Multidecadal mapping of tidal inlet morphodynamics using analysis ready data to generate satellite derived bathymetries

This study investigates the suitability of these products to generate SDB models. A tidal inlet on the East Australian Coast (Rous Inlet) was chosen to evaluate the accuracy of the Satellite Derived Bathymetry (SDB) models generated using Analysis Ready Data (ARD) Landsat data available from Digital Earth Australia (DEA). Novel methods were applied to define the limits of optically shallow water. Validation was conducted using contemporaneous Landsat image capture and a publicly available Digital Elevation Model derived from a bathymetric LiDAR survey. An R2 value of 0.88 was achieved for the depth calibrated test-set. Cloud-free imagery for the study site was processed at approximately annual timesteps. The uncalibrated relative depth surfaces were then normalized and processed using the terrain analysis tool r.geomorphons in GRASS GIS. The resultant datasets depict evidence of clear shifts in the sedimentary units at the inlet and the study demonstrates that the DEA ARD datasets are suited to depth modelling using empirical SDB algorithms and terrain analysis using uncalibrated but normalised relative depth surfaces. It is hoped that the workflow adopted in this study can be adapted to any ARD dataset for a optically shallow water, particularly with a sand substrate.