降雨变化对鄱阳湖区乐安河流域非点源产污的影响

IMPACT OF RAINFALL VARIATION ON NON-POINT SOURCE POLLUTION IN LE’AN RIVER WATERSHED,POYANG LAKE BASIN

以鄱阳湖典型入湖河流乐安河为例,构建SWAT模型,基于流域2020年土地利用类型空间差异特征,选取2011(枯水年),2014(平水年),2015(丰水年)作为典型降雨年份探究降雨差异对流域营养盐产污规律的影响。结果表明:不同降雨条件下流域营养盐产污负荷顺序为丰水年>平水年>枯水年。下游沿主支分布区域径流量以及中下游德兴-鄱阳万年段的TN和TP对降雨量增加的响应更为敏感;流域径流量对降雨量减少的响应空间差异不显著,婺源-德兴段的TN和TP对降雨量减少的响应程度高,而鄱阳-万年段对降雨量减少的响应程度则较低。研究结果可为流域制定针对性污染控制措施,进一步有效削减入鄱阳湖营养物负荷提供科学参考。

Taking Le’an River,a typical into-lake river of Poyang Lake as an example,the SWAT model was constructed.Based on the spatial variation characteristics of land use types in the watershed in 2020,the years of 2014(normal year),2015(wet year)and 2011(dry year)were selected as typical rainfall years to explore the influence of rainfall variation on nutrient pollutants production regulations.The results showed that the nutrients production load of the watershed showed a trend of wet year>normal year>dry year.The runoff along the main branch area downstream,and the TN and TP in the Dexing-Poyang Wannian section in the middle and downstream were more sensitive to the increase of precipitation.The spatial differences in the response in runoff volume to rainfall reduction in the watershed were not significant.The TN and TP in the Wuyuan-Dexing section responded to the decrease in rainfall to a high degree while the response to the decrease in rainfall in the Poyang-Wannian section was lower.The research results will provide scientific reference for the development of targeted pollution control measures in the watershed and further reduce the nutrient load into Poyang Lake effectively.