超采背景下地下水化学特征演变及机制分析——以新疆昌吉州东部奇台县为例  

Evolution and mechanism analysis of groundwater chemical characteristics in the context of overexploitation——A case study of Qitai County,eastern part of Changji Prefecture,Xinjiang

作　　者：刘清华 吴彬[1,2] 武刚 高凡 杜明亮[1,2] 曹伟 LIU Qinghua;WU Bin;WU Gang;GAO Fan;DU Mingliang;CAO Wei(College of Water Conservancy and Civil Engineering,Xinjiang Agricultural University,Urumqi 830052;Xinjiang Key Laboratory of Hydraulic Engineering Security and Water Disasters Prevention,Urumqi 830052;Xinjiang Changji Prefecture Water Resources Management Center,Changji 831100;Xinjiang Uygur Autonomous Region Water Resources Centre,Urumqi 830000)

机构地区：[1]新疆农业大学水利与土木工程学院,乌鲁木齐830052 [2]新疆水利工程安全与水灾害防治重点实验室,乌鲁木齐830052 [3]新疆昌吉州水资源管理中心,昌吉831100 [4]新疆维吾尔自治区水资源中心,乌鲁木齐830000

出　　处：《环境科学学报》2024年第4期168-178,共11页Acta Scientiae Circumstantiae

基　　金：自治区“三农”骨干人才培养项目(No.2022SNGGGCC009)。

摘　　要：地下水超采不仅引发生态与地质环境问题,而且对水质产生影响.探究超采背景下地下水化学演变特征,对区域地下水资源开发利用与保护具有重要意义.本文基于2001―2020年16眼原位井长系列监测数据及2020年30组地下水水质数据,采用Piper三线图、Spearman秩相关系数法、Gibbs图、离子比值法等方法对奇台县近20年地下水化学变化特征进行了分析.结果表明:(1)超采背景下,近20年奇台县平原区矿化度(TDS)呈下降趋势,水质趋于淡化.地下水化学类型主要由SO_(4)·HCO_(3)-Ca·Mg型过渡到SO_(4)·HCO_(3)-Ca·Na和SO_(4)-Ca型.(2)2001年和2020年地下水水位与水化学特征空间变化规律具有一致性,地下水位降幅较大区域对应的Mg^(2+)、Na^(+)、Cl^(-)含量变幅也相对较大,地下水化学组分受地下水超采影响较大.(3)超采背景下,地下水埋深增大,蒸发浓缩作用减弱甚至消失.地下水化学组分受岩石风化溶滤作用和矿物的溶解与沉淀的制约影响,地下水中优势阳离子主要源于岩盐、石膏的溶解.Groundwater overexploitation not only cause ecological and geological environmental issues but also affect water quality.Analyzing the characteristics of groundwater chemical evolution under overexploitation conditions is of great significance to the development,utilization,and protection of regional groundwater resources.Based on long-term monitoring data collected from 16 in-situ wells from 2001 to 2020 and 30 groups of groundwater quality data in 2020,Piper diagrams,Spearman rank correlation coefficient method,Gibbs diagrams and ionic ratio method were used in this study to analyze the change characteristics of groundwater chemistry in Qitai County over the past 20 years.The results showed that:(1)Overexploitation resulted in a decline in the TDS of water in the plain area of Qitai County,leading to an improvement in water quality in the past 20years.The chemical type of groundwater mainly transitioned from SO_(4)·HCO_(3)-Ca·Mg type to SO_(4)·HCO_(3)-Ca·Na and SO_(4)-Ca types.(2) The spatial variation patterns of groundwater levels and water chemical characteristics in 2001 and 2020 were corresponded.In addition,groundwater overexploitation greatly affected the groundwater hydrochemical characteristics,showing significant changes in Mg^(2+),Na^(+),and Cl^(-)concentrations in areas where the reduction in groundwater levels was relatively deep.(3) Overexploitation activities resulted in an increased groundwater depth,weakening or even eliminating the effects of evaporation and concentration.The chemical composition of groundwater was affected by rock weathering and leaching as well as mineral dissolution and precipitation.The major cations in groundwater were mainly derived from rock salt and gypsum dissolutions.

关 键 词：地下水 水化学特征演变 地下水超采 奇台县 

分 类 号：X832[环境科学与工程—环境工程] X523