Гидрология: текущие исследования

Hydrological Variability in a Forest Watershed Undergoing Accelerated Urbanization: The Case of Mefou (South Cameroon)

Abstract

Valentin Brice Ebodé1,2*, Jean Guy Dzana1, Etienne Merlin Salvador Mewassi Aboui3, Raphael Onguéné2, Bérenger Koffi4, Gil Mahé2 and Jean Jacques Braun2

Climate change and variability and anthropogenic forcings such as land use change are the main forcings of river discharge variability. However, understanding their simultaneous impact on river discharge remains limited in some parts of the world like in central Africa. To shed light on this issue, this article has as objective to investigate the impact of rainfall variability and land use changes on river discharge in the Mefou basin over the recent period (1963-2018). To achieve this goal, hydrometeorological data of this basin were analyzed using the Pettitt and Mann Kendall tests. Likewise, land use changes were also analyzed using supervised classifications of Landsat satellite images over the period (1973-2018). Average and extreme flows of Mefou river have increased since 1985-86, unlike the rainfall, which generally decreased for all seasons from the 1970s, apart from summer, where the reverse was observed. Changes in land use (increase impervious areas and a decrease in forest and water bodies) seem to be the main cause of the increase in runoff observed. The rainfall plays an essentially amplifying role in the increase in discharge in the seasons during which they occur. These results could be useful for the improvement of future simulations of the Mefou river flow.