The Oyama Canal, June 11, 2021.

Image Credit: SUBMITTED/Tween Lakes Resort

A grassroots effort to get the channel connecting two Okanagan lakes – Wood and Kalamalka – would be great for boaters but may do serious harm to both lakes.

That’s the news the District of Lake Country council got from experts at a strategy meeting earlier this month.

At issue is so much sediment has built up in the channel between the two lakes it’s getting difficult for boats to navigate the channel.

Andrew Spear started a campaign to get the canal dredged two years ago.

“It’s just bad because it’s a really fun thing to do with the kids, going through the canal to get from one lake to another… and right now it’s next to impossible,” he told iNFOnews.ca in June. “I’m concerned for the safety aspect of the canal, a lot of boats are being damaged and when summertime hits, the tourist aspect of things makes it dangerous. Many times we’ve gone through there and had to help other boats navigate though.”

READ MORE: Dredge work to improve canal linking Kalamalka and Wood Lakes tied up in red tape

In response to such concerns, Lake Country council called in some local experts to brief them on the implications of dredging the channel. The news was not good from an environmental perspective.

Heather Larratt, of Larratt Aquatic Consulting, has been studying the lakes for decades and warned that people need to be concerned about what is happening there just from natural forces, like floods and wildfires, let alone human interference.

Floods erode the shoreline and carry nutrients and contaminants into the lake, she explained. A layer of ash from forest fires can increase the phosphorus levels.

A major “cyano” algae bloom in Wood Lake last spring, while not unusual, was bigger and earlier than normal.

READ MORE: Interior Health discourages swimming in Wood Lake due to algae bloom

“When we watch algae blooms, they can sort of be the canary in the coal mine, giving us the first signal that there’s change afoot and we need to understand what is going on,” Larratt said. “From a food chain perspective, cyanobacteria is junk food. They are not good for the food chain so they are signalling to us that things are not good in that environment.”

Traces of such algae blooms do drift into Lake Country’s water intake at the north end of Kalamalka Lake because the water between the two lakes generally flows in that direction.

What is more disturbing is that there is now a “serrated” bloom in Wood Lake, something Larratt has never seen before.

“I don’t like it when lakes that I’ve studied for decades suddenly do something that I’ve never seen them do before,” she noted. “I don’t like that. Usually you see serration where there is a ton of bacteria that has shown up.”

She knows of only two other B.C. lakes with such a bloom and they are much smaller than Wood Lake.

Larratt doesn’t know what’s causing the bloom but suspects it may be partially due to wildfires.

READ MORE: Kamloops Fire Centre sees record-breaking number of hectares burned this year

Added to those worries is the possibility of stirring up the sediment in the channel. Once those contaminants are buried five centimetres deep, they’re sealed off from the lake water. But, if they’re disturbed, they can dissolve back into the water.

“Once we kick that sediment up into the water column, it will tend to stay there,” Larratt said. “The sand and silt part, those will drop out quite quickly. Clay, bacteria and materials that dissolve back out of that sediment, once it’s disturbed, take weeks to resettle – if at all.”

That, combined with the fact that a dredged channel would invite more, larger boats to travel through, means more damage could result, especially from wake boats which creates waves that are much more damaging to shorelines and lake bottoms than other types of boats, she said.

Still, there is a strong desire by some to dredge the channel, as has been done in the past.

“It is a very well-used waterway between Wood and Kal Lakes and with recreational boaters, the fishermen, even with the RCMP and emergency personnel, going back and forth while patrolling the water, it’s nearly impossible to get through right now,” Kevin Dimery, vice-president of the board with Tween Lakes Resorts, told iNFOnews.ca in June.

Jason Schleppe, with Ecoscapes Environmental Consultants, has been dredging sand out of Okanagan Lake for years at the Cook Road boat launch.

At the strategy session, he explained the complicated application process that will likely be required to get permission to do the work.

Just to get a provincial permit will likely take two to three years and cost anywhere from $100,000 to $500,000, depending on how much detailed study is required, he said.

Permits will also likely be needed from the federal Department of Fisheries and Oceans.

Since a dredging barge is not likely to fit in the channel, massive suction hoses would be needed. They cost $1,200 to $1,500 an hour to operate.

Disposing of the sediment will also be a challenge. It can be put into huge “geotubes” but, unlike sand, this sediment is likely to clog up the membranes and prevent water from seeping out.

Dredging could cost from $200,000 to $1 million,” Schleppe estimated.

In total, given that there are so many unknowns, costs could range from $500,000 to more than $2 million and dredging would likely have to repeated periodically, he said.

Some of those unknowns include determining what aquatic life is in the sediment and how quickly it could re-establish once removed, what kind of modelling senior governments might want and issues such as whether adjoining property owners are onside or might fight the dredging for fear of damage to their properties.

The information from the strategy session will be put into a report and used by the District of Lake Country to solicit public input on whether residents are in favour of even starting on such a project, which one Lake Country councillor suggested could take 10 years.

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