Using MODFLOW and GIS to Assess Changes in Groundwater Dynamics in Response to Water Saving Measures in Irrigation Districts of the Upper Yellow River Basin

The irrigation districts of the upper Yellow River basin are highly productive agricultural areas of North China. Due to the severe water scarcity, application of water-saving practices at both farm and district levels are required for sustainable agricultural development. An integrated methodology was developed adopting loose coupling of the groundwater flow model MODFLOW with ArcInfo Geographic Information System to assess the impacts of irrigation water-saving practices and groundwater abstraction foreseen for the year of 2020 on the groundwater dynamics of the Jiefangzha Irrigation System (JFIS) in Hetao Irrigation District, upper Yellow River basin. The model was calibrated and validated with datasets of years 2004 and 2005; the model efficiency EF was respectively 0.98 for calibration and 0.99 for validation. Results of the simulation of the groundwater dynamics of the study area show that water-saving practices referring to canal lining and upgrading hydraulic structures applied in 60% of the area, and upgraded farm irrigation technology in 50% of the area may consist of a reasonable solution. Their implementation would lead to reduce groundwater evaporation by 43 mm and the total diversions from the Yellow River by 208 mm, i.e. about 20% of present volumes diverted. Most of routines and strategies for model construction may also be used for other regions, especially for irrigation districts in the upper Yellow River basin.