Ongoing issues with water quality at Buffalo Pound Lake continue to cause concerns for Regina and Moose Jaw where officials are asking water users to reduce their consumption.
The reservoir is the main source of water for the two communities.
According to the people who operate the water treatment plant, weather conditions have made the source water difficult to process and that has reduced the supply.
'They have to slow down the filtration plant.' - Sam Ferris, Water Security Agency
Sam Ferris, an executive director with Saskatchewan's Water Security Agency, explained that the underlying issue relates to unexpected algae blooms in the lake.
Ferris said that the algae produce oxygen, as all plants do, which is dissolved in the water.
When that water undergoes treatment, however, the oxygen starts to bubble and those bubbles interfere with the treatment process.
"The oxygen comes out of solution, forms small bubbles and causes problems," Ferris said.
The bubbles disrupt a part of the process that is supposed to force minute contaminants to the bottom of the water treatment vessel.
"So they have to slow down the filtration plant," Ferris said.
That slow-down reduces the amount of water the treatment plant can deliver to Regina and Moose Jaw.
Cause remains a mystery
Ferris said it is not exactly clear why algae blooms have been forming in the lake.
"We're not really certain as to the cause," he said. One theory is that the algae was forming, unexpectedly, in the winter months.
"I did detect a little bit of odour in the water in the late winter months," Ferris said. "And sometimes, depending on how cold the winter is and how much snow cover there is, you can actually get early blooms forming because you'll get light penetration through the ice and start setting up the conditions for algae blooms."
Ferris said the tell-tale odour may have been a sign of things to come.
"I think that was probably an early warning sign that something was afoot for the spring months," he said.
Adding fresh water from Lake Diefenbaker
The most recent action, to combat the issue, has been to add water from Lake Diefenbaker to Buffalo Pound.
That fresher water, however, has a long way to go before it reaches the water treatment intake pipes.
"It's a 20-mile long lake and its going to take some time for that to show," Ferris said, noting the release of water into the lake will see the reservoir's overall water level rise for about five weeks, at a rate of 5 mm per day.
He added that other measures were also being explored, including the types of chemicals used in the process and stirring up the water near the intake pipes.
Officials have said a change in the weather, including rain and wind, would help.