Bed profile changes due to tsunami effects on near shore coasts: Tuzla case study

The concern of this study is the investigation of tsunami effects on the seabed profile as these may be important for the coastal structures, like sea outfalls or breakwaters. Tsunami is well known with its huge wave heights and destructive effects on the coastal region. A 2D numerical model was set using the software, COSMOS to calculate the cross-shore sediment transport and to evaluate profile changes in the coastal seabed. The study area is Tuzla region, a densely populated industrial coastal area in the South East of Istanbul. The model was run for different kinds of tsunami waves. Not only the bed profile changes, but also the wave heights, breaker depths, peak wave bottom orbital velocities, wave set-up and cross-shore sediment transport rates were determined. The results indicated that, at a water depth around 40∼50 m, some tsunamis were found to have a wave height at the order of 15 m, which became about 5 m at a depth of 10 m. The wave set up near the coast was about 1.5∼2 m. The results also implied that tsunami waves, with their destructive nature, could lead to dramatical vertical changes of the seabed.