Seawater Intrusion Monitoring And Macroscopical Trend Forecast Simulation In Rongcheng City

Seawater intrusion issues have been spotted and investigated pervasively during acentury year’s significant attention brought by the scientists. Few concerns have also achievedsignificant achievements on the definition of seawater intrusion, physical mechanism,investigation approach, mathematical simulation, monitoring techniques by now.In consequence of excessive exploit of groundwater recent years, Rongcheng City hadsuffered deterioration of water quality conducted by seawater intrusion and massivelyjeopardized drinking water security and industrial and agricultural production of the localplace. The thesis investigated the current seawater intrusion situation of the area based onanalyzation of the years’ historical materials, calculated the intrusion sphere with the assist ofwater level monitoring and hydrogeochemistry techniques; using Artificial Neural NetworkModel forecast the seawater intrusion situation. The achievements are as follows:(1) Piper figures based on hydrogeochemical analysis method interpret thehydrogeochemical type of groundwater as HCO3-Ca、HCO3·C1-Ca·Mg and Cl·SO4-Mg·Nafrom inland to coastal area.(2) Geophysical method including Auslog borehole survey method and AGI high-densityresistivity method was applied to detect the tectonics and hydrogeololgy conditions of thecoastal area, as well as aquifer structure and boundary of the seawater intrusion. Theillustration shows that conduit between the freshwater and seawater is unobstructed,permeability and connectivity of the aquifer is also considerably fit for the intrusion.(3) Demarcated the seawater intrusion boundary by250mg/L of the chloridion and drawthe salinity contour. The result shows that the seawater intrusion area has reached81.10km2by the end of2013, increased44km2in10years.(4) Back propagation neural network based on MATLAB simulate the seawater intrusionprocess. After a proper training using the data of the historical precipitation and the volume ofgroundwater utilization, a model is setting to forecast the macroscopical trend of the seawaterintrusion situation.The investigations and research works what have done and the achievements that haveachieved mentioned above can be expected to contribute to the seawater intrusion control andthe ecological management for the local government to implement on the next step.