%0 Book Section
%9 OS CH : Chapitres d'ouvrages scientifiques
%A Nguimalet, C.R
%A Orange, Didier
%A Waterendji, J.P.
%A Yambele, A.
%T Hydroclimatic dynamics of upstream Ubangi river at Mobaye, Central African Republic : comparative study of the role of savannah and equatorial forest
%B Congo basin hydrology, climate, and biogeochemistry : a foundation for the future
%C Washington (USA) ; Hoboken
%D 2022
%E Tshimanga, R.M.
%E Moukandi N'kaya, G.D.
%E Alsdorf, D.
%L fdi:010087867
%G ENG
%I AGU ; Wiley
%@ 9781119656975
%K PRECIPITATION ; REGIME HYDROLOGIQUE ; PLUVIOMETRIE ; DEBIT ; VARIATION ANNUELLE ; SECHERESSE ; RUISSELLEMENT ; AQUIFERE ; ETUDE COMPARATIVE ; COUVERT VEGETAL ; SAVANE ; FORET DENSE ; COURS D'EAU ; BASSIN VERSANT
%K SERIE CHRONOLOGIQUE ; CHANGEMENT CLIMATIQUE ; 1938 2015
%K CENTRAFRIQUE
%K OUBANGUI COURS D'EAU ; MOBAYE ; KOTTO COURS D'EAU ; KEMBE ; BRIA ; MBOMU COURS D'EAU ; BANGASSOU ; ZEMIO ; UELE COURS D'EAU ; BILI COURS D'EAU
%N 269
%P 83-96
%R 10.1002/9781119657002.ch6
%U https://www.documentation.ird.fr/hor/fdi:010087867
%> https://www.documentation.ird.fr/intranet/publi/2023-10/010087867.pdf
%W Horizon (IRD)
%X The rainfall reduction in the 1970s, less marked in Central Africa than in West Africa, still had a major impact on the hydrological regimes of the region's large rivers. The study of the hydropluviometric behavior of the Ubangi River at Mobaye  has the advantage of being a study of a basin excluding anthropogenic impact. Forest cover and population density have not changed since at least 1970. Statistical analysis of the breaks in the long rainfall time series to Mobaye (1938-2015) confirms a long period of drought from 1969 to 2006, corresponding to a reduction of 8% in rainfall. Also, the study of the corresponding hydrological series indicates a second downward break in 1981, marking an exceptional hydrological drought.  Flows increased in 2013, a few years after the rainfall increase. The statistical study of the annual rainfall/flow series of the upstream basins over the period 1951-1995 (the Kotto River in Kembe and Bria, the Mbomu River in Bangassou and Zemio, and the Uele River + Bili hydrographic system) highlights different hydrological behaviors related to the vegetation cover. On the one hand, the savannah basins show a continuous hydrological deficit marked by a runoff coefficient (CE) that fell to only 5% from the 1990s.  On the other hand, the basins under forest show a runoff increase since 1990, marked by a CE above 10%. Under savannah, the part of the flow infiltrating to recharge the aquifer would have decreased faster than under forest, which results in a runoff CE very significantly negatively correlated with the savannah area present in the studied watershed.
%S Geophysical Monograph
%$ 062MECEAU