Mrs Callon was "intoxicated to a significant degree and such intoxication would have added to the compromised mobility she suffered due to age and other ill-health".
A possible scenario was that, while distressed and intoxicated on October 31 last year, Mrs Callon had fallen down the bank next to her home and into the river, Mr Crerar said.
From the evidence of her doctor and other witnesses, there was nothing to indicate any failure to provide Mrs Callon with appropriate medical or other support and there was no evidence that any individual or organisation contributed to her death, Mr Crerar said.
Mrs Callon was reported missing from her home on November 1 and a search was carried out by police, family and members of the public. Her body was found in the river that afternoon, near the riverbank and snagged by willow tree roots.
Dr Eric Wegener, of Roxburgh, gave evidence Mrs Callon had extremely poor balance because of central nervous system atrophy. He also thought she "overindulged" in alcohol and had taken steps to ensure she did not continue to have a driver's licence.
Mrs Callon had problems coping at home because of mobility problems and required help from caregivers and district nurses.
A friend and real estate agent, Brigitte Paterson, had helped Mrs Callon sell her Roxburgh home and buy a replacement home in Alexandra. She gave evidence Mrs Callon was sad and depressed in the weeks before her death.
Mrs Callon's daughter, Sally Dodds, gave evidence of "everything going wrong" for her mother over the past several years, after the deaths of her husband, close friends and relatives. This was compounded by continuing ill-health, a lack of independence and mobility and the stress created by the sale of the house.
Senior Constable Chris Blackford said police were satisfied there were no suspicious circumstances in the death of Mrs Callon.
Where to get help
• Lifeline: 0800 543 354 (available 24/7)
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• The Word
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• Rainbow Youth: (09) 376 4155
• CASPER Suicide Prevention