Wave transmission in harbors through flushing culverts

An important aspect that must be considered in harbor design and construction is the water quality within the basin, which depends on the water exchange between the harbor and the surrounding water body. The most internationally distinguished methods to counteract diminished flushing and insufficient renewal occurring leeward of coastal structures include mechanical shakers, overflows, pumps, permeable breakwaters, and flushing culverts. Among these methods, the construction of flushing culverts is favorable due to the low costs of construction and operation. In the present paper, wave transmission through flushing culverts was investigated experimentally in two physical models. Incident wave and transmitted wave heights were determined using wave gauges for various combinations of wave characteristics and geometric characteristics of the flushing culverts. Wave height transformation through the flushing culvert was processed and analyzed for all experimental conditions. The sensitivity of the wave transmission coefficient with respect to other dimensional and non-dimensional parameters was comprehensively investigated in order to define which parameters could most effectively predict the wave transmission coefficient. The wave transmission coefficient increased when the incident wave period, the width, and the height of the flushing culvert increased, the incident wave became steeper, the length of the flushing culvert decreased, and the incident wave angle approached 90o. An empirical equation that correlates the wave transmission coefficient with the wave characteristics and the geometrical characteristics of the flushing culvert was derived using non-linear regression analysis.