A study of seiches in the Split harbour (Adriatic Sea)

This paper examines the occurrence of seiches inside the Split harbor (Adriatic Sea). The measurements indicating the seiche periods were carried out with the pressure gauge placed near the harbor entrance. Spectral analysis of the data suggests a resonant behavior appearing in front of the harbor, that covers the periods between 7.7 and 28.5 min. The seiches were documented to occur at the periods of 6.5, 3.0, 1.6 and 1.15 min, and were verified by the barotropic 2D numerical model. In addition, two model runs were executed: the first one with the present topography and the second one with the nautical marina removed (built in 1972). The comparison should quantify the influence of the marina on the seiche characteristics. Namely, the leading seiche modes of 7.1-min and 5.0-min periods, calculated for the present topography, were probably joined in the 6.2-min mode before 1972. On the other hand, the numerical model showed that the 3.0-min seiche mode keeps its period, having the maximum amplitude at the north end of the harbor calculated for both runs. Finally, the seiches may endanger the navigation near the entrance and within the marina during the enhanced seiche episodes.