Abstract
<title>Abstract</title> <p>Large tropical river basins are complex socio-ecological systems whose sustainable management increasingly depends on integrated information infrastructure capable of supporting prediction, planning, and adaptive governance. The Congo River Basin (CRB), the world’s second-largest river basin by discharge and area, remains one of the least monitored major hydrological systems despite its global significance for climate regulation, biodiversity conservation, carbon storage, inland navigation, hydropower development, and regional livelihoods. To address persistent information gaps, fragmented monitoring networks, and growing environmental pressures, this paper presents the Congo Basin Catchment Information System (CB-CIS), a digital hydrological infrastructure designed to support systems-based water resources management. CB-CIS integrates catchment classification, hydrological modelling, remote sensing, geospatial databases, socio-economic information, and governance dimensions within a unified hydro-informatic architecture organized around hydrologically meaningful catchments rather than administrative boundaries. The system employs a multi-level nested catchments framework comprising physiographic, socio-economic, and socio-hydrological dimensions, resulting in 403 operational management units and 1740 detailed catchments across the basin. A multidimensional database incorporating 128 variables across seven thematic domains supports analysis, visualization, modelling, and decision-making. Built on interoperable geospatial and database technologies, CB-CIS enhances prediction in ungauged basins, improves monitoring network design, facilitates knowledge transfer across catchments, and strengthens transboundary water governance. This paper demonstrates how digital hydrological infrastructure can transform fragmented observations into actionable knowledge and provides a transferable framework for strengthening integrated water resources management in large, data-scarce tropical river basins worldwide</p>