HydroCAD Pond FAQ

[ralaimo]

The Pond FAQ in HydroCAD suggest that the "pond" be set up as a separate subcatchment with a Tc of zero and CN of 98-100. Is this recommendation just for a wetpond or for all basins? For a dry basin, why would the CN be 98-100 instead of using the CN based on the surface of the basin? Why would the Tc be zero instead of calculating a short Tc from the farthest point in the dry basin to the outlet structure?

 

[psmart]

For a dry pond you could use the Tc and CN for the underlying ground.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[TerryScan]

I am usually conservative and give at least the bottom of a "dry" basin a 98 CN. The basin is typically dry during dry weather. During a modeled event, it is typically wet the majority of the evaluated time.