Study on seawater intrusion in Laizhou bay coastal zone based on groundwater model

Abstract

Seawater intrusion in coastal zone is a common gradually changed geological hazard. After seawater intrusion, the coastal groundwater is polluted into seawater, which directly causes great damage to local industrial and agricultural production and residents' health. In order to better understand the geological hazard, the chlorinity of groundwater in six monitoring sites which had different distance with the coast was detected by silver nitrate titration method based on the groundwater model of Laizhou Bay coast to collect the chlorinity of groundwater in the six monitoring sites from April 2013 to April 2017. The local seawater intrusion was analyzed taking the monthly average precipitation data in February and March of the same year into account. The results showed that in terms of time distribution, groundwater chlorinity in the monitoring site far from the coast had no significant fluctuation as time went on, but had an upward trend. Groundwater chlorinity in the monitoring site near the coast fluctuated significantly with time and had an upward trend. Especially in 2015, drought caused more seawater intrusion and greater chlorine fluctuation; in spatial distribution, with the increase of distance with the coast, the chlorinity of groundwater decreased gradually except fluctuation in 2015 caused by drought, the seawater intrusion area was approaching inland as time went on, and the transverse distribution of seawater intrusion area was irregular.