Assessment of Current and Future Land Use and Land Cover in the Oueme Basin for Hydrological Studies

Abstract

The modification of land use is a crucial factor in the dysfunction of ecosystems. It greatly influences the hydrological cycle of basins. This study focused on the Oueme basin, which represents almost half of the total area of Benin, and aimed to describe the current and future evolution of its land cover using the maps of the Land Use Land Cover Dynamics project (1975, 2000, and 2013). A temporal analysis of the surface states was performed with QGIS, and the potential land cover in 2025, 2050, and 2085 was estimated using the Markov chain algorithm in the IDRISI software. The results showed that the Oueme basin was predominantly savanna (77.70% in 1975, 66.29% in 2000, and 57.10% in 2013). Forest areas, which represented the second class in 1975 with a total proportion of 13.34%, gradually decreased to 8.66% and 6.89%, respectively, in 2000 and 2013. Conversely, cultivated areas had more than tripled in 2000 and quadrupled in 2013. Residential areas increased rapidly in the southern part of the basin, with an acceleration in the recent period (6% between 2000 and 2013, against 2% between 1975 and 2000). This probably led to the lower stability rate in this zone (56%) compared to Oueme upper (74%). The recent period was more affected by changes in the surface conditions, and these changes are likely to be amplified in the future (probable total disappearance of forested areas by 2085). We recommend clarifying the impacts that each land use category generates/will generate on the hydrological cycle of this basin.