Land Use and Land Cover Dynamics and Their Impact on the Water Body Regime in the Dallol Bosso Sub-Basin (West of Niger)

Abstract

In Niger, land use and land cover changes have affected hydrological processes and water regimes at various scales. However, the significant changes observed in land use and land cover dynamics over the past few decades have negatively impacted the living conditions of the population and the state of natural ecosystems, particularly in the Dallol Bosso sub-basin, where agriculture and livestock are the primary sources of income for the population. This paper investigates the dynamics and trends of changes in land use types and their relationships with surface water regimes over the last fifty years (1972-2023) in the Dallol Bosso sub-basin. To achieve this, the study employed data obtained from Landsat and Sentinel 2 during the years 1972, 1990, and 2023 and ground observation (water bodies’ location and regime). Method and various geospatial analysis tools are used to estimate land use and land cover changes, monitoring land degradation. The result showed that the development of cultivation and settlement led to runoff (water erosion) and the emergence of ephemeral water bodies. The analysis of land use and land cover change indicates that settlement increased from 0.21% in 1972 to 0.5% in 2023 and that tiger bush and shrub savanna have declined considerably, by 1,332 hectares per year for tiger bush and 4,634 hectares per year for shrub savanna between 1990 and 2023. Also, the study showed that degraded areas, stable areas, and improved land represent respectively 21%, 64%, and 15% in the study area from 2001 to 2022. Therefore, we conclude that climate change and demographic pressures have led to the loss of certain natural land cover (tiger bush and savanna), and increased water erosion and the presence of more ephemeral water bodies, subject to excessive evaporation.