Impact of nonpoint source pollution on water quality of the Bahe River

Based on the flood events and normal discharge events were monitored from July to December in 2009 at the Maduwang section on the Bahe River. Impact of Nonpoint Source Pollution on Water Quality of the Bahe River was analyzed. The results indicate that: (1)The concentrations of COD, TN, NH₃-N, NO₃-N, NO₂-N, and TP in the flood events are lower than those in normal discharge events. (2)The load transport rate of each pollutant gradually increases up to peak value, and then starts to drop, which is in accordance with the process of flow change. The concentrations of COD, NO₃-N, TP and TN increase initially and then decrease, as well as the concentrations of NH3-N and NO₂-N decrease initially and then increase. (3)Estimated NPS pollution load by mean concentration method: the NPS pollution load of COD, TP, TN, NH₃-N of the Bahe River in the year of 2009 are 8735.03t, 44.59t,726.48t and 246.54t. (4)The NPS pollution load proportions of COD, TP, TN NH₃-N of the Bahe River in the year of 2009 are 31.92%, 35.47%, 46.15% and 42.31%.Therefore, the NPS accounts a large proportion for water pollution of the Bahe River, which can not be ignored.