Never heard anything about this incident.
I don't believe the following would be part of what you saw with ambulances, etc, but I do see that there is ongoing work along the east side of the 331 causeway. It appears that they have several boats out there, and have put in pilings with orange flashing lights, running parallel with the road, about 40 meters from the road. There are many big black pipes being prepared to be placed (into the water near those pilings I guess). I'm not positive, but I think that particular pipe is used to pump the pretreated sewage water from South Walton to spray fields located north of the bay.