Investigating the role of the Cuvette Centrale wetlands in the hydrology, sediment and carbon fluxes of the Congo River basin

Keywords: Cuvette Centrale, Hydrology, Sediments, Carbon,

The Congo River basin is among the largest Rivers in the world in terms of discharge and drainage area. At the heart of the basin lies the Cuvette Centrale-one of the most extensive wetlands in the world. The increasing pressure on wetland resources continues to threaten the role wetlands play in maintaining water resources and ecological service functions. Therefore, in order to understand the role of the Cuvette Centrale in water resources and ecological service functions linked to the quality of water and life in the basin, we first need to quantify its role in the hydrological, sediment and carbon dynamics. To achieve this aim, we use the Soil and Water Assessment Tool model (SWAT) – modified for tropical environments, in order to analyze the hydrology, sediment and organic carbon fluxes flowing in and flowing out of the Cuvette Centrale of the Congo River basin (CRB). The model was calibrated and validated for the 2000-2006 and 2007-2012 periods respectively by comparing the discharge and sediment output with different data sources (gauging stations and altimetry) at a daily and monthly time step. Then by adapting equations of dissolved organic carbon (DOC) and particulate organic carbon (POC) from literature, we are able to quantify the role of the Cuvette Centrale in the CRB carbon dynamics.The results reveal that the models for hydrology, sediments and carbon can represent both temporally and spatially the exports in a watershed and sheds more light on the important regulatory function of the Cuvette and the need for sustainable land use practices as well as protection of ground water resources  in order to maintain wetland water quantities and quality.