Tuesday, 19 July 2016

Can Muriel Lake be saved?

For the Bonnyville Nouvelle

An old photo taken of Muriel Lake is held in front of the current lake conditions show just how much the water levels have declined over the years.
Submitted photo
 The fight to save Muriel Lake continues, but depending on who you ask, the culprit draining the lake has yet to be identified.

The Muriel Lake Basin Management Society (MLBMS) held it's annual meeting on July 10.

The society has been pushing hard to determine the root causes of the declining water levels in Muriel Lake, which is at its lowest levels in modern history.

“It's been a 40 year trend of dropping lake level,” said MLBMS president Peter Cordingley.

Cordingley noted that while the society was incorporated in the late 1990s, the lake has been losing volume steadily since 1981.

Yvonne Veraart, who regularly attends gatherings at the lake, noted that the lake has changed dramatically over the years.

“It used to be a pristine lake. Now it's more like a bog.”

Muriel Lake was once an average of nine metres deep, but today it is sitting at about four metres. According to Cordingley, that amounts to a loss of nearly 2.5 billion litres of water.

“The quality of the water is really decreasing, it's to the point where you don't swim in it anymore,” commented Cordingley. “It used to be a trophy fishing lake, and now all the fish are dead. They died in the winter of 2013 because of the low oxygen and water levels. They can't survive the winters anymore.”

What is causing the lake to evaporate is still a mystery. A series of Alberta Government studies in 2009 and 2012 by Ernst Kerkhoven and Brent Welsh of Alberta Environment concluded that the most likely culprit is changes in the local climate, with the most involved factors being reduced precipitation and increased temperatures. According to Cordingley, the usage of the land may also be a factor.

“Alberta Environment says it's all natural. Basically evaporation from the lake exceeds the rainfall, and we're getting very little run-off from the lake. Only about five per cent of the rain that falls in the region makes it into the lake,” conceded Cordingley. “We look at the lakes around Muriel Lake and Bonnyville, they do go up and down, but then they come up again. So we disagree with Alberta Environment. It's not all natural and it's not a natural cycle.”

Industry used to draw water off the lake for its own use but, according to Cordingley, that stopped in the 1980s. However, that didn't stop the decline of the water levels.

Running on the theory that there might be something happening with the aquifer that feeds the area, the society installed two monitoring stations in wells in 2015 to keep track of groundwater levels.

“We think that there could be another impact in that the lake may be connected to groundwater aquifers. There may have been impacts which have caused less contribution from the groundwater aquifers,” suggested Cordingley. “So we're now monitoring the groundwater aquifers and we're getting data from that which suggests that the pressure of the reservoir is higher than the lake water. So if there is a conduit of water flow we should be getting water from that aquifer into the lake. The lake is going down and the aquifer seems to be going down.”

The MLBMS also contracted an environmental engineering company to do an assessment of the land using current and historical aerial photos from as far back as 1959 to map surface water flow into the lake. That study identified a few small water basins in the area that have changed shape and size over time.

“Those are areas we need to do more work to see if things like roads or industrial and agricultural activities have impacted those water bodies and altered the flow of water into our lake,” noted Cordingley.

Another possibility is the correlation of an explosion in the local beaver population. According to Cordingley, back in the 1980s it was possible to canoe up and down the creeks feeding into the lake. However, that is no longer possible, with up to six beaver dams being sighted every kilometre up the creek.

A plan has been put in place to install 10 “Beaver Deceivers”, essentially small pipes that are run through beaver dams, allowing for greater water flow and prevent the dams from keeping water from the lake.

The MLBMS is now waiting for Alberta Environment to give them the go ahead to install the pipes.
Cordingley commented that something needs to be done soon or the lake would be unsalvageable.

“There's very little boating or swimming or recreational use of the lake anymore,” he noted. “There used to be hundreds of people boating. So it's having an impact on the tourism industry in the area.”

No comments:

Post a Comment