Research on the non-point source pollution characteristics and water environmental capacity within small river basin of agricultural areas a case study of the small watershed near Gan village, Tanxia town

A small watershed of a tributary of the Gantang River was chosen as the study object. The water environment capacity and the amount of non-point source pollutants entering the river were calculated by combining field measurements and survey data. The results reveal that the water quality in the basin exceeds the standard severely, with 23.12t of TN, 1.64t of TP, 58t of CODMn, and 12.05t of NH3-N exceed during the plentiful period; The watershed exceeded the TN standard by 14.3t, TP by 1.64t with 17.489t of CODMn remaining in water environmental capacity and 0.71t of NH3-N exceed during the drought period. Finally, suggestions for the prevention and control of the water environment in the watershed were proposed in response to the pollution characteristics, which are of great significance for improving the water environment of the agricultural area