Assessing functional relationships of catchment physiographic controls and hydro-climate processes in the Congo River Basin

If we consider a natural system as an entity, it is therefore obvious to understand that its behaviour as a whole depends upon the individual contributing units, and their interactions. The dynamic interactions of the landscape structural units determine the functional characteristics of the landscape features such as the flow patterns, transfer pathways, catchment response to events and inputs such as natural and human induced disturbances. A previous study towards catchment classification for hydrological prediction and water resources management in the Congo Basin used an a priori approach to determine homogenous climatic-physiographic regions that are expected to underline dominant hydrological processes characteristics. A set of 1740 catchment units were partitioned across the whole Congo Basin, based on a set of comprehensive criteria, including the natural break of the elevation gradient (199 units), inclusion of socio-economic and anthropogenic systems (204 units), and water management units based on traditional (customary) nomenclature of the rivers within the basin (1337 units). The identified catchment units were used to assess existing datasets of the basin physical properties, necessary to derive descriptors of the catchments characteristics, thus yielding 11 homogenous groups that are consistent with the current perceptual understanding of the Congo Basin physiographic and climatic settings. Based on the aforementioned perquisite work, the current study uses this a priori classification in combination with a set of signatures of streamflow regime to derive functional relationships of the catchments, necessary to enable hydrological prediction and water management in the Congo Basin.

Keyword: Catchment classification, Congo River Basin, a priori clustering, hydrologically relevant groups, functional relationships