In Civil 3D, parcels cannot be created, edited, or deleted. They are defined when parcel segments enclose an area. Just like you can't edit the length of a line, you can edit the beginning point and the ending point but you can't edit the length, it is defined as the distance between the starting and ending points. In order to edit a parcel, you must edit the parcel segments that define it. The thing that often times causes confusion is the name "Site". In my opinion, this is a horrible name for this concept because civil engineering professionals, when they think of the term "site" they think of the location of the project. They go on a "site visit". A site is technically a topology. Everything in the site interacts with everything else in the site. Add to that, alignments within a site act as parcel segments. My guess is you have some alignments in your site that are enclosing an area and defining a parcel.
