After more than 48 hours of heavy rainfall, conditions began to ease Saturday morning, but the City of Fernie, B.C., says untreated wastewater is still being released into the Elk River. 

Officials say a surge of water, particularly from stormwater inflow, overwhelmed the system’s capacity, prompting the use of an emergency bypass at the city’s main sewage lift station. It remains in place to prevent sewage backups into homes, businesses and critical infrastructure, the city says.

Environment and Climate Change Canada issued a rainfall warning for the Elk Valley, forecasting close to 50 millimetres of rain through Friday evening, along with high freezing levels — conditions that can significantly increase runoff. 

The Elk River runs roughly 220 kilometres from its headwaters in the Rocky Mountains near Elk Lakes Provincial Park through several communities, including Elkford, Sparwood and Fernie, before flowing south into Lake Koocanusa and across the Canada-U.S. border. 

“We were doing our absolute best to avoid this, but the amount and duration of the rainfall pushed our system beyond what it can safely handle,” said Jenny Weir, Fernie’s director of engineering and public works. 

“If we didn’t do that, our main lift stations could be damaged, which would lead to a much longer inability to treat wastewater,” she said. 

Weir said another consequence could have been wastewater backing up into people’s homes, creating both property damage and public health concerns. 

The city says wastewater flows remain “very elevated,” continuing to place significant pressure on the system despite a break in rainfall. 

Officials say the bypass is only used as a last resort when flows exceed system capacity, and will remain open until conditions allow it to be safely closed. 

Crews have also been responding to localized flooding across the community, including clearing blocked culverts, drains and catch basins. Multiple washouts have been reported on Coal Creek Road, which remains closed. 

A High Streamflow Advisory remains in effect for the region, with officials urging residents to use caution near waterways and remain aware of changing conditions. 

The Regional District of East Kootenay says its emergency operations centre is working with the City of Fernie, Interior Health and other agencies as the situation continues. 

The incident marks the second time in less than a year that Fernie’s wastewater system has been pushed beyond capacity during heavy rainfall events. 

Officials say similar challenges have occurred during extreme weather in recent years, pointing to growing pressure on infrastructure during periods of intense precipitation. 

The city is already working on long-term upgrades to its wastewater system, including expanding treatment capacity and improving lift stations. 

In the meantime, officials are asking residents to continue limiting non-essential water use and ensure sump pumps, downspouts and perimeter drains are not connected to the sanitary sewer system. 

CBC News reached out to the B.C. Ministry of Environment for comment. The ministry said it is aware of the situation and is monitoring it, but could not provide further details, adding it will follow up when more information becomes available. 

The city says it does not have a real-time estimate of how much wastewater needs to be released to relieve pressure on the system, noting those volumes are calculated once conditions have stabilized.