Abstract

The Brazzaville-Kinshasa hydrometric stations monitor 98% of the Congo River catchment. Located at the outlet of a stilling basin (the giant Malebo pool), they measure water levels just upstream of a stable and sensitive control (the Djoue rapids). Once the offset between the staff gauges of Brazzaville and Kinshasa evaluated, a long series could be reconstructed from daily stage readings since 1902. In addition, 154 gaugings have been collected, 139 using mechanical currentmeters in 1955-1962 (85) and 1971-1981 (54), and 15 using an ADCP since 2010. The gaugings cover the entire hydrological cycle as well as the main flow phases and almost all the stage range observed over the last 120 years. This work evaluates the stability of the control thanks to the ADCP gaugings initiated 30 years after the end of the currentmeter gaugings. It also establishes stage-discharge rating curves with uncertainty estimation, by combining the prior knowledge on the hydraulic controls and the information content of the uncertain gaugings via the Bayesian method BaRatin. A first estimate of the moving bed velocity of the Congo River during floods in the Brazzaville-Kinshasa cross-section is presented.