| Loess Mesa Irrigation District is located in the middle of Guanzhong Basin of Shaanxi,And agriculture of Guanzhong plays a very important role. But the existence and uneven distribution of rainfall and groundwater inadequate water, the region will seriously affect the economic development. therefore, countries to build a number of irrigation project, thus easing the shortage of water resources and enhance economic development. as the social and economic development, the demand for water resources are ever-growing number of underground mining be solving the serious shortage of water, but in the underground water level continued to decline for environmental problems.In a comprehensive review of the research and study of underground movement regular basis, in addition, the ground and dynamic features refers to the dynamics of intensive study. the system for Loess Mesa Irrigation District termed a typical addition to all, established the conceptual model, and rely on the geological feflow and gis in addition to software groundwater numerical simulation of motion in 2013, finally, a typical addition to the tendency to predict the movements of the ground. this paper studies the main conclusions are:(1) The thesis analyses the irrigation water flow trend, interannual and annual variations of groundwater level, spatial and temporal variations, comprehensively summarizes 1983-2009 dynamic characteristics of irrigation groundwater and the problems, and provide theoretical basis for the future In-depth study and regulation. The detailed conclusions are: Phreatic water level of irrigation is between 405-558m, and the groundwater level of the Beishan edge of the alluvial fan in the north is higher than the level of platform area in the south, except for some low-lying land, groundwater flow field is basically from northwest to southeast. In different locations, because of the different of the loess aquifer and the water permeability coefficient, the water table dynamic changes is different during the year. But the overall trend of groundwater level is slight rebound in the process after the start of winter irrigation, and then decline. In March and April, there is a peak. After the spring irrigation, groundwater levels will rebound, and groundwater level begins to decline after the arrival of summer by a wide margin, before the rainy season, a peak will be appeared and then the groundwater level begins to rise. Since 1983, the overall variation trend of groundwater level dynamic is rising– decline. Overall, irrigation, rainfall and artificial groundwater exploitation will mostly affect groundwater level dynamics, and followed by geological factors.(2) According to hydrogeological conditions of BaoYang Irrigation, hydro-geological model is generalized and established, and GIS and FEFLOW software is used to establish numerical model. After adjusting parameters, operation, identification of the model, a more reasonable and more accurate hydrogeological parameters(see Table 6-9) is ultimately obtained, and the spatial and temporal variation of groundwater dynamic is visually simulated. And according to the comparison of measured flow field and simulated flow field, we can see that the general trend of measured and simulated flow field is same, the correlation coefficient is 0.8060～0.8987, the average root mean square error of simulated and observed values is 0.4732. This error is small, which shows that the established numerical model is reasonable, has a better reflection of the actual situation of groundwater, and is feasible for groundwater dynamic prediction.(3) According to the socio-economic development of the study area, meteorological conditions, water demand in different sector and agricultural water-saving measures, two different scenarios are assumed, pre-set Huiyuan items is added to identified proven FEFLOW numerical model, and loess of the original irrigation water level in 2013 is predicted. Groundwater level in both scenarios falls comparing with 2009, comparatively, the groundwater decline rate of the scenario one is bigger than the rate of the scenario two. But the decline rate of both scenarios are not big, that is to say, compared 2009 groundwater table is no more than 1. 3m,the groundwater decline rate is effectively controlled in irrigation... |
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