Determination of rainfall erosivity in akwa ibom state using modified forunier index

Abstract

In the tropics, rainfall is known to be the cause of soil erosion through the detachment and runoff process. This issue has been known to be a global issue causing environmental threat and deterioration. In modeling soil erosion by water, rainfall is considered as the energy driving force. Its study is important in understanding the aggressivity of the rainfall and its interpretation. Modified Fournier index defines the aggressivity of a rainfall to cause erosion. It was used in this study based on the availability of the monthly and annual rainfall data. A rainfall data of 34 years was obtained from Nigerian Meteorological Agency (NIMET). The amount of rainfall ranges from 1840.7 to 3837.9mm representing 2000 and 2012 respectively. From the monthly MFI obtained, it shows that lower MFI values are associated with dry season while higher MFI values are associated with rainy season. July has the highest monthly MFI. The yearly MFI ranges from 220.2 to 561.3. From the statistical analysis carried out, a high variance was observed among the grouped data. P-value was given as 0.76 which signifies that the grouped data are not equal therefore differs from each other. The result obtained from the study shows that the aggressivity of the rainfall within the study area is very high in nature, therefore, having the ability to cause detachment and of soil particles and transportation.