Towards the Development of a New Erosivity Equation

Authors: Amobichukwu Chukwudi Amanambu*, University of Florida
Topics: Geomorphology, Soils, Physical Geography
Keywords: MAP; MFI; RUSLE; Erosivity; Polynomial equation; Rainfall
Session Type: Poster
Day: 4/5/2019
Start / End Time: 8:00 AM / 9:40 AM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: Download

Erosivity is the capability of rainfall to cause soil loss by water. The modern application of the erosivity (R) equation began with Universal soil loss Equation (USLE) and later Revised Soil Loss Equation (RUSLE). The information needed to calculate R using the daily rainfall amount and intensity are usually not available. Though several methods have been proposed, however, there is need to develop an equation for places of inadequate climate records and limited information on erosivity records (e.g. isoerodent maps) as in Africa and some parts of Asia. This study, therefore, proposes the use of a 2nd order polynomial quadratic equation to relate Modified Fournier Index (MFI) and Mean Annual Precipitation (MAP), in the absence of R records for the derivation of erosivity. The resultant equation was, therefore, used as a surrogate to derive R. Monthly rainfall records from Lower Niger basin, Africa, with 30 meteorological stations were used as the test sites from 1981-2014. The results were then compared with those generated from previous equations using the Taylor diagram. The result shows that the newly derived equation does not over or underestimate annual R, and it is positively correlated (>0.80) when compared to five other widely used equations. It is, therefore, recommended that this equation and its derivatives be applied in regions of limited climate data, also, in tropical and subtropical areas since the use of MFI and R relationships in such area may give spurious results.

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