They share the data about the level of the reservoir:
http://cdec.water.ca.gov/histPlot/DataPlotter.jsp?staid=ORO&...
The wet season last year basically filled the reservoir up from its lowest levels. So a project started in the middle of 2014 would need to leave the system operable by December, and they have that same ~6 month period in pretty much every year.
Nobody ever seems to do this. We always wait for disasters before fixing or maintaining anything. This, despite the fact that we pay taxes, plenty of taxes, to fully staff, train and employ departments with thousands of people who are supposed to actively be looking after these things.
It's the infrastructure equivalent of a sysadmin who never looks after security and then, when all hell breaks loose, proclaims we need to do something about security.
There's lots of possibilities. Maybe they didn't do inspections last year. Maybe they did inspections and noted damage that did not yet warrant repair. Maybe they did inspections and missed damage. Maybe they were unable to secure funds to repair the damage. Maybe the damage was noted too late to do repairs last fall. Etc.
The thing to do is wait and see if they come forward with a reasonable explanation of what went wrong and then feed that information into the maintenance plans at this dam and others.