流域景观格局对非点源污染影响的定量评估-以辽宁省汤河流域为例

Studies have shown that landscape pattern characteristics will impact the river water quality greatly. However the influence mechanism is and complicated and still not clear. For the past few years, quantitating the relationships between Landscape patterns and river water quality is always a hot research area. This study intends to establish an eco-hydrological model of Tanghe River basin, a typical tributary of Taizi river in Liaoning Province, and to explore the formation and migration process of non-point source pollution. In this study, methods used for data collection include: 1) Land use data will be obtained by multiple applying field investigation, remote sensing image interpretation and GIS analysis technology; 2) Sampling point water quality data will be acquired by combining methods of historical hydrologic data collection and field investigation. 3) Multi-scale Landscape pattern indexes data will be computed using the landscape pattern analysis software Fragstats. Based on the data above: 1) SWAT model for Tanghe River basin will be established, and the simulation accuracy of non-point source pollution modelling will be verified by nitrogen and phosphorus pollution data from both hydrometric station and water quality sampling. 2) Landscape pattern indexes which can exert more influence on water quality will be distinguished. The coupling relationship between landscape pattern and non-point source pollution will be analyzed quantitatively. 3) Scenarios of diffident landscape pattern will be simulated by GIS, and then the influence of them will be calculated by well calibrated SWAT model. This study can provide scientific basis for revealing the interaction process and mechanism of landscape elements affect river water quality, can guidance the land use optimizing, landscape planning and non-point source pollution control.

流域景观格局对河流水质的影响巨大且十分复杂，定量解析该影响关系是当前科学研究的难点。本研究拟建立辽宁省太子河一典型混合型小流域——汤河流域的生态水文模型，探索流域非点源污染的形成及迁移过程，并进行全流域、多时期水质调查采样，验证模型非点源污染输出在子流域尺度上的准确性。基于水质调查数据，开展多空间尺度景观组成指标、景观空间配置指标与非点源氮、磷污染关系的系统对比，筛选对于本典型区河流非点源污染产生显著影响的景观格局特征因子,并定量评估各类指标对流域非点源污染影响的贡献率，综合评价流域景观格局与非点源氮、磷传输之间的耦合关系。最后基于生态水文模型进行景观组成与格局情景模拟，科学、定量地选取最佳景观格局优化方案。本研究可为河流非点源污染和陆地景观要素相互作用过程与机理揭示提供理论基础，为生态水文模型非点源污染模拟的准确性提供佐证，为流域土地管理、景观规划和非点源污染调控提供科学依据

流域景观格局对河流水质的影响机理十分复杂，定量解析该影响非常困难。本研究以辽宁省太子河支流-汤河流域为研究对象，对研究区数期遥感影像进行了解译获得土地利用数据，结合土壤，地形，气象，水文等数据，建立了汤河流域的SWAT水文模型，对流域水文循环过程进行了长时间序列模拟，探索了流域水资源时空分布规律。同时，项目组对汤河流域进行了全流域、多时期水质调查采样，采用紫外分光光度法、过硫酸钾消解法和纳什试剂光度法对水样进行了总氮、总磷含量检测。选取了斑块密度（PD）、最大斑块指数（LPI）、景观分裂指数（DIVISION）等景观格局指数，对多空间尺度景观组成及配置进行了研究。并采用相关分析、冗余分析等方法探索了景观格局与非点源氮磷污染关系。基于水文模型模拟景观配置情景对河流非点源污染的影响是下一步研究重点。