Mechanical problems and human error may be behind fatal B.C. dam incident

Multiple investigations are underway to determine what caused the Cleveland Dam to suddenly release a torrent of water into the Capilano River, but it's clear that this fatal incident stands apart from other recent dam disasters in B.C.

On Friday, Metro Vancouver commissioner Jerry Dobrovolny told reporters there are no structural issues with the North Shore dam, and it's safe to be in the area. 

But it could take a while to determine what caused a spillway gate to open unexpectedly during planned maintenance on Thursday, leading to a rapid change in water flow that caused at least one death.

Dobrovolny said he understands there's frustration about the lack of immediate answers.

"We would like to know yesterday exactly what happened," he said.

Some combination of mechanical, computer and personnel problems could be to blame.

"We have systems in place to protect against human error. We have humans in place to protect against system error," Dobrovolny said.

"When you see a situation like this, it's generally that there's a breakdown … on both sides of the equation."

Past dam disasters caused by structural failure

That means what happened at the Cleveland Dam is likely quite different from other high-profile dam accidents B.C. has seen in recent decades. 

Those have tended to be the result of structural failures — the province says there's an average of one or two dam failures annually across B.C.

That includes high-profile examples like the 2014 Mount Polley disaster or the Testalinden Creek incident of 2010, when an earthen dam on the Testalinden reservoir south of Oliver failed following heavy rains and released enough water to destroy five homes and large swaths of vineyard and orchard land. 

A similar failure on Cannon Creek east of Quesnel in 1995 caused the death of 48 cattle as well as $500,000 in damages to the local road system and nearby agricultural land.

But sudden discharges of water caused by human or mechanical error have been responsible for some major environmental and human tragedies around the world as well.

"Canada has less than its share, but the need to maintain and look after our infrastructure is paramount," Dobrovolny said.

Dozens of Hindu pilgrims were killed in 2005 when water was mistakenly discharged from a dam in central India, causing a flash flood at a popular bathing spot on the Narmada River.

In the 2015 Gold King Mine disaster in Colorado, U.S. Environmental Protection Agency and contract workers accidentally caused the release of 11 million litres of wastewater and mine tailings containing heavy metals into the Animas River.

The crew was supposed to be there to pump out contaminated water from a defunct mine, but the heavy equipment used by the EPA created a massive leak in the dam instead, causing serious contamination of river water in at least three states.

And just last year, the U.S. Army Corps of Engineers accidentally discharged the Lost Creek Lake Dam in Oregon, sending water rushing into the Rogue River with no alarm to warn of the danger. Several people were fishing on the river at the time, but no one was killed or seriously injured.

During Friday's news conference, Dobrovolny confirmed there are no alarms or flashing lights set up to warn the public about the sudden release of water from the Cleveland Dam.

He said officials will look into creating a warning system, but it would need to be comprehensive, providing warnings throughout the watershed, not just directly below the dam.