Observation of Relationship between Surface Flow Velocity and Mean Velocity

Abstract

Surface velocity measurement using electromagnetic waves is common in flood season discharge surveys in Korea. In order to expand the relatively safe non-contact discharge survey, this study investigated the reliability of the coefficient that converts surface velocity to mean velocity in rivers and waterways. Surface and mean velocity were investigated for agricultural reservoir spillways, gravel rivers, and irrigation canals, and the volumetric capacity of agricultural reservoirs was confirmed. As a result of the investigation, the mean velocity conversion coefficients according to the riverbed slope or riverbed material were very diverse, such as 0.61, 0.90, 0.52, and 0.88. The above result makes it clear that each investigation point has a unique conversion coefficient according to the characteristics of the bed material. In other words, accurate discharge investigation is possible by knowing the unique conversion factor to each point. The importance of water management due to climate change is increasing day by day. Accurate flow rate for rivers and waterways will be used as an essential factor for quantitative water resource management in the future.