Consider using a Sankey Diagram to help visualize workflow.

I've seen hierarchy charts used to depict workflow, but always thought they were missing something--nodes that can have two parents, for example. A Sankey diagram solves that problem, and provides a trivial way to introduce the concept of how much volume moves between "nodes". Also, by definition, a flowchart is "a type of diagram that represents a workflow or process". The Sankey diagram looks like it's flowing much more than a hierarchy chart.
For more information, check out David Pallmann's convincing case for using Sankey diagrams to visualize workflow.
I was able to create this workflow visualization in 10 minutes by forking the Highcharts's Sankey demo and customizing the series data to the following:
data: [
['Event Submission', 'Event Submission Close', 250],
['Event Submission', 'Create Incident', 750],
['Event Submission Close', 'Approve', 240],
['Event Submission Close', 'Reject', 10],
['Approve', 'After Action Review', 640],
['Create Incident', 'Contained', 400],
['Create Incident', 'Provide Analysis', 150],
['Create Incident', 'Incident Close', 125],
['Contained', 'Containment Approval', 370],
['Contained', 'Containment Rejection', 30],
['Incident Close', 'Approve', 110],
['Incident Close', 'Reject', 15],
['Containment Approval', 'Eradicated', 320],
['Containment Approval', 'Provide Analysis', 50],
['Eradicated', 'Eradication Approval', 315],
['Eradicated', 'Eradication Rejection', 5],
['Eradication Approval', 'Recovered', 315],
['Eradication Approval', 'Provide Analysis', 5],
['Recovered', 'Approve', 310],
['Recovered', 'Reject', 5]
]