NSW Coastal Catchment Hillslope Erosion Projections using NARCliM2.0 - 2025

Brief description

This dataset comprises projected values and projected changes in hillslope erosion (also referred to as soil loss) for estuarine catchments in New South Wales (NSW), Australia. Estimates were derived using the latest New South Wales and Australian Regional Climate Modelling (NARCliM2.0) climate projections.

Hillslope erosion was estimated for each catchment using NARCliM2.0 rainfall projections within the framework of the Revised Universal Soil Loss Equation (RUSLE). Projected rainfall data were used to estimate rainfall erosivity, one of the five RUSLE parameters. The remaining parameters retained previously established values for southern Australia (Yang 2014; Yang 2015; Yang et al. 2018) and include soil erodibility (K), cover management (C), slope length and steepness (LS), and support practice (P).

NARCliM2.0 projections were prepared at a 4 km spatial resolution for two Shared Socio-economic Pathways (SSP1-2.6 and SSP3-7.0), derived from five Global Climate Models (GCMs) and downscaled using two Regional Climate Models (RCMs). The GCMs include:

* ACCESS-ESMI1-5 (CSIRO, Australia)
* EC-Earth3-Veg (EC-EARTH consortium, The Netherlands and Ireland)
* MPI–ESM1-2-HR (Max Planck Institute for Meteorology, Germany)
* NorESM2-MM (Norwegian Climate Center, Norway)
* UKESM1-0-LL (Met Office and Natural Environment Research Council, UK)

Rainfall projections were interpolated to a 100 m spatial resolution to match the remaining RUSLE factors. Projected hillslope erosion values were generated for all estuarine catchments in NSW for one historical epoch (1990–2009) and three future epochs:

* Near Future (NF): 2020–2039
* Mid Future (MF): 2050–2069
* Far Future (FF): 2080–2099


The historical epoch serves as the baseline against which changes for each future epoch were calculated. These 20-year future periods were selected to capture climatic variability while maintaining near-stationarity of climate variables within each epoch.

To ensure comparability, changes in hillslope erosion are presented as percentage differences relative to the baseline using a consistent colour ramp with 18 bins (10% intervals) ranging from –80% to 80%. Values increase from red (projected decreases) to blue (projected increases) relative to the historical period.

This dataset was used in Umeh et al. (2026) to estimate catchment sediment yield potential to estuaries and associated intertidal wetlands by spatially aggregating hillslope erosion estimates across each estuarine catchment. The resulting sediment yield potential estimates were used to assess future sediment supply potential available to support the vertical resilience of selected estuarine intertidal wetlands under climate change and sea-level rise.

Accordingly, this dataset provides a process-based, region-wide assessment of projected hillslope erosion across NSW estuarine catchments and forms the basis for subsequent assessments of catchment sediment yield potential to estuarine wetlands.

Projected hillslope erosion values are provided as raster datasets, while differences between historical and future epochs are supplied as vector datasets. Detailed information on file naming conventions, raster files, and shapefile attributes is provided in the accompanying ReadMe documentation.

Readers are encouraged to refer to the accompanying scientific publication for detailed information on the methodology, assumptions, modelling procedures, and the subsequent derivation of catchment sediment yield potential estimates for estuarine wetlands under climate change.

__References__

Umeh, C.N.V., Mason, T.J., Khojasteh, D., Karimi, S.S. and Hughes, M.G., 2026. Projected sediment supply deficits threaten intertidal wetland resilience to sea-level rise in southeast Australia. Science of The Total Environment, 1013, p.181222.

Yang, X., 2014. Deriving RUSLE cover factor from time-series fractional vegetation cover for hillslope erosion modelling in New South Wales. Soil Research, 52(3), pp.253-261.

Yang, X., 2015. Digital mapping of RUSLE slope length and steepness factor across New South Wales, Australia. Soil Research, 53(2), pp.216-225.

Yang, X., Gray, J., Chapman, G., Zhu, Q., Tulau, M. and McInnes-Clarke, S., 2018. Digital mapping of soil erodibility for water erosion in New South Wales, Australia. Soil Research, 56(2), pp.158-170.