Personally I am not sure, but I doubt it is open enough to paddle... there is not much reason to keep it clear. I would bet that trying to work through would be life threatening this time of year due to the bugs.
I do believe that the larger creek to the right is open all the way to the next river to the east that feeds back to Ponce. I recently went through that creek on a boat to photograph the mature red mangroves that have somehow managed to avoid the hurricanes.
BTW... I don't recommend camping at graveyard.