Numerical Modeling On Capture Zone Of The Haolebaoji Groundwater Source Site,in The Erdos Area,China

In northern China,groundwater is the major or unique source of water supply,which plays an important role in advancing the development of agriculture and meeting people's demand of domestic water.In planning and construction of groundwater source site,it is necessary to consider both demands of the society and the protectable environments.In a specific period,after the flow of yielding well is steady,the area where all the water flow into the well,such the area is called capture zone.Reasonable identification of the capture zone is crucial to evaluate the scope of environmental impact and delineate the protection zone.When the conditions are complex,numerical simulation methods for groundwater flow is widely used in the analysis of the capture zone.Before the practical research,the thesis explores the features of the capture zone of water source site which seize the side runoff by way of the Groundwater Modeling System.The results show that the three-dimensional shape of single well capture zone of rectangular aquifer is related to the precipitation and the water filtration pipe position,provided that the condition is ideal enough.Moreover,the feature of the multiple wells capture zone is similar to that of the single well.Each well disturbance has less influence on the profile.The major influence lies in the plane interference that is related to the position of a single well.Haolebaoji Water Source Site located in the north of Erdos Basin,is close to the lake and causing a change in the water table.Using the GMS software,a three-dimensional numerical model was established based on the actual situation in the study area and by way of field investigations and data collection.Meanwhile,the three-dimensional shape of capture zone in the study area and its plane and section shapes were determined by adopting the MODPATH technology.The Shenhua Water Source Site and the Boyuan Water Source Site belong to Haolebaoji,and the capture zone of water sources under single and simultaneous yielding conditions are respectively simulated.It was found that under the single mining condition,the maximum vertical depth of the capture zone has reached the Cretaceous Luohe Formation aquifer,and neither of the water source in the two fields reaches the boundary of the Cretaceous bottom.When the two water source sites are simultaneously extracted,the maximum area of the capture zone and the maximum vertical depth increases,and the average capture elevation does not change significantly.Besides,there is a interference area between them and the size of the area is 60.9 km~2,which is 9.7%of Shenhua Water Source and 35.8%of the Boyuan Water Source under single yielding condition.As for the water source site which is rely on the lake,it does influence on the catchment of lakes SuBei and HuTong.Under the natural situation,the catchment of SuBei lake contains the north of lake,which covers the area of 845.5 km~2,and the catchment of HuTong lake is surrounding of lake,which is 396 km~2.Under the steady condition which is after the yielding,the SuBei catchment area is significantly reduced but the impact on the HuTong lake watershed is relatively small.