People boating on the Northwest Territories' Great Slave Lake have noticed a change in the water's appearance recently.
A section of the East Arm of "The Big Lake," as it's locally known, has become muddied and brown.
Steve Ellis said the lake was "pretty normal" in July, but he noticed the murky water during the second week of August.
Ellis said he visits the East Arm every summer, and has been doing that for about 20 years and has never seen that.
"It was completely different, like absolutely chocolate milk," said Ellis. "You couldn't see light penetration. It was brown, brown, brown water."
I started dodging logs that were floating on top of the water. - Kyle Enzoe
He said when he approached the main expanse of the lake, he saw a pretty clear demarcation line into the cloudy water.
"It was impenetrable murk," said Ellis.
He said he suspects it's coming downstream from the Slave River, which flows from Alberta into the N.W.T.
"What I worry about is that this is a pristine clear lake ... [so] what does this mean for fish? What does it mean for habitat there?"
Longtime boater Kyle Enzoe from Łútselk'e also noticed the change in the water.
Enzoe said he's been travelling on the lake for decades, but said he's never seen cloudy water reach that far into Great Slave Lake.
Enzoe said he had a close encounter with some of the debris floating in the murky waters.
"I started dodging logs that were floating on top of the water. There was a little bit of waves, [but] not serious," he said.
Enzoe said his boat hit a log and his motor cranked to the right and "almost capsized [his] boat." He was able to slowly pull to shore and saw his boat was damaged.
"The sticks, I've never seen it go that far," said Enzoe, about the tree debris floating on the lake. Enzoe said he was able to make it back home safely.
WATCH | Murky waters on Great Slave Lake from aerial view
'Sediment plume' from Slave River: gov't
The N.W.T. Environment and Natural Resources Department sent an emailed statement to CBC and said it's aware of a "sediment plume" in the East Arm.
"The department believes the high water levels, especially from the Slave River, are creating the sediment plume," it states.
The department said it is sampling the water in the East Arm, Slave River, and Slave River Delta.
"These samples are necessary to get a better understanding of the sediment plume and to gather more information on this occurrence."