Xiao-kang Xin *, Wei Yin , Ke-feng Li . Estimation and discussion of non-point source pollution loads with new Flux method in Danjiangkou Reservoir area, China. Water Science and Engineering (2017), doi: 10.1016/j.wse.2017.05.001.
Abstract: The estimation of non-point source pollution loads into the Danjiangkou Reservoir is of great significance for environmental protection in the watershed. In order to
overcome the drawbacks of traditional watershed numerical models, a base flow separation method was established coupled with a digital filtering method and a flux method. The digital filtering method has been used to separate the base flows of the Hanjiang, Tianhe, Duhe, Danjiang, Laoguan, and Qihe rivers. Based on daily discharge, base flow, and
pollutant concentration data, the flux method was used to calculate the point source pollution load and non-point source pollution load. The results show that: (1) In the year 2013, the total inflow of the above six rivers accounted for 95.9% of the total inflow of the Danjiangkou Reservoir. The total pollution loads of chemical oxygen demand (CODMn) and total phosphorous (TP) from the six rivers were 58.2 ×103 t and 1.863 × 103 t, respectively, and the non-point source pollution loads were 39.82 × 103 t and 1.544 × 103 t,
respectively, indicating that the non-point source pollution is the major factor (whose contribution rate was 68.4% for CODMn and 82.9% for TP). (2) The Hanjiang River is the most significant contributor of pollution loads to the Danjiangkou Reservoir, and its CODMn and TP contribution rates reached 79.3% and 83.2%,respectively. The Duhe River
took the second place. (3) Non-point source pollution mainly occurred in the wet season, accounting for 80.8% and 90.9% of the total CODMn and TP, respectively, in 2013. It is concluded that pollution prevention emphasis should be placed on non-point source pollution.
Key words: Danjiangkou Reservoir; Non-point source pollution; Base flow separation; Digital filtering method (DFM); Flux method (FM)
