Sediment transport and bathymetric change at Hornafjörður tidal inlet - Field data analysis and mathematical modeling

Sammanfattning: Commercial fishing makes the coastal inlet in Hornafjörður to an important navigational link for the port of Höfn in southeast Iceland. Low water depth caused through sediment accumulation along the ebb shoal generates navigational problems and the phenomenon of glacial rebound seems to intensify this problem. Economic losses caused by the inability of fishing boats to navigate through the coastal inlet due to insufficient water depth along the ebb shoal are estimated with 4.5 million ISK (ca. $ 50.000) per year and effect the local society. This thesis aims to gain a better understanding of the complex morphology caused by large longshore sediment transports and local gradients with the help of mathematical modeling. With this knowledge measures such as structures and different activities to ensure sufficient navigational depth can be implement. A intense investigation of local transport patterns with the help of bathymetry measurements has been carried to intensify the knowledge about local particularities. This knowledge has been used to set up a sufficient mathematical model with the help of the open TELEMAC-MASCARET system. Results show that the morphologic pattern for high energy events are governed by the tidal flow and wave currents to almost same parts and sediment movements along the ebb shoal could be minimized with the implementation of a structure along the south barrier.