Numerical Simulation of Water-Salt Movement Under Well-Canal Combined Irrigation Scheme in Qingtongxia Yinbei Irrigation District

The well-known ancient Qingtongxia Irrigation District, one of the largest irrigation projects in China, is still suffered from serious salinity problem caused by the high groundwater table, high mineral concentration in ground water, and intense phreatic evaporation. By using the HYDRUS computer program, one-dimensional water-salt movement was simulated under diffirent well-canal combined irrigation schemes with typical irrigation regime for cropping wheat in spring and corn in late summer. It is found that different irrigation conditions, for example, the surface irrigation, well-canal combined irrigation, etc. have different effects on the soil reclamation. Hence, the simulated results will provide a guidence for the reclamation of the salinity soil and rehabitation of the irrigation district.