FAQS

Here you'll find commonly asked questions for the Lake Eugenia Water Quality Improvement Project

Updated as of June 4, 2025

WHY IS BLUE GREEN ALGAE A PROBLEM? THERE HAS BEEN ALGAE IN LAKE EUGENIA FOR MANY YEARS.

Blue green algae blooms have been intensifying in Lake Eugenia for the past 10 years.

The blooms are toxic and threaten animals, pets, small children, and immune system-compromised adults with a non-treatable fatal outcome if the toxin is ingested in a large quantity. Healthy adults will become nauseous from exposure to these toxins.

WHY HAVE THE BLUE GREEN ALGAE BLOOMS INTENSIFIED IN LAKE EUGENIA?

Lake Eugenia is subject to the same stressors that impact lakes in the northern United States and southern Canada. Due to climatic change, the ice on/ice off season has grown shorter.

Lakes near urban areas have been populated for many years, which has led to deposits of nutrients from decaying matter, improperly treated sewage, shoreline runoff, road culvert direct drainage, and upstream nutrient inflow.

These factors have provided the nutrients that support the rapid and early growth of blue green algae.

WHAT IS THE IMPACT OF BLUE GREEN ALGAE IN LAKE EUGENIA?

The impact of blue green algae is being felt in at least three different ways:

A negative impact on the ecology of the Lake. Reduced water clarity and algae toxicity are not advantageous to promote a healthy ecosystem.
A direct impact on the recreational benefits that Lake Eugenia offers. Grey Bruce Health posted warning signs in early July due to the blooms.
A negative impact on economic values. Lake Eugenia contributes an estimated $16,000,000 annually to the local economy. Blue green algae toxicity in Lake Eugenia has been widely publicized and is frequently mentioned in social media. This is threatening property valuations on the Lake. Tax revenues from the Lake are over $2M annually, and the assessed valuation of Lake properties is ¾ of a billion dollars.

WHO HAS CONDUCTED THE SCIENTIFIC RESEARCH AT LAKE EUGENIA?

Hutchinson Environmental, from Bracebridge, ON, has studied the Lake and issued the reports posted on the Friends of Lake Eugenia website. Hutchinson has an international reputation for lake analysis and for suggesting water quality improvement measures.

All studies have been provided to and reviewed with the Grey Sauble Conservation Authority.

WHY DOESN’T THE LAKE FLUSH ITSELF OUT WHEN IT IS DRAINED?

The nutrients reside at the bottom of the Lake. Water drained from the spillway or through the penstocks is taken from the top of the Lake, leaving the nutrients in place for another season.

Although the penstocks drain from the bottom of the small lake, the shallow channel to the penstock pool acts as an underwater dam, preventing water from being withdrawn from the deepest part of the main lake.

WHAT CAN BE DONE?

Two proven approaches to improving lake water quality exist. They are not mutually exclusive and must be used in tandem for the most effective results.

The first is establishing controls on nutrient-rich drainage to the Lake, i.e., shoreline management. These include:

Mandatory septic inspection.
Control of road culvert inflow to the Lake.
Prohibition of phosphorus fertilizer use.
Establishment of buffer zones on the Lake shoreline. This is done through education.
Monitoring of upstream nutrient inflow.

The second is to actively remediate the nutrients (phosphorus in the case of Lake Eugenia) in the Lake to make them unavailable for algae growth.

WHAT NEEDS TO BE DONE TO IMPROVE SHORELINE MANAGEMENT?

The Municipality of Grey Highlands is responsible for establishing mandatory septic inspections and reconstructing road culverts draining directly into the Lake. Friends of Lake Eugenia has appeared before the Grey Highlands’ Council annually for the past three years, requesting that the necessary regulations be adopted to protect the Lake.

The Friends’ requests have been forwarded to the recently formed Lake Task Force. Encouraging a reduction in fertilizer use and the establishment of buffer zones on the shoreline is an ongoing educational effort.

Nutrient inflow from upstream sources is currently being monitored and does not seem to be a primary issue.

WHAT IS ACTIVE REMEDIATION?

Active remediation to improve water quality in a lake involves working within the lakebed to reduce the available phosphorus that supports blue green algae growth.

Remediation methods can include:

Dredging to remove phosphorus-laden sediment.
Aeration to mix stratified water to encourage the natural iron/phosphorus bond in oxygenated water. This bond makes the phosphorus unavailable for algae growth.
A flocculant, such as alum, can be used to bind with the phosphorus and precipitate the bound material to the bottom of the lake, making it unavailable for algae growth. This was the original approach to the remediation of Lake Eugenia.
Direct oxygenation through a distribution system in the deepest part of the lake.

WHAT ARE THE SELECTION CRITERIA FOR CHOOSING A REMEDIATION METHOD?

Dredging is highly disruptive to the Lake environment and may release more phosphorus than it removes. Consider the issue of transportation and disposal of dredged materials, classified as hazardous waste, over twenty acres at a depth of three feet.

Aeration has proven effective in reducing phosphorus in the water column in hard-bottom lakes, which can be aerated without disturbing and releasing the phosphorus in the bottom sediments. Lake Eugenia research has indicated that introducing aeration at 30 to 35 feet to de-stratify the lake will agitate the bottom and provide additional phosphorus for algae growth.

WHAT ARE THE SELECTION CRITERIA FOR CHOOSING A REMEDIATION METHOD?

Dredging is highly disruptive to the Lake environment and may release more phosphorus than it removes. Consider the issue of transportation and disposal of dredged materials, classified as hazardous waste, over twenty acres at a depth of three feet.

Aeration has proven effective in reducing phosphorus in the water column in hard-bottom lakes, which can be aerated without disturbing and releasing the phosphorus in the bottom sediments. Lake Eugenia research has indicated that introducing aeration at 30 to 35 feet to de-stratify the lake will agitate the bottom and provide additional phosphorus for algae growth.

The research on Lake Eugenia supports the use of a flocculant, specifically alum, to contain sedimentary phosphorus and remediate the lake. However, receiving approval for the use of alum in this manner presents governmental obstacles that will take a large amount of time and money, making it impractical.

As an alternative to the use of alum, direct oxygenation of the “dead zone” of the lake has been researched and found to be a viable solution. Direct oxygenation works similarly to a soda fountain dispenser, only on a larger scale. Water from the bottom of the lake is pumped through a device that injects oxygen into the water stream and distributes it through a network of permeable hoses on the bottom of the lake. Oxygen availability restores the iron/phosphorus bond, making the phosphorus unavailable to support blue-green algae growth. The oxygenated water also improves fish habitat. This option has been approved by the Ministry of the Environment, Conservation and Parks (MECP).

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