Ecology and Resilient Infrastructure ISSN:2288-8527(Online) 응용생태공학회 논문집

This study aimed to evaluate the field applicability of the STIV (Space-Time Image Velocimetry) system, a non-contact image velocity measurement technique, for discharge gauging in agricultural channels and to explore standardization methods for reliable continuous monitoring. Comparative measurements were conducted both during daytime (6 runs) and nighttime (4 runs) using the STIV system and the standard equipment, ADCP (Acoustic Doppler Current Profiler), at the Eougyo agricultural channel in Wanju-gun, Jeollabuk-do. The results confirmed the technical validity of the STIV system by demonstrating high repeatability under both day and night conditions. However, the STIV-measured discharge consistently exhibited a systematic error relative to the ADCP measurements, showing an average error of 13.48% during the day and 17.78% at night. This systematic error indicates that the generic depth-averaged velocity coefficient (velocity coefficient) applied for velocity estimation overestimated the actual velocity profile of the site, suggesting that a recalibrated depth-averaged velocity coefficient around 0.75 is necessary for the Eougyo site. Furthermore, the slight increase in error rate during nighttime confirmed issues related to reduced accuracy due to illumination changes. These findings show that STIV is technically viable for measuring discharge in agricultural channels and can contribute to the future expansion of CCTV-based water resource survey systems. However, to ensure stable operation, site-specific depth-averaged velocity coefficient calibration based on ADCP measurements, the implementation of day/night dual-model correction and securing high-performance auxiliary lighting are essential follow-up tasks.