【作者】 杨建飞；

【导师】 刘俊民；

【作者基本信息】 西北农林科技大学 ， 农业水土工程， 2011， 硕士

【摘要】 黄土原灌区位于陕西省关中盆地中部,在关中国民经济中占有相当重要的位置。但该区域存在降雨量时空分布不均、地表水水量不足等问题,严重影响该区域国民经济的发展。因此国家建设了一批灌溉工程,从而缓解当地水资源紧缺的局面,提高经济发展速度。随着社会经济的发展,人们对水资源的需求量也日渐增多,地下水开采成为解决该区水资源严重不足的主要方式,但是导致了地下水水位持续下降等环境问题。因此研究灌区地下水的补排关系、动态规律对于灌区水资源合理开发和利用有着十分重要的作用,关乎整个灌区的国民经济发展速度和生态环境安全。本次研究在全面总结国内外地下水动态规律研究的基础上,对灌区地下水水位动态变化机理及动态特征进行了深入而系统的研究。同时对黄土原典型灌区水文地质进行概化,建立了水文地质概念模型,并依赖FEFLOW和GIS软件对灌区地下水动态进行数值模拟,最后对2013年典型灌区的地下水动态趋势进行了预测。本次论文研究的主要结论有:(1)本次论文通过对黄土原灌区地下水流场总体趋势、地下水水位年际变化特征、年内变化特征以及时空变化特征的分析,全面总结了1983—2009年末灌区地下水水位的动态特征,为今后深入研究灌区地下水动态及调控提供理论依据。研究表明:灌区潜水水位介于405-558m之间,山前洪积扇前缘的北部水位高于南部台原区水位,除部分洼地以外,地下水流场基本是从西北向东南人后靠近南北边界排除。在不同地址单元内,因含水层黄土的渗透系数以及给水度的不同,地下水位年内动态变化差异也不一样,但总体趋势是冬灌开始以后,地下水有一个小幅回升的过程,然后又下降,在3、4月份出现一个峰值,春灌后水位又有回升,夏季到来后地下水开始下降且幅度较大,到雨季来临之前又出现一个峰值,之后水位又开始回升。自1983年以后,地水位年际动态变化总体趋势是上升—下降。总体来说,灌溉、降雨以及人工开采对黄土原灌区地下水位水位动态变化的影响最大,其次是地质因素。(2)根据宝羊灌区水文地质条件,概化并建立水文地质模型,同时借助GIS,利用FEFLOW软件建立相应的数值模型,通过对模型进行多次调参、运行、识别,最终获取了较合理、较准确的水文地质参数(见表6-9),从而实现了该区地下水位动态时空变化的可视化模拟。同时通过实测流场和模拟流场的对比发现:地下水模拟流场和实际流场总趋势基本一样,模拟值与实测值之间的相关系数为0.8060～0.8987,典型代表观地下水位模拟值与实测值之间的平均均方根误差为0.4732,说明模拟值和实测值的误差较小,所建立的数值模型较合理,能够较好的反映地下水动态的实际情况,对于下一步的地下水动态预测是可行的。(3)根据研究区社会经济发展状况、气象条件、各部门用水情况以及农业节水措施等,假设两种不同的情景方案,将预先设定的地下水汇源项加入经过验证识别的FEFLOW数值模型,预测2013年黄土原灌区水位变化。两种方案下,2013年地下水较之前2009年仍然是下降的,方案一较方案二总体水位降幅较大,但是两种方案地下水变化幅度都不大,与2009年地下水水位相比不超过1.3m,灌区地下水下降速度得到有效控制。更多还原

【Abstract】 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更多还原