Accelerated numerical simulation to investigate morphology changes around small tidal inlets

Abstract

Among the state-of-the-art methods to study coastal processes using numerical modeling, input reduction techniques are advantageous with a significant reduction of required resources, particularly when conducting long-term simulations. This paper evaluates the suitability of these techniques to perform an accelerated morphological simulation, using a Delft3D coupled wave-hydrodynamic-sediment transport model for a small, jettied tidal inlet system (Currumbin Creek, Australia). Three different wave data reduction techniques were applied, namely categorized wave cases (CWC), synthetic wave events (SWE), and seasonally averaged wave events (SAWE). The results were compared with each other and a benchmark study – in particular, the required annual entrance dredging (equivalent to infilling) volume. The CWC, SWE and SAWE methods resulted in about +7%, – 8% and +1% larger infilling volume than the benchmark study, respectively. SAWE was found to be the fastest of all. However, in contrast to the SWE method, no intermediate results would be achieved using the CWC or SAWE methods and only the final pattern of sedimentation or the final volume of channel infilling can correctly be obtained.