A New Procedure to Estimate the RUSLE EI sub(30) Index, Based on Monthly Rainfall Data and Applied to the Algarve Region, Portugal

The rainfall-runoff erosivity factor R used in the revised universal soil loss equation (RUSLE) is a good indicator of potential erosion risks and transport capabilities of runoff generated by erosive storms, but often data for computing this factor are lacking and other indices are substituted that may reduce the effectiveness of RUSLE. One difference between R and the alternative indices often involves time scales (individual storm rainfall vs. monthly averages taken over a year). A new procedure for estimating the rainfall erosivity parameter (EI sub(30)) on a monthly time scale is presented. Data from the Algarve region, Portugal, are used to illustrate this procedure.