Custom Stage Storage Hydrocad 1

[gscotchie]

Hi,

I'm trying to determine the best way to model the volume of the existing pond (see attached file).

The bottom elevation is 242' and the top is 246'. The tricky part for me is this existing pond has a sediment mound built up over time at elevation 244'.

I have determine the total pond volume to be around 4290 CY in AutoCAD, however, I'm not sure how to enter the proper contour elevation, perimeter, and area data to extract the sediment accumulation. I'm trying to use the custom stage data, Surface Area option.

My current model shows a volume of 4474 CY. This is about 184 CY too much. Any ideas on how to take the sediment accumulation into account would be appreciated.

Thank you,

gscotchie

 

[psmart]

Assuming that you know the area at the sediment elevation of 244', I would start there, entering data from elevation 244 to 246.

If you don't know the area at 244, then you can start the storage definition at 242 and set the routing starting elevation to 244. This will effectively pre-fill the pond to the specified sediment elevation.

Remember that the volume calculation will depend on the selected shape (Prismatic, Conic, Pyramidal, Irregular). For pond with naturally sloped sides Conic is generally the best option.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[psmart]

Perhaps I misunderstood your situation: If the sediment is mounded, and not spread level, then you will need to start your storage data at the bottom elevation of 242. You should be able to enter surface areas using the HydroCAD custom storage option with a "conic" shape. Keep the stages as small as possible - perhaps 1 foot.

The "irregular" shape is really not applicable to this situation and will probably give erroneous results. Stick with conic.

Peter Smart
HydroCAD Software

http://www.hydrocad.net

 

[gscotchie]

psmart,

Thank you for your quick response. I was able to use the culative storage method to model the existing pond.