| Groundwater is an important part of water resources for the survival of human beings,is a kind of precious natural resources, and is also one of the important factors that affectthe ecological environment. Groundwater resource is not only a basic resources for thedevelopment of the capital, but also a strategic resource and an important guarantee for thedevelopment of Beijing. For many years, groundwater accounts for two-thirds of the totalwater supply in Beijing, and is one of the few big citis in the world where groundwater isthe main source of water supply. At the same time, Beijing is a city of severe watershortage. With rapid development of urban construction and urbanization process andcontinuous growth of urban population, the conflict of water resource between supply anddemand that has become the primary problem restricting the urban sustainabledevelopment is increasingly conspicuous. Beijing has suffered a long lasting drought since1999. The current flow field has changed a lot compared with the natural flow field in1960s. Due to continous drought, rivers hav become dry and its recharge decreased, andsome emergency water source fields were constructed for supplying water. Thus, thestorage was depleted greatly and the aquifer would be dewatered in the future. Control ofgroundwater abstraction and increase the recharge should be the important task forgroundwater resources management in Beijing.The present situation of groundwater abstraction and the history of groundwaterregime are deeply analyzed in this thesis. A groundwater flow model was established forBeijing plain and an evaluation model was constructed to analyze sustainable developmentof groundwater. The main contributions of this thesis are:(1) The historical changes of groundwater levels in different areas of Beijing plainwere analyzed with a time series method. Through the analysis from point to surface, itwas found that water levels had dropped obviously in the urban area and the area ofalluvial-diluvial fan of the yongding river, especially in the years of continous drought, andwater levels had dropped to historic lows.(2) Multiple-regression deconvolution was used to analyze the comprehensive impactof atmospheric loading and earth tide on water levels in two observation wells in Beijingplain，and the analysis results indicate that this method can efficiently analyze and calibratethe effect of atmospheric loading and earth tide on water levels in observation wells.(3) A hydrogeologic conceptual model was constructed for Beijing plain, where the aquifer system was divided into five aquifers and four aquitards. Then3D steady andtransient groundwater flow models were established for Beijing Plain with GMS. Thecalibrated model was used to analyze groundwater flow systems and water balance. Theeffects of drought on groundwater levels and storage were also discussed.(4) The constructed3D transient groundwater flow model was used to simulate tengroundwater resources development schemes. With considering some facters such asgroundwater exploitation, river outflow, groundwater levels and so on, an evaluation indexsystem was constructed. Based on the groundwater flow model and the index system amulti-object decision model was established for estimation of groundwater developmentschemes and proven to be very useful for scientific analysis of reasonable development andutilization of groundwater resources.(5)The measures to realize sustainable development and utilization of groundwaterwere summarized, including comprehensive utilization of surface water, groundwater, andtransfer water from other areas, regulation of groundwater by underground reservoirs,pumping-limit and artificial recharge, building groundwater resources strategic reserve andpolicies of dry management, and so on. |
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