Influencing factors and countermeasures of irrigation return flow pollution in Ningxia Yellow River Water Irrigation District

In this paper, the factors influencing pollution from irrigation return flow in Ningxia Yellow River Water Irrigation District (NYRWID) was analyzed. Analysis on pollution in NYRWID from irrigation return flow indicates that among the 200 barrel drains investigated, 13 are seriously polluted. The main pollutants include NH₃^＋-N, TP, fluorides, COD and BOD, all of which exceed safety limits. The results further show that the subjective natural conditions, used agricultural chemicals, obsolete irrigation projects and traditional production modes, enhance large amounts of pollutant movement trough irrigation return flows into the Yellow River. Pollution prevention and countermeasures advanced are referenced to further research. Prevention measures like strengthening management of irrigation return flow, intensifying scientific research, increasing financial investment and emphasizing water resources saving and protection can go a long way to abating pollution in NYRWID.