The Swan River is one of Australia's deadliest inland waterways for accidental drownings, according to a report.
Royal Life Saving Society Australia statistics, to be released today, reveal 24 people drowned in the Swan between July 1, 2002 and June 30, 2012 - the fourth highest toll of any Australian river, creek or stream.
The Lower Swan River, from the Narrows Bridge to Fremantle, had the most fatalities over the decade with 10, followed by the Perth Waters section (eight). Six deaths occurred in the upper section from Graham Farmer Freeway to Middle Swan.
Men accounted for more than 80 per cent of drownings.
Almost half the drownings were people aged between 25 and 44. A third of deaths were the result of falls into the water and five involved watercraft accidents.
Alarmingly, 42 per cent of drownings in the Swan involved alcohol, well above the national average. RLSSWA senior manager of health promotion and research Lauren Nimmo said many people were complacent on big rivers compared with their behaviour on the ocean.
Ms Nimmo said the high level of recreational activity on the Swan meant accidents were more likely.
"The water is quite calm, there are no waves or rips like there are along the coastline, so people tend to underestimate the risks that they can be exposed to," she said. "The Swan River doesn't really look like a dangerous place to recreate but the conditions can change very quickly and people may not be prepared for those changes.
"Time and again we see people taking unnecessary risks that often have tragic outcomes, especially where alcohol is involved."
The Fitzroy River in the Kimberley and Blackwood River in the South West rounded out WA's top three deadliest spots with three drowning deaths each. In total, WA recorded 62 river drowning deaths over the decade, well behind NSW's 246.
Australia's longest river, the Murray, accounted for the most deaths (43). The Brisbane River, with 33 deaths, was second and Victoria's Yarra River (29) third.
The Federal Government has committed $15 million to reduce drownings over five years, including funds for the RLSS Australia to target black spots for river drownings.