Detention Ponds and Time of Concentration Calculations

[Scott Horowitz]

How are detention ponds treated in calculating a "proposed" drainage area's time of concentration? Does the calculation include the length of flow in a pond or are ponds ignored and the calculation ends at the upstream end of a pond?

 

[psmart]

Normally the effects of the pond are assessed by a hydrograph routing calculation, rather than including the pond in the Tc, which cannot accurately simulate the behavior of most ponds.

This means that the Tc calculation will normally end at the inflow to the pond, and the pond routing calculation will take over at that point.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[ClemsonVet]

agreed