【作者】 乔晓英；

【导师】 王文科；

【作者基本信息】 长安大学 ， 地质工程， 2008， 博士

【摘要】 准噶尔盆地是西北四大内陆盆地之一,盆地中部古尔班通古特沙漠为我国第二大沙漠,著名的艾比湖是盆地最低排泄点。盆地南缘的天山北麓山前平原区,属于国家西北三大开发区之一,然而该区地处内陆干旱地区,降水稀少,蒸发强烈,生态环境脆弱。区内地下水资源不仅是社会、经济发展的重要物质基础,又是生态环境的重要组成部分,而且还是地质环境系统的信息载体。受气候变化及人类活动的影响,区内地下水循环条件发生改变,地下水环境趋于恶化,从而诱发了地下水降落漏斗、泉流量衰减、地下水污染、土壤次生盐渍化及下游天然植被退化与土地沙化加剧等地质生态环境问题。因此,围绕着地下水循环条件变化下的地下水环境演化及其可再生性研究就构成了解决该区经济、社会持续发展与生态环境保护的关键,也为西北类似地区地下水可持续利用提供示范作用。本文以准噶尔盆地南缘为研究区,以地下水系统理论为指导,以地下水循环条件变化为切入点,以地下水环境演化及地下水可再生性为主线,运用环境科学、系统科学、地下水水文学等学科的基本理论,采用定性、定量相结合的手段,通过影响地下水状态改变的自然、人为因素分析,从量与质两方面揭示地下水环境演化过程及其发展趋势。从水资源可再生理论出发,探讨地下水可再生性基本理论与方法。主要成果包含五大部分。一是区域地下水循环形成条件及其循环模式探讨。地下水循环系统与周围介质进行物质、能量与信息交换,导致地下水补给、排泄及径流条件的改变,为此总结了准噶尔盆地南缘五种地下水循环模式:“山间盆地”多次循环型、“山前褶皱带”多次循环型、“山间谷地”多次循环型、“山前凹陷盆地”多次循环型、“山前凹陷盆地”一次循环型。围绕地下水资源、生态与环境属性及其资源供给、生态维持与调控及地质环境稳定等功能,分析了该循环模式与地下水环境演化及其可再生性之间的关系。因而地下水循环是地下水环境演化及其可再生性的基础;二是地下水环境演化过程及其驱动力分析。以“状态—驱动力—响应”研究为主线,从地下水状态改变出发,以地下水位动态、地下水量动态、地下水质动态为环境要素,分析地下水动力场、地下水化学场演化过程,探讨地下水开发引发的地质生态环境负效应。从自然因素与人类活动两方面,采用灰色关联分析、主因子分析等方法,揭示了盆地地下水环境演化的驱动力,其中盆地南缘山前平原地下水环境受气候变化影响较大,细土平原主要受人类活动影响;三是地下水环境演化趋势预测。以地下水位、地下水量、地下水质等地下水环境要素为例,分别采用人工神经网络模型、数值模拟模型、指数平滑趋势模型预测了地下水动力场、地下水水化学场的演化趋势。结果表明,地下水位在不同水文地质单元呈现下降或上升等趋势;地下水质无论矿化度还是硝酸根离子含量均呈上升趋势;四是地下水可再生性评价理论与方法初步探讨。提出地下水可再生性概念,即综合反映地下水资源补给与调蓄、更新与恢复能力;地下水可再生性表现为周期性、可变性、有限性、复合性等特征;地下水可再生性的影响因素既有水文气象条件、补给水源条件、地下水循环交替条件等自然因素,又有地下水开发利用程度、人类其他工程建设活动等人为因素。由此建立了天然补给可用率、回归补给率、调蓄系数、补采平衡率、地下水贮留时间、导水系数6项指标组成的地下水可再生性评价指标体系;以地下水系统构造评价单元,通过层次分析法确定指标权重,在探讨评价标准基础上,运用综合指数模型和模糊综合评判模型进行评价。评价结果表明,山间洼地、河流上游河谷地带地下水可再生性指数>0.4,具有很强的地下水可再生能力,沙漠边缘地下水可再生性指数<0.01,地下水可再生能力最弱,细土平原地下水可再生性指数0.1-0.2,地下水可再生能力较弱;五是地下水可再生性维持途径与调控技术研究。首先,选取盆地南缘玛纳斯流域为典型流域,通过山间洼地地下水库与山前平原地下水库“两库”联合调蓄的数值模拟,估算了山间洼地地下水库与山前平原地下水库的最大调蓄库容分别为14.62×108m3和6.01×108 m3,合计20.63×108 m3。并计算了“两库”地下水的更新速率分别为24.89a和133.07a;其次,以乌鲁木齐河流域乌拉泊洼地的西山应急水源地建设为例,模拟该水源地建设对已建甘诃子水源地及其周边生态环境的影响,探讨了集中供水水源地的地下水调控模式;最后通过调蓄、调控、调水、节水等方案的仿真模拟,提出了地下水可再生性维持的综合措施,并分析所取得的经济与环境效益,为缓解区内水资源短缺与水资源浪费的矛盾,提高水资源利用效率提供技术支撑。更多还原

【Abstract】 The Junggar basin is one of the four inland basins. The Gu’erbanTonggute desert is laid in the middle, and the Aibihu lake is the lowest discharge zone. The plain, of north piedmont of the Tianshan mountains, which laid on the south edge of the Junggar basin, is one of the three development regions in Northwest of China. Because it is laid in the arid inland region, precipitation is rare, whereas evaporation is strong and eco-environment is very vulnerable, so groundwater is not only the key material base of society-economy development, but also the important composition of eco-environment, meanwhile, the information media of geology environment system. With influence of climate change and human activities, the groundwater cycle conditions have changed, groundwater environment has deteriorated, a lot of geological and eco-environmental problems have caused, such as groundwater dropdown hopper, groundwater containment, spring exhaustion, secondary salinization, vegetation degeneration and land dissertation so on. So researches on groundwater environment evolution and groundwater renewability with change of groundwater cycle conditions, is a key to solve regional sustenance development of society-economy and eco-environment improvement, meanwhile, a typical region of groundwater sustainable utilization to the similar northwest districts.Directed by groundwater system theory, embed in change of groundwater cycle conditions, enclosed by the main line of groundwater environment evolution and groundwater renewability, the paper, with the south edge of Junggar basin as typical regions, applied the basic theory of environment science, system science, and groundwater hydrology so on, reveals evolution process and development tendency on groundwater environment by analysis of natural and human factors affecting groundwater states combining qualitative means with quantitative method. Then, it discusses the basic theory and method of groundwater renewability on the basis of resource renewability theory. The research achievements are consisted of five parts as follow.The first achievement is about researches on formation conditions and cycle patterns of region groundwater cycle. During material, energy and information transformation between groundwater cycle system and its circular media, some conditions of groundwater recharge, discharge and runoff have changed, and then form five groundwater cycle patterns, which are many times cycle in an intermountain basin, many times cycle in a folded piedmont, many times cycle in an intermountain valley, many times exchanges in a sunken piedmont, one time exchange in a sunken piedmont. Circling with resource property, ecology and environment properties of groundwater, the thesis analyzes the relationship among these cycle patterns, groundwater environment evolution and groundwater renewability.The second achievement is about analysis on evolution process and driving force of groundwater environment. Firstly, with the main line of“states—driving force—response”, from the view of change of groundwater states, with regime on buried depth of groundwater table, that on groundwater volume and groundwater quantity as environment factors, this paper analyzed groundwater environment evolution process and geological eco-environment effects. Secondly, from natural factors and human factors, by meanings of method such as grey relation analysis and main component analysis so on, it revealed driving force of groundwater environment evolution. And also it showed that climate change is the main influence factor in pediment plains, however, human activities is the main one in the clay plain zone.The third achievement is about evolution forecast on groundwater environment. With buried depth of groundwater table, groundwater volume, groundwater quality as groundwater environment factors, by a BP netWare model, a numerical simulation model, an index smooth model to forecast evolution tendency of groundwater dynamic field and its chemical field respectively. The research results showed that groundwater level may decline or rise in different hydrogeological units, whereas either groundwater mineralization or NO3- concentration raised.The forth achievement is about initial discussion on basic theories and method on groundwater renewability. Firstly, the paper put forward to a concept on groundwater renewability, that is, the total capability about groundwater recharge, regulation and storage, renewability and recovery. The concept has periodicity property, limitation property, compound property and so on. Among influence factors of groundwater renewability, which include not only natural factors such as hydro-meteorological conditions, recharge source conditions, groundwater cycle conditions etc., but also human factors such as groundwater development and utilization degree, human engineering construction activities etc.. Secondly, this paper established assessment index system of groundwater renewability, including natural recharge ratio, return recharge ratio, regulation and storage coefficient, balance ratio between recharge and exploration, groundwater residence time, transmissivity. Also it discussed relative assessment standards, Then by Analytic Hierarchy Process (AHP) weight method, based on assessment units of groundwater system; it assessed groundwater renewability by means of the comprehensive index model and comprehensive fuzzy model. Assessment results showed that groundwater renewability index was larger than 0.4 in intermountain zones and valley zones of the upper reaches of rivers, which means stronger renewability, that the index is smaller than 0.01 in the marginal zone of desert and oasis, which means weaker renewability, and that the index is from 0.1 to 0.2 in clay plains, which means medium renewability.The fifth achievement is about maintenance approaches of groundwater renewability and regulation control techniques. Firstly, choosing Manasi river watershed as a typical watershed, simulating combination regulation and storage of two kinds of groundwater reservoirs, the paper evaluated that the reservoir storage capacity was about 14.62×108m3 in intermountain zones and 6.01×108m3 in pediment plains,the total being up to 20.63×108m3, and that its renewability velocity was about 24.89a and 133.07a respectively. Secondly, with planning-construct Xishan urgent water source field as an example, in Wulabo low land of the upper reaches of Urimqin river valley, the paper simulated influence of construction on the water source field on Ganhezi finished water source field and its surrounding, discussed regulation and control patterns of well field for concentrated water supply. Finally, it put forward to synthetic measures to groundwater renewability, and consequently analyzed economic and social benefit by numeric stimulation of some schemes including regulation and storage, regulation and control, shifting water and saving water so on. All these can provide technique support to relieve contradiction between water resource shortage and water wastage, and to improve utilization efficiency of groundwater resources.更多还原