基于SWAT模型的梅江流域非点源污染时空分布特征

利用SWAT模型对亚热带季风湿润区红壤背景下江西省梅江流域非点源污染进行了模拟，并根据实测数据对模型的参数进行了率定和验证。在确定模型适用性的基础上，进行氮、磷营养盐负荷计算，分析了流域非点源污染负荷时空分布特征。结果表明：研究区非点源污染负荷具有显著的时空分布特征，在时间变化上，氮、磷污染负荷与降雨有明显相关性，R2分别是0.909和0.921；硝态氮年平均污染物负荷排放方式主要以下渗为主，下渗硝态氮排放量占总量的63%，与流域内高植被覆盖率有关；在空间分布上，有机氮与有机磷空间分布基本一致，流域内污染物主要分布在梅江中下游的黄陂河与会同河流域，不同土地利用下非点源污染负荷以耕地排放量为主。

Temporal-Spatial Distribution of Non-Point Source Pollution in theMeijiang River Watershed Based on SWAT Model

SWAT (Soil and Water Assessment Tools) model was used to calculate the non-point source pollution in the Meijiang River Watershed, which is a red soil region under the background of subtropical monsoon climate in Jiangxi Province. According to the measured data, SWAT model was adjusted to analyze the temporal-spatial distribution patterns of the non-point pollution load in the region. The hydrological processes and Nitrogen and Phosphorus nutrient loads were also calculated. Results showed that there was significant temporal-spatial characteristic in the watershed. In the time series, Nitrogen and Phosphorus pollution loads had obvious correlation with rainfall, the correlation coefficient was 0.909 and 0.921 respectively. The average annual emissions were mainly composed of infiltration, the contribution rate was 63%, that was associated with high vegetation coverage in the basin. On the spatial distribution, pollutants in the basin were mainly distributed in the Huangpi and Huitong valleys in the middle-lower reaches of the Meijiang, the spatial distribution of organic Nitrogen and that of organic phosphorus were basically identical. The loss amount of soil nutrient such as Nitrogen and Phosphorus under different land-use showed a great spatial variability in the region, the farmland had a high contribution to the non-point source pollution load. The results reveal the temporal-spatial distribution characteristics of non-point source pollution, and can be for reference of the conservation of soil and water and control of non-point source pollution in the watershed.