The female driver, 37, was trying to commit suicide, according to Tampa police. She has been taken into custody under the Baker Act.
A man on a jetski who was going by the scene thought it was a vehicle accident and was able to pull her out of the car and get her onto the embankment, said Andrea Davis, Tampa police spokeswoman.
The driver was not injured.
There was no injuries.
Tampa police are waiting for a tow truck to remove the Ford Taurus from the water, Davis said.
Charlton Foster jumped in the water to help rescue the woman and called 911.