The system flows alternative allows you to specify additional and known flow, along with other contributing sources of water that are not part of the model. The System Flows alternative consists of the following attributes:

• ID: Displays the unique identifier for each element in the alternative.
• Label: Displays the label for each element in the alternative.
• Flow (Known): Used to identify a known flow into the piped system.
• Flow (Additional): Flow added directly to the piping system at the catch basin.
• External Tc: The time of concentration for an external source not included in the model.
• External CA: The rational contributing area of an external source not included in the model.