When the waters rise to flood levels in a reservoir system operated by Rio Tinto Alcan in northern British Columbia, a small band braces for a grim ritual: the evacuation of "spirit houses" from a graveyard.
This week, for the fourth time in several decades, members of the Cheslatta band rushed to remove the sacred grave markers from cemeteries along the shores of a lake below the Skins Lake spillway, about 150 kilometres southeast of Prince George.
Pouring through Alcan's spillway, which is a release valve for the reservoir system that feeds the powerhouse for an aluminum smelter in Kitimat, is a biblical flood of water, produced by a long, wet summer and fall.
As the water level crept up the shoreline of Cheslatta Lake, band members picked up and carried to higher ground 140 spirit houses. The markers, coffin-sized structures that look like small buildings, lie atop graves, and are meant to shelter the spirits of the remains buried in the ground beneath.
"That's all we can do, short of digging up the graves," said Mike Robertson, senior policy adviser with the Cheslatta.
Each gravesite is marked with long metal rods, bearing crosses, and corner pins so they can be relocated with metal detectors after waters recede.
Mr. Robertson said that, since the reservoir system was created in 1952, when Alcan built the Kenney Dam across the Nechako River, the graveyards have been evacuated four times because of "controlled release" floods. The most recent flood was in 2007.
He said the spirit-house removal was done with the help of Alcan, which paid for work crews and provided a helicopter to rush them to the graveyards.
The spirit houses "were stacked in the bush like cordwood" and will remain there until floodwaters recede, Mr. Robertson said.
"It was an emotional time.… You never get used to seeing your ancestors moved," he said. "It's pretty hard on people. That's your grandfather or great uncle. I know the people there that day were quite angry.… it is also troubling having in the back of your head that it could happen again anytime, even though there are solutions to this problem."
The Cheslatta band has long called for a facility to be built into Kenney Dam, so that water could be released directly into the Nechako River, rather than diverting it into the reservoir, where the excess flows out through the Skins Lake spillway.
Mr. Robertson said floodwaters have exposed coffins in the past, and in 1952 bodies washed into the lake and were never recovered. The lake was later consecrated as a graveyard itself. He said the floods also erode riverbanks and pour silt into Cheslatta Lake, hurting the char which spawn there.
The provincial government and Alcan have for years discussed building a water-release facility at Kenney Dam, mostly to assist salmon in the Nechako River, but the project has never come to fruition. Talks are expected to resume soon.
"We haven't given up on the water-release facility," Mr. Robertson said. "We want some comfort that man-made water flows that are ripping through our valley won't continue."
Colleen Nyce, spokeswoman for Rio Tinto Alcan, said the high-water releases were necessitated by heavy rainfall all summer and fall, following a winter with above-average snow packs.
"We have been spilling this year higher than normal. But we have been spilling to a level that would not cause any flooding. However, just recently, last week, it was determined that we had to increase the spillway discharge in order to manage the safe operation and condition of the reservoir," she said.
"It's always a sad situation. It's not one that we want to be in," she said of flooding the Cheslatta graveyards.
She said if Rio Tinto Alcan didn't release the water now, extreme flooding could come later.