，解决现有方法中难以提取湖泊、水库、平行河道、非连续河道、集水区定义误差等问题。对SWAT模型进行改进，根据圩区的调度规则优化模拟圩区内外的水量交换，通过定义环状和交叉河网拓扑关系 进行河道水量动态调配。通过建模方法和模型的改进，对太湖流域湖西区的非点源污染过程进行分布式实证模拟，旨在探索适合国情和地域特点的平原河网区氮、磷迁移过程分布式模拟所涉及的相关理论和关键技术，理解平原河网区非点源污染过程机理，为水环境污染治理措施的进一步优化提供科学基础。

通过水文空间要素的解析，构建了表达平原河网区河流、湖泊、水库、圩区、水文节点和集水单元等水文空间要素及其拓扑关系的矢量数据模型；研究解决了平原河网区水文节点提取、河道流向定义等方法，提出了表达交叉河网结构中多流向节点的栅格编码算法，以及在矢量河网流向和湖、库、圩空间单元约束下的栅格流向矩阵修正算法，研发了基于数字河湖网络的平原河网区空间离散化的新方法。根据圩区的排涝和灌溉管理措施，研究圩区蓄水、排涝和引水灌溉过程的水量调度规则，建立圩区内外水量调配过程模型并和SWAT进行了集成，研究解决了分布式流域模型对平原河网区交叉（环状）河网结构的空间建模方法和水量动态调配计算方法。通过野外调查和长期的监测，积累和更新了研究区基础地理数据。本研究通过建模方法研发、模型改进以及基础数据的获取等三个方面的努力，解决了现阶段平原河网区非点源污染分布式计算存在的相关瓶颈问题。已发表相关研究论文5篇， 其中SCI 检索2 篇， EI 检索2 篇；获得软件著作权1 项，申请发明专利一项。指导博士论文1篇，硕士论文6 篇。