Dam volume calculation

[Anonymous]

Hi.
I need to calculate the storage volume for a dam. I have a LIDAR surface. The LIDAR was done when the dam was empty. The dam wall is man made.
I have used three methods in Civil 3D to determine the volume:
Conical method
Avg end method
Volumetric analysis
After some reading it was clear that the volumetric calculation is the most accurate(?)

The question:
Is there a way in HEC-Ras that I can use to calculate the storage volume of the dam? I need to verify my answer I got in Civil 3D

Hope to hear soon from the experts!

[Anonymous]

For steady flow, RAS will report the cumulative volume in a reach. From the Profile Output Table go to Options and select define table and look for volume.

So if you modeled the reservoir as a series of large cross sections you could back out the volume.

If you want a really accurate answer, create a 2D model of the reservoir.

You can specify the starting water surface in the 2D area. Create a short dummy run and then go look in the computation log file (from the Unsteady Run Editor, Options), it will show the starting water volume in the 2D area.

I guess you could also start with it dry and just run a flow boundary until it fills up and compute the volume from the flow.

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