Fresh Water Injection Test to Mitigate Seawater Intrusion and Geophysical Monitoring in Coastal Area

해수침투 저감을 위한 담수주입시험 및 지구물리 모니터링

  • Park, Kwon-Gyu (Groundwater and Geothermal Resources Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Shin, Je-Hyun (Groundwater and Geothermal Resources Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Hwang, Se-Ho (Groundwater and Geothermal Resources Division, Korea Institute of Geoscience and Mineral Resources) ;
  • Park, In-Hwa (Groundwater and Geothermal Resources Division, Korea Institute of Geoscience and Mineral Resources)
  • 박권규 (한국지질자원연구원 지하수지열연구부) ;
  • 신제현 (한국지질자원연구원 지하수지열연구부) ;
  • 황세호 (한국지질자원연구원 지하수지열연구부) ;
  • 박인화 (한국지질자원연구원 지하수지열연구부)
  • Published : 2007.11.30

Abstract

We practiced fresh water injection test to identify its applibility as a method of seawater intrusion mitigation technique, and monitored the change of borehole fluid conductivity and the behavior of injected fresh water using borehole multichannel electrical conductivity monitoring and well-logging, and DC resistivity and SP monitoring at the surface. Well-logging and multichannel EC monitoring showed the decrease of fluid conductivity due to fresh water injection. We note that such an injection effect lasts more than several month which means the applibility of fresh water injection as a seawater intrusion control technique. Although SP monitoring did not show meaningful results because of weather condition during monitoring and the defects of electrodes due to long operation time, DC resistivity monitoring showed its effectiveness and applicability as a monitoring and assessment techniques of injection test by means of imaging the behavior and the front of fresh water body in terms of the increase of resistivity with reasonable resolution. In conclusion, we note that geophysical techniques can be an effective method of monitoring and evaluation of fresh water injection test, and expect that fresh water injection may be an practical method for the mitigation of seawater intrusion when applied with optimal design of injection well distribution and injection rate based on geophysical evaluation.

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