Alberta Environment has presented more details and options for the rising lake levels at Sylvan Lake to town council.
The highest average daily water level for Sylvan Lake was recorded on Aug. 11, 2011, when the lake level rose to 937.308 metres above sea level, David Helmer, regional approvals manager for Alberta Environment, told council on Tuesday.
This surpassed the previous record of 937.24 set in July of 1995.
“It’s important to remember lake levels naturally fluctuate, based on what’s going in and what’s going out,” said Helmer, speaking to precipitation and evaporation.
The natural outlet channel off Sylvan Lake is functioning as it should and is not blocked or silted in, added Helmer. One of the twin culverts off the lake was 80 per cent blocked last summer but further research from Alberta Environment determined this has little to no effect on rising lake levels.
“We are confident the hydraulic control point is at the natural outlet,” said Helmer. “These are naturally occurring high levels.”
The outlet does have a limited capacity, noted Helmer, and only so much can flow through there, but it is not artificially blocked and causing high lake levels.
There had also been concerns expressed that Cygnet Lake was backing up water, said Helmer. This is not the case as Cygnet Lake, a controlled lake, is too far downstream.
Options presented for Sylvan Lake included maintaining the outlet and cleaning it of vegetation growth, upgrading the outlet channel further to Hwy 20, or installing a control structure at the lake outlet.
Aside from water level concerns, the town could also opt for erosion protection or the use of natural buffers to further protect the lake, said Helmer.
Erosion protection includes the installation of rock armouring. Natural buffers would include plants and brush bundles to heal and protect the banks.
Coun. Graham Parsons asked Helmer about the possibility of pulling the sand back for a beach again.
Helmer said such methods have environmental ramifications and it would have to be looked at in much greater detail.
rfrancoeur@www.reddeeradvocate.com