Sara4r: an R graphical user interface (GUI) to estimate watershed surface runoff applying the NRCS - curve number method

This paper introduces a graphical user interface (GUI) for the R software that allows the rainfall-runoff relationship to be calculated, using the curve number method. This GUI is a raster-tool whose outputs are runoff estimates calculated using land use/land cover and hydrologic soil group maps. The package allows the user to select among three different antecedent moisture conditions and includes modifications about the initial abstraction parameter. We tested this GUI with data derived from two watersheds in Mexico and the outputs were compared with those produced using a well-established GIS tool in a vector environment. The results produced by these two approaches were practically the same. The main advantages of our package are: (1) 'Sara4r' is faster than previous vector based tools; (2) it is easy to use, even for people with no previous experience using R; (3) the modular design allows the integration of new routines; and (4) it is free and open source.

Automated summary

This paper introduces a graphical user interface for the R software that allows the calculation of rainfall-runoff relationship using the curve number method. The GUI provides runoff estimates based on land use/land cover and hydrologic soil group maps, with options for different antecedent moisture conditions and initial abstraction parameter modifications. Testing with data from two watersheds in Mexico showed comparable results with a well-established GIS tool, highlighting the speed, user-friendliness, modularity, and open source nature of the new package.