Field Evaluation of a Pumping-Based Automated Sampler for Suspended-Sediment Monitoring in Small to Medium Rivers

Suspended sediment data are essential for hydrological and water resource management, including predicting riverbed changes, estimating reservoir sedimentation, calculating sediment yield, and supporting river management planning. Suspended sediment also causes turbidity, which complicates water treatment and negatively impacts aquatic ecosystems. These issues highlight the need for precise and continuous monitoring. Although long-term monitoring and research on sediment transport have been conducted worldwide for decades, Korea still lacks sufficient systematic, long-term datasets and technological development, resulting in a shortage of usable information. Conventional samplers such as the D-74 and P-61 face limitations in field application due to the need for multiple personnel, high costs, safety risks, and accessibility constraints. Moreover, indirect methods such as ADCP backscatter and LISST diffraction still require further validation with ground truth data.

To address these limitations, we developed a pumping-based automated sampling system and evaluated its field applicability in a small- to medium-sized river in Korea. The system was installed at a field site in Yeoju, Korea, across three cross-sections, with a total of 16 intake ports distributed at 5–6 depths per cross-section to enable automated multi-depth sampling under varying stage conditions. A joint field campaign, conducted alongside ADCP, LISST, conventional samplers, and surface grab sampling, provided comparative measurements for suspended-sediment characterization and sediment-load estimation. The system operated stably over water-level fluctuations and produced reproducible samples, indicating strong potential for safer and more efficient long-term monitoring.

In conclusion, this study demonstrates that the pumping-based automatic sampler can serve as a practical alternative to conventional suspended sediment measurement methods. The system reduces safety risks, labor, and costs while enabling multi-depth and multi-cross-sectional sampling, thereby providing more accurate suspended sediment distribution and total load estimation. Beyond its application in small- and medium-sized rivers, this approach has the potential to be extended to larger rivers and diverse hydrological conditions, offering a robust technical foundation for advancing suspended-sediment monitoring programs.