Flow out of detention pond decreases with less storage

Bentley Product:: SewerGEMs V8i (Selectseries 5) Version 08.11.05.58 64 Bit

Project Notes: Analyzing Node DB-Detention Pond

Model A:
Includes 8 detention systems to control runoff before it enters detention pond DB.

Model B:
Includes 4 detention systems to control runoff before it enters detention pond DB.

Issue:

The flowrate into node DB does not change with additional detention storage under 10-Year Storm Model
The flowrate out of node DB increases with additional detention storage (model A) under 10-Year Storm Model. 

Additional notes:

Upstream detention nodes include orifice and weirs to control watershed runoff.

SewerGEMs - NEWR.zip

Parents
  • Hi Jesse,

    Thank you so much for your assistance. This has helped me understand the model some more and the continuity error has dropped since adding pond outlet structure at POS-19 as you suggested. 

    Is there a way to model the overflow per factor 1? In other words, when the upstream detention structures fill up, does the overflow make its way to detention pond DB?

    The goal of the the upstream structures is to control the downstream runoff and pond elevation, so I wanted to confirm if the overflow doesn't get get lost or neglected because the ponds fill up. 

    Thank you,

    Suraj 

Reply
  • Hi Jesse,

    Thank you so much for your assistance. This has helped me understand the model some more and the continuity error has dropped since adding pond outlet structure at POS-19 as you suggested. 

    Is there a way to model the overflow per factor 1? In other words, when the upstream detention structures fill up, does the overflow make its way to detention pond DB?

    The goal of the the upstream structures is to control the downstream runoff and pond elevation, so I wanted to confirm if the overflow doesn't get get lost or neglected because the ponds fill up. 

    Thank you,

    Suraj 

Children