Modelled Hillslope Erosion over New South Wales

This landing page is a collection of data packages and reports which supports the Modelled Hillslope Erosion over New South Wales.

Hillslope Erosion

Soil erosion by water includes sheet and rill erosion (also referred to as hillslope erosion)
is a major form of land degradation in NSW landscapes. Hillslope erosion was
calculated using the revised universal soil loss equation (RUSLE) which estimates soil
loss (t ha-1 yr-1) by runoff. Rainfall-runoff erosivity (R) factor (MJ mm ha-1 hr-1 yr-1) in
RUSLE was estimated using a daily rainfall erosivity modelling for NSW and long-term
rainfall records (Yang and Yu 2015). The soil erodibility (K) factor (t ha h ha-1 MJ-1 mm-1)
was estimated from digital soil mapping products and soil profile data (Yang et al 2017).
Slope length and steepness (LS, unitless) factor was calculated, on catchment basis, from
hydrologically corrected digital elevation model (SRTM DEM-H) based on comprehensive
algorithms considering cumulative overland flow length (Yang 2015). The time series
groundcover products (the latest version, V310) from Moderate Resolution Imaging
Spectroradiometer (MODIS) were used to estimate groundcover and RUSLE cover and
management (C, unitless) factor (Yang 2014). Time-series hillslope erosion datasets and maps were produced on monthly and annual bases from 2000 to present. The state and trends of hillslope erosion
across New South Wales are summarised in Yang (2020). The relevant references are 
below: 

Cover Erosion

This occurs when there is vegetation or ground cover, like grasses, shrubs or leaf litter, on the slope.  The cover helps protect the soil from direct raindrop impact, reduces the velocity of surface runoff, and increase infiltration.  As a result, erosion rates tend to be lower because the cover acts as a natural barrier that holds soil in place.

Bare Soil Erosion

This takes place on slopes with exposed soil, lacking any form of vegetation or cover. Bare soil is more vulnerable to erosion because there's nothing to cushion the impact of rainfall or slow down water flow.  The lack of cover results in higher runoff velocity, which intensifies erosion processes, leading to greater soil displacement, sediment transport and potentially faster degradation of the slope.
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Yang, X., Gray, J., Chapman, C., Zhu, Q., Tulau M., McInnes-Clarke, S. (2017). Digital mapping of soil erodibility for water erosion in New South Wales, Australia. Soil Research. 56(2), 158-170. https://doi.org/10.1071/SR17058.
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Yang X (2015) Digital mapping of RUSLE slope length and steepness factor across New South Wales. Soil Research 53, 216-225. https://doi.org/10.1071/SR14208.
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Yang X, Yu B (2015) Modelling and mapping rainfall erosivity in New South Wales, Australia. Soil Research. 53, 178-189. https://doi.org/10.1071/SR14188.
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Yang X (2014) Deriving RUSLE cover factor from time-series fractional vegetation cover for soil erosion risk monitoring in New South Wales. Soil Research 52, 253-261. https://doi.org/10.1071/SR13297. 
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Yang X (2020) State and trends of hillslope erosion across New South Wales, Australia. Catena 186, 104361. https://doi.org/10.1016/j.catena.2019.104361.
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Interactive Map

To view the Hillslope bare soil and cover erosion annual layers via SEED map <a href="https://geo.seed.nsw.gov.au/vertigisstudio/web/?app=cabd04d595ec43c1aaf4298e80e83ec2&amp;workflow=36ea26c1-e8e2-4355-8600-5d1558259ad3&amp;workflowParams=%7B%22portalItems%22:%20%5b%7B%22itemId%22:%20%2208dc3d21e8fa47f69a732b38b87f3687%22,%20%22layerIds%22:%20%220,9,19,48,39,29%22%7D%5d%7D" title="Interactive Map">'Click Here'</a>

The ‘Show on SEED map link will load some of the data due to its complexity. To load more layers please go to the Layer Catalogue and add them. Get help on using the Layer Catalogue <a href="https://www.seed.nsw.gov.au/need-help/finding-and-using-data-on-seed-map/how-to-use-layer-catalogue" title="How To">'Click Here'</a>

Tags: Hillslope erosion
Organization: NSW Department of Climate Change, Energy, the Environment and Water