HEC-HMS Modeling For Pond with Pump 1

[dhodges3]

I have a site where we are putting a detention pond that will need a lift station. With the new requirements to show the 10-yr and 100-yr WSEs, I'm not really sure how to model this or come up with the WSEs. Do I need to set the system to have a set discharge rate (and would it be the 100-yr rate or the 10-yr rate)? I can't seem to wrap my head around how to even start modeling this.

Any help would be appreciated!

Thanks!

 

[Ekenny_G]

In HEC-HMS, in your "Reservoir" - detention pond, you can add a 'Pump' to your outlet option and set the intake elevation, and 'ON' 'OFF' elevations for your pump. These are the elevations that the pump will be triggered to start and then stop after pumping down. This options requires you have some information about the pump performance (Head Discharge Curve) and losses.

The other option is to use a constant flow rate or discharge from the pump in Elevation-Discharge table as a 'Paired Data' linked to the Reservoir outlet. To simplify it, you assume the pump is discharging at a constant rate even as the elevations in your detention pond change. On top of the menu bar, go to Component > Create A Paired Data > select 'Elevation-Discharge Functions'. That should get you started.