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陈悦

Study on the Evolution Mechanism of Lake-groundwater System in Desert Coal Mining Area ——A Case Study in Bojianghaizi Basin

陈悦

Titre : Study on the Evolution Mechanism of Lake-groundwater System in Desert Coal Mining Area ——A Case Study in Bojianghaizi Basin

Auteur : 陈悦

Grade : Master These 2021

Université : Inner Mongolia University

Résumé partiel
Coal mining activities in arid and semi-arid areas often lead to a series of ecological and environmental problems,such as aquifer drainage,lake shrinkage and disappearance,vegetation decline,surface desertification,etc.,which has become a major limiting factor for the sustainable development of regional economy and ecological and environmental security.Bojianghaizi Mine Field and Youfanghao Mine Field are located in the transition zone between Mu Us Sandy Land and Kubuqi Desert in the coal mining area of Bojianghaizi Basin.During the development process,it is easy to cause serious influence on the lakes and groundwater in the basin.Taking Bojianghaizi Basin as an example,this paper studies the evolution and genesis of lake-groundwater system in desert coal mining area.Based on the physical geography and hydrogeology data of the study area and field investigation and sampling,remote sensing interpretation,mathematical statistics,Piper trigram,Gibbs map,correlation analysis,ion proportion analysis,saturation index and contour map were used to analyze the interannual variation of the main lakes and its driving factors.The characteristics of lake-groundwater system hydrochemistry,the sources of main components and the temporal and spatial evolution of groundwater chemical field in the basin were studied.The main conclusions are as follows :(1)The area of the core lake in the study area showed a shrinking trend in the past 40 years,and the area decreased by 82%.The process of lake area change can be divided into three stages:the normal fluctuation stage from1979 to 1999 ;From 2000 to 2015,the period of continuous contraction ;From2015 to 2017,the period of recovery growth.Climatic warming and drying is the climatic factors that affect the lake area change,while the construction of water conservancy projects,ecological restoration projects and coal mining are the human factors that lead to the shrinking of lake area.The decrease of surface and underground runoff caused by human activities and the lack of effective water supply are the main reasons for the shrinking area of Tao-Ahaizi Lake.(2)Both the regional unconfined water and the confined water are weakly alkaline,and the content of TDS in unconfined water ranges from 554.75 to1192.48mg/L.The confined water was 554.41~1298.07mg/L.Sodium ion is the dominant cation,followed by calcium and magnesium ion.In the anions,carbonate ion and sulfate ion are the most,followed by chloride and nitrate ion.The average TDS value of the lake is 4385.21mg/L,and the average p H value is 9.90,which belongs to the strongly alkaline and slightly saline lake.The contents of Na+and Cl-in the lake water were the highest,and the content of F-fluoride in the lake water exceeded the standard.The main hydrochemical types of unconfined and confined water are HCO3-Na type,and the lake water is Cl-Na type.

Mots clés : Lake-groundwater system ;Coal mining ;Hydrogeochemistry;Water rock interaction ;

Présentation (CNKI)

Page publiée le 22 octobre 2021