奥林匹克森林公园典型人工林地非点源污染输出特征分析

选取北京奥林匹克森林公园的典型人工林地为研究对象,通过对天然降雨径流过程及泥沙、氮、磷等污染物浓度随径流变化过程的监测,研究公园典型密草林她覆盖下,不同坡形及人工沟渠汇流条件下的径流及污染物浓度、形态和负荷的输出特征.结果表明,相同降雨条件下,林地1的坡长/坡宽比小,径流深度大,林地1坡度较大的草皮型汇流沟渠对径流的削...

The characteristics of non-point source pollution in typical artificial forest lands in Beijing Olympic Forest Park

In order to discover the characteristics of non-point source pollution in Beijing Olympic Forest Park, two typical artificial forest lands with different topography and vegetation covers were selected as the case to study the rainfall-runoff process and pollutant concentrations combined with natural rainfall events. The results showed that the runoff depth of site 1 with smaller length/width ratio was deeper than site 2 with larger length/width ratio. The planted grass swales in site 2 had a better performance in runoff reduction than the artificial turf swales in site 1. A high variability of sediment concentration range and a lower variability of total nitrogen (TN) and total phosphorus (TP) concentration range were obtained during runoff process. The most part of TN and TP lost were in dissolved form, in which, the TDN/TN and TDP/TP ratios were from 60%~80% and 60%~64% in the two sites respectively. In a 6.8mm rainfall event, the observed runoff depth was 0.16mm, and the loss of TN and TP were 0.74mg•m-2 and 0.09mg•m-2 respectively in site 1; while there was no runoff yield in site 2. In a 45mm rainfall event, the runoff depth was 7.77 mm, and the loss of sediment, TN and TP were 1662.82mg•m-2, 35.58mg•m-2 and 3.24mg•m-2 respectively in site 1; while in site 2, the runoff depth was 0.41mm, and the loss of sediment, TN and TP were 86.48mg•m-2, 2.49mg•m-2 and 0.31mg•m-2 respectively. It was shown that the runoff depth could reflect the significant impact on pollutants loss. Thus reducing the runoff yield is critical to non-point source pollution control in the park.