基于改进的SWAT模型的山地流域吸附态总磷负荷模拟

SWAT模型模拟的产沙量为流域总产沙量,而无法获得产沙量的空间分布以及与产沙量关联的吸附态负荷的空间分布。为此,针对山地流域,提出“径流连通性因子”,基于该因子,形成改进的产沙量以及吸附态总磷负荷的时空分布模型,并对模型进行验证。应用所构建的模型,采用小流域推广法,将非完整流域的行政区域三峡库区中所包含的小流域模型及其模型参数分别扩大模拟范围,总体覆盖整个库区,实现对三峡库区产沙量和吸附态总磷负荷时空分布的模拟,确定出产沙和产生吸附态总磷负荷的关键源区。所构建的模型可用于其他山地流域。

Simulation of adsorbed phosphorus load in a mountainous watershed based on an improved SWAT model

In the SWAT model, the simulated sediment yield is the total sediment yield of the basin; thus, it is impossible to obtain the spatial distribution of the sediment yield and the spatial distribution of the adsorbed load associated with sediment yield. For this reason, a runoff connectivity factor was proposed for a mountainous basin, based on which a temporal and spatial distribution model of improved sediment yield and total adsorbed phosphorus load was formed and verified. By using the model and the method of small watershed expansion, the small watershed model and its model parameters in the Three Gorges Reservoir area of the administrative region of the incomplete watershed were expanded to cover the whole reservoir area in order to realize the simulation of the temporal and spatial distribution of the sediment yield and the total adsorbed phosphorus load in the Three Gorges Reservoir area and to determine the key source areas of the sediment yield and total adsorbed phosphorus load. The model constructed in this study can be applied to other mountain basins.