Holly Buchanan and her father Angus, 45, died in Loch Lomond when their dinghy lurched suddenly, throwing the pair into the water on March 13, 2005.
Police conducted extensive searches of the area but their bodies were never found.
In November last year, the remains of a foot were washed up on Inchmoan Island in the loch and forensic tests at Glasgow University identified it as Holly, Strathclyde Police said today.
Mr Buchanan had taken his daughters, pupils at the High School of Glasgow, for a day trip on the loch, stopping off for a picnic on one of the islands.
A report into the tragedy found the boat's steering system was faulty and the family had not worn lifejackets as they were accidentally left at home.
The Marine Accident Investigation Branch (MAIB) said elder daughter Chloe, then 15, tried to save the pair by jumping in the loch but she lost sight of them.
The cold water, with a temperature of around 3C, would have had a very quick affect in reducing their ability to stay afloat, the MAIB ruled.
Since the accident the Loch Lomond & The Trossachs National Park Authority has made it compulsory for boat users to wear a lifejacket.
Strathclyde Police said further searches of the area since November had proved unsuccessful and the family of the pair have been informed of all developments.