Swimlane activity diagrams are used in hospital management systems to describe the flow of activity through a series of actions. The activity diagram is a critical diagram for explaining the procedure. An activity diagram depicts the overall control flow. The waterfall model, a popular software engineering development life cycle model, can create a hospital management system. It describes a linear and sequential development method. It has distinct objectives for each stage of development. A swimlane activity diagram for a hospital management system can also define steps in a use case diagram. Modeled activities can be both sequential and concurrent.