If you have documents that need to be shared with your department, copy or move them to your departmental folder in Google Drive. These files will be available to your colleagues even after your Swarthmore account is deleted.
If you're migrating from a personal Google Drive account to Swarthmore, transferring your Google Docs is easy. Just select all the documents you want to migrate, go to the Share menu, and grant your Swarthmore account Edit access to the files.
Next, log into your Swarthmore Google Drive. The files you just shared should appear under "Shared with Me". Select all the documents, right-click (or control-click) on them and choose Add To My Drive. This will copy the files permanently to your Swarthmore Google account.
(Alternate Method) Select all the documents you want to transfer, go to the More Actions drop down, and click on Download. This will compress all the documents into a zip file and download it to your hard drive. Afterward, you can go to your Swarthmore Google account and hit the New > Folder Upload button in the top left corner, and re-upload all the documents you just downloaded.
Note that any documents for which you are a collaborator but not the owner will not transfer correctly with either of these methods; you'll need to contact the owner of those documents and tell them to re-share them with your new account.