Revised Determination of the Rainfall-runoff Erosivity Factor R for Application of USLE in the Czech Republic
Janeček Miloslav, Tippl Eliška Kubátová and Martinhttps://doi.org/10.17221/6507-SWRCitation:Miloslav J., Eliška Kubátová and Martin T. (2006): Revised Determination of the Rainfall-runoff Erosivity Factor R for Application of USLE in the Czech Republic. Soil & Water Res., 1: 65-71.
The evaluation of a series (1961–2000) of ombrographic records from 13 selected stations of Czech Hydrometeorological Institute provided long-term annual summation values and annual peaks of the rainfallrunoff erosivity factor R in the USLE. The evaluation indicated that by defining an erosive rainfall event as (a) rainfall ≥ 12.5 mm or (b) rainfall intensity > 6 mm per 15 minutes, there were on average 8 erosive rainfall events per station, varying from 1 to 25. The long-term summation values of R factor were in the range of 42 to 106 (average 66) and annual peaks ranged from 19 to 38 (average 29). If the criteria (a) and (b) were to be fulfilled simultaneously, there were on average more than 2 erosive rainfall events per year per station, the number varying from 0 to 12. The long-term summation values of R factor ranged from 25 to 67 (average 45), with annual peaks from 17 to 36 (average 27.5). The long-term investigations of soil losses by erosion on experimental runoff plots, near Třebsín (Prague-West district), caused by storms, reveal that these losses were mostly caused by rainfall events satisfying both criteria (a) and (b) at the same time. The results of this investigation suggest that the average value of the erosivity factor R = 20 recommended for the Czech Republic until now should be increased to R = 45 and/or 66, which in practical terms would necessitate more stringent conservation measures.Keywords:
water erosion; storms; rainfall erosivity (R) factor; USLE