In a report released this morning, Coroner Mary-Anne Borrowdale made no recommendations but highlighted work done by the Department of Conservation (Doc) following the "tragic loss" of Tegan Ariel Chen in January last year.
Tegan and her family were visiting Fiordland on holiday from New South Wales.
They had joined an overnight cruise of Milford Sound and had a "perfect day" before they drove back towards Te Anau, stopping at several points along the way, including the Lake Marian Falls track in the Hollyford Valley .
The Marian Creek runs alongside the track and the coroner noted it was an "alpine, very cold and fast-flowing river".
The family walked the track and stopped at the end of a boardwalk, which led on to rocks above the river.
No man-made or natural structures separated the boardwalk from the outcrop.
Tegan and her brother Luke squatted near the edge of the rocks and their father Adrian Chen stood "only metres away".
As her father watched, Tegan went to stand, slipped and fell into the river.
Mr Chen ran beside her as she was swept downstream and yelled to her to grab on to something.
"Initially, Tegan was able to hold on to a rock and raise herself up, but she was quickly swept off the rock and out of sight."
Tegan was found unresponsive 420m downstream and although given CPR — first by bystanders and then by a doctor — she could not be revived.
The coroner ruled her death an accidental drowning.
No previous serious incidents had been reported on the track and neither Marian Creek nor the rocky outcrop was identified in a 2018 Doc hazard assessment.
However, following a storm in 2020, "subtle changes in vegetation" were noted at the rocky platforms.
"Doc now believes that some of the lost vegetation may have been acting as a natural boundary between the walkway and the outcrop, and that its loss may have made the edge area more attractive for visitors to access," Ms Borrowdale said.
Since Tegan’s death, the rocks had been covered with a platform encircled by barriers.
Prominent warning signs were installed and the track was reclassified as predominantly having visitors with lower skill levels and a higher need of management.
Specialist and local staff identified safety-related issues and changes were made to management of similar sites.
The coroner commended Doc’s "thoroughness and thoughtfulness" and following its "significant safety improvements", made no comment or recommendation.
"Tegan’s tragic fall ... was an accidental slip, during a happy family journey, which had appalling consequences," the coroner said.
The coroner offered her "sincere condolences to Tegan’s family and friends, and to all those who keenly feel her loss".
