LAUSR

The aim of this study is to explore the specific situation of nonpoint source pollution in Ulansuhai Nur basin, so as to provide reasonable and scientific pollution control and water area protection schemes. According to the socioeconomic statistics and water quality information of Ulansuhai Nur basin from 2008 to 2019, taking chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) as the control indicators, the sources of nonpoint source pollutants (urban domestic sewage, livestock breeding, rural domestic area pollution, rural agricultural production area pollution, and aquaculture pollution) are analyzed. And the amount of each pollution source into the lake is analyzed according to the discharge coefficient and inflow coefficient. The inflow amount and the changing trends of COD, TN, and TP discharged from each pollution source are compared and analyzed, and the main sources of pollution for each control indicator are explored. The causes of water pollution in Ulansuhai Nur basin in recent 10 years are analyzed so as to provide theoretical basis for water pollution control in Ulansuhai Nur basin. The results show that the COD and TN intake in the Ulansuhai Nur basin increase year by year between 2008 and 2019, the pollution load is serious, and it mainly comes from urban domestic sewage and rural agricultural production pollution; the TP intake shows a trend of increasing first and then gradually decreasing, and the inflow amount of pollutants is relatively small and is mainly from livestock breeding; which indicate that the load of nonpoint source pollution in Ulansuhai Nur basin has exceeded the capacity of the lake greatly, causing serious harm to water quality, so proper measures should be taken to control it.