WMS:TR-55 Time of Concentration

Three different options exist for determining the basin time of concentration (tc).

1. The time of concentration can be computed outside of WMS and entered into the appropriate edit field.
2. The Compute Tc – Basin Data button can be chosen and one of the time of concentration (or lag time) equations specified (this option is only available when you have computed basin data from either a TIN or a DEM).
3. Finally, a series of time computation arcs may be used to define overland, sheet, and channel flow with in a basin and then travel times for each arc are summed to compute the total travel time or time of concentration for the basin. The Compute Tc – Map Data button accesses the dialog which allows you to combine arcs within the currently selected basin to compute a time of concentration. A description of the time computation coverage can help in understanding how to do this.

Related Topics

• TR-55 Overview
• Entering TR55 Parameters
• Basin Data