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

Two hurt in reported stabbing in Enderby

Police respond to reports of stabbing to find two men in similar condition near Canyon Road

Mandatory masks part of SilverStar’s winter plan

SilverStar starts season late to prepare for pandemic protocols

Vernon police catch porch pirate

A 45-year-old Vernon woman faces charges of theft under $5,000, possession of stolen property

Travel from Coldstream to Lake Country along Kal Crystal Waters trail

Completed extension on Kal Crystal Waters trail uses historic highway

Major UBCO bus changes from Vernon eliminate Oyama, include Kelowna

Oyama Isthmus loop removed, stop across from Kelowna airport added

Record-breaking 165 new COVID-19 cases diagnosed in B.C. in 24-hour period

Fifty-seven people are in hospital battling the novel coronavirus

Interior Health reports four new cases of COVID-19

First hospitalization since mid-August announced

Rail traffic starts moving after 60-car derailment near Hope

Clean up effort ongoing after 60 cars carrying potash crashed along a rail bridge

Spoon-wielding man draws police presence in Penticton

Police say no one was harmed during the incident

March to protect old growth, stop industrial logging coming to B.C. Legislature

Organizers say they want to give frontline communities a bigger say in nearby logging

B.C. releases details of $1.5B economic recovery plan, $660M in business tax incentives

Economic plan includes support for employers, as well as training for workers

‘Not criminally responsible’ hearing slated for man convicted of Abbotsford school stabbing

Gabriel Klein was found guilty in March of killing Letisha Reimer, 13, in 2016

Most Read