Yukon Energy wants to lower Marsh Lake to reduce summer flood risk
High snowpack in Southern Lakes area means there's potential for more flooding this year
Yukon Energy is again asking for permission this year to lower the level of Marsh Lake, in anticipation of possible flooding this summer.
The company has submitted an "urgent" application to the Yukon Water Board to amend its licence for this year. If approved, Yukon Energy would open a downstream dam this spring to allow Marsh Lake to drop by up to 10 centimetres below what's normally allowed.
"What that does is [it] just creates more room in Marsh Lake to accept melting snow during the freshet period," said Andrew Hall, president of the Yukon Energy Corporation (YEC).
"We're looking at what precautions and measures we can take proactively to increase the amount of flow through the system and also mitigate, you know, how high the lake levels get this coming summer."
The Yukon government is already preparing for potential flooding this summer in some parts of the territory, though officials say it's still too soon to predict the risk. A lot depends on the weather in the coming months, and how fast the snow melts.
The snowpack in some parts of the territory is at record levels right now, but not in the Southern Lakes region which includes Marsh Lake. It's still higher than normal there, though — at 140 per cent of the 1980 to 2001 median.
Last year's snowpack in the Southern Lakes region was higher, and that contributed to the summer's flooding. Many residents in the Southern Lakes and Lake Laberge area were under evacuation alerts by July, and the Canadian military sent soldiers to Yukon to fill sandbags and build protective berms.
Yukon Energy also attempted to get ahead of things last March, asking to lower Marsh Lake 10 centimetres below what's allowed in its licence. The request was granted but the company didn't actually succeed in getting the lake level down that low.
There was just too much water in the system, Hall said, even before spring melt. Part of that was because some hydro units were down for emergency repairs last winter and so less water could move through the system.
"We're about 50 centimetres lower this year than we were this time last year," Hall said.
"So basically, we're in much better shape this year to be able to use the 10 centimetres if the Water Board grants it."
Yukon Energy's application to the Water Board is open for public comment for one week — from Wednesday until Mar. 23.
Board director Roger Lockwood said the application will be publicly available on the board's website on Wednesday.
"The board is planning to meet prior to the end of the month to review the information received following the closing of the public comment period, and I suspect they will make a decision as soon as practical, after that," Lockwood said.
Hall is not certain how much of an impact that extra 10 centimetres might make. It does not mean that summer flood levels will be 10 centimetres lower, he said.
"It's not quite a one-to-one saving. But I mean, as we said in the application, every centimetre counts, if you speak to any homeowner out there that was facing a flooding situation," he said.
Concerns about wildlife habitat
YEC maintains that any environmental impacts from lowering Marsh Lake by up to 10 centimetres will be negligible. Still, last year's application did raise concerns for some Yukoners about wildlife.
"Maintaining wetland habitat, in my opinion, is more valuable than attempting to protect property which can itself be protected in other ways and, if lost, replaced," one person wrote to the Water Board.
The Kwanlin Dün First Nation also raised concerns about fish and bird habitat both in Marsh Lake and downstream, though the First Nation did support YEC's application as a way to protect settlement lands and citizens' residences downstream.
The Water Board ultimately decided to approve that application.
"In balancing the intervener concerns, the results of YEC's studies, and the commitment by YEC to gradually reduce the water levels, the Board finds the risks of flooding to the environment and property is greater than the short-term environmental impacts from lower water levels in Marsh Lake," the board wrote in its decision.