A close up image of an algae bloom in Shuswap Lake near Ashby Point taken in April 2020. (Interior Health photo)

Shuswap Lake Algae bloom the result of “perfect storm” of factors

Shuswap Watershed Council states influx of nutrients and increased sunlight are causes

The Shuswap Watershed Council (SWC) says the large algae bloom in Shuswap Lake is the result of various factors which amount to a “perfect storm scenario.”

Program manager Erin Viera said algae is a natural part of Shuswap Lake’s aquatic ecosystem but changes in conditions can cause more prominent blooms. She said blooms are common when sunlight increases and runoff down creeks and rivers brings a fresh supply of nutrients into the lake.

Referring to a recent SWC study on the origins of the nutrients that are brought into Shuswap Lake by the Shuswap and Salmon Rivers, Viera noted that most of the nutrients from the rivers come from the valley bottoms. Agriculture, housing and commercial development in the watershed all affect the nutrient levels in the river.

Read More: Interpretive salmon classes at Kingfisher Creek get financial aid

Read More: Local governments call on Okanagan boaters to keep wakes low in shallow water

Viera said that as 2020 has been a very wet year, the Salmon River has been running higher than usual for months. The soil in the valley bottoms has also been saturated by rain causing nutrients to be flushed out of the soil into the river and down stream to Shuswap Lake. As the nutrients — particularly phosphorous — from the river settled in Salmon Arm bay, favourable conditions for the growth of large amounts of algae were created.

She said a similar effect was probably created in Tappen Creek and White Creek, which also flow into Salmon Arm Bay.

Viera added that the heavy rains this year might’ve contributed to the release of “legacy phosphorous” which is stored in soil for years or even decades. Septic systems near the lake and the Salmon Arm wastewater treatment plant are also sources of nutrients, but Viera said water quality monitoring has shown that they are smaller sources than the Salmon River.

Read More: Algae bloom highlights nutrient concerns in Shuswap water quality report

Read More: Money available to curtail nutrient pollution of Shuswap watershed

Nutrient increases lead to algae blooms in Salmon Arm Bay more than other parts of the lake because its shallow depth causes it to warm up more quickly. It is also relatively stagnant, and conditions are favourable to algae growth if the water isn’t mixed by currents or windstorms.

Water quality monitoring is also ongoing on the algae bloom itself. Viera said authorities are ensuring the bloom doesn’t pose a safety risk to swimmers or beach goers. If it becomes hazardous, notices will be posted at affected sites.



jim.elliot@saobserver.net

Like us on Facebook and follow us on Twitter

Environment

Get local stories you won't find anywhere else right to your inbox.
Sign up here

Just Posted

Interior Health reports three additional COVID-19 cases in region

The number of cases in the region since the beginning of the pandemic are now at 492

Interior Health continues to tackle COVID-19

IH president Susan Brown says don’t become complacent about pandemic

Conservative opposition critic tours through Kootenay riding on listening tour

Pierre Poilievre, the Tory finance critic, gathering local feedback on pandemic supports, recovery issues

Fundraiser set up to help 10-year-old Summerland girl with cancer

Danica Yeoman is undergoing treatment at BC Children’s Hospital

Professional development for physiotherapists comes to Golden

Normally physios and massage therapists have to travel long distances for this kind fo course

3 new deaths due to COVID-19 in B.C., 139 new cases

B.C. confirms 40 ‘historic cases,’ as well

Supreme Court Justice Ruth Bader Ginsburg dies at 87

The court’s second female justice, died Friday at her home in Washington

‘This is a very difficult sentencing’; Judge delays Okanagan manslaughter trial to next week

The courts heard Friday that Bourque “did not intend to cause harm” but that her actions were “reckless”

Emaciated grizzly found dead on central B.C. coast as low salmon count sparks concern

Grizzly was found on Gwa’sala-‘Nakwaxda’xw territory in Smith Inlet, 60K north of Port Hardy

VIDEO: B.C. to launch mouth-rinse COVID-19 test for kids

Test involves swishing and gargling saline in mouth and no deep-nasal swab

Young Canadians have curtailed vaping during pandemic, survey finds

The survey funded by Heart & Stroke also found the decrease in vaping frequency is most notable in British Columbia and Ontario

B.C. teachers file Labour Relations Board application over COVID-19 classroom concerns

The application comes as B.C.’s second week of the new school year comes to a close

CHARTS: Beyond Metro Vancouver, COVID-19 cases in B.C. haven’t increased much recently

COVID-19 case counts outside of Metro Vancouver have been level since July

70-year-old punched in the head in dispute over disability parking space in Nanaimo

Senior’s turban knocked off in incident at mall parking lot

Most Read