Study and analysis of seasonal soil degradation in Lower Guinea and Forest Guinea

Abstract

Seasonal degradation of roads has become a recurring concern over the last two decades in Guinea. The most visible causes are those of their supports: the soil. Out of concern for the consequences of this scourge on the daily life of the population, the aim of this study is to understand the causes and propose solutions. On the Coyah_Kindia road, a terrible traffic jam was recorded on September 14, 2020 (∼3H/Km). The humidity of the road surface layers gives them very slippery characteristics, reflecting a plastic fringe of their fine fractions. The Péla-Yomou section, during rainshowers on the 22 km section along the Yomou-Nzérékoré national road, shows enormous degradation of the roads, with very acute soil slippage (even for pedestrians). Our GIS and remote sensing work removes the ambiguity about the main reasons for the degradations, which are more attributable to erosion than to the destruction of the vegetation cover (seen as a whole and not in the analysis of the classes that make it up), which, for the intervals of years [1982, 2021], fluctuates from 70%, 63%, 67% and 71% in Coyah, against 70%, 61%, 57% and 68% in Kindia, then 68%, 88%, 69% and 73% in Yomou. Our geoscientific analyses show a diversity of facies in terms of age, nature and reaction to the permanent constraints (meteorological and anthropogenic) to which they are subjected, while the soils, which are often less indurated and weathered in places, show great sensitivity to landslides that cover the low-lying areas often crossed by roads.