Automated Water Quality Observation in Tidal Flats
A Scientific Solution Emerges
The answer to why and to what extent the tidal flats of the West Coast become turbid has been revealed.
The Korea Institute of Ocean Science and Technology (President Lee Heeseung, KIOST) has identified a very high correlation between turbidity (NTU) and total suspended matter concentration (TSM) observed in the Gomsoman tidal flat on the West Coast, and published the results in the December issue of the international earth sciences journal "Water."
Notably, this paper was selected as the cover article in recognition of its achievement in establishing a significant turning point for automated observation in complex coastal environments such as tidal flats.
Until now, there have been few studies that quantitatively verified the relationship between turbidity and total suspended matter concentration over long periods in coastal environments like tidal flats. This is because factors such as tides, waves, river inflow, and biological disturbances act simultaneously, causing significant fluctuations in suspended matter concentration even over short periods, making it difficult to precisely compare the two indicators under the same conditions.
To address this, the research team led by Dr. Lee Junho at KIOST established a multi-observation system at the main tidal channel at the entrance of the Gomsoman tidal flat, combining CTD instruments for measuring salinity, water temperature, and depth; RCMs for measuring current direction and velocity; tide gauges; automatic measurement devices; and water sampling at various depths. Using this system, they continuously observed turbidity and total suspended matter concentration for 13 hours.
Vertical time series distribution of turbidity (NTU) and total suspended matter concentration (TSM).
As a result, the coefficient of determination (R²) between turbidity and total suspended matter concentration was found to be 0.94, confirming a very high correlation between the two indicators. Based on this, the team derived a calculation formula (turbidity = 0.3671 × total suspended matter concentration), enabling highly accurate estimation of suspended matter concentration in the main tidal channel at the entrance of the Gomsoman tidal flat by measuring only turbidity in the future.
The coefficient of determination (R²) is an index that expresses how consistently turbidity values and total suspended matter concentration values are related, using a number between 0 and 1. The closer R² is to 1, the more accurately one value can be estimated from the other.
Vertical results of net suspended sediment flux in the intertidal mudflat research area of Gomsoman, West Coast.
This study is significant as it demonstrates that even in highly variable coastal environments like tidal flats, key water quality indicators can be precisely identified through automated observation. It provides a scientific foundation to enhance the efficiency of tidal flat monitoring and management in the future.
Lee Heeseung, President of KIOST, stated, "The 'Korean Tidal Flats,' listed as a UNESCO World Natural Heritage site, are highly valuable not only for marine biodiversity but also as an important carbon sink for the ocean. We will continue to accumulate scientific data using advanced observation technologies such as drones, topographic surveys, and high-resolution estuary and coastal modeling, and contribute to establishing a systematic management foundation for tidal flats."
This study was conducted as part of the "Development of Tidal Flat Spatial Information Change Monitoring Technology" research project, managed by the National Institute of Hydrography and supported by the Korea Institute of Marine Science & Technology Promotion under the Ministry of Oceans and Fisheries.
Title of the paper: Site-Specific Net Suspended Sediment Flux and Turbidity-TSM Coupling in a UNESCO Tidal Flat on the Western Coast of Korea: High-Resolution Vertical Observations / Lee Junho, Yoo Joohyung, Kim Geunyong, et al., KIOST, Water (Switzerland), Vol. 17, No. 23, November 25, 2025 (online)
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