农村沟-塘系统水环境过程与格局优化研究——以风岭水库小流域为例

农村沟-塘湿地作为我国存在几千年的小水利工程，在维持水环境过程与功能方面发挥巨大作用。目前，在国家规模化农业政策的背景下，农村沟-塘湿地将面临被填平的威胁。为了深入认识沟-塘湿地在控制雨洪风险与面源污染方面的作用，本研究拟选择江苏省高-宝-邵伯湖区的风岭水库小流域，将沟-塘湿地作为一个系统，探究其水环境过程与格局之间的关系。研究将以单塘湿地水环境功能为基础，利用系统动力学模型分析单塘水环境变化过程；在此基础上从沟-塘网络系统角度，通过构建基于图论的景观网络水环境过程模型，揭示沟-塘网络格局与水文、水质之间的维持关系；并进一步对不同沟-塘网络情景下的水环境过程进行模拟，提出农村沟-塘系统格局优化的最佳方案，以期达到利用有限沟-塘湿地提高水资源利用率、控制农业营养盐输出的目的。因此，本研究的湿地系统认知对深化景观格局与过程研究具有重要理论价值；同时，能够为农村流域水环境保护和利用提供科学依据。

Rural ditch-pond wetland existed as small water conservancy projects in China for thousands of years, which play an important role in maintaining the process and function of water environment. There is increasing awareness that solutions to agricultural non-point source pollution and resulting impacts on downstream water bodies may require a watershed approach to management. The adjustment of land use structure will be carry out under the policy of industrial agriculture, which is the moment to using ditch-pond system to solve the problem of water environment. Reasonable structure of ditch-pond system that may be emulated in developed watersheds to enhance the efficacy of peak-flow attenuation and pollutant removal. This study will choose Fengling watershed as the study area, wherein the ditch-pond system have orderly management and fully ecological service function. This application describes use of simulation modeling to explore the relationship between ditch-pond system patterns and water environment in the watershed scale. Firstly, dynamic systems model and location weighted landscape contrast index were developed to modeling the process of water environment in pond. Secondly, based on the model above and graph theory, landscape network model will be developed in watershed. This model will simulate watershed hydrology, suspended sediment transport and nutrients removal and transformation. Finally, landscape patterns of ditch-pond system can be optimized in terms of both area and numbers of ponds and network characteristics based on the model for purposes of water conservation and agriculture sustainability. The study attempts to explore structure-process of ditch-pond system in landscape scale, which oriented new methodology for ditch-pond system. And the methods and results will be made to provide scientific guidance for regional agriculture planning and land use.