Study Of Regulation And Storage Of Groundwater Reservoir In Taiyuan Xizhang Basin

Groundwater resources plays an important role in the national economy, social development and environmental construction. Groundwater of Xizhang basin is one of the main water supply sources of Taiyuan. With the increasing of population and rapid development of agriculture, industry and city construction in recent years, exploitation and utilization efficiency of groundwater resources has been improved continuously. Water environment problems such as decline of groundwater level, deterioration of groundwater quality have been observed in Xizhang basin.Groundwater reservoir, as an efficiency, environmental protection, economic groundwater self-restraint protection of the exploitation and utilization project, is extensively utilized at home and abroad. Considering the long-term benefit, to build groundwater reservoirs with planning and target is prime interest for a variety of concerns, including solving water resources spatiotemporal maldistribution, improving water resources utilization efficiency, ameliorating region ecological environment, ensuring social economy sustainable development of Taiyuan.Based on analyzing hydrology, weather, areal geology and hydrogeological conditions, the conceptual model was generalized. The numerical model of groundwater was established. The model was calibrated and validated on the basis of water level regime data in 2005. Regional water balance was analyzed taking 2005 as actuality year. Postulate of building groundwater reservoir in basin and characteristic water level criteria(CWLC) of groundwater reservoir were discussed; Maximum and minimum reservoir capacity, regulating reservoir capacity of Xizhang groundwater reservoir were figured out based on hydrogeologic parameters and CWLC. Regulation capacity, recharge source and recharge approach of Xizhang ground water reservoir were analyzed. Finally, groundwater level variation characteristics were predicted and researched using seven schemes according to different discharge and exploitation flux after building impervious curtain at Sangei horst.The research results showed that the Xizhang groundwater reservoir has a area of 109.54km~2 . The maximum storage capacity of unconfmed aquifer is 6.313×10~8m~3 and the maximum storage capacity of confined aquifer is 21.863×10~8m~3. The maximum rational regulation and storage space of unconfmed aquifer is 4.209×10~8m~3 and the maximum rational regulation storage space of confined aquifer is 0.018×10~8m~3. When the discharge flux of unconfmed aquifer was reduced to 50% of the actual one after building impervious curtain at the horst of Sangei, and groundwater exploitation was reduced by 1103.68×10~4m~3/a, about 78% of whole area would have the water level of 768m (reaching the preplanning demand) only by the natural recharge of the aquifer at the end of 2020(Scheme five). The scheme five was recommended as the best one. Adopting scheme five would make the water level reach the aim in 2020, the effect on the discharge in south boundary would be minished, and it would minish building height of underground engineering, reduce the cost of the project, enhance the economic benefit.The research results would provide argumentation reference for building groundwater reservoir, and the scientific basis for managing groundwater and building candidate water sources of Taiyuan.