Run Off Tracking - Grid Surface

This command draws a 3D polyline starting at a picked point and going downhill until reaching a local minimum or end of the surface. In effect this flow line simulates the path of a rain drop. The program also reports the distance and slope of the flow line. These values can be used in time of concentration calculations. This command uses a grid model for the surface which works well for existing ground surfaces. The Run Off Tracking command that is in the main Watershed menu works with triangulation surfaces which works well for design surfaces.

In the options dialog, the Max Local Minimum Depth is the most the program will allow the flow to jump over.


Prompts

Select Surface Model Choose .grd file
Watershed options dialog
Pick origin point of rain drop:
pick a point
Horizontal distance: 10315.58, Slope distance: 10392.95
Vertical drop: 982.08, Avg slope: 9.52%, Max slope: 52.34%
Pick origin point of rain drop (Enter to end):
press Enter

Pulldown Menu Location: Watershed > Watershed By Grid Surface
Keyboard Command: runoff_grd
Prerequisite: surface .GRD file