Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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Application of Geophysical Methods for Developing Saline Groundwater from an Coastal Aquifer

해안지역 염지하수 개발을 위한 물리탐사 적용 사례

  • Lim, Sung Keun (Rural Research Institute, Korea Rural Community Corporation) ;
  • Song, Sung-Ho (Rural Research Institute, Korea Rural Community Corporation) ;
  • Kim, Soo Hong (Gyeongnam Regional Headquarters, Korea Rural Community Corporation)
  • 임성근 (한국농어촌공사 농어촌연구원) ;
  • 송성호 (한국농어촌공사 농어촌연구원) ;
  • 김수홍 (한국농어촌공사 경남지역본부)
  • Received : 2018.10.18
  • Accepted : 2018.11.12
  • Published : 2018.11.30
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Abstract

The purpose of this study was to obtain a large amount of saline groundwater around coastal aquaculture farms. Thus, we have proposed a method for evaluating the potential amount of saline groundwater resources through the combined analysis of geophysical methods. Refraction seismic survey and electrical resistivity survey were conducted in the vicinity of fish farm at Hadong, Gyeongnam Province. As the result, the velocity of layer in the range of 900 ~ 2,400 m/s was found to be saltwater aquifer with high water content. Geological drilling investigation and analysis of soil samples also showed that the soil at study area was the same as the texture of sandy loam layer in agricultural radial collector wells installed by KRC (Korea Rural Community Corporation). Futhermore, the study area turned out to be quite possible to develop saline groundwater from the coastal shallow aquifer. Therefore, parallel analysis of refraction seismic surveys and electrical resistivity surveys at coastal area are expected to be very useful for the detection of the aquifer composed of sand and gravel layers with high porosity in sandy sedimentary layers along the coastal area.

이 연구에서는 해안지역 육상 양식장 주변에 대한 다량의 염지하수 확보를 목적으로, 물리탐사 자료의 복합해석 및 공간분석을 통한 염지하수 개발 가능량 평가 방안을 제시하였다. 경남 하동군 인근 양식장 주변을 대상으로, 굴절법 탄성파 탐사 및 전기비저항 탐사를 수행한 결과, 탄성파 속도가 900 ~ 2,400 m/s 구간이 지층 내 함수비가 높은 주요한 염지하수 대수층으로 파악되었다. 이 구간에 대한 시추조사 결과 현재 한국농어촌공사의 방사상 집수정이 이미 설치된 지역들의 표토 토성과 같은 사양토 지역인 것으로 파악됨에 따라, 연구대상 지역은 대용량 염지하수 개발이 충분히 가능한 것으로 해석되었다. 따라서 향후 전기비저항 탐사와 더불어 굴절법 탄성파 탐사를 병행하여 해석하는 경우, 해안지역의 사질 퇴적층 내 공극률이 높은 모래 및 자갈층으로 구성된 대수층의 탐지에 활용이 매우 클 것으로 판단된다.

Keywords

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Fig. 1. Geological map near Hadong site from Jingyo geology map (KIGAM, 1973).

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Fig. 3. Location map of resistivity and seismic survey lines at Hadong site.

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Fig. 4. The results of resistivity survey and seismic survey at Hadong site.

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Fig. 5. The result of seismic survey at Hadong site.

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Fig. 6. Analysis of three dimensional modeling using the results of seismic survey. (a) seismic velocity model (b) layers over velocity 900 m/s (c) layers of velocity range from 750 ~ 900 m/s (d) layers of velocity range from 900 ~ 2,400 m/s.

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Fig. 7. Soil texture of 10 m deep in (a) BH-2 and (b) BH-3 boreholes.

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Fig. 2. (a) Location map of seven boreholes and (b) Columnal sections of each borehole with N values from SPT.

Table 1. Drilling results for developing saline groundwater.

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