# WMS:Travel Times from Basin Data

WMS computes many geometric parameters when using the **Compute Basin Data** command for either a TIN or DEM. These parameters form the basis of the empirical equations used to compute lag time and time of concentration. The *Basin Time Computation* dialog allows selecting from a series of pre-defined equations (Dodson & Associates, 1992), or create a user defined equation using any of computed basin parameters to compute time of concentration or lag time. If the equation is a function of variable not computed by WMS then enter the value in this dialog before a travel time can be computed. The process of computing travel times for a selected basin from computed basin data involves the following two steps:

- Select an equation (or create a new one).
- Follow the instructions provided in the
*Instructions / Results*text window until all of the necessary data are correctly defined (also any of the variables computed by WMS can be edited).

### Auto Recomputing

By default once an equation is specified for a basin, the lag time and time of concentration will be computed automatically each time that basin data are computed or when the curve number changes. If not wanting to have the equation updated when basin data changes then turn on the *Do not Auto-recompute parameters* check box for the selected basin.

### Exporting Results to a Report

The **Export Data** and **Copy To Clipboard** buttons are used to create a text report that summarizes the equation, variables, and computed time of concentration or lag time for the basin. Exporting the data will create a text file and allows either appending to an existing file (so that a single report for multiple basins can be created) or creating a new file. Copying to the clipboard places the report text on the Windows clipboard so that it is available for pasting into other documents.

## Related Topics

- Assigning Equations to a Basin
- Customizing Equations
- Exporting Results
- Geometric Parameters Used by Equations
- Travel Times from Map Data

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