These pages provide resources that help explain what is interpretation and help you "do" interpretation
External Resources from leading organizations
This is free video course that is put together by the National Park Service. You do have to register to watch this video but it is free. This is a great introduction into what Interpretation is all about. Worth your time if your new to the subject or looking to refresh your knowledge.
This is a link to some Teacher Curriculum's that could be adapted for river use. Here is one on Fire Ecology
The National Association for Interpretation is a great resource and also the organization that offers the Certified Interpretive Guide (CIG) certification.
Some ROW Resources
Building an outline is central to being an effective interpreter. This document guides you through the process and provides some examples.