How To: Remove Unwanted Google Calendars for iOS and Mac
If you have a LOT of delegated Google Calendars that you don't want to show up, or provide notifcations for on your Mac or iOS devices, you can remove them by using Google's Calendar Sync Select tool.
https://www.google.com/calendar/syncs...
Just login with your Google account, and select which ones you want to remove from your mobile or desktop calendars. They'll still appear in your Google Calendar through the web.