The Cleveland Dam had several failures of the drum gate, causing water to be uncontrollably released into the Capilano River running through Capilano River Regional Park. Warning sirens were not installed until after the death of two men in 2020.[4]
In 1975, a nine-year-old girl was killed by a surge of water released from the dam.[5] The area had no warning signs or alarm at the time. Signs were later added to warn visitors of the potential hazards of the dam.[5]
In 2001, four fishermen were trapped in the river when the water level surged without a warning after the spillway's drum gate inadvertently dropped open.[5] WorkSafeBC issued several orders to reduce the risk to workers and the public, including but not limited to: "spillway gate lockout, access to the riverway by workers where lockout is not required, mancheck systems, emergency rescue and evacuation, public warning signage, and warning alarms".[5] However, some of the orders were ignored and public-facing warning alarms were never installed.[5]
On October 1, 2020, the dam's drum gate opened unexpectedly during maintenance, causing water to gush out onto Capilano River. The torrent of water killed one person with another person missing and presumed dead.[3] Several park goers were trapped within Capilano River Regional Park.[6] While many managed to escape by themselves, four people had to be rescued.[7] The Capilano River's water level rapidly increased by 3.58 metres (11.7 ft), pushing 413 cubic metres (14,600 cu ft) of water per second at its recorded peak.[6] These flow rates normally only occur in the rainy season. The anglers at the river edge had no warning except the sound of rushing water as the dam has no public alarm system to warn of a water surge. The popular recreation site had many people scrambling to get out of the way while others in safe areas witnessed their rush to escape.[8]After this accident, warning sirens were installed at three locations along the river.[4]