基于Hydrus-1D的中宁平原包气带水分运移规律研究

发布时间：2018-06-01 16:51

本文选题：中宁平原 + 包气带　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：包气带是地下水与大气圈、地表水圈联系的必要途径,它既是自然界中水循环系统的一个有机组成部分,也是大气-作物-土壤-地下水的物质能量传输系统的一个重要环节,研究包气带水分运移规律对阐明地下水的形成以及水循环的研究有重要意义。中宁平原是卫宁平原的一部分,属于沿黄经济区,是宁夏重要的粮食产区。受引黄灌溉影响,这里的地下水与地表水交换频繁,水循环方式以垂向交换为主,蒸发为主要的排泄途径,因此研究地下水的垂向补给和排泄规律,有利于正确评价地下水资源量,科学合理的开发和利用地下水资源。在了解了国内外对于包气带水分运移规律的研究方法及进展以及研究区水文地质条件的基础上,本研究利用包气带原位试验取得的土壤负压数据和气象观测数据以及室内实验取得的土壤物理参数,使用Hydrus-1D软件建立了包气带水分运移数值模型,并在模型的基础上对包气带水分运移规律进行了分析。原位试验分为裸地组和植被覆盖组,试验期分为2013年和2014年两期。利用试验数据对模型进行了率定,通过均方根误差、相对误差、纳什效率系数和决定系数四个拟合效果指标对单个模型和整体的拟合效果进行了评价,认为拟合效果较好,模拟值和实测值随时间变化的趋势接近,基本上能够反映土壤物理性质和包气带水分运移特征。利用模型分析了地表蒸发随气象、植被、地下水位以及土壤性质的关系,认为大气蒸发能力越强,植被需水量越高,地下水位埋深越浅,土壤的导水性能越好则地表蒸发作用越强烈。研究区的小规模降雨对地下水几乎无补给作用,连续的降雨和足量的灌溉是地下水补给的有利条件,利用预测模型得出在干旱且地下水位埋深处在平均水平时,小于50mm的降雨对于地下水补给来说为无效降雨量。
[Abstract]:Aeration zone is a necessary way to connect groundwater with atmosphere and surface hydrosphere. It is not only an organic part of water circulation system in nature, but also an important link of material and energy transfer system between atmosphere, crop, soil and groundwater. It is of great significance to study the law of water migration in aeration zone in order to clarify the formation of groundwater and the study of water circulation. Zhongning Plain is a part of Weining Plain, which belongs to the economic zone along the Yellow River and is an important grain producing area in Ningxia. Affected by the irrigation of the Yellow River, the groundwater and surface water are exchanged frequently, the water circulation mode is mainly vertical exchange and evaporation is the main discharge way. Therefore, the vertical recharge and discharge law of groundwater are studied. It is propitious to evaluate the quantity of groundwater resources correctly and to develop and utilize groundwater resources scientifically and rationally. On the basis of understanding the research methods and progress of water migration in aeration zone at home and abroad as well as the hydrogeological conditions in the study area, Based on the soil negative pressure data and meteorological observation data obtained from in-situ test of aeration zone and the soil physical parameters obtained from laboratory experiments, a numerical model of moisture transport in aerated zone was established by using Hydrus-1D software. On the basis of the model, the law of water migration in the aeration zone is analyzed. The in situ test was divided into bare land group and vegetation cover group, and the trial period was divided into 2013 and 2014. The experiment data were used to determine the rate of the model. The fitting effect of the single model and the whole model was evaluated by four fitting effect indexes: root mean square error, relative error, Nash efficiency coefficient and determinant coefficient, and the fitting effect was considered to be better. The variation trend of simulated and measured values with time is similar, which can basically reflect the physical properties of soil and the characteristics of moisture migration in aeration zone. The relationship of surface evaporation with meteorology, vegetation, groundwater level and soil properties is analyzed by using the model. It is considered that the stronger the capacity of atmospheric evaporation is, the higher the water demand of vegetation is, and the shallower the groundwater level is. The better the water conductivity of soil is, the stronger the evaporation is. The small rainfall in the study area has almost no recharge to the groundwater. Continuous rainfall and sufficient irrigation are the favorable conditions for groundwater recharge. The prediction model is used to get the conclusion that the groundwater level is at the average level when the groundwater level is dry, and the groundwater table depth is at the average level. Rainfall less than 50mm is ineffective for groundwater recharge.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.2

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