潮河流域非点源污染控制关键因子识别及分区

将GIS技术、ArcSWAT模型与分析技术相结合,以农耕养殖程度较高的北京密云水库上游潮河流域为研究区,通过对流域近20年非点源污染负荷时空变异情况进行模拟,识别影响非点源污染流失的关键因子,进行非点源污染控制区划.结果表明,总氮和总磷年均负荷量分别为563.3,28.7t/a,氮磷负荷空间分布特征表现为:丰水年以地势较高且农业耕作活动频繁区域为主,平水年和枯水年表现为靠近河道的农业用地与畜禽养殖区为主.采用多因素方差分析11种不同因素对流域非点源污染负荷的影响程度表明,施肥量是影响氮磷输出的最主要的因子,坡长、土壤类型、土地利用方式及坡度是影响氮磷输出的次重要因子;针对潮河流域长期传统耕作以及化肥过量施用的现状,土壤有机磷的含量也会对总磷的输出产生一定的影响.潮河流域可划分为3个污染控制区,第1类:污染控制区(以近河道耕种区为主,面积186.74km²),第2类:污染治理区(农村生活及畜禽养殖区为主,面积23.09km²),第3类:生态修复区(高坡度强降雨区为主,面积1365.25km²).该研究结果可有效提升流域非点源污染治理的效率,为水源地流域环境保护提供参考.

Identification of key factors and zonation for nonpoint source pollution controlin Chaohe River watershed

Non-point source pollution(NPS) had deteriorated water quality in Miyun Reservoir watershed. GIS technology, ArcSWAT model, and statistics analysis were coupled to identify the zonation of NPS control in Chaohe river watershed, one main tributary in northeast of Miyun Reservoir watershed, with relative strong intensive agricultural activities. The results showed that annual average loads of TN and TP were 563.3t/a and 28.7t/a, respectively. The spatial distribution of NPS pollution load was greatly diverse with different precipitation and terrain in Chao river watershed. In high flow year, the agricultural land at higher elevation had the highest NPS pollution loads, whereas in the normal and low flow year, the agricultural land and livestock area also contribute the major pollution load; the fertilizer application amount was identified as the most important factor of TN and TP loss. Meanwhile, the slope length, soil type, land use, and slope degree were also more important factors; The content of organic P in soil may contribute to TP loss due to long term cultivation and overuse of fertilizer in Chaohe river watershed; Three zones for NPS control in Chaohe river watershed were divided as pollution control zone where the agricultural activities was intensive, pollution treatment zone where was livestock breeding area and villages, ecological restoration zone where was high soil erosion at higher elevation.