Water Erosion Factors Modeling in the N’Zérékoré City, Republic of Guinea

Soil erosion from water has become a relevant issue at global level. In Guinea in particular, erosion has worrying effects, due to natural conditions and human impact, especially in the Nzérékore city in forest region.This paper proposed a soil erosion modeling by rainfall effect in the prefecture of N'Zérékoré.To achieve this objective, monthly and annual rainfall data for the N'Zérékoré city were collected at the meteorological station over the period from 1980 to 2024. The analysis of rainfall aggressiveness was possible using the Fournier index. For data processing, we used Microsoft Excel, Python and the ARIMA (AutoRegressive Integrated Moving Average) model for soil aggressiveness predicted by rainfall. It was found that, from 2000 to 2009, erosion was higher compared to other periods with a rate of 60%, or 6 years of high rainfall aggression. From the periods 1990 to 1999 and 2010 to 2019, the lowest rainfall aggressiveness was recorded, with 60% or 6 years of low erosivity. However, from period 1980 to 1989 the highest rate (70%) of very high rainfall erosivity was recorded. The results show three levels of rainfall aggressiveness on an annual scale: a very high level of erosivity with a rate of 22.2% or 10 years, followed by a high level of 35.6% or 16 years of strong erosion. The moderate erosivity level corresponds to 42.2% or 19 years. The model predicts a stability of the erosivity index around 77.14 over the period 2025-2034. During the forty (45) years the rainfall erosivity index was very unstable characterized by strong erosion, however it would be stable in the next ten (10) years.