【作者】 连珺；

【导师】 钱会；

【作者基本信息】 长安大学 ， 环境工程， 2007， 硕士

【摘要】 本文在野外调查的基础上,应用环境同位素方法,对银川平原地下水的补给机理和循环模式进行了分析,研究成果为客观认识该地区地下水的的可更新能力,制定合理的水资源开发利用模式提供了科学依据。这对于保证当地经济的可持续发展、缓解水资源短缺矛盾,保护银川平原地下水资源具有重要的意义。主要的研究内容和结论如下:（1）根据大气降水的同位素资料,阐明了大气降水δ¹⁸O的季节变化及其与降雨量、蒸发量的关系,建立了银川平原雨水线方程,与全球雨水线比较,得出结论认为研究区雨水在下降过程中明显受到了强烈蒸发作用的影响。（2）分析了研究区黄河水、湖水、单一潜水、上覆潜水、承压水的环境同位素分布特征,在此基础上,研究了各区地下水的补给来源,探讨了各类水体之间的相互关系,确定了单一潜水区潜水和多层结构区上覆潜水补给源的补给比例,潜水和承压水的越流补给比例及排水沟排泄地下水的比例。结果表明:贺兰山东麓山前洪积倾斜平原单一潜水主要由基岩裂隙水补给,青铜峡黄河冲积扇单一潜水及多层结构区上覆潜水主要由黄河水补给。在城市地下水集中开采区,第一承压水接受上覆潜水的平均补给比例到达了64.17%,排水沟排泄地下水的比例为62%。（3）利用同位素分馏理论计算了研究区湖水、上覆潜水、沟水的蒸发比例,得出结论认为:由南到北,湖水和上覆潜水受到蒸发作用的影响越来越大。（4）利用插值法对银川平原1953年以来各年的大气降水氚浓度进行了恢复,通过建立指数模型计算出潜水的滞留时间,并拟合出平均年龄。得出结论:研究区潜水积极参与了现代水循环,其平均更新时间为48年。最后,利用Vogel、Tamers、Pearson模型计算出承压水年龄,表明除补给区和承压水水位漏斗区外,银川平原承压水年龄均属于“古水”,天然条件下径流缓慢、地下水更新速度小。更多还原

【Abstract】 Based on field survy,we use environmental isotopes to analyze the recharge mechanism and cycle patterns of the groundwater in Yinchuan plain.The research results provide scientific base to realize the renewable property of groundwater and way to reasonable exploration,which is significant to mitigate the shortage of water resource.The results are summarized as following:（1） According to the environmental isotope dates of precipitation in Yinchuan plain,the paper clarifies the seasonal variation ofδ¹⁸O,the relationships betweenδ¹⁸O、precipitation and evaporation.It also establishes the Local Meteoric Water Line（LMWL）, which is compared with the Global Meteoric Water Line（GMWL）.Result shows that the precipitation is influenced by strong evaporation.（2） The paper also analyzes the distribution characteristics of environmental isotope in different water bodies:Yellow River water,lakes,single-layer structured phreatic water subsystem,multi-layer structured phreatic water subsystem,confined water,studies the main recharge of groundwater,discusses the relationship between these types of water in Yinchuan plain,and gets kinds of recharge percentage and discharge percentage:recharge percentage of single-layer structured phreatic water and multi-layer structured phreatic water,leakage recharge percentage between phreatic water and confined water,discharge percentage of drainage ditches.Results show that:the main source of groundwater supply of single-layer structured phreatic water subsystem in the area of piedmont acclivitous alluvial and flood plain is groundwater in base rock of Helan Mountain Eastern Region.The main source of groundwater supply of single-layer structured phreatic water subsystem in Yellow River alluvial fan in Qingtongxia and multi-layer structured phreatic water subsystem in the area of alluvial and flood plain is Yellow River water,leakage recharge percentage between phreatic water and confined water is 64.17%,discharge percentage of drainage ditches is 62%.（3） Isotope fractionation model is established to analyze the evaporation percentage of lakes,multi-layer structured phreatic water and drainage ditches from South to North. Conclusions are obtained that:influetion of evaporation on lakes and multi-layer structured phreatic water become larger and larger from South to North.（4） Inoder to recover the tritium concentration in precipitation from 1953 to 2004 for Yinchuan plain,interpolation method has been employed,and the tritium concentration in precipitation has been recovered.Then,exponential model is established to caculate the age of the phreatic water.The results show that the pheatic water has an active renewable property,for being renewed once in 48 years.At last,we use Vogel、Tamers、Pearson models to calculate the age of confined water,coming to the conclusion that the confined water in Yinchuan plain is paleogroundwater except in the recharge area and in the depression cone of deep groundwater,which has a very slow circulationg rate and low renewing capacity.更多还原