Lake Spillway Design

[WaterMagna]

To model a lake in hydrocad with a normal pool elevation set by the primary spillway, is it necessary to define any area under the pool elevation?

Also, should the lake be included in the watershed, noted by defining the lake and watershed separately inside the subcatchment?

 

[psmart]

Defining the storage below the normal pool elevation is optional. Including this "dead storage" allows proper calculation of the plug flow detention time. Just remember to set the starting elevation to match the spillway elevation.

To allow for rainfall on the surface of the pond you need to model this area as part of an adjacent subcatchment, or as a separate subcatchment with Tc=0 and CN=98+


Peter Smart
HydroCAD Software

http://www.hydrocad.net