Creating a ditch around a circular tank

[mkiker07]

I am trying to create a ditch around a proposed clearwell layout. I am wanting to have a level grade around the clearwell slope down to a proposed ditch line.

Then have the opposite side of the ditch line grade to an existing ground surface at a 3:1 slope to allow regular mowing of the proposed grade. 

I have tried creating feature lines but I am not sure that is the solution.

[neilyj666]

I'd probably use featurelines for this

[mkiker07]

Is there a step process that you would recommend.

I created a feature line around the tank and assigned it the grade level elevation. I then created another feature line offset 5 feet from the tank and assigned it four elevations, making sure it slopes the same direction as the existing ground.

I then tried to Grade to Surface with the second feature line and it will not tie into the existing ground surface in certian areas. I cannot seem to fix it.

[doni49]

---

@mkiker07 wrote:

I am trying to create a ditch around a proposed clearwell layout. I am wanting to have a level grade around the clearwell slope down to a proposed ditch line.

Then have the opposite side of the ditch line grade to an existing ground surface at a 3:1 slope to allow regular mowing of the proposed grade. 

I have tried creating feature lines but I am not sure that is the solution.

---

If you tell us WHY you feel this way, we might be able to help you solve that issue.  I think I agree with NeilyJ.  Featurelines would be my preferred method unless you've got something that we don't know about.

[doni49]

---

@mkiker07 wrote:

Is there a step process that you would recommend.

I created a feature line around the tank and assigned it the grade level elevation. I then created another feature line offset 5 feet from the tank and assigned it four elevations, making sure it slopes the same direction as the existing ground.

I then tried to Grade to Surface with the second feature line and it will not tie into the existing ground surface in certian areas. I cannot seem to fix it.

---

Screenshots and/or posting data samples will help anyone here to be able to try and help you.  Otherwise, all we can do is guess.

What's happening at those locations where it "doesn't tie in"?

[mkiker07]

Here are a couple screenshots. I set elevations from surface originally with the second feature line offset from the clearwell and then set the grades at a slop from south to north to flow the same direction as existing ground.

[neilyj666]

As a first step, check that there are no zero (or other spurious) levels on the featurelines.

[Neilw_05]

It appears to me the grading is having a problem finding a solution in the area where it sharply transitions from fill to cut. Note how the transition occurs at a contour. Looking at that contour I wonder if it has been smoothed. I would look for anomalies in the surface in that area. The surface seems to have a warp in that area all the way down the hill. You might also try smoothing the surface there or perhaps manually draw some contours across the warped area and add them to the existing surface definition to see if that helps.

[mkiker07]

There is no zero elevations in the feature line. Is it possible to smooth a surface in one area?

I could also send a copy of this file for a better look.

[neilyj666]

It would be useful to get the file as it should provide some clues as to what's going on

[mkiker07]

I can email it to you or is there a more preferred way to send it to you?

[neilyj666]

can you post here?

[mkiker07]

It is saying the file is too large. The file is currently 12344 KB. Even if I try sipping the file it won't allow me to attach it here.