The first time you open the TR-55 simulation dialog (no matter whether you have a basin, an outlet, or nothing selected) the only option available in the TR-55 dialog is the Initialize TR-55 Data button. In order to allocate memory in WMS for TR-55 variables you must initialize the data once. Should you decide to work with a different model you may want to choose the Delete TR-55 Data button. If you are planning on using a TIN, DEM, or feature objects to delineate and compute watershed parameters you should initialize TR-55 data first so that computed parameters can be stored in the TR-55 data structures.
Related Topics:
TR55 Overview
Basin Data
Outlet Data