Numerical Simulation Of Seawater Intrusion In A Region Of DaLian

Dalian is one of serious parts of seawater intrusion in China. In the 1970s with the development of industry and agriculture, more and more groundwater is pumped at coastal areas. The destruction of dynamic balance between groundwater and seawater leads to seawater intrusion, pollution of groundwater and salinization of farmland. It has a serious impact on the development of economy and ecological environment. In the late 1990s, the exploitation of groundwater began to under control, seawater intrusion slow down, but the area of seawater intrusion is still increasing in the study area. Based on the available information, this paper simulates the situation of seawater intrusion from the year of 2007 to 2009 by assuming future year's groundwater exploitation and calculating the probability of rainfall.Based on the analysis of the regional geological and hydrological conditions, especially the funnel region of Nanguanling and Zhoushuizi, this paper present a hydro geological conceptual model and a groundwater flow model, and solving these models with Finite element software-FEFLOW. In the process of establishing the model, groundwater recharge and exchange is analyzed carefully, and found the items of groundwater recharge and exchange are rainfall, irrigation feedback, exchange of river, exchange of BC2, and exchange are industrial pumping, agricultural pumping, evaporation, discharge of BC2 .Based on the water level and chloridion concentration data of observation wells, adjusting the parameters to make the results of simulation meeting to the values of observation. After checking the model, forecasting the area of the seawater intrusion in the next three years with the rainfall probabilities of 25 percent, 50percent,75percent,and with the exploitation groundwater of 2006.The situation of seawater intrusion still has been better when the guaranteed rate of rainfall is 75 percent, so the exploitation groundwater of 2006 is reasonable. That is to say in accordance with the 2006 exploitation of underground water,seawater intrusion can be better with the probability of 75%,and the two funnel of groundwater level has been raised obvious in the study area.