As environmental monitoring systems increasingly automate the collection and processing of environmental sensor network data, the technical components of such systems can automatically obtain and maintain higher levels of situation awareness—awareness of the monitored part of reality. In order to increase confidence in the correctness of situation awareness maintained by such systems it is important to explicitly model provenance. We present an alignment of the PROV ontology with ontologies used in a software framework for situation awareness in environmental monitoring, called Wavellite. The extended vocabulary enables the explicit representation of provenance in Wavellite applications. We demonstrate the implementation for a concrete scenario.