Composite Topography-Bathymetry Digital Elevation Model for Queensland Estuaries

This dataset provides a high-resolution (5 m) composite topography-bathymetry Digital Elevation Model (DEM) for all estuaries along the Queensland coast from Cape York to Gold Coast. The DEM was specifically developed to support hydrodynamic modelling of tidal inundation in Great Barrier Reef (GBR) coastal wetlands and estuaries, and served as the foundational elevation dataset for the SCHISM (Semi-implicit Cross-scale Hydroscience Integrated System Model) hydrodynamic model simulations of Highest Astronomical Tide (HAT) published at https://data.csiro.au/collection/csiro:66491v4.

The composite DEM integrates multiple authoritative elevation data sources across the land-water interface, including terrestrial LiDAR, bathymetric surveys, satellite-derived intertidal topography, and modelled tidal creek bathymetry. A key innovation is the use of satellite-derived water observations and allometric relationships to estimate tidal creek depths based on local creek width, enabling representation of tidal conveyance into coastal floodplains that are not captured by traditional survey methods.

The DEM is referenced to the Australian Vertical Working Surface (AVWS, EPSG:9458) quasi-geoid vertical datum and projected in Australian Albers Equal Area (EPSG:9473) coordinate reference system. The dataset covers the entire Queensland coastal zone with elevations ranging from approximately -60 m (offshore) to +15 m (terrestrial), with a mask layer indicating the data source for each pixel.

Spatial Coverage: Queensland coast from Cape York to Gold Coast.

Temporal Coverage: Data sources span from 2010 to 2024, with the composite DEM representing conditions circa 2022-2024.

Resolution: 5 m horizontal resolution, processed in 5000 m × 5000 m tiles in Australian Albers Equal Area projection (EPSG:9473). Composed into a single Cloud-Optimised GeoTIFF with ZSTD compression.

Vertical Datum: quasi-geoidal Australian Vertical Working Surface (AVWS, EPSG:9458). AVWS can be translated to AHD using GA published grids in PROJ. Coastal Mean Sea Level relative to AVWS has been previously published here: https://doi.org/10.25919/6672-jx11

Format: Cloud-Optimized GeoTIFFs (COG) with (1) elevation (CSIRO_TOPOBATHY_V8_5m_DEM.tif), (2) data source mask (CSIRO_TOPOBATHY_V8_5m_FLAGS.tif).