蒲河流域氮污染负荷模拟及时空分布

目前世界上许多国家仍面临严重的非点源污染问题,其中氮素污染负荷仍是水资源研究与环境治理方面的重点问题。利用SWAT模型,结合地形地貌、土地利用、气候条件等因素对氮污染负荷进行模拟及时空分布研究,对非点源污染治理具有重要意义。在辽宁省沈阳市蒲河流域基础资料搜集基础上,应用GIS结合SWAT构建模拟研究数据库,根据蒲河水系分布将流域划分为23个小流域215个水文响应单元,分别对氮素形态、氮污染负荷贡献率、氮污染关键区以及流域氮污染的时空分布等进行模拟研究。结果表明:1)氮以有机氮、NH4+-N、NO3--N、NO2--N的形式存在于水体中,NO3--N含量最高。2)时间上,TN量在年内各月呈波动变化,且TN流失具有明显滞后性。3)空间上,流域有机氮和NO3--N整体呈现由东北向西南扩散,上游及中游地区含氮量高于下游地区,1号子流域为氮素污染关键区,3、9、10号为次要关键区,TN贡献区主要集中在流域出口至马家窝棚水域。

Nitrogen pollution load simulation of the Puhe River Basin and the spatial and temporal distribution

At present, many countries face severe non-point source pollution, in which the load of nitrogen pollution is still the key issues of water resource and environmental governance. The load of nitrogen pollution and its spatial and temporal distribution were simulated and analyzed by using SWAT model with the topography, land use, climate condition and other factors, which will be great significant for non-point source pollution control. Based on basic data collection of Puhe River Basin of Shenyang City, Liaoning Province, simulation research databases was built by SWAT model coupled with GIS. The whole basin was divided into 23 sub-basins and 215 hydrological response units according to water type distribution of Puhe. Nitrogen forms, contribution ratio of nitrogen pollution load, critical nitrogen pollution areas and the nitrogen pollution distribution of spatial and temporal were simulated. Results showed that ： 1 ） The nitrogen mainly exists by forms of organic nitrogen, NH4 -N, NO3- -N, NO2- -N in water, in which that of NO3--N is maximum. 2） On the temporal scale, the content of TN fluctuated monthly, moreover, TN loss was hysteretic significantly. 3） At the spatial scales, organic nitrogen and NO3- -N in the basin diffused from northeast to southwest direction. The nitrogen content of upstream and midstream was higher than the downstream region. In addition, No. 1 sub-basin is the key nitrogen pollution area in the basin, No. 3,9 and 10 sub-basin are the secondary nitrogen pollution areas. The TN contribution region mainly located at the area from basin outlet to the water of Majiawopeng.