Development and Field Application of a Pumping-Based Automatic and Remote Suspended Sediment Sampling System

Suspended sediment concentration (SSC) in rivers is commonly measured using depth-integrated sampling with a D-74 sampler. Although this method provides reliable reference data, it requires manual operation from bridges using winches, which involves considerable manpower and cost and poses significant safety risks, particularly during flood events. Due to these operational constraints, SSC measurements in Korea are conducted at only a limited number of stations each year despite the existence of a nationwide sediment monitoring network. To address this limitation, recent studies have actively explored indirect SSC estimation techniques based on acoustic backscatter intensity measured by horizontal acoustic Doppler current profilers (H-ADCPs). However, the application of such techniques critically depends on the availability of in situ SSC samples for calibration and validation. In this study, a pumping-based automatic and remote suspended sediment sampling system was developed to overcome the limitations of conventional manual sampling methods and to enable continuous and safe sampling during flood events and night time conditions.

 

The developed system consists of a sampling unit, a pumping unit, a control unit based on a remote terminal unit (RTU), and power supply and communication units. The sampling unit was designed with a multi-channel structure to sequentially fill multiple sample bottles in a single operation, and a strain-gauge-based load cell was applied to control the sampled mass with a resolution of 10 g. The pumping unit was designed to ensure stable water intake under high-turbidity and high-flow conditions. The control unit was configured based on a remote terminal unit (RTU) to integrate pump operation, sampling sequence control, sampled mass monitoring, and system status diagnostics. The control program supports both manual operation and automatic scheduling, and implements time-based and event-triggered sampling control schemes to enable unattended operation.

 

The system was deployed at a natural river site and operated under various flow conditions. Field application results showed that SSC samples collected by the automatic system exhibited similar concentration trends compared to those obtained by conventional manual sampling. Furthermore, continuous and unattended sampling was successfully achieved during flood conditions without on-site human intervention. The results indicate that the proposed system effectively improves operational safety and efficiency in suspended sediment sampling and can serve as a practical infrastructure for enhancing sediment monitoring networks.

 

This work was supported by the Ministry of Climate, Energy, and Environment (MCEE), Republic of Korea (Grant No. RS-2024-00397970).