USPED calculates spatial distribution of erosion and deposition areas.
Erosion and losses of phosphorus display large variations in both time and space. Identifying the most sensitive areas is thus a necessity to ensure mitigation measures are made at the right place and to have the biggest effect.
The production of a new high-resolution, high precision Swedish digital elevation model (DEM), aid in identifying hotspots: the areas in a catchment which are likely to have erosion and surface runoff.
The USPED model (Unit Stream Power-based Erosion Deposition, Mitasova, 2001) is an empirical model to identify erosion and deposition areas within a catchment at a high resolution. Using the model, it is possible to rank vulnerability to erosion of individual fields, or parts of fields. Calculations so far show that the USPED model together with the new high-resolution DEM (2 m grid) successfully identifies erosion-prone hotspots in catchments. These locations correspond to the farmers’ own observations of erosion.
We have used USPED to calculate the erosion risk for all agricultural areas in southern Sweden (Djodjic and Markensten, 2019).
The erosion risk map for the catchment area Norrström can be viewed in our storymap "Rätt åtgärd på rätt plats" (in Swedish)
We have also used a dynamic version of USPED to model transport of suspended solids in small agricultural streams (Sandström, 2022; Sandström et al. 2023).
The figure shows results from the modeling with USPED in the Milsboån catchment in Dalarna, Sweden (Djodjic, 2008). Red indicates erosion areas and green deposition areas.
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Djodjic, F. 2008. Identifiering av riskområden for fosforförluster i ett jordbruksdominerat avrinningsområde i Dalarna. Institutionen för miljöanalys, Sveriges lantbruksuniversitet, Rapport 2008:5.
Djodjic, F. & H. Markensten. 2019. From single fields to river basins: Identification of critical source areas for erosion and phosphorus losses at high resolution. Ambio 48: 1129-1142.
Mitasova, H, Mitas, L & Brown, WM. 2001. Multiscale Simulation of Land Use Impact on Soil Erosion and Deposition Patterns. In Stott, DE, Mohtar, RH & Steinhardt, GC (eds). Sustaining the Global Farm. Selected papers from the 10th international Soil Conservation Meeting.
Sandström, S. 2022. Sources, composition and transport of fluvial suspended sediment and attached phosphorus in agricultural catchments : a cross-scale analysis. Acta Universitatis Agriculturae Sueciae, 2022:49. Swedish University of Agricultural Sciences.
Sandström S., Markensten H., Futter M.N., Kyllmar K., O’Connell D.W., Bishop K. and Djodjic F. 2023. Distributed dynamic modelling of suspended sediment mobilization and transport from small agricultural catchments. Front. Environ. Sci. 11:1196048. doi: 10.3389/fenvs.2023.1196048