Evaluating the characteristics of hydraulic driven non-point source pollution yield in agricultural watershed

Non-point source (NPS) pollution is one of the major pollution sources in agricultural watershed, and the NPS pollution is the governing factor for polluting surface water. In this paper, series of hydrologic response units were set in various land-use plots to observe the runoff yields and NPS pollution yields from 2008 to 2010. The rainfall and fertilization were recorded in various types of land-use. Based on the long-term observation data, the characteristics of flow yield and critical precipitation intensities for generating runoff were quantified, and the hydraulic driven NPS pollutions (TN, TP) were analyzed temporally and spatially. The results show the flow yield is positive to total amount and intensity of precipitation and hillslope, but negative to vegetation canopy and Tillage intensity. Based on surface hydraulic conditions, the NPS pollution yield on various lands are calculated statistically. The seasonal fluctuations of NPS pollution yield rates are strongly related to flow production and human artificial fertilization. This work will enhance the understanding of NPS loss in agricultural watersheds.