Civil Project Workflow, Base Files, Proposed Linework and As Builts-How do you handle it?

When working on specifically (but not limited to) civil site projects, like a residential or commercial site design (waste water, potable water, drainage, etc.), I have used different types of workflows or standard to manage our data.  In the past the places I worked at created a base file for all linework involved.  I have also worked where we create two separate base files; proposed line work and existing conditions.  You can also include into that any survey linework as a separate, or combined, base file.  I don’t want to go into any software specific discussion here, I just want to look at a general workflow process for the life of a project.  How do you do it?  How should it be done?



Here is the issue.  We create are linework.  We submit the project.  The project is constructed and now it’s time to turn it over to the local municipalities, utility companies, HOA, etc.  That means that “As-Built” drawings must be created.  How do you handle this part of the project?  There are two approaches at this point; create a new base file for as-built data, add as-built data to the current base proposed base file.
If you add the data to your working base file then that new (the as-built info) will be displayed in all of your drawing files that reference your base file.  If you want as-built data everywhere then you are ok.  But what if you need to modify the proposed drawings for some other permit, exhibit, change order, etc.?  The as-built info could confuse whomever you are sending the new drawings too.
If you create a separate As-Built base file then you only see that info where you reference the new base file.  Down the line, let’s say in Phase two of the project, somebody else is working on the project and they have no idea there is an as-built base file.  They try to tie into to you project but the data they have is invalid because the project changed slightly in construction.

There are some basic issues that come up during the life of a project like this that need addressing.  Both methods of updating the data address the same issues but try to avoid different potential pitfalls.  Which method is better?  Why?  Is there a third option?  Does the size of a company determine which method to use?  Why?

These problems are not new.  They have been around for decades but yet companies still struggle with them.  How do you handle this issue?  Don’t forget that Phase 3 and 4 are also coming and that we are about to hire a bunch of new Project Managers, engineers, and techs that have no idea what we did in the past.