The result was we couldn't access the water from Barclay on the days that were marked closed for Barclay Bay.
We were able to access the water from Turner Gulch pretty much until the day of the event (and the night before the event).
I.e. you can't access through Turner nor the view point on the day of the event.
I guess if you have a boat and don't mind camping, you can probably camp up the canyon and access the water that way.
NOTE: I've never looked into what restriction they have in place for boating.
The following was the snippet of the reminder email I sent last year.
You are welcome to try contacting the organizers and/or Army Corps of Engineers.
I wasn't planning to contact them again this year as I was assuming it will be the same as last year.