LAFAYETTE COLLEGE, DEPT OF CIVIL & ENVIRONMENTAL ENGINEERING
HEC-HMS Part 2
CE 421, Fall 2005
The previous handout (HEC-HMS Part 1) covered installing the program and setting up the
Basin Model and the Meteorologic Model for your project. This handout covers “Control
Specifications”, running the model, and model outputs.
Control Specifications
Under the Component menu, select Control Specifications and then New for setting the control
specifications, which are the time parameters for the simulation. A New Control Specifications
window will appear will similar boxes as when you created the new Basin Model and new
Meteorologic Model. Name it something useful. The directory path should be the same as for
your project files. Select OK.
A Control Specifications window will then appear as shown below. Specify the time parameters
for the run (start date/time, stop date/time, time interval). Since we are using synthetic 24 hour
storms and routing the hydrographs through detention basins (which delays the outflow), the
actual dates don’t matter, but run the simulation for at least 3 days. The default date format is 15
Oct 2005 and the default time format is 12:00 (24-hour military style). The time interval
determines the time resolution of the output. You should select an interval that is smaller than the
smallest sub-basin and reach travel time, and no more than the 0.5-hr interval of the SCS design
storm. The time interval shown below may be too long for some applications.
