丹江口水库入库非点源污染负荷的计算与讨论

Calculation and discussion of non- point source pollution loads in Danjiangkou Reservoir Area

正确估算丹江口水库入库非点源污染负荷对于水源区水环境保护具有重要意义。根据丹江口库区6条主要入库河流汉江、天河、堵河、丹江、老灌河、淇河控制水文站2013年逐日流量数据,采用数字滤波法对基流进行了分割。以逐日流量、河川基流量和代表污染物(CODMn和TP)2013年逐月浓度监测值为基础,采用通量法计算了背景污染负荷和点源污染负荷、非点源污染负荷。结果表明:(1)6条河流入库流量占总入库流量的95.9%,非点源污染已成为丹江口水库水质变化的主导因素。(2)汉江是入库污染负荷的最大来源,其次是堵河。(3)由于非点源污染伴随降雨汇入河道,水库污染负荷主要集中于丰水期,2013年度丰水期CODMn和TP的比例分别达到了80.8%和90.9%。

Correctly estimating the non -point source pollution loads in Danjiangkou Reservoir Area is important to the envi- ronmental protection of the water source area. The Digital Filter method is used to separate the base flows of Hanjiang River, Tianhe River, Duhe River, Danjiang River, Laoguan River and Qihe River in the reservoir basin according to the daily discharge data. Based on the daily flow, the base flow and monthly typical pollutant concentration in 2013, a flux model is set up to calcu- late the background pollution loads, point - source pollution loads and non - point source pollution loads respectively. The calcu- lation results show that in 2013, the inflow discharge of the 6 rivers accounted for 95.9% of the total inflow, and the total pollu- tion loads of CODMn and TP from the 6 rivers are 58.2 thousand t and 1.86 thousand t, while the non - point source pollution loads are 39.82 thousand t and 1. 544 thousand t, so the non - point source pollution is the decisive factor; Hanjiang River is the largest pollutants contributor to Danjiangkou Reservoir and followed by Duhe River; the non - point source pollution enters into the river channel with rainfall, so the pollution load concentrates in the flood season, CODMn and TP accounted for 80.8% and 90.9% of the total pollutants in the reservoir in flood season of 2013.