Invasive species, biosolids, and algae blooms: how are Victoria’s lakes doing?

Monitoring trends in Victoria’s lakes and the watersheds is no simple task. For starters, there are a lot of lakes—the BC Freshwater Atlas states that there are 386,049 lakes in the province, and a 2005 estimate put over 10,000 of those lakes in the Vancouver Island region.

Lakes are complex and don’t exist in isolation. Each lake is part of a larger watershed, connected by streams, wetlands, and groundwater, and something that happens many kilometers away from a lake can still have a significant impact on it.

Many volunteer-driven organizations are active in stewardship and conservation of Victoria’s lakes—a complex task given that different levels of governments regulate what can happen in the water, on the surface, or on lands surrounding the water. Some lakes border parks or nature sanctuaries; others border houses, golf courses, agricultural lands or highways; and further up-Island many are in logging territory, behind locked gates and largely unknown to the public.

Of the 31 local lakes featured in the Lakes of Victoria, BC Guidebook, 27 have a portion of their shores bordering a public park, while others are in nature sanctuaries or grounds of non-profit organizations. There are another 10 lakes in the same geographical range which are not in the book as their shores border private property.  There are many more lakes within the Capital Regional District, which includes the protected Greater Victoria Water Supply Area and the sprawling Juan de Fuca Electoral Area.

Due to their proximity to urban settlement, Victoria’s lakes, streams and watersheds are experiencing increased pressure. Eric Bonham, a board member for both the Greater Victoria Greenbelt Society and the BC Lake Stewardship Society, says it’s critical to involve the community in protecting lakes—from bringing in and recognizing volunteers, to working with academics, to bringing school groups out to lakes to nurture respect for those environments.

“[It’s] important to ensure children grow up with a deep respect for nature,” he says.

At Crabapple Lake deep in the Sea to Sea Regional Park the waterlilies are a beauty—however this species, Nymphaea odorata, is not indigenous to Vancouver Island. Photo: by Adam Ungstad / Submitted

Invasive threats: introduced plants and animals

Rick Nordin has been a board member of the BC Lake Stewardship Society since it formed in 1997, and spent much of his career working for the BC government studying inland bodies of water.

Now retired, the top thing on Nordin’s mind is the intentional and unintentional introduction of invasive species.  “There are regular incidences of people leaving their goldfish and turtles in lakes, or introducing aquatic plants like milfoil, nymphaea water lillies, non-indigenous cattails, and yellow flag iris,” he says.

Invasive species upset the natural balance within an ecosystem, and cause cascading effects.

The American bullfrog is a highly aggressive, territorial carnivore threatening Victoria’s lakes.      It eats anything it can fit in its mouth, including the much smaller indigenous Pacific chorus frogs and other indigenous salamanders, snakes, and even ducklings. Even if they don’t directly eat or attack other species, they compete against them for food or other resources.

Boating, stand-up paddle boards, and fishing are common ways that invasive aquatic plants spread between lakes. Fragments of a plant can hitch a ride on recreational equipment, and then fall to the sediment of another lake when its owner goes for their next paddle, or dumps a bait bucket into another lake.

This is how aquatic plants like Eurasian water-milfoil—a huge problem for Shawnigan Lake, Elk/Beaver Lake, Prospect Lake, and many others—is able to spread. Cleaning, draining, and drying equipment after each lake adventure is a good way to reduce that spread.

As for pet goldfish or turtles that you can no longer care for? If you are not able to find another caregiver, it’s likely best to take it to a veterinarian or wildlife rehabilitator to be euthanized instead of releasing them into ecosystems where they don’t belong, where they can harm wild species.

Prospect Lake as seen from Whitehead Park. Photo: Lori James Derry of the Friends of Tod Creek Watershed / Submitted

Biosolids: a potential new threat to the Tod Creek Watershed

For the Friends of Tod Creek Watershed, a community-based organization engaged in stewardship of local recreational favourites such as Prospect Lake, Killarney Lake, and Durrance Lake, a key concern is the impact of people.

“Aside from spreading invasive species, people can unintentionally disturb indigenous flora and fauna, degrade shorelines, and leave behind other traces of their activity such as plastic and human waste,” explains Winona Pugh, chair of the organization.

There’s another risk that worries the Friends of Tod Creek Watershed: the risk posed by recycled sewage, otherwise known as biosolids, at the nearby Hartland Landfill. Due to ongoing difficulties in managing biosolids, the board of the Capital Regional District lifted a ban on the land application of biosolids at the Hartland Landfill in 2020, without public consultation.

Since then the Butchart Gardens and the Peninsula Biosolids Coalition have said that the amount of biosolids spread at Hartland Landfill to date far exceeds what was originally approved, and have issued a call on the Province and the CRD to immediately stop spreading biosolids and to resume burying them as hazardous waste until a safe disposal method is approved.

“The proximity of the landfill to our National Historic Site Garden, many organic farms, public recreation areas and the headwaters of important local watersheds makes burial of biosolids an urgent and necessary decision for the CRD Board to make,” says Dave Cowen, CEO of Butchart Gardens.

Glenn Harris, a senior manager with CRD Environmental Services says the biosolids aren’t damaging the ecosystem. “Ongoing compliance monitoring has shown that concentrations of metals and fecal coliforms… are significantly below all regulatory standards,” he wrote in an email, adding that more than 150 domestic wells are regularly tested, while runoff and dust from the landfill are controlled to keep them from entering the ecosystem.

With the engineered and administrative controls in effect for biosolids management at Hartland Landfill, the CRD is confident that biosolids do not pose a risk to neighbouring lands and waterways. The CRD has indicated that the biosolids growing medium (BGM) produced at Hartland Landfill will not be applied to any areas outside of the landfill property, and all surface water discharges from the northern and southern boundaries of the landfill are regularly monitored to ensure compliance with water quality guidelines.

Paddling among the indigenous pond lilies at Elk/Beaver Lake. Photo: Ernie Dickey / Submitted

Algae blooms and oxygenation at Elk/Beaver Lake

They can be hard to detect with the naked eye—sometimes leaving a sheen on the surface of a lake, and sometimes not even that—but a blue-green algae bloom can be deadly. The CRD regularly posts warnings online and signs at the lakes themselves, warning against swimming or letting pets go in the water.

These blooms have occurred in larger lakes such as Elk/Beaver Lake and Langford Lake, as well as smaller, shallower lakes like Prior Lake and Thetis Lake. They are an unsettling trend across the continent, and the North American Lake Management Society (NALMS) has undertaken studies to map their presence using satellites.

While cyanobacteria do occur naturally in lakes, there are many human-driven causes that can accelerate them. They are caused by an overabundance of nutrients such as phosphorus, which can build up in lake sediments and come in from fertilizer run-off from agriculture and lawns, household cleaning products, and leaky septic systems.

The Capital Regional District and the Province of BC are implementing an oxygenation system to improve the overall quality of the water in Elk/Beaver Lake. Oxygenation will help to sequester phosphorous, reducing the occurrence of cyanobacteria and improving fish habitat. Once completed, the project will provide a model for other lakes in the Victoria area.

Down by the dock

A recent blog post by the Prior Lake Naturist Preservation Committee tells of a trend at Prior Lake—higher than usual water levels—caused by iconic Canadian engineers, beavers.

Despite the inconvenience of flooded shorelines, representatives of the committee, William and Danny, write, “Beavers are an integral part of a balanced natural environment, and it is important to accept that we must find ways to co-exist, as the beavers and their dam are here to stay.”

Love Victoria’s lakes?  Get involved. Become a member, volunteer, or make a donation to one of the many organizations working in local stewardship and conservation.  Here’s a handy list of 25 of them.

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Enjoyed this article? Get your copy of the book to learn more about Victoria’s lakes!

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Complete with a “Lakes 101” section and illustrations of local riparian and aquatic plants and animals,  the Lakes of Victoria, BC Guidebook is an essential resource for anyone interested in local lakes.

The book features 31 lakes from the Saanich Peninsula to the Sooke Hills, and includes places to walk, hike, swim, fish or paddle in addition to essential information like parking, facilities, and accessibility.

With trail maps, photographs, and local history, everyone will learn something new about Victoria’s lakes.

“An excellent resource on local lakes.”

- BC Lake Stewardship Society

Delightful and enchanting… a lovely book.”

- Times Colonist

Buy your copy of the book here.

Update on July 20 at 11am: The biosolids section of this story has been updated.