三峡库区大宁河流域非点源污染研究

Research on non-point pollution sources in Daning River watershed of the Three Georges Reservoir

以大宁河流域巫溪水文站控制流域为研究对象，应用分布式非点源污染模型SWAT，利用实测流量、泥沙负荷及氮、磷负荷数据对模型进行了率定和验证，并模拟了大宁河流域的径流量和营养物质氮、磷的排放。结果表明，月平均流量在率定期和验证期的效率系数分别达到了0．93和0．62；泥沙负荷的效率系数分别为0．70和0．34；氨氮和总磷的效率系数分别达到了0．31和0．37。大宁河流域污染物质的排放存在着较大的空间差异，有机氮和有机磷的5年平均排放量区间分别为2．01～38．15和0．35～5．89kg/（hm^2·a），其中，流域西南部子流域的有机氮和有机磷平均排放量最大，分别为38．15和5．89kg/（11m^2·a），是大宁河流域污染物排放的最敏感区域。

The soil and water assessment tool （SWAT） was used for simulating non-point pollution sources in the Daning River watershed. It was first calibrated and then validated on monthly and annual basis for the years 2000 - 2004 using streamflow and nutrients loads. The results showed that the efficiency coefficients for the simulation of streamflow were 0.93 for calibration and 0. 62 for validation. In calibration and validation periods, the efficiency coefficients were 0.70 and 0.34 respectively for sediment load and 0. 31 and 0. 37 for the simulation of NH3-N and TP . A great spatial difference existed in the study area for nutrients loads. The annual mean loads range from 2. 01 -38.15 kg/（hm^2·a） for organic nitrogen and from 0. 35 -5.89 kg/（hm^2·a） for organic phosphorous. In the southwest of study area, the annual mean loads of organic nitrogen and organic phosphorous were 38.15 and 5.89 kg/（hm^2·a） respectively.