AutoCAD Civil 3D

[#1]

I need to know how I can get a NEW Contour to cutoff/end at an Existing Contour?  Right now when I add a new 126 Contour that ties into an existing 126 contour at 2 different locations the New Contour encloses itself.  Now why it doesn't do that for the New 125 that is doing the same type thing I don't know (unless it realizes there is another New Contour).  I've attached a screen cap for better understanding. 

[#2]

If you turn on yopu surface triangle you will see there is a big flat area inside you 126 contour that causes it to close. You need to add (for the sake of the TIN) a Limit of disturbance feature line or similar data that tells the TIN ther is no 126 elevation. If you drew a fl and extracted existing ground elevation along the fence line it should be a start.

[#3]

Thanks for your suggestion Joe, but that didn't work.  I drew in a polyline where the straight line enclosure was taking place, then created a feature line from said polyline and assigned elevations from the existing surface and added to my FG surface as breaklines.  The New 126 Contour still wants to close at the same location.  Any more suggestions?

[#4]

I presume you 126 contour was digitized in and not the product of a grading. Therefore all the elevation inside your 126 = 126. Looking at you topo image they in reality have to be in between 127 and 126. So, you need to either define elevations between you daylight line or delete the triangles generated betwee the 126 and 127.

Or remove the contour data in this region and great a grading from the daylight line and paste its surface into you fg surface. It all about triangles; clean them up to represent your intent.