Irrigation & Drainage Systems Engineering

Field Assessment of Basin Irrigation Performance in Hetao, Inner Mongolia

Abstract

Miao Q and Shi H

Hetao irrigation district (Hetao) is located in the upper reaches of Yellow River basin. Surface irrigation is used because there is a high charge of sediments in the irrigation water and is appropriate to leach salts. Basin irrigation is the most used irrigation method. Traditional practices are inadequate for saving water and surface irrigation modernization is needed. A better knowledge of the performance of irrigation systems is required to base that modernization. An experimental research work was developed at Dengkou Experimental Station to assess the irrigation performance in laser land leveled fields. It is located on an irrigation sector supplied in agreement with a rotational delivery scheme managed by the Water Users Association (WUA), which usually practices a total of 7 events and the autumn irrigation. The typical field length is 50 m, with a width between 10 and 50 m, with a silt loamy soil. The irrigation performance was assess from field measurements carried out in several fields, cropped with the main irrigated crops, wheat, maize and sunflower. The irrigation field evaluation was based on observations of advance and recession times, soil moisture, inflow discharges, application time, topographic survey and crop development data. In addition, infiltration curves for typical and seasonal irrigation events were developed, and the Kostiakov infiltration parameters were estimated from field observations using the inverse method with the SIRMOD model. The irrigation operative parameters and the performance indicators were obtained, concluding that the distribution uniformity is very high, between 90 and 96%, and that the cutoff time has a very sensitive effect on beneficial water use fraction. Finally, the results of this study allowed the appropriate knowledge, including the crop irrigation scheduling data, for the irrigation design models aimed at developing irrigation alternatives.