Assessment of Shoreline Changes and Evaluation of Coastal Protection Methods to Mitigate Erosion

Abstract

In this paper, the combined use of satellite images and morphodynamic models is applied to assess the coastline changes of an erosion-prone deltaic zone in Northern Greece (Nestos River delta). Satellite images over the last 31 years were used to estimate the erosion rates at the eastern, central and western parts of the delta. The numerical model LITPACK, coupled with wave and hydrodynamic nearshore models, was calibrated based on these results, and was further utilized to predict the shoreline evolution with and without “hard” protection works. Results show that the model underestimated erosion rates over all studied sub-sections, but showed fair agreement to remote sensing analysis when focusing on the zones of major erosion. “Hard” coastal protection structures were tested to assess their mitigation efficiency in terms of longshore and cross-shore sediment transport reduction. LITPACK considered that the scenario of seven rubble-mound breakwaters with low seaward and lee-side slopes, positioned between 9 m and 19 m depicted the best results, even reversing coastline retreat process.

Keywords:

• Erosion
• coastline change
• satellite image analysis
• morphodynamic modeling
• LITPACK
• protection structures