Low sedimentation in the Sélingué dam reservoir (Mali-Guinea). Evidence of the stability of south Sudanese savannah at the scale of a large drainage basin very little affected by man

Luc Ferry (1) , Michel Mietton (2) , Kenji Fujiki (3, 4) , Myriam Laval (3, 2) , Ntjie Coulibaly (5) , Nadine Braquet (6) , Didier Martin (7)

1 IRD - Institut de Recherche pour le Développement
2 EVS - Environnement, Ville, Société
3 CRGA - Centre de Recherche de Géographie et Aménagement (Lyon 3)
4 LIVE - Laboratoire Image, Ville, Environnement
5 DNH - Direction Nationale de l'Hydraulique du Mali
6 UMR G-EAU - Gestion de l'Eau, Acteurs, Usages
7 UMR G-EAU - Gestion de l'Eau, Acteurs, Usages

Hydromorphogenic dynamics in West African drainage basins are complex phenomena that can be understood and measured through the study of sedimentation processes in reservoirs. By plotting a new topographic map of the reservoir, this study shows the limited sedimentation of Sélingué reservoir (Mali) in contrast with estimates prior to the building of the dam. Used together with studies on the specific degradation of large drainage basins and sediment transport, this study sheds new light on the hydrodynamic mechanics of a given bioclimatic environment. Specifically, for a drainage basin remarkable for its homogeneity of land use and vegetation, the study highlights the prime importance of the role of vegetation and human occupation in these hydromorphogenic processes. A new assessment of the storage capacity of the reservoir is made in the light of these findings.

Mots clés: Bathymetric profile sedimentation reservoir specific degradation South-sudanese climate dense dry forest savannah population density Sélingué reservoir Sankarani watershed Mali Guinea; Bathymetric profile; sedimentation; reservoir; specific degradation; South-sudanese climate; dense dry forest; savannah; population density; Sélingué reservoir; Sankarani watershed; Mali; Guinea

Domaines: Hydrologie

Luc Ferry, Michel Mietton, Kenji Fujiki, Myriam Laval, Ntjie Coulibaly, et al.. Low sedimentation in the Sélingué dam reservoir (Mali-Guinea). Evidence of the stability of south Sudanese savannah at the scale of a large drainage basin very little affected by man. G-Eau Working Paper/Rapport de Recherche, n° 5b, 2018. ⟨hal-04558961⟩