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Research Article / 우수학생논문상

Volumetric estimation method in river body based on SWOT satellite water surface elevation data

SWOT 위성 수위 자료 기반 하천 수체 담수량 산정 기법 개발

Seogyeong Leea
,
Suin Choib*
,
Kyeongdong Kimc
,
Dongsu Kimd
,
Hanbyul Parke
이 서경a
,
최 수인b*
,
김 경동c
,
김 동수d
,
박 한별e
aPh.D Course, Department of Civil & Environmental Engineering, Dankook University, Yongin, Korea
bPh.D Course, Department of Civil & Environmental Engineering, Dankook University, Yongin, Korea
cPostdoc, IIHR-Hydroscience & Engineering, University of Iowa, Iowa City, Iowa, USA
dProfessor, Department of Civil Engineering, Dankook University, Yongin, Korea
eUndergraduate Student, Department of Civil & Environmental Engineering, Dankook University, Yongin, Korea
a단국대학교 토목환경공학과 박사과정
b단국대학교 토목환경공학과 박사과정
c아이오와대학교 박사 후 연구원
d단국대학교 토목환경공학과 교수
e단국대학교 토목환경공학과 학사과정
*Corresponding Author
31 October 2025. pp. 883-897
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Abstract

Climate change and urbanization have increased the demand for technologies capable of precisely monitoring variations in river and lake water levels and storage volumes. However, conventional ground-based observation networks are spatially limited, restricting the acquisition of reliable hydrological information in large basins and transboundary rivers. To address these limitations, the Surface Water and Ocean Topography (SWOT) satellite, launched in 2022, provides the first high-resolution global measurements of water surface elevation (WSE) and river width. In this study, SWOT-derived WSE data were combined with CAD-based terrain information to analyze water-level variations in the Nakdong-Geumho River confluence and to establish stage-volume rating curves. Storage volumes were estimated by integrating cross-sectional differences between WSE and terrain elevation using GIS-based Cut/Fill analysis, and validated against stage records from the Samunjin Bridge gauging station. The results showed that SWOT-derived WSE exhibited strong consistency with ground-based observations, with a mean absolute percentage error (MAPE) of 1.68% and a percent bias (PBIAS) of 1.53%. Furthermore, the stage-volume regression model achieved high explanatory power (R2=0.959) with very low errors. This study represents the first application of SWOT-based WSE data for quantitative freshwater volume estimation in Korea, providing robust evidence of its reliability. These findings highlight the practical value of satellite-based hydrological observations and underscore SWOT’s potential as a novel tool for large-scale freshwater monitoring.

Keywords
SWOT satellite
Water Surface Elevation (WSE)
Freshwater volume estimation
Remote hydraulic observation
Stage-volume relationship

기후변화와 도시화로 인해 하천 및 호소의 수위와 담수량 변화를 정밀하게 모니터링할 수 있는 기술의 중요성이 증대되고 있다. 그러나 기존 지상 관측망은 공간적 제약으로 인해 대규모 유역이나 접근이 어려운 하천 구간에서 안정적인 수문 정보를 확보하는 데 한계가 있다. 이러한 문제를 보완하기 위해 2022년 발사된 SWOT (Surface Water and Ocean Topography) 위성은 세계 최초로 고해상도의 수면고도(WSE)와 수면폭 정보를 제공하여 광역 담수 수계의 정량적 관측을 가능하게 한다. 본 연구는 국내 최초로 SWOT 위성에서 산출된 WSE 자료와 CAD 기반 지형 자료를 결합하여 낙동강-금호강 합류부 구간의 수위 변화를 정량적으로 분석하고, 수위-담수량(stage-volume) 관계곡선을 구축하였다. 분석 과정에서 기본적인 품질 관리 절차를 거쳐 SWOT 수위 자료의 신뢰성을 확보하였으며, DEM-WSE 차를 활용한 GIS 기반 Cut/Fill 계산으로 담수면적과 체적을 산정하였다. SWOT 기반 수위는 지상 수위관측소와 비교하여 MAPE 1.68%, PBIAS 1.53%의 높은 정확도를 보였고, 수위-담수량 회귀모형은 R2=0.959로 우수한 설명력을 확보하였다. 본 연구의 의의는 SWOT 위성의 수위 정보와 고해상도 지형자료만으로 하천 담수량을 산정할 수 있음을 국내에서 처음으로 실증했다는 점에 있다. 이를 통해 지상 관측소가 부족하거나 부재한 구간에서도 신뢰성 있는 수위-저수량 관계 구축이 가능함을 보였으며, 이는 기존 지상 기반 관측체계를 보완하는 위성 수문학적 접근의 잠재력을 제시한다.

키워드
SWOT 위성
수면고도(WSE)
담수량 추정
원격 수리 관측
수위-담수량 관계식
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Information
  • Publisher :KOREA WATER RESOURECES ASSOCIATION
  • Publisher(Ko) :한국수자원학회
  • Journal Title :Journal of Korea Water Resources Association
  • Journal Title(Ko) :한국수자원학회 논문집
  • Volume : 58
  • No :10
  • Pages :883-897
  • Received Date : 2025-08-04
  • Revised Date : 2025-09-16
  • Accepted Date : 2025-09-18
  • DOI :https://doi.org/10.3741/JKWRA.2025.58.10.883
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