Pond design for multiple storm events to achieve the desired flows

[Serene111]

I was trying to adjust the parameters (i.e. elevation, dimension, length, etc.) for outlet culverts, orifices, and weirs to achieve the desired flows at three rainfall events (i.e. 1-yr, 10-yr, and 100-yr). However, it is very difficult to adjust the parameters manually to meet one rainfall event, and even more difficult to meet all three rainfall events. I have been adjusting the parameters manually for the past two days and I was wondering if there is any optimization function in HydroCAD to do this?

 

[psmart]

Usually you would start with the smallest event, designing suitable outlet(s), and then work up to the larger events, adding additional storage and outlets as required. You can use the pond sizing report to estimate the required storage for each event

http://www.hydrocad.net/pondsizing.htm

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[Serene111]

Thank you Peter.

 

[beej67]

This should be very easy to do manually if your pond is big enough. Like, ten minutes tops. If you're struggling with it, take a step back and do this.

Throw your pond stage storage out for a moment. Draw in a vertical box that's got a lot of volume in it. Use one slot weir and nothing else, and vary the width of the slot until all your storms barely meet. Write down the 100 year storage in your concept pond. Compare that to your designed pond. If the volumes are significantly different, in particular if this concept pond is much larger in volume than the pond you have to work with, then you'll need to go back to the drawing board and figure out how to get more storage in your pond. You can't fit ten pounds of (flood storage) in a five pound bag.

Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East -

http://www.campbellcivil.com