Use of topographic data and GIS for the management of water flows for the development of lowlands in the Gnannandji watershed in the Centre of Bénin

Abstract

Water management is a key condition for sustainable agricultural development in rural areas. In Ouèssè commune, central Benin, lowland areas have strong agroecological potential but remain underutilized due to topographic, pedological, and climatic constraints that hinder their rational development. The study explores the integration of topographic data and Geographic Information Systems (GIS) to analyze and to improve water flow management in the Gnannandji watershed. A methodology combining GNSS surveys, a 30-year rainfall study, field soil analyses, and simple hydrological modelling enabled the generation of thematic maps [slopes, runoff and DEM (Digital Elevation Model)] and the identification of priority intervention zones. Results showed high rainfall variability, a topography favouring runoff, and soils with low to medium permeability. Integrating these data into a GIS made it possible to prioritize interventions and propose appropriate structural works (bunds, drainage ditches and embankments). These findings demonstrate the relevance of a spatialized, integrated approach to promote sustainable water management and strengthen agricultural resilience.