卫宁平原地下水资源及地下水循环研究

发布时间：2018-08-02 21:34

【摘要】：卫宁平原地处我国西北干旱地区,区内干旱少雨,蒸发强烈,水资源贫乏。随着城镇化的发展,卫宁平原作为宁夏重要的经济开发区和主要的粮食产区,缺水情况严重,供水矛盾日益突出。因此查明卫宁平原地下水赋存情况,合理评价卫宁平原地下水资源量并认清区内地下水循环特征,对实现卫宁地区水资源的高效利用及保障生态安全具有重要的现实意义。基于上述研究目的,本文通过不同方法说明卫宁平原区域地下水资源各组成量大小,阐明区内地下水循环特征及年龄分布特征,为今后进行卫宁地区地下水资源的科学决策提供信息支持。本文首先采用均衡法计算出卫宁平原地下水资源组成及其数值大小。在此基础之上,利用GMS软件建立卫宁平原的三维地下水稳定流和非稳定流数值模型,并利用实际观测孔水位对模型进行拟合和校正。模拟结果表明区内地下水总补给量为3.092×108m3/a,主要的补给来源为田间灌溉入渗、渠系渗漏和降雨入渗补给,占总补给量的82.8%;总排泄量为3.106×108m3/a,以排水沟排泄、蒸发排泄和向黄河排泄为主,研究区表现为微弱的负均衡。为直观揭示研究区的地下水循环系统及其特征,本文选取典型剖面建立了剖面二维数值模型。模拟结果显示,典型剖面上分布有局部、中间和区域循环系统三个级次的地下水循环系统。但由于研究区地形平坦,起伏很小,故剖面上呈现局部循环系统不发育,以中间循环系统为主的特征。循环强度上,局部和中间循环系统的地下水渗流速度和水循环强度大于深部的区域循环系统。而在黄河附近和丘陵台地与平原分界处渗流速度达到最大,地下水循环主要集于剖面中部的中间循环系统。在对剖面水流系统特征有了一定认识后,于前述二维剖面水流模型基础上建立了14C溶质运移模型,研究卫宁平原地下水年龄分布。模拟结果表明,在剖面浅部和中部,地下水年龄较轻,14C视年龄表现为几百到2000年内,为现代水,更新性好。在剖面深部,14C视年龄在15000年左右,局部出现大于30000年的区域,表现为古地下水。
[Abstract]:Weining Plain is located in arid area of northwest China. With the development of urbanization, Weining Plain is an important economic development zone and main grain producing area in Ningxia. The water shortage is serious and the contradiction of water supply is becoming more and more serious. Therefore, it is of great practical significance to find out the occurrence of groundwater in Weining Plain, to evaluate the quantity of groundwater resources reasonably and to recognize the characteristics of groundwater circulation in Weining Plain for the efficient utilization of water resources and the protection of ecological security in Weining Plain. Based on the above research purposes, this paper explains the composition of groundwater resources in Weining Plain by different methods, and clarifies the characteristics of groundwater circulation and age distribution in Waining Plain. It provides information support for scientific decision of groundwater resources in Weining area in the future. In this paper, the composition and numerical value of groundwater resources in Weining Plain are calculated by equalization method. On this basis, the numerical models of steady and unstable groundwater flow in Weining Plain are established by using GMS software, and the model is fitted and corrected by using the actual observation hole water level. The simulation results show that the total recharge of groundwater in this area is 3.092 脳 108m3 / a, and the main recharge sources are field irrigation infiltration, canal system leakage and rainfall infiltration recharge, accounting for 82.8% of the total recharge amount, and the total excretion amount is 3.106 脳 108m3 / a, mainly from drainage ditch, evaporation discharge and discharge to the Yellow River. The study area shows a weak negative equilibrium. In order to reveal the groundwater circulation system and its characteristics in the study area, a two-dimensional numerical model of the section is established in this paper. The simulation results show that there are three levels of groundwater circulation system in the typical section: local, intermediate and regional circulation system. However, because the terrain is flat and the fluctuation is very small, the local circulation system is not developed in the section, and the middle circulation system is the main feature. In terms of circulation strength, the groundwater seepage velocity and water circulation intensity of local and intermediate circulation systems are higher than those of deep regional circulation systems. However, the seepage velocity near the Yellow River and between the hilly platform and the plain reaches the maximum, and the groundwater circulation is mainly concentrated in the intermediate circulation system in the middle of the section. After a certain understanding of the characteristics of the profile flow system, a 14C solute transport model was established on the basis of the two dimensional profile flow model mentioned above to study the age distribution of groundwater in Weining Plain. The simulation results show that, in the shallow and middle part of the profile, the groundwater age of 14C is younger than that of 2000, and it is a modern water with good renewability. In the depth of the section, the age of 14C is about 15000 years, and the local area is more than 3000years, showing paleogroundwater.
【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】：2017
【分类号】：P641.8

【相似文献】