Its not permanently down, just the "seiche" effect of the east wind pushing the water out and the normal fall drop. Click the link to the right and top that shows current water levels for Parry Sound and you can see the drop/rise on a day that the wind shifts. That link takes you to an hour by hour for the past 24 hours.
I have attached and interesting graph. It is the Parry Sound waterlevels for August 1 to Oct 13th. The vertical bars in the line graph are the variation in levels over that day. The scale is "meters over chart datum". So you can see that the water levels are staying up for now. If you look at the big changes in a day, it is on the days that the wind shifts a lot somewhere on the system. IF you look at yesterday to today, you see a huge swing as the wind shifted back to NNW and filled the bay again.