Study of the groundwater vulnerability of Sockcho area by using GIS

Study Area: north eastern part - Sockcho Why we have to select this area – did not study this area before - so we want to know that this area’s groundwater vulnerability (risk) Area Km 2 Introduction of the study area 행정구역구분 연구지역

DRASTIC Depth: point depth – kriging - reclassified Recharge: governing equation – grid - reclassified Aquifer and vadose zone: geology - reclassified Soil: soil map - reclassified Topo: CAD (7111, 7114) – selection – tin – grid - reclassified Conductivity: table data - reclassified Procedure of the study

Depth of Water Vadose Zone Ground Water Range (m) Rating Weight5 Ranges and Ratings for Depth to water (Aller et al.,1987) - Depth to water : 지표로부터 지하수면까지의 깊이

Depth of Water Depth point location We have to do kriging because of getting depth of total area We can use this data for making kriging (blue) Depth - reclassified This is the point data of depth (green)

Net Recharge P Groundwater table Aquifer Soil Vadose zone ET DR Net Recharge (mm/year) RangeRating Weight4 Ranges and Ratings for Net recharge (Aller et al.,1987) 지하수 함양 – 지하수면에 도달하여 대수층에 저유량을 증가시키는 수직적인 물의 흐름으로 정의 ( 구민호, 이대하,2002) RECHARGE = P - Q - I

Net recharge Recharge - reclassified

Aquifer and vadose zone media RangeRating Typical Rating Massive Shale Metamorphic / Igneous Weathered Metamorphic/ Igneous Glacial Till Bedded Sandstone,Lines tone and Shale Sequences Massive Sandstone Massive Limestone Sand and Gravel Basalt Karst Limestone Weight3 Present joint Absent of joint Coarse grain Soil Fine grain RangeRating Typical Rating Confinig Layer 11 Silt / Clay Shale Limestone Sandstone Bedded Limestone, Sandstone, Shale Sand and Gravel with significant Silt and Clay Metamorphic / Igneous Sand and Gravel Basalt Karst Linestone Weight5 Ranges and Ratings (Aller et al.,1987)

Aquifer and vadose zone media Use Sockcho geological map 1: Vadose - reclassifiedAquifer- reclassified

Soil Media 1:50,000 Soil map ( 농업과학기술원 ) Reclassified soil map

Topography Vadose Zone Ground Water Topography (Percent Slope, %) RangeRating Weight1 Ranges and Ratings for topography (Aller et al.,1987) - Topography : 지형의 Percent Slope 로 분류

7111, 7114 layer select CAD file Selection Topography

Topographic Map Tin Reclassified topographic map

Hydraulic conductivity [cm /s] RangeRating 4.7x x x x x x x x x x x Weight3 Ranges and Ratings for Hydraulic conductivity (Aller et al.,1987) Aquifer Soil Aquifer Soil Aquifer Hydraulic Conductivity

Drastic Index map [r=rating] [w=weight] Topography TrTwTrTw + Depth to water DrDwDrDw + Recharge RrRwRrRw + Aquifer media ArAwArAw + Soil media SrSwSrSw + CrCwCrCw Hydraulic conductivity Impact of vadose zone IrIwIrIw + Index Map

Index map

Drastic index map has been prepared to determine groundwater vulnerability of the study area - compared with land use map – it shows river area is high vulnerable than surroundings Forest area is less vulnerable than city area as it is already crowed – i.e. possibility of contamination is high in city area GIS is very powerful tools so that useful data/results can be obtained by using GIS Conclusions

- 조시범 외,1999,GIS 를 이용한 경기도 평택군 지역의 지하수 오염 가능성 평 가 연구, 한국지하수토양환경학회 - 민경덕, 이영훈 외,1996,DRASTIC 을 이용한 지하수 오염 가능성 분석 및 그 래픽 사용자 인터페이스 개발연구, 한국지하수토양환경학회 - 조시범, 손호웅,2004, 지하수 오염 예측을 위한 GIS 활용 연구, 지구물리학회 - 함세영 외,2004,DRASTIC 과 지하수 수질에 의한 창원시 지하수 오염취약 성 평가 -Aller L et al.,1987, DRASTIC : A Standardized System for Evaluating Ground water pollution potential using hydrogeologic settings References

Thank You Everybody!!!