When you have completed a project (either the event has passed or your term is over) you can archive the project to save the historical data and details without cluttering your projects page. 

BEFORE ARCHIVING: Make sure to add an advisor and if possible, the person incoming to your position for the following year as collaborators. Collaborators can continue to see the project in their archives, but once a project is archived additional collaborators cannot be added. 

Projects can only be archived through the desktop version. 

Collaborate > Projects > Project Title

 Open the project you want to archive, make sure you've added all necessary collaborators, and then press the archive icon to move the project and all it's contents to the Archive folder within Projects.