Drought taking over as a topic of concern ‘up north’

Joe McWilliams
Lakeside Leader

The topic of drought – long thought to be a matter for ‘down south’ is coming up fairly frequently around the M.D. of Lesser Slave River council table these days. The most recent discussion had to do with the M.D.’s attempts – along with a few other north-central Alberta municipalities – to be included in a federal drought designation.

We are in a drought, M.D. Ag Fieldman Kendra Kozdroski told council. Not as severe as they’ve got it down south, but a drought just the same. Hay yields, for example, were down something like 30 per cent last year, she said.

Also part of the discussion at a recent council meeting was the bogeyman of something called ‘inter-basin transfers’ of water. This is something that is not permitted in Alberta, under the Water Act. But such rules can be changed, observed Reeve Murray Kerik.

And in spite of the ban, according to the Athabasca Watershed Council, “in certain circumstances, a special act of the legislature may allow a proposed transfer to proceed, after public consultation.”

Not that anyone in authority has proposed such a thing, at least not that we’ve heard. But with reservoirs in southern Alberta being as low as 19 per cent of capacity (St. Mary’s Reservoir, as of March 6), some people will probably be thinking about it.

So it’s undoubtedly a very good thing that southern Alberta has been getting more snow in the latter part of this winter. In the north, it’s been the driest winter most people can remember. Lesser Slave Lake continues to shrink, as does the river that drains it.

How low is the Lesser Slave River? It isn’t one of the ones listed by the province on its website. Many of the rivers that do appear on the government’s ‘drought conditions’ page are at the lowest level in the last 25 years. That includes the Athabasca, which isn’t getting a lot of help from the Lesser Slave watershed these days. Measured below Fort McMurray, it was at a 25-year low. The Smoky River, at Watino, was at a 24-year low on March 12.

If the flow over the weir in the Lesser Slave River drops below six cubic metres per second, it creates a big headache for Slave Lake Pulp, possibly among other users. That company uses water for processing purposes in its mill, and discharges effluent back into the river. According to its operating license with the province, something called the ‘biological oxygen demand’ caused by the effluent has to be below a certain number – otherwise it endangers fish. No problem at normal river flows, but when the water gets very low, it is. Just such a crisis happened 20 or so years ago one late fall, when the water actually stopped flowing over the weir altogether, putting the pulp mill – not to mention a lot of fish – in jeopardy. To say nothing of other downstream water users, one of which is Cardinal Energy. So is the M.D., for its Mitsue Industrial Park raw water customers.

In response, the M.D. installed several large pipes to siphon water over the weir. It also arranged some dredging upstream, to increase flow out of the lake.

Since then, the province installed a gate, next to the fish ladder structure, that can, when opened, to do the same things the siphons did. Meghan Payne, the Executive Director of the Lesser Slave Lake Watershed Council, says except for operational checks the gate hasn’t been opened since its 2015 installation. Perhaps this could be the year.

Payne says the flow gauge for the Lesser Slave isn’t working right now, so there’s no way of telling how close to that 6 m3/sec threshold it is. On March 20, the lake level was 575.86 metres above sea level; the height of the weir is 575.5m, so that’s cutting it pretty fine. Last week’s modest snowfall notwithstanding, the lake will likely continue to shrink until there’s some significant precipitation.

Is that likely to happen? Payne attended a session on weather and climate and its impact on agriculture on March 20. She says the presenter spoke about the El Niño effect, which is evidently to blame for the dryness. The presenter expects El Niño to fade sometime this summer and be replaced by La Niña, which will bring rain.

Payne says the presenter gave an optimistic report for agriculture (focusing on the Peace Country), saying there is still some “deep soil moisture” that will support germination and growth until the rains arrive later in the summer. Also predicted that the Slave Lake area would be wetter than further west.

The weir on Lesser Slave River, as it appeared in early November 2006, with no water flowing over it.
This government lake level graph shows fluctuations over the last century or so. Prior to the installation of the weir at Slave Lake, the dark blue represents an estimate of what the levels would have been had the weir been in place, vs. what they actually were (in lighter blue).
Image provided by Lesser Slave Lake Watershed Council
Still flowing….the Lesser Slave River is low, but it has a bit to go before reaching the level of November 2006, when it stopped going over the weir.

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