辽宁太子河流域非点源氮磷负荷模拟分析

以辽宁太子河流域为研究区,为定量估算该区非点源氮磷污染负荷,经过实地调研和资料收集后,利用单位负荷法和SWAT模型相结合的方法对流域进行1997~2008年径流、泥沙和营养盐输出的模拟研究,进行了多参数、多目标和多站点详细的参数率定和模拟验证,最后分析了非点源氮磷负荷的时空分布规律.结果表明:径流模拟效果较好,泥沙和营养盐模拟结果符合要求,模型在太子河流域适用性较好,可以模拟分析该地区的非点源污染负荷问题;1997~2008年年均总氮和总磷负荷为17357.43t和7110.91t,氮磷负荷的时空分布受降雨径流过程的影响,汛期(6~9月)负荷总量占全年的77.76%和80%;负荷强度的空间差异较大,全流域多年平均值为13.20,5.41kg/hm2,流域内污染负荷关键源区是灯塔市和辽阳县.

Simulation study and analysis of non-point source nitrogen and phosphorus load in the Taizihe Watershed in Liaoning Province

In order to estimate the non-point source (NPS) pollution loads of nitrogen and phosphorus in the Taizihe watershed quantitatively, after a detailed field survey and data collection, the method of unit load and export coefficient modeling and the soil and water assessment tool (SWAT) were comprehensively used to simulate the runoff, sediment and nutrients loads during 1997to 2008. Based on the observed runoff, sediment loads and water quality data, detailed calibration and validation of multi-parameters, multi-objective and multi-site were carried out. Then, the temporal and spatial distribution of NPS pollution loads of nitrogen and phosphorus load was analyzed. The results showed that the simulation of runoff was pretty good. The simulation results of sediment and nutrients loads met the requirements. The model had good adaptability in the Taizihe watershed and was available. The model could be used to simulate and analyze the NPS pollution problems. The annual average loads of the TN and TP from 1997 to 2008 were 17357.43t and 7110.91t. The temporal and spatial distribution of the TN and TP loads was affected greatly by the process of rainfall-runoff. The total load during the flood season (from June to September) accounted for 77.76% and 80% of the annual load. The spatial distribution of the TN and TP loads varied greatly, with the long-time average annual values of the TN being 13.20kg/hm2and TP being 5.41kg/hm2. The Dengta City and the Liaoyang County, located in the middle and lower of the Taizihe watershed, were the critical source areas of NPS pollution.