
The City of Revelstoke has issued a notice of an algae bloom at Williamson Lake, advising residents to take precautions, such as avoiding direct contact with the bloom. The notice was issued on July 8, 2022.
This week, inquiries by revelstokemountaineer.com into what residents reported to be an algae bloom at Williamson Lake has revealed that the City of Revelstoke does no water quality testing at the popular swimming lake and that it does not participate in an Interior Health program designed to monitor and report to the public on swimming water quality.
This means there has been no city testing for harmful E. coli levels or for harmful algae blooms at the lake. There are different kinds of algae blooms; not all are harmful to human health and some have varying degrees of impacts on human, wildlife and pet health. The B.C. government refers residents to its Algae Watch webpage for more comprehensive public education on algae blooms.
The causes of algae blooms are complex and depend on a variety of factors including timing, nutrients, temperature, light, and stable conditions.
In early July, the water colour was murkier than usual in the lake, causing residents to wonder on social media what was going on. Residents talked about the changed colour on social media and readers reached out to revelstokemountaineer.com asking what was happening with the unusual colour this year.
Revelstokemountaineer.com began inquiries into the changed colour of the lake this year starting with Interior Health on July 2. We also later reached out to the City of Revelstoke and the Ministry of Environment.
July 2, 2022

July 1, 2021

On July 2, we reached out to Interior Health to ask of the City of Revelstoke has a Beach Safety Plan, a document designed to help manage water quality health issues, and if it coordinates testing and communication with Interior Health on water quality.
Interior Health maintains a water quality advising website that regularly reports water quality at regional beaches and also notifies of blue-green algae blooms. You can see its beach advisory webpage here: https://www.interiorhealth.ca/health-and-wellness/environmental-health-and-hazards/public-beaches
The website includes details listing the type of algae bloom and levels of E. coli detected during testing.
Interior Health responded on July 5, saying that the City of Revelstoke does not have a beach safety plan and that it does not submit water quality samples to Interior Health. It said it does not have any records of water quality testing at the lake.
Interior Health confirmed that participation in its water quality monitoring program is optional for municipalities.
City of Revelstoke

On July 5, revelstokemountaineer.com reached out to the City of Revelstoke, asking if the city does water quality testing, has a beach safety plan, and has records of water quality testing. We also asked why the city does not participate in the Interior Health monitoring program, and why it does not publish water quality health information independently.
In a July 6 response, the city said it was working with Interior Health to test water quality at the lake. “At this time, an Environmental Health Officer has not yet visited the site,” a spokesperson wrote.
“Historically there have been no documented water quality issues at Williamson Lake Park & Campground Park and Interior [H]ealth does not routinely test water to determine algae species or presence of toxins,” the city wrote in a statement. In response to follow-up questions, the city confirmed it does not test water quality of the lake and maintains no records of water quality testing.
The city said it does not have a beach safety plan and that they are not required.
A July 8 statement issued by the City of Revelstoke via its Facebook page confirmed an algae bloom at the lake and said water quality testing is underway. It advised avoiding contact with the bloom and discouraged swimming in areas where the bloom is present, and rinsing off if you come into contact. It advised against consuming water from the lake and advised providing pets and livestock and alternative source of drinking water.
The statement did not identify the type of algae bloom and said testing was ongoing.
Ministry of Environment
When asked about the changes to the lake since last year and any potential causes, a Ministry of Environment spokesperson stated: “The ministry’s Surface Water Quality Monitoring Sites Interactive Map does not have water quality results for Williamson Lake near Revelstoke. However, the automated snow weather stations in the area currently have snow pack and are experiencing rapid melt, which could result in runoff and increased turbidity in the lake. Without photos, it is difficult to assess whether the unusual colour reported in the lake is a result of turbidity from runoff, pollen (as described) or a harmful algae bloom,” the spokesperson wrote. “I don’t think we can definitively attribute the golf course as a cause for the discoloration based on the information provided and other potential factors. Algae Watch is [the Ministry of Environment’s] public reporting mechanism for suspected Harmful Algae Blooms; if there is a suspected spill or pollution event, then the public should contact the RAPP line. Of course, if there is a human health or recreational concern, then the responsible Health Authority should be contacted.”
Revelstokemountaineer.com submitted before and after photos and surface water photos of the lake to the Ministry of Environment. “Shared with staff who say it could potentially be an algae bloom,” the spokesperson replied after receiving the photos.
He added: “We recommend visiting the Algae Watch website which has example photos of algae and other aquatic phenomena including pollen, and to submit photos through the website for identification by staff and for posting on its interactive map. If a human health concern develops, IHA should be contacted as the responsible agency.”
Algae Watch
Both Interior Health and the Ministry of Environment say residents should report potential algae blooms to the government’s Algae Watch website.