Study On The Scheme Of Groundwater Exploited Under The Prevention Of Seawater Intrusion In The Nankang Basin

At present, socioeconomic develop rapidly, the sense of people to protect waterresources is poor and the exploitation and utilization to water resources isunreasonable, which lead to contradiction increasingly prominent between demandand supply of freshwater resources. In recent years, some coastal areas in China andother countries, seawater intrusion becomes increasingly serious because ofover-exploitation of groundwater, resulting in fresh water resources have beenseverely damaged, human health and economic development are also threatened. Inorder to control the further deterioration of this situation, many effective preventionmeasures have been explored based on the control the exploitation of ground waterwhich has acquired more significant treatment effect.The groundwater exploitation of NanKang basin in Beihai has a long history;Groundwater is main water source of current urban and rural life water, industrial andmining enterprises industrial water and well irrigation agricultural water. With thedevelopment of city and economy, the demand for water grows sharply. The scope ofgroundwater depression cone in the coastal zone of municipal district in westernNankang basin has expanded continuously for previous groundwater overexploitation,for some of groundwater depression cone, the zero foot water contours even havebeen out of the coastline and have caused seawater intrusion.To counter the environmental geological issues resulted from seawater intrusion,the thesis simulates groundwater flow in Nankang basin I, II confined pore aquiferwith GMS software, takes seawater intrusion as a point of departure and then designsa set of optimum groundwater exploitation schemes in Nankang basin I, II confinedpore aquifer. The study includes mainly the following three aspects:(1) This study expounds hydrogeological conditions of Nankang basin, presentsembedding conditions, circulation characteristics, dynamic types, chemicalcharacteristics and the current situation of exploitation and existent problems.(2) Three dimensional model of Nankang basin strata is established and the basiccharacteristic of each separate pore aquifer including its bottom aquifuge is discussed.On this basic, by combining with the generalized criterion of hydrogeologicalconditions of the groundwater flow system, the emulation layer of porous aquifer, theboundary conditions and hydrogeological area etc. are determined in Nankang basinto construct and improve the hydrogeological conceptual model. Subsequently, inorder to provide a basis for follow-up study of establishing groundwater exploitationschemes preventing seawater intrusion, this study analyzes the function of preventingseawater intrusion of Nankang basin porous aquifer.(3) Utilizes GMS software MODFLOW on the numerical simulation of Nankang basin I, II confined porous aquifer groundwater, the simulation period is from August1995to October2010, then a comparative analysis is made on the results obtainedfrom the simulation and the test. Meanwhile, the BP neural network model is built andcompared with predictions results of MODFLOW. According to the different rainfallsituations in future, five kinds of situations are drawn up to predict2020Nankangbasin I, II confined porous aquifer groundwater level, and groundwater exploitationschemes preventing seawater intrusion are proposed to provide the department ofwater administration with scientific basis for managing groundwater resourcescientifically in seawater intrusion area and making plans reasonably on groundwatersustainable development and utilization.