This command calculates the time of concentration (Tc) by the TR-55 method. Time of concentration is the time required for water to flow from the most distant point in the watershed to the measurement point.
The TR-55 method divides the flow into sheet, shallow
concentrated and channel types, and Tc is computed by summing all
the travel times for consecutive components of the drainage
conveyance system. You can have any number of each of the three
types of flow: Sheet, Shallow and Channel. For example, you could
have two different channel flows in case you had two different
types of channels in series. Use the Add button to add flows. You
can add Sheet, Shallow and Channel flows individually or all
together.
When adding a flow, the Select Flow Line From Screen function
allow you to pick a 3D polyline and split it into segments of
sheet, shallow and channel flow precisely. The Manning's n for the
sheet and channel flow can be chosen from a table by clicking the
Select button. Clear button will clear all fields in the dialog for
entering new data.
Pulldown Menu Location: Watershed -> Time of
Concentration > TR-55 Method
Keyboard Command: flowtc
Prerequisite: None