Numerical Simulation Of Groundwater Exploitation And Poor Quality Water Migration In Yishiliang Water Source In Dingbian County

Dingbian county is an important energy chemical base of Shaanxi Province which located in the junction area of Shaanxi?Gansu?Ningxia?Inner Mongolia province. Dingbian is poor in water resoures, and the quality of groundwater is relatively bad due to the distribution of large area of high fluoride water and brackish water, which increases the difficulty of groundwater development and utilization. The contradiction between water supply and water demand is increasingly prominent with the rapid development of economy and society, and has become an important bottleneck restricting the local economic and social development. Dingbian has begun to implement the relocation and poverty alleviation plan, Yishiliang water source has been selected to resure the emergency water supply of the resettlement area for the short-term and long-term. Therefore,the study on the hydrodynamic field chances as well as the poor quality water migration caused by exploitation of ground water have great realistic significance to the rational utilization of groundwater resources and the safely of water suply,as well as promote the development of local economy and society.This paper based on hydrogeologic survey, exploration, test and analysis of water quality, systematically analyzes the hydrogeological condition and the present situation of groundwater balance in the study area, deeply researched the spatial distribution feature and the interrelation between low fluoride water and high fluorine highly mineralized water in water source area, quantitatively divided the suitable mining area and suitable mining depth of the water source area. The conceptional hydrogeological model and the three-dimensional groundwater flow simulation mathematical model as well as the solute transport mathematical model of the study area were established, based on PM groundwater flow simulate software established 3-D groundwater numerical simulation model,according to groundwater observation data and test data, the identification and validation of this model are worked out. Based on groundwater numerical simulation model, three kinds of ground water exploitation plan was predicted and analysised, finally the second exploitation plan was selected as the optimal plan; Based on the solute transport model, the impact of the poor quality water migration to the water quality of the exploited wells was predicted under condition of the second exploitation plan; Based on the prediction analysis, confirme water supply quantity was 182.50×10~4m~3/a(5000m~3/d),which can meet the long-term needs for water in migration area, and the drawdown of water supply well is allowed,the groundwater recharge is abundant, the migration of poor quality water will not affect the exploition area, the water quality of water sources is guaranteed.This paper based on numerical simulation of groundwater flow, make a prediction and analysis of the hydrodynamic field chances as well as the poor quality water migration caused by exploitation of ground water,the study provide scientific basis for rational protect and utilization of groundwater resources as well as guaranteeing the water safety for resettlement area, meanwhile,the study also provide technical support for local social and economic development and ecological environmental protection, research results provide a reference for rational protect and utilization of groundwater resources in the arid areas of northwest district.