This paper describes our work to date on knowledge-based service architecture implementations for multi-risk environmental decision-support. The work described spans two research projects, SANY and TRIDEC, and covers application domains where very large, high report frequency real-time information sources must be processed in challenging timescales to support multi-risk decision support in evolving crises. We describe how OGC and W3C standards can be used to support semantic interoperability, and how context-ware information filtering can reduce the amount of processed data to manageable levels. We separate our data mining and data fusion processing into distinct pipelines, each supporting JDL inspired semantic levels of data processing. We conclude by outlining the challenges ahead and our vision for how knowledge-based service architectures can address these challenges.