B.C. planning for worst-case scenario if Chilcotin River landslide bursts

Rivers tin beryllium a nosy spot to hit nan summertime heat.

This August agelong weekend, though, B.C. officials are informing residents and visitors to enactment distant from nan Chilcotin and Fraser rivers because of a imaginable unreserved of h2o from a landslide successful nan Central Interior.

As of Saturday morning, emergency alerts are still successful spot because of nan distant but monolithic landslide that’s blocking nan Chilcotin River.

Located astir 100 km southwest of Williams Lake, nan landslide came down Wednesday, damming nan stream and creating a impermanent reservoir astir 11 km long.

The landslide is 22 km upstream of nan Farwell Canyon Bridge, which is astir 82 km from Williams Lake. The Chilcotin River yet feeds into nan Fraser River.

The fearfulness is if nan reservoir abruptly breaks, nan downstream unreserved of h2o could beryllium disastrous.

“We cannot stress capable really important it is for group surviving successful nan area and downstream of nan descent to stay vigilant and enactment distant from nan stream for their ain safety,” said Nathan Cullen, nan province’s h2o and onshore resources minister.

B.C.’s Emergency Management Minister, Bowinn Ma, says nan best-case script is simply a gentle clearing (water flowing complete nan dam’s top) that doesn’t return flood debris down nan river.

However, some Ma and nan B.C. River Forecast Centre opportunity they’re readying for nan worst-case scenario:A burst reservoir pinch h2o rushing down nan Chilcotin and into nan Fraser River.

The state issued an emergency alert precocious Friday, informing group anyplace connected nan Chilcotin River aliases on its banks betwixt nan Hanceville Bridge and nan Fraser River to evacuate immediately.

A geotechnical engineering professor astatine UBC Okanagan, Dwayne Tannant, says nan h2o “will erode and trim done that dam, astir apt releasing a important beat of water.”

“It’s really each up to Mother Nature,” added Margo Wagner, chairperson of nan Cariboo Regional District. “We can’t accent capable really important it is for group to enactment distant from nan banks of nan Chilcotin River.”

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Wagner says nan banks astir nan Chilcotin River are sandy and limestone and person been affected by wildfires.

“So nan ungraded is beautiful porous and nan interest is that nan unreserved of h2o – whether nan reservoir breaks aliases nan h2o goes complete nan apical — could origin different onshore slippage,” said Wagner.

“We’ve been talking pinch nan cultivation ranchers on nan Chilcotin to region their cattle from nan banks, and make judge that everybody is arsenic safe arsenic possible.”

The River Forecast Centre says its modelling shows that if that occurs, nan level successful nan Chilcotin River would beryllium good supra highest outpouring runoff until it gets to nan Fraser River, while nan estimated flows successful nan Fraser would beryllium beneath emblematic outpouring highest h2o levels.

Ma says they are sending flood mentation instrumentality and sandbags to immoderate communities on nan Fraser River and are readying successful lawsuit there’s a request to evacuate immoderate communities, though that is unlikely.

The national fisheries section is besides monitoring nan situation. It says big chinook and sockeye salmon are presently coming successful nan stream and apt to beryllium affected by nan blockage.

Wagner added this reminder: “It’s champion to enactment disconnected nan Fraser and surely disconnected nan Chilcotin because that will beryllium nan stream that will beryllium first impacted.”

— with files from nan Canadian Press