| Xinhe Town is the most seriously seawater intruded area of Qingdao. The seawater intrusion goes through three stages: initial development, accelerated development and decelerated development. Three transgressions in history, especially the Huangha and Xianxian Transgression, formed the paleo-seawater which became the main"salt source"in Xinhe area. The geomorphic types include piedmont pluvial plain, alluvial-and-coast plain, and coast plain. The area also can be divided into three hydro geological areas: completely fresh water area, salt-fresh water multilayer structure area and completely salty water area. The seawater intrusion in this area mainly comes from salty water, partly accompanied by modern seawater intrusion. The seawater intrusion in Xinhe was monitored for 2 years, From July, 2007 to June 2009, mainly by hydrochemistry method and high density resistivity method. The hydrochemistry method was applied to collect data of Cl- concentration, salinity, conductivity, pH, and water lever. Based on the monitoring data of 2008, the water intrusion situation of this area was analyzed: the hydrochemical and high density resistivity data show that the seawater intrusion of Xinhe is serious and has kept in a slowly developing process.Through the previous study and our observation, the seawater intrusion has dramatically influenced the industrial and agricultural development and brought troubles to the local residents. Besides, the water intrusion also disequilibrates local ecological balance.According to the monitoring data and previous study, the decreased rainfall in Xinhe area is the main cause of seawater intrusion, and the direct cause is over-exploration of groundwater. Other factors may also influence the intrusion, such as geology, geomorphology, storm surge and mariculture.Combined monitoring data and field work, this essay proposes control measures and provides suggestions for Xinhe to fight against seawater intrusion. The key solution is to explore groundwater reasonably and pay attention to bionomic control simultaneously. |
