The Black Sea Catchment Observation System has been developed in the frame of the EU/FP7 enviroGRIDS project to inform about crucial regional environmental issues. This system is now making resources accessible to a large community of users for data management and publishing, for hydrological models calibration and execution, for satellite image processing, for report generation and visualization, and for decision support. In this special issue, we present the different components that were developed as well as the encountered challenges in order to bring innovative contributions into the Global Earth Observation System of Systems. One of the major issues was to enable data exchange across different heterogeneous components and infrastructures, more specifically Spatial Data and Grid infrastructures. The interoperability standards proposed by the Open Geospatial Consortium (OGC) support the scalability and the efficient combination of the complex specialized functionalities and the computation potential of these platforms. Another important issue was to build the human, institutional and infrastructure capacities to contribute and use this new observation system.