A boil water advisory issued for Fort McMurray and surrounding areas due to flooding will remain in place until September.
The Regional Municipality of Wood Buffalo issued a media release Monday that said the advisory would remain in effect for all neighbourhoods in Fort McMurray, Anzac, Draper, Gregoire Lake Estates and Saprae Creek Estates.
Floods forced about 13,000 people from their homes in Fort McMurray after an ice jam on the Athabasca and Clearwater rivers caused water levels to rise. All mandatory evacuation orders were lifted in the RMWB by 6 p.m. Sunday.
According to Deputy Chief Administration Officer Matthew Hough, the water treatment plant is “physically safe.”
He said the river level reached an elevation where it went the wrong way down an overflow pipe. That mixed river and drinking water.
The RMWB said Alberta Health Services will not drop the advisory until the water treatment plant and entire 375-kilometre potable water distribution system have been flushed, disinfected and tested. The process will take several months.
“The river water has created a film-like substance on the inside of our pipes,” said Hough, explaining a safe amount of chlorine had to be used.
The five-phase plan is expected to begin on Friday. The RMWB said AHS could lift the boil water advisory incrementally as each phase is completed and approved.
The first phase of the plan will see the water treatment plant flushed and decontaminated, which is expected to take 10 days. Phase 2 involves temporarily installing flushing and diffusing equipment on fire hydrants and continuously flushing them for 10-12 hours per day to turn over water from the Thickwood and Timberlea reservoirs and distribution networks. Phase 3 will flush the Lower Townsite and Waterways, followed by Beacon Hill and Saprae Creek in Phase 4 and a final flush of the entire system in Phase 5.
The RMWB said the three stages of residential flushing will take 30 days each. The final flush of the system is scheduled to take 20 days.
The entire process is expected to be finished in early September, but officials called that a “worst case.”
“It is possible that a number of these actions can occur at the same time,” cautioned Hough.
“If we can do this quicker, we will.”
The advisory could be lifted in some individual neighbourhoods before others.
While water might appear clear and safe, officials warned it is not.
“When it comes to water treatment and the safety of the consumer, there is not grey area,” Hough said about why the entire pipe network had to be cleaned. “It is black and white.”
The current schedule completes the water treatment plant phase in 10 days, the three phases of residential flushing in 30 days each, and the final flushing of the entire system for 20 days in phase five to conclude in early September.
The boil water advisory does not currently apply to the communities of Conklin, Fort Chipewyan, Fort Fitzgerald, Fort McKay and Janvier. Residents in Gregoire Lake Estates and Anzac, who use water tanks with trucked water from the Conklin water treatment plant, are also not affected.
On April 27, a boil water advisory was issued for the Fort McMurray First Nation #468, which has since secured an alternative source of potable water. The water being delivered to cisterns in this community remains potable and is not affected by this advisory, the RMWB said Monday.
The Northern Lights Regional Health Centre is getting potable water from the Civeo water treatment plant north of Fort McMurray, so it is not included in the advisory.
The plant does not have enough capacity to supply the entire city.
The flooding in the northern Alberta region affected several low-lying areas along the Athabasca and Clearwater rivers, including downtown Fort McMurray.
Residents there returned to soaked walls and muddy basements on the weekend. Some of the homes won’t be inhabitable because of water damage.
General information about how to use water safely during a boil water advisory, can be found on the AHS website.