R-factor

The R-factor is a measure used in erosion and (overland) sediment modelling to quantify the effect of rainfall on soil erosion. It is typically defined in the context of the RUSLE equation, in which gross erosion for an agricultural parcel is estimated.

Specifically, the R-factor is a measure for the total erosivity of a number of rainfall events within a defined timeframe (year, month, number of days). The factor is computed by calculating the erosivity for every rainfall event in a timeseries, and taking the sum of the erosivity of all events in one year. These yearly values can be used to compute an average value, the R-factor, presenting the rainfall erosivity for a given period. An in-depth explanation of the formula's is given here <rfactor>.

The aim of this package is to provide an interface for computing the erosivity and R-factor (in batch). The interface allows to apply commonly used formulation of the R-factor (i.e. Brown and Foster, 1987 or McGregor et al, 1995) next to custom user-defined functions. In addition, it allows to apply custom user-defined input data processing functions, next to the standard input format.

The implemented formula's in this code are developed in a context of rainfall in Belgium (Verstraeten et al., 2006). Yet, the current Python implementation allows for an easy integration of alternative functions and relations. An in-depth analysis of the application of this code on Flanders can be found in in this report.

Note

In the earlier versions (<0.1.0) of the R-factor package, Matlab was used for the core computations. Since version 0.1.0, a faster Python implementation is provided. Using the version 0.0.x will provide other results compared to version >0.1.0, as explained in the package documentation.

Get started

This package makes use of Python (and a limited number of dependencies such as Pandas and Numpy). To install:

pip install rfactor

Make sure to check out the installation instructions and follow the example in the Get started section of the package documentation.

Rainfall and erosivity data

Any 10 minute ezqolurion input rainfall should work, but input rainfall data for the initial project were provided by the Flemish Environment Agency (VMM) and the Royal Meteorological Institute (RMI). The data from the Flemish Environment Agency (VMM) are available via waterinfo. The input rainfall data from the Royal Meteorological Institute (RMI) are not shared in this project. Please contact the RMI if you would like to obtain the a copy of the RMI rainfall input data.

The erosivity data calculated with the rainfall input data are provided by the partners of this project, and are used as test data for analysing the R-factor for Flanders.

Code

The open-source code can be found on GitHub.

Documentation

The documentation can be found on the R-factor documentation page.

License

This project is licensed under the GNU Lesser Public License v3.0, see LICENSE for more information.

Contact

For technical questions, we refer to the documentation. If you have a technical issue with running the model, or if you encounter a bug, please use the issue-tracker on github: https://github.com/watem-sedem/rfactor/issues

If you have questions about the history or concept of the model that are not answered in the documentation please contact KU Leuven via https://ees.kuleuven.be/en/geography/modelling/erosion/watem-sedem/contact.

Do you have questions about the application of R-factor in Flanders? Please contact 'Departement Omgeving' of the Government of Flanders on cn-ws@omgeving.vlaanderen.be

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Note

This project has been set up using PyScaffold 3.2.3. For details and usage information on PyScaffold see https://pyscaffold.org/.

References

Brown, L.C., Foster, G.R., 1987. Storm erosivity using idealized intensity distributions. Transactions of the ASAE 30, 0379–0386. McGregor, K.C., Bingner, R.L., Bowie, A.J. and Foster, G.R., 1995. Erosivity index values for northern Mississippi. Transactions of the ASAE, 38(4), pp.1039-1047.