Sensor networks promise to bridge the gap that, for too long, has separated computing applications from the physical world that they model and in which they are ultimately embedded. Sensor networks are and will continue to be important in environmental management. However, many scientific and technological challenges need to be tackled before sensor networks are exploited in their full capacity for aiding decision support for environmental applications. This project addresses two of these challenges: (a) the development of an integrated information space where new sensor networks can be easily discovered and integrated with existing ones and possibly other data sources (e.g., historical databases), and (b) the rapid development of flexible and user-centric environmental decision support systems that use data from multiple, autonomous, independently deployed sensor networks and other applications.To address this challenge, the SemsorGrid4Env project will investigate and develop technological infrastructure for the rapid prototyping and development of open, large-scale Semantic Sensor Grids for environmental management. In particular, SemsorGrid4Env will enable:1. A semantically-consistent view of several heterogeneous sensor networks as a global Grid data resource;2. Rapid development of Grid services that combine real-world real-time data, coming from autonomous, heterogeneous sensor networks, with legacy historical data;3. Rapid development of open, flexible, contextual knowledge-based thin applications (e.g., mashups) for environmental management.As more and more sensor networks are independently developed and deployed, the SemsorGrid4Env outcomes will leverage their use of sensor networks in environmental management scenarios that were not foreseen or that transcend their original purpose. To test and demonstrate SemsorGrid4Env results, we propose two environmental monitoring and management use cases.