新疆伊犁—巩乃斯河谷地下水循环演化规律研究

发布时间：2018-05-22 09:34

本文选题：伊犁㧟巩乃斯谷地 + 地下水循环　；参考：《长安大学》2015年硕士论文

【摘要】：伊犁-巩乃斯谷地地处我国西北边陲重要城市-伊犁自治州境内。在国家实施的一带一路‖经济战略上占有十分重要的地位。区内经济的快速发展对水资源的要求量日益提高,由于区内地下水分布广泛,便于开发利用,是区内水资源的重要补充之一。由于以往在该地区开展的水文地质工作程度有限,导致对于研究区的水文地质以及地下水循环认识程度较低,尚不能为研究区内科学合理利用地下水资源提供支撑。因此,开展研究区地下水循环演化规律研究工作对地下水资源合理开发利用以及生态环境保护具有重要的理论及实践意义。本文以区域地下水循环理论为指导,综合运用水文地球化学、环境同位素水文学以及地下水流数值模拟等理论与技术,对伊犁-巩乃斯谷地地下水循环演化规律进行分析研究。取得了以下成果与认识:(1)伊犁-巩乃斯谷地是一个断陷谷地,整个谷地,第四系沉积厚度不均,在300-800米不等。南北向上,从山区到河谷区,地下水由山区(补给区)经过山前冲洪积平原(径流区)排泄伊犁河(排泄区)。东西向上,特克斯河汇入巩乃斯谷地之前,含水层结构为单层的,在伊犁河段出现多层结构。伊犁河是区内最低侵蚀基准面,地下水总体是由东向西流动。(2)水化学研究结果表明,南北向上,地下水化学类型由北向南依次为HCO3-Ca-、HCO3-Ca-Mg、HCO3-SO4-Ca-Mg-Na为主。东西向上,地下水化学类型由东向西水化学类型依次为HCO3-Ca、HCO3-SO4-Ca-Mg、HCO3-SO4-Ca-Na。总体上看,地下水矿化度以小于1g/l为主,水质良好。(3)同位素研究结果明,区内主要补给源为大气降水,潜水地下水的更新速率在不同的地貌单元是不同的,在强倾斜砾质平原地下水循环周期在5-10年,在缓倾斜含砾细土平原及冲洪积细土平原地下水循环周期30-40年。与潜水相比,承压水(埋深200m)的14C测试结果表明,地下水在承压水含水层中滞留时间较长,其地下水年龄在2万年以上。(4)通过建立区域地下水流数值模型,刻画了地下水动力场演化,主要发育三级地下水循环系统,分别为局部地下水流循环系统、中间地下水流循环系统和区域地下水流循环系统。于此向对应也划分了三个地下水径流区,分别为浅部强径流区(0.5m/d)、中部中等径流区(0.1~0.5m/d)和深部弱径流区(0.1m/d)。(5)研究区存在两种典型的水循环模式:一是南北向上,山区的大气降水或冰雪融水形成河流,河流由于渗漏形成基岩裂隙水。随着沉积环境变化、地形坡度变缓,一部分基岩裂隙水在山前冲洪积扇有泉水等出露地表,而另外一部分地下水则继续向前运动,最终排泄伊犁河。二是东西向上,东部山区是研究区海拔最高点,受地势影响,东部山区约90%的大气降水或冰雪融水以地表径流的形式向西流动,汇入巩乃斯河,而约10%的大气降水或冰雪融水则转为地下水。
[Abstract]:Yili-Gongnisi Valley is located in the territory of Yili Autonomous Prefecture, an important city in the northwest of China. In the national implementation of Belt and Road economic strategy occupies a very important position. With the rapid development of regional economy, the demand for water resources is increasing day by day. Because of the wide distribution of groundwater in the region, it is easy to develop and utilize, which is one of the important complements of regional water resources. Due to the limited degree of hydrogeological work carried out in this area in the past, the degree of understanding of hydrogeology and groundwater circulation in the study area is low, which can not provide support for the scientific and rational utilization of groundwater resources in the study area. Therefore, it is of great theoretical and practical significance to study the regularity of groundwater circulation evolution in the study area for the rational development and utilization of groundwater resources and the protection of ecological environment. Based on the theory of regional groundwater circulation and the comprehensive application of hydrogeochemistry, environmental isotopic hydrology and numerical simulation of groundwater flow, this paper analyzes and studies the regularity of groundwater cycle evolution in Yili Gunesi Valley. The following results and understandings have been achieved: (1) the Yili-Gonesi Valley is a rifted valley, and the deposition thickness of the entire valley and Quaternary is uneven, ranging from 300m to 800 m. From the mountainous area to the valley area, the groundwater flows from the mountain area (recharge area) through the mountain front alluvial plain (runoff area) to discharge the Yili River (discharge area). Up east and west, the aquifer structure was monolayer before the Tex River flowed into the Gunas Valley, and a multilayer structure appeared in the Ili section. Yili River is the lowest erosive datum in this area, and the groundwater flows from east to west. The results show that the chemical types of groundwater are mainly HCO3-Ca-Mg-Na from north to south in order of HCO3-Ca-MgHCO3-SO4-Ca-Mg-Na. The chemical types of groundwater from east to west are HCO3-CaHCO3-SO4-Ca-MgN HCO3-SO4-Ca-Na. On the whole, the mineralization degree of groundwater is smaller than 1g/l, and the water quality is good. The results show that the main recharge source in this area is precipitation, and the regeneration rate of groundwater is different in different geomorphological units. The groundwater cycle period is 5-10 years in strongly inclined gravelly plain, 30-40 years in gently inclined gravelly soil plain and alluvial fine soil plain. Compared with phreatic water, the 14C test results of confined water (buried depth 200m) show that the retention time of groundwater in confined water aquifer is longer, and the groundwater age is more than 20,000 years. The evolution of groundwater dynamic field is described. There are three types of groundwater circulation system, namely, local groundwater circulation system, intermediate groundwater circulation system and regional groundwater circulation system. In this direction, three groundwater runoff zones are also divided into two typical water cycle models: shallow strong runoff area (0.5 m / d), middle runoff area (0.1 ~ 0.5 m / d) and deep weak runoff area (0.1 m / d ~ (5). Two typical water cycle models exist in the study area: first, the north and south directions are upward. Precipitation or ice-snow meltwater forms rivers in mountainous areas, and rivers form bedrock fissure water due to leakage. With the change of sedimentary environment, the slope of topography becomes slow, some of the fissure water of bedrock is exposed to the surface such as spring water in the alluvial fan in front of the mountain, while the other part of the groundwater continues to move forward and eventually drains the Yili River. Second, east-west, the eastern mountainous area is the highest altitude in the study area. Affected by the topography, about 90% of the precipitation or ice melt water in the eastern mountainous area flows westward in the form of surface runoff, and flows into the Gonas River. About 10% of the precipitation or ice and snow melt water is converted to groundwater.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P641.2

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