Experimental evaluation of the applicability of LISST-200X for high-turbidity measurements

Gwangmin Ok; Jongmin Kim; Bo Gyeong Choi; Young Do Kim

doi:10.3741/JKWRA.2025.58.S-3.1551

All Issue

2025 Vol.58, Issue 12S-3 Preview Page Next Page

Research Article

Experimental evaluation of the applicability of LISST-200X for high-turbidity measurements 실험기반 LISST-200X 활용 고탁수 측정 적용성 평가 연구

31 December 2025. pp. 1551-1562

PDF XML

Abstract

Recent extreme rainfall and typhoon events driven by climate change have caused severe high-turbidity problems in reservoirs and rivers, posing significant challenges for water quality management. Conventional methods for measuring suspended sediment concentration (SSC) rely on manual sampling and laboratory analysis, which are time-consuming and unsuitable for real-time monitoring. Furthermore, the accuracy of turbidity–SSC relationships is often compromised by variations in particle size distribution, while high-turbidity conditions induce multiple scattering within the optical path, leading to overestimation of both concentration and particle size. To address these limitations, this study evaluated the applicability of the LISST-200X equipped with a Path Reduction Module (PRM) for SSC measurements under high-turbidity conditions. Experiments were conducted in an indoor recirculating flume using four particle-size fraction scenarios derived from sediment distributions observed in the upstream region of the Soyang River Basin. SSC was sequentially measured using both the standard LISST-200X and the PRM-mounted LISST-200X, while turbidity was simultaneously monitored with a YSI-EXO2 sensor. The acquired datasets were stratified by particle-size fraction, and variability was reduced by applying temporal averaging and a median filter technique. The results showed that the measurement range expanded from approximately 250 FNU with the standard LISST-200X to 300 FNU with the PRM, confirming the feasibility of stable monitoring even under high-turbidity conditions. Incorporating particle-size stratification significantly improved the linearity of turbidity–SSC relationships, with the median filter effectively removing outliers and reducing variability. This study provides experimental evidence that the LISST-200X with PRM can serve as a practical tool for SSC monitoring in high-turbidity environments, while also demonstrating that integrating particle-size variability and correction techniques enhances the accuracy and reliability of turbidity-based SSC estimation models.

Keywords

Turbidity

suspended sediment concentration

LISST-200X

Path Reduction Module

YSI-EXO2

최근 기후변화로 인한 집중호우와 태풍으로 발생하는 고탁수 문제는 저수지와 하천의 수질관리에 심각한 문제를 발생시킨다. 기존의 부유사 농도 측정은 채수와 실험실 분석에 의존하여 실시간 모니터링에 한계가 있으며, 탁도-부유사 관계식 또한 입자 크기 분율에 따른 정확도 저하 문제가 제기되어 왔다. 또한 고탁도 조건에서는 광학 경로에서 다중 산란이 발생하여 농도와 입도를 과대 추정하는 한계가 있다. 이를 개선 하기 위해, 본 연구는 광 경로를 줄여주는 보조 모듈(Path Reduction Module, PRM)을 활용하여 고탁수 조건에서의 부유사 농도 측정 가능성을 검토하였다. 실험은 소양강 상류에서 조사된 입도 분포를 반영하여 네 가지 분율 조건을 설정하고 실내 순환수로에서 진행하였다. 동일 조건에서 기본 LISST-200X와 PRM 장착 LISST-200X를 순차적으로 측정하였다. YSI-EXO2를 병행하여 탁도를 측정하였으며, 취득된 데이터는 분율별로 세분화한 후 시간 평균화 및 median filter 기법을 적용하여 부유수 농도의 변동성을 보정하였다. 그 결과, PRM 모듈 적용 시 측정 가능 범위가 약 250 FNU에서 300 FNU로 증가되어 고탁수 환경에서도 안정적인 모니터링이 가능함을 확인하였다. 또한 입자 크기 분율을 반영할 경우 탁도-부유사 관계의 선형성이 크게 향상되었으며, median filter는 이상치 제거와 변동성 저감에 효과적이었다. 본 연구는 LISST-200X와 PRM을 활용한 실험적 검증을 통해, 탁도 기반 부유사 농도 추정 모델의 정교화와 고탁수 환경 모니터링의 실용적 개선 가능성을 제시하였다.

키워드

탁도

부유사 농도

LISST-200X

Path Reduction Module

YSI-EXO2

References

Bright, C., Mager, S., and Horton, S. (2020). “Response of nephelometric turbidity to hydrodynamic particle size of fine suspended sediment.” International Journal of Sediment Research, Vol. 35, No. 5, pp. 444-454.

10.1016/j.ijsrc.2020.03.006

Bright, C.E., and Mager, S.M. (2020). “A national‐scale study of spatial variability in the relationship between turbidity and suspended sediment concentration and sediment properties.” River Research and Applications, Vol. 36, No. 8, pp. 1449-1459.

10.1002/rra.3679

Chung, S.W., and Oh, J.K. (2006). “River water temperature variations at upstream of Daecheong Lake during rainfall events and development of prediction models.” Journal of Korea Water Resources Association, KWRA, Vol. 39, No. 1, pp. 79-88.

10.3741/JKWRA.2006.39.1.079

Chung, S.W., Lee, H.S., and Jung, Y.R. (2008). “Turbidity modeling for a negative Buoyant density flow in a reservoir with consideration of multiple particle sizes.” Journal of Korean Society on Water Environment, Vol. 24, No. 3, pp. 365-377.

Eads, R., and Lewis, J. (2007). Comparisons of turbidity data collected with different instruments. Report on a Cooperative Agreement, USDA Forest Service, Pacific Southwest Research Station, CA, U.S., pp. 1-27.

Ehrbar, D., Schmocker, L., Vetsch, D.F., Boes, R.M., and Doering, M. (2017). “Measuring suspended sediments in periglacial reservoirs using water samples, laser in-situ scattering and transmissometry and acoustic Doppler current profiler.” International Journal of River Basin Management, Vol. 15, No. 4, pp. 413-431.

10.1080/15715124.2017.1327866

Haun, S., Kjærås, H., Løvfall, S., and Olsen, N.R.B. (2013). “Three-dimensional measurements and numerical modelling of suspended sediments in a hydropower reservoir.” Journal of Hydrology, Vol. 479, pp. 180-188.

10.1016/j.jhydrol.2012.11.060

Jansen, F., and Teuling, A. (2019). “Evaporation from a large lowland reservoir—(dis) agreement between evaporation methods at various timescales.” Hydrology and Earth System Sciences Discussions, Vol. 26, pp. 1-27.

10.5194/hess-2019-393

Jun, Y.H., Seok, I.J., and Byung, H.K. (2021). “Prediction model suitable for long-term high turbidity events in a reservoir.” Journal of the Korean Society of Hazard Mitigation, Vol. 21, No. 3, pp. 203-213.

10.9798/KOSHAM.2021.21.3.203

Kerr, S.J. (1995). Silt, turbidity and suspended sediments in the aquatic environment: An annotated bibliography and literature review. Technical Report, Ontario Ministry of Natural Resources, Ontario, Canada.

Kim, B.C., and Jung, S.M. (2007). “Turbid storm runoffs in Lake Soyang and their environmental effect.” Journal of the Korean Society of Environmental Engineering, Vol. 29, No. 11, pp. 1185-1190.

Kim, J., Kwon, S., Chung, S., and Kim, Y.D. (2025). “Turbidity and suspended sediment relationship based on sediment composition and particle size distribution.” Scientific Reports, Vol. 15, No. 1, 16286.

10.1038/s41598-025-00435-240348788PMC12065833

Kim, J., Lee, S.U., Kwon, S., Chung, S.W., and Kim, Y.D. (2022). “Improvement of turbid water prediction accuracy using sensor-based monitoring data in Imha Dam reservoir.” Journal of Korea Water Resources Association, KWRA, Vol. 55, No. 11, pp. 931-939.

10.3741/JKWRA.2022.55.11.931

Kim, T.W., Kim, Y.D., and Yi, Y.K. (2012). “A study on field experiment and numerical modeling for efficiency analysis of selective withdrawal in Imha reservoir.” KSCE Journal of Civil and Environmental Engineering Research, Vol. 32, No. 2B, pp. 113-121.

Kim, W.G., Jung, K.S., and Yi, Y.K. (2006). “The variation of water temperature and turbidity of stream flows entering Imha reservoir.” Korean Journal of Limnology, Vol. 39, No. 1, pp. 13-20.

Kwak, S., Lee, K., Cho, H., Seo, Y., and Lyu, S. (2017). “Field measurement of suspended material distribution at the river confluence.” KSCE Journal of Civil and Environmental Engineering Research, Vol. 37, No. 2, pp. 467-474.

10.12652/Ksce.2017.37.2.0467

Landers, M.N., and Sturm, T.W. (2013). “Hysteresis in suspended sediment to turbidity relations due to changing particle size distributions.” Water Resources Research, Vol. 49, No. 9, pp. 5487-5500.

10.1002/wrcr.20394

Mikkelsen, O., and Pejrup, M. (2001). “The use of a LISST-100 laser particle sizer for in-situ estimates of floc size, density and settling velocity.” Geo-Marine Letters, Vol. 20, No. 4, pp. 187-195.

10.1007/s003670100064

Murillo-Bermúdez, L.F., Salustiano-Martim, A.L.S., Poleto, C., and Dalfré Filho, J.G. (2023). “Correlation of turbidity and suspended sediment concentration in natural water flow using alternative data of water treatment plant, case of study in the upper Jundiaí river, Brazil.” International Journal of River Basin Management, Vol. 21, No. 2, pp. 233-241.

10.1080/15715124.2021.1961794

Sehgal, D., Martínez‐Carreras, N., Hissler, C., Bense, V.F., and Hoitink, A.J.F. (2022). “A generic relation between turbidity, suspended particulate matter concentration, and sediment characteristics.” Journal of Geophysical Research: Earth Surface, Vol. 127, No. 12, e2022JF006838.

10.1029/2022JF006838

Sequoia Scientific, Inc. (2022). LISST-200X user’s manual (Version 2.3), Accessed 17 September, 2025, <https://www.sequoiasci.com/wp-content/uploads/2016/02/LISST-200X_Users_Manual_v1_3B.pdf>.

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 :12
Pages :1551-1562
Received Date : 2025-10-06
Revised Date : 2025-11-16
Accepted Date : 2025-11-18
DOI :https://doi.org/10.3741/JKWRA.2025.58.S-3.1551

Journal of Korea Water Resources Association ISSN:2799-8746(Print) 2799-8754(Online) 한국수자원학회 논문집

All Issue