Water inspectors hunt source of Jackfish Lake algal bloom

Aerial view of Jackfish Lake
Aerial view of Jackfish Lake (left) looking toward Yellowknife.
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Water inspectors want to change how run-off from Yellowknife’s dump is monitored as they try to understand algal bloom in the city’s Jackfish Lake.

The lake has experienced a sludgy algal bloom – a rapid increase in the algae population – each spring for the past two years.

The territory’s Department of Environment and Natural Resources (ENR) is trying to figure out why the algal bloom has started happening, and believes run-off from the dump could be playing a role.

“We’ve done some lab analysis and some testing, and confirmed it’s a cyanobacteria – a blue-green algae, a bloom,” said Robert Jenkins, the territory’s director of water resources.

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“We know algal blooms are associated with an increase of nutrients into water, so we want to have a better understanding of what’s going on in the system.”

Jenkins’ department has written to the Mackenzie Valley Land and Water Board, asking it to amend the City of Yellowknife’s water licence to include testing at the dump for potential sources of those nutrients.

In full: Letter from ENR to regulatory board regarding water testing (pdf)

“We asked the board to basically add some parameters to the city’s water licence – specifically phosphorus or phosphates,” Jenkins told Moose FM.

“Those are nutrients and phosphorus is one that’s essentially a key driver in algal growth, so we’re trying to better understand potential inputs into the lake.

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“Phosphorus does occur naturally – we could have weathering of rock or uptake through soil. But there could also be phosphorus introduced through breakdown of food waste, water going through that.”

The city monitors water using a chain of surveillance network stations. The current water licence says phosphorus must be monitored at stations around the Fiddlers Lake sewage facility, but not by the two stations at the city’s solid waste facility.

Water samples from the stations at the dump are taken twice yearly, in June and September.

In May, the territory’s chief public health officer – Dr Andre Corriveau – suggested the Jackfish Lake algal bloom did not pose a significant health risk to the city’s residents. The Northwest Territories Power Corporation does not believe its Jackfish power plant is the cause.

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Jenkins told Moose FM he needs to know more before he can be sure of what’s happening and what advice to give.

“The point we’re at is gathering information,” said Jenkins.

“We need to have a better understanding, then we’ll be in a better position to know if there are any potential issues there.”

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