Available with 3D Analyst license.
You can evaluate runoff patterns on a surface model by using the Create Steepest Path tool 
. The Create Steepest Path tool calculates the direction a ball would take if released at a given point on the surface. The tool works with raster, triangulated irregular network (TIN), LAS dataset, or terrain surfaces. The ball will take the steepest path downhill until it reaches the perimeter of the surface model or it reaches a pit—a point that all surrounding areas flow into. The result is a 3D graphic line added to the map or scene.
You can use the Create Steepest Path tool to evaluate the integrity of a surface model, for example, to find paths that end unaccountably or meander off in a direction different from runoff on the actual site. If you're going to use the model for runoff studies, you'll need to correct such anomalies.
- In ArcMap or ArcScene, click the Create Steepest Path button .
- Click the surface at the location where you want the path to begin.
The steepest path is drawn on the map.
The steepest path results can be displayed in a profile. For more information on how to display these results in a profile, see Creating profile graphs from steepest path results.