| The karstic groundwater in Lishi Synclinal Basin is the important water supply sources of Lishi city. In recent years, exploitation of karstic groundwater have been expanding continuously with the rapid development of economic society and the increase of urban population in Lvliang city, and a series of water environmental problems such as decrease of water resources, continuous decline of groundwater level and form of cone of depression are occurred. Using the favorable geological, hydrogeological conditions of basin to develop the underground reservoir and realize the surface water and groundwater joint storage and scheduling is of great importance to the protection of karstic groundwater, utilization efficiency of water resources and the urban water supply security.Base on fully collecting data and conducting an investigation on utilization of water resources as well as water environment, it is adopted the method that the field hydrogeological investigation combined with theoretical analysis. Finally, Lishi synclinal basin boundary were scientifically delineated, meanwhile, properties of the boundary and the drainage channel basin to the Liulin spring were determined. The spatial distribution, geological structure and lithology characteristics of Lishi synclinal basin were systematically analyzed. Some aspects of synclinal basin karst groundwater system were discussed, such as storage conditions, cycling conditions, dynamic characteristics and chemical characteristics of water. Besides, the exchange and transformation between the internal aquifer system about Cambrian, Ordovician and other external environment about surface water, wells, mining were researched, which were deepening the understanding of basin hydrogeological conditions.According to the karst features and structural characteristics for water reserve as well as the basic conditions to build underground reservior in study area, the paper discussed the feasibility and the scientific evidence to build karst reservior in Lishi Synclinal Basin. It turns out that:the basin area has good space to reserve water. The basin bottom composed of archaeozoic metamorphic rock is relatively impervious aquifer and its boundary is also relatively closed. No uncontrollable and big as well as conductive fracture existed in the reservior.Aquifer space of Cambrian and Ordovician is large and its depth is relatively stable, the capacityof the reservior with the area of 521.53km2 is large and its storage capacity is relatively powerful. The confluence area of the basin is large, occupy an area of 924.07 km2, the aquifer of underground reservoir has a strong resupply ability, the supply way unblocked and water supply ability strong. After the implementation of "source supply project", the organic combination scheduling of basin underground reservoir and surface reservoir of upstream tributary of Sanchuan river can be easily realized; Basin area has currently possessed a perfect groundwater exploitation system. Therefore, it is feasible to build underground reservoirs in Lishi syncline basin.According to geological structure, aquiferous storage conditions and kinematic characteristics in Lishi Synclinal Basin, hydrogeological conceptual model and numerical simulation model of underground water are established. These models are distinguished and checked by using Visual MODFLOW and observational data of groundwater level in 2008. The result showed that, the established models, boundary conditions and hydrogeological parameters were corresponded with the fact, and could be used to predicted groundwater level. Use the year 2008 as status, regional balance analysis is done. The mainly recharge of water resources in simulated zone include precipitation recharge and river recharge, while the discharge include artificially exploitation and drainage to Liulin springs. The change of aquifer storage in regional is positive equilibrium.According to water level control standard of confined aquifer, the highest and lowest water level was determined, respectively. By using hydrogeological parameters which have been identified and verified, current situation and the maximum water level of water regulation and storage capacity were calculated. It turns out that:the largest storage capacity of karstic groundwater reservoir is 35.70 million stere, current situation water storage capacity is 16.41 million stere. The former subtract latter is 19.29 million stere. Therefore, it is significant to storage of water resources in the confined aquifer.Use a numerical simulation model for the simulation and forecast of the karstic groundwater level changes in reservoir region, on the conditions that the production volume to be 28.71 million stere per year, and the production volume to be 23.71 million stere per year, and with the status year drainage of 75%, 50%,25% towards LiuLin springs. The predicted results indicate that the production volume to be 28.71 million stere and drainage to be 75%,50% of the status year, storage change of aquifer is in negative equilibrium, while the drainage to be 25% of the status year, storage change of aquifer is in positive equilibrium; when production volume changes reduce to 23.71 million stere, the storage change of reservoir region of aquifer are in positive equilibrium, this is beneficial to Karst groundwater level to recovery.
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