A police officer on the scene said at the time: "The women and the girls were extremely lucky."
Seeing her mother was unconscious, Giana-Lee freed her sister from the partially submerged car and carried her to the riverbank.
"I got her out of the carseat and she slipped because the rocks were slippier," she said. "But I grabbed her up and took her to the riverbank."
Giana-Lee then returned to attempt to free her mother.
The accident was witnessed by a passing motorist, who reached the girls and gave them warm clothing as they waited for firefighters to free their mother, who had suffered a serious head injury.
A human chain was used to get the three up the bank and they were taken to Opotiki by ambulance, when poor weather hampered rescue helicopters' efforts to reach them.
They were airlifted to Tauranga Hospital, where the girls' mother was admitted to the intensive care unit.
Both girls were also admitted but were quickly discharged as they had received only minor bruising in the accident.
Giana-Lee was able to give emergency service personnel and doctors crucial information about the crash - astounding them with her calm demeanour in a situation that would overwhelm most adults.
Her aunt, Jade Moore, was amazed by Giana-Lee's composure and quick-thinking in the time of crisis.
"It came as a surprise when we were told what Giana-Lee had done, all the information she had given and how calm she was during the whole ordeal. Our family is extremely proud of her," Mrs Moore said.
Giana-Lee's mother has only recently returned from Wellington Hospital. Although there's no lasting damage, she needs further rehabilitation.
For more coverage of the awards, go here or to nominate someone, go to the Pride of New Zealand Awards website.
