NSW Sediment Yield Projections under NARCliM2.0 - 2025

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

This dataset provides the first process-based, region-wide assessment of soil availability for estuarine intertidal wetlands of NSW, complementing previous studies that focused primarily on the effects of sea-level rise (SLR). Together, these datasets provide a more comprehensive understanding of current and future trends affecting the state’s intertidal wetlands. Datasets of absolute sediment yield are provided as raster files, while differences between historical and projected epochs are supplied as vector files.

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 initially used to estimate rainfall erosivity, one of the five RUSLE parameters. The remaining parameters of the RUSLE retained their previously established values for Southern Australia (Yang, 2014; 2015; Yang et al., 2018) and include soil erodibility (K), cover management (C), slope length and steepness (LS) and the support practice (P). NARCliM2.0 projections were prepared with a 4-km spatial resolution for 2 Shared Socio-economic Pathways (SSP1-2.6 and SSP3-7.0), derived from 5 global climate models (GCMs) and downscaled to 2 regional climate models (RCMs). The GCMs include: 
<ul>
<li>ACCESS-ESMI1-5 (CSIRO, Australia) </li>
<li>EC-Earth3-Veg (EC-EARTH consortium, The Netherlands and Ireland) </li>
<li>MPI–ESM1-2-HR (Max Planck Institute for Meteorology, Germany)</li>
<li>NorESM2-MM (Norwegian Climate Center, Norway) </li>
<li>UKESM1-0-LL (Met Office and Natural Environment Research Council, UK)</li>
</ul>

Rainfall projections were interpolated to a 100-metre spatial resolution to match the remaining RUSLE factors. The absolute sediment yield values were then generated for all estuarine catchments in NSW for one historical epoch (1990–2009) and three future epochs:
<ul>
<li>Near Future (NF): 2020–2039</li>
<li>Mid Future (MF): 2050–2069</li>
<li>Far Future (FF): 2080–2099</li>
</ul>

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

To ensure comparability, differences in sediment yield are presented as percentage change relative to the baseline using a consistent colour ramp with 18 bins (10% intervals) ranging from –80% to 80%. Differences in sediment yield increase from red (negative) to blue (positive), where red indicates projected decreases and blue indicates projected increases relative to the historical period. 

Detailed information on file naming conventions, raster files, and shapefile attributes is provided in the accompanying ReadMe documentation. Readers are also encouraged to refer to the accompanying scientific article (under review) for detailed information on the methodology, assumptions, and modelling procedures.

Tags: Coastal Management, Sediment Yield, Water Wetlands and Coastal
Organization: NSW Department of Climate Change, Energy, the Environment and Water