Universities we work with often need to manage multiple academic catalogs, usually an undergraduate and a graduate catalog. We have two primary ways of doing this: either by managing catalogs from the same system, or having totally separate sites.
Option 1: Managing Academic Catalogs from the Same System
The initial use case is to manage separate undergraduate and graduate catalogs. For example, for Southwestern Adventist University, these are two separate publications, and they wanted to keep the content separate for their distinct audiences. However, they didn't want to manage two fully separate sites — with all their users, branding, configuration, and so on — and they wanted to be able to share content between sites.
This same sort of setup could be used if your college had distinct campuses with distinct offerings, or if you had multiple separate schools within your college that you wanted to completely separate — a college of business and a college of arts, for example.
When you edit a page, you can easily mark which catalog or catalogs it belongs to, and it will automatically show up on that catalog in the appropriate place.
On the back-end, you can easily sort content by which catalog it belongs to, and edit or adjust from there as needed.
Option 2: Managing Academic Catalogs as Separate Sites
Typically we use this option when the two catalogs won't share users or content. As separate sites, it means that any content or user information remains on separate sites. For example, if you change the "Mission" page on one site, it won't change on the other, and likewise with any changes to user information.
Universities often use this option when the two catalogs are totally separate documents run by separate teams, like Villanova University's Undergraduate Catalog and Graduate Catalog. Catalogs can still share branding elements (but don't have to), but most other elements will remain on their separate sites.