Experimental Study on Estimation of Water Level Rise behind a Low-crested Structure Using Water Level-discharge Relationship

Abstract

Low-crested structures (LCSs) that are installed to reduce the incoming wave height, such as detached and submerged breakwater structures, allow more overflow than do general breakwater structures and increase the water level behind the structure. In the LCS design stage, because the increased water level distorts the results of laboratory experiments, the effect of the rise in the water level must be determined. In this study, an experiment was conducted to determine the water level-discharge relationship and analyze the characteristics of the water level rise behind permeable and impermeable LCSs with various wave conditions. It is found that the slopes of the water level-discharge relationship with the same significant wave period are approximately identical for the permeable and impermeable LCSs. In addition, the slopes of the water level-discharge relationship for different significant wave heights are linear for the permeable LCSs but not for the impermeable LCSs. These results can be useful for selecting a suitable planar configuration for LCSs in field site applications. © 2021 Coastal Education Research Foundation Inc.. All rights reserved.