Yellow River Irrigation and Analysis of the Drainage Characteristics of Ningxia

In this paper, the water volume of the recirculation ditches in the Yellow River irrigation district is divided into the base flow and return water of farmland irrigation. The water volume in the no irrigation season is mostly the base flow, generally reflects the point source and source load discharge in the irrigation area. The irrigation season is mainly based on return water of farmland irrigation, which generally reflects the nonpoint source load carried in the farmland water. The comparative analysis shows that the fourth drainage ditch has the largest proportion, followed by the third drainage ditch, the second drainage ditch, the first drainage ditch and the fifth drainage ditch, indicating that point source pollution of the fourth drainage ditch is the most serious. The point source pollution of the fifth drainage ditch is relatively low. Taking the fourth drainage ditch with the smallest proportion of return water of farmland irrigation as an example, the water quality of the point source drainage is worse than the water quality of the farmland drainage water, indicating that the four-row point source pollution is the most serious, and the point source pollution of the fifth drainage ditch is relatively minimal.