Trying to calculate volume on a gravel bar in the stream

[Rubixcube10]

How exactly do I go about doing this? I created my surface and outlined the gravel bar. I clicked on "Bounded Volumes" and selected the bounded polygon. Once I clicked it, I got a Fill (Adjusted) = 17761.2 Cu.Yd & Current Datum elevation: 0.00' Did I do this right? I remember doing the volume of a garbage cell and had to create 2 surfaces. Before and After garbage was dumped but I don't think I need to create a second surface for this situation. Thanks

[neilyj666]

You will need two surfaces - what you have calculated is the volume from the surface to 0 elevation

[Rubixcube10]

So do I make a surface acting like the gravel bar isn't there 1st, Then make another surface with the gravel bar included? In reality, with my existing surface that has the gravel bar included pretty much becomes my 2nd surface? Thanks for the help

[neilyj666]

That's pretty much it...:)

[Rubixcube10]

Well I've created the 2 different surfaces and did the Volume Calculation, picked the base surface 1st then the comparison surface next. Why do I have a cut and fill data? which one is correct? Cut 4.806 CuYd Fill 148.967 CuYd Net 144.161 CuYd I also tried to print this exporting it and making a .xml file but when I open it, it takes me to the internet and spits out numbers that don't match up with the results

[Joe-Bouza]

I would extract the toe of slope for the gravel bar and use that as a base datum, unless I had deeper info of theGB

[Rubixcube10]

I did exactly that. I held the toe and its respective points along the toe for the base surface. Then for the comparison surface I held the same toe and added all the points and breaklines that are in the gravel bar. I just don't understand the results. Why do I have a cut and fill data? which one is correct? Cut 4.806 CuYd Fill 148.967 CuYd Net 144.161 CuYd I also tried to print this exporting it and making a .xml file but when I open it, it takes me to the internet and spits out numbers that don't match up with the results

[Pointdump]

Rob,

"Why do I have a cut and fill data?"

Some small part of your Comparison Surface is below the Base Surface. C3D figures both Cut and Fill Areas, and then gives you a Net.

Dave

[neilyj666]

Can you post the dwg - I suspect something like this is happening?

You could try an ispoachyte analysis and this will identify where the cut and fill are - or much quicker, you could try MINIMUMDISTBETWEENSURFACES which will draw the cut/fill line for you

[Joe-Bouza]

Then your toe data are not an exact match?

[Rubixcube10]

Here it is. I have the base topo layer turned on and the comparison turned off. The blue line is the toe of the gravel bar that I used for my topo limits on both surfaces.

[Rubixcube10]

It seems that I can't attach my DWG. Not to mention I can't even see the board list. It's been a blank screen the whole time.

[Joe-Bouza]

There is a size limit?

you can also try changing the extension to txt and we can rename it

[Rubixcube10]

The file isn't big at all, 1000KB. I think it's just a weird glitch. Probably another reason why I don't see any posts in the forum. It just keeps saying loading. Maybe I'm having a loading problem. I don't understand the "changing the extension to txt and we can rename it" Do you want me to send a txt file with just the points of the gravel bar and toe? Is that what you mean?

[neilyj666]

A file that size should be ok...Joe's suggestion is to rename the file from filename.dwg to filename.txt (you could try zipping it first and then the rename)

[Rubixcube10]

After looking at the points I think I might have figured it out. There's a point or two that actually have a lower elevation by a tenth or two compared to the toe of the gravel bar. Maybe that's why I'm getting a cut and fill data? I'll try the rename option too.

[Rubixcube10]

Yeah, it must be the site or the computer but it won't let me attach anything at all. Every time I click "add attachment" it sends me back to the top of the page and nothing else.

[Joe-Bouza]

GIGO, right.

"it behooves us to be cognizant of what we do" 😉