| located in the central of Guanzhong Basin, North of the Weihe River, Weibei loess mesa is a unique landform of Loess Plateau in Northwest China, which is also relatively short in water resources. The completion of the irrigation eased the situation of shortage in water resources. With the continuous development of social economy and changing irrigation water requirement, the status of groundwater and its future changes remains a major issue which has been concerned. Therefore, the study of formation conditions of groundwater, dynamic types, numerical simulation and prediction, has great theoretical and practical value for the sustainable use of groundwater resources and ecological environment construction.This study comprehensively summarize the results and progress of numerical simulation of groundwater home and abroad. On this basis, select a relatively complete unit of the landscape-Baoji Gorge, wool Bay Irrigation District (baoyang irrigation) as a typical irrigation study. Through analysis of the collected date such as geological and geomorphic data, meteorological data, irrigation data, hydrogeological data, groundwater monitoring data, mechanism of dynamic change of groundwater level and the dynamic characteristics were analyzed. By summarizing the hydrogeological conditions of the typical irrigation, established a regional hydrogeological conceptual model. And using FEFLOW and GIS as a platform, established a numerical simulation model fort Typical Irrigation. The main conclusions:(1) Bao Yang Groundwater system is an open natural-artificial composite system. Through the analysis of sources and conditions of supply and drainage in Typical Irrigation, year variation, interannual variation, comprehensively understand the formation mechanism of groundwater and its influencing factors in Bao Yang irrigation. Irrigated area has groundwater level between 387.74m～602.25m. The water level in north is higher than the south. Groundwater is basically flow from north to south, meanwhile to the east and west sides. The overall trend is first decreased, increased again in 6-8 months. Since the irrigation water has been came, there were also large inter-annual difference in groundwater level. The general trend is intense increasing-relatively stable-slow down. The human factor (supply canal and field infiltration and groundwater extraction) is the main factor to drive changes for groundwater level. (2) based on Hydrogeological conceptual model generalized, to rely on GIS platform, using finite element simulation software FEFLOW to set up the corresponding numerical model and adjust parameter, identification. Through model validation and simulation not only get more reasonable and accurate hydrogeologic parameters, but also achieved the dynamic spatial and temporal changes in groundwater level visual simulation. Model simulation effect is basic good. Simulating groundwater flow is consistent with the actual flow field in overall trend. Representative of groundwater observation wells between simulated and measured values, the average RMS error is 0.455m. Representative of well simulated and measured values, the average correlation coefficient is 0.653.(3) According to socio-economic development, agricultural restructuring and the situation of industrial and agricultural water saving potential in study area, assuming irrigation water use programs under different scenarios, taking the predicted groundwater sources afflux water yield into validated identification FEFLOW numerical model, to forecast groundwater level trend. It provides some reference for study of groundwater resources mining model, optimal allocation, science and regulation in Bao Yang irrigation.
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