利用DPeRS模型估算巢湖流域氨氮和化学需氧量的面源污染负荷

巢湖作为安徽省重要的饮用水源,其面源污染问题受到广泛关注.本文利用一种基于遥感分布式面源污染计算模型——DPeRS(Diffuse pollution estimation with remote sensing)模型,估算了巢湖流域2010年氨氮(NH+4-N)和化学需氧量(CODCr)面源污染物负荷,并进行污染特征解析,结果表明:1巢湖流域污染物以耗氧有机物为主,2010年产生NH+4-N 1562 t,进入水体800 t;CODCr9×104t,进入水体5×104t.22010年不同月份面源氨氮和CODCr污染负荷均有显著性差异,其中,7—8月氨氮和CODCr污染产生量较高.3空间分布上,氨氮和CODCr污染物主要集中在巢湖流域西北部地区;从区县角度来看,合肥市市辖区面源污染物产生量及入河排放量最大.4污染类型分析结果表明:城镇径流是氨氮最主要的面源污染源,且氨氮污染负荷与城镇人口密度的相关系数达到0.98,氨氮污染负荷与农田氮平衡的相关系数为0.65;而畜禽养殖是CODCr最主要的面源污染源,且CODCr污染产生负荷与畜禽养殖密度之间有显著的空间关联性,其相关系数达到0.91.

Application of DPeRS model on estimation of non-point source pollution load of ammonia nitrogen and chemical oxygen demand in Chao Lake basin

As the important drinking water source, Chao Lake has attracted much attention on its non-point source (NPS) pollution problem. In this study, a distributed model DPeRS (Diffuse pollution estimation with remote sensing) was developed to analysis the spatial pattern of NPS of ammonia nitrogen (NH₄⁺-N) and chemical oxygen demand (COD_Cr). Simulated results showed that the discharge of NH₄⁺-N was 800 t with the total production being 1562 t and COD_Cr was 5 ×10⁴ t with the total production 9 ×10⁴ t in 2010. The dramatic differences were identified on monthly NH₄⁺-N and COD_Cr pollution loads in 2010, and the pollution production from June to August were the largest in the year. The NH₄⁺-N and COD_Cr pollution were mainly located in the northwestern of Chao Lake Basin (CLB), and Hefei city discharged the big amount of NPS production. The pollutant source analysis showed that urban runoff contributed most of NPS NH₄⁺-N production. The NH₄⁺-N loads were related to urban population density with the correlation coefficient (R²) of 0.98. Also the NH₄⁺-N pollution loads was closely related to agricultural N balance with R² of 0.65. The livestock was the most important source for NPS COD_Cr, which had an evident relationship with animal density (AD) with R² of 0.91.