Conceptual and Methodological Foundations for the Articulation of Geospatial Data on Water Resources in South America’s Cross-Border Hydrographic Basins

When observing transboundary waters through the lens of Integrated Water Resources Management (IWRM), it is essential to emphasize the principle of watershed unicity, which must overcome geopolitical interests while being supported by technical criteria. This paper used a multilevel and multiscale approach for integrated management of transboundary water resources in two South American transboundary river basins: the Javari River Basin (between Brazil and Peru) and the Quaraí River Basin (between Brazil and Uruguay). The Food and Agriculture Organization (FAO) provided spatialized data for South American watersheds. Our research focused on several broad issues concerning regional transboundary water management: (a) Because only Peru and Brazil use the Otto–Pfafstetter method, a uniform method within a regional agreement about methodological differences for delimiting hydrographic basins in each country is required; (b) It is necessary to organize accurate databases to avoid problems of mismatched borders by overlapping national databases or mismatches due to scale problems; (c) It is also necessary to establish a coordinating body capable of working with each country’s representatives. In this case, building integrated and collaborative cartographic database becomes critical; (d) Because river meanders can change, historical data of a river’s morphology is required. In this sense, this research provides guidelines to make water management in transboundary rivers feasible in South America.