Analysis Of Seawater Intrusion Characteristics And Assessment Of Seawater Intrusion Disaster In Northern Changshan Island

Seawater Intrusion is that seawater or saltwater intrude into the continent along the aquifer. Under the effects of the natural and artificial factors, the hydrodynamic conditions of aquifer in the coastal area has been changed, which break the equilibrium between the seawater and the freshwater, hence the salt-fresh interface moves on the continent. Northern Changshan Island is located in the North of the Shandong Peninsula, lonely in the Bohai Sea. Impacted by the intensive wave and tidal current coupled with groundwater over-mining, seawater intrusion in this area becomes increasingly severe.This paper based on the periodic data from field survey from June 2012 to December 2013, analyzed the distribution of Chloride concentration, mineralization and the distribution of groundwater level, then basicly got the distribution and dynamic change trend of the seawater intrusion in northern Changshan Island.1、Spatial analysis in Arc GIS software was employed to assess the seawater intrusion in the Northern Changshan Island by selecting Cl- concentration and mineralization as assessing indexes. The results show that seawater intrusion in northern Changshan Island is primarily in a way of planar invasion.The intrusion area in the phreatic aquifers reaches 2.13 km2, accounting for 17% of the study area.Highly-invaded area is 0.04 km2. Seawater intrusion in artesian aquifers is severe, and the area is about 2.48 km2, accounting for 19% of the island area.2、The geographical location of northern Changshan Island is very special and its quaternary strata is quite single. Through a comprehensive analysis of the factors that affect seawater intrusion in northern Changshan Island,we found that:Through a comprehensive analysis of the influential factors of seawater intrusion in northern Changshan Island, we found that the dominant factors are rainfall and groundwater mining. Increase in rainfall and decrease in groundwater mining can both alleviate seawater intrusion.3、This study examined the mechanism of seawater intrusion in the northern Changshan Island through a combination of field water sampling and high-density resistivity method measurement. Moreover, the aquifers were sorted according to their intrusion extent. Results from previous studies were incorporated to assess the state of seawater intrusion in this area. This study can provide scientific guidance for the mitigation of seawater intrusion and groundwater management.