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From Natural Phenomenon to Potential Concerns: Decoding Algae Bloom in Kelowna’s Ponds

Algae growth is a common occurrence in natural ponds, particularly in shallow bodies of water with limited circulation. Prolific algae growth can cause a dense mass of it to form, which is called a bloom. Concerns have been raised regarding algae bloom in Wilden ponds, especially Hidden Lake due to more apparent algae growth this year (2023).

This blog post aims to educate residents and visitors about algae bloom, its contributing factors, and the distinction between harmless and harmful (cyanobacteria) forms of algae. While algae growth is a normal part of aquatic ecosystems, some species may produce toxins or compounds that can be harmful to humans and animals. It’s not possible to identify and confirm harmful algae growth by sight, lab tests are necessary.

Algae Bloom in Natural Ponds:

In natural ponds like those found in Wilden, algae bloom is a normal phenomenon. Shallow waters with limited circulation like Walroy/Hidden Lake and Still Pond provide favourable conditions for algae growth. In the past, these ponds would dry out during hot summer months. Bio-filtration systems were implemented during Wilden’s development in that area as well as for Blair Pond in the Clear Pond neighbourhood to maintain water levels and prevent them from drying out and turning into mud puddles in the hot summer months. Ever since the water levels have been stabilized, wildlife has been able to thrive here.

In Wilden’s Phase 1 Rezoning Application from November 2001 the existing land use back then was described as the following: “With the exception of an agricultural parcel located adjacent to Walroy Lake, the Phase One area is currently used only for recreation. A number of unmarked walking, biking and four-wheel drive trails exist in the Phase One area. These unofficial trails have caused significant erosion and disturbance resulting in wetland disturbance and destruction.”

Photo scans from a report by an environmental consultant in 2002.

Contributing Factors to Algae Growth:

Several factors contribute to algae growth in ponds. Nutrient availability, warm temperatures, stagnant or slow-flowing water, sunlight exposure, pH imbalance, and excessive organic matter can all promote algae growth. The Okanagan Basin Water Board provides valuable information on blue-green algae, its causes, and impacts, which can be accessed here.

Algae growth in ponds can vary depending on weather conditions. The dry, hot weather in Kelowna, such as in the late spring and during summer months, may contribute to increased algae growth.

Distinguishing Harmless and Harmful Algae:

It is important to differentiate between harmless and harmful forms of algae. Harmless algae play a vital role in aquatic ecosystems, while some blooms may produce toxins or compounds harmful to humans and animals. For visual guidance on distinguishing between the two, refer to the informative resource provided here and here.

Please keep in mind that only certain algae species produce toxins, but it’s not possible to identify them by sight. Lab tests are necessary!

Reporting Algae Bloom Observations:

Public bodies of water, such as Still Pond and Walroy/Hidden Lake, are classified as crown land. As a result, they are under the jurisdiction of the City of Kelowna and managed by the province of British Columbia. If you have any concerns regarding algae blooms, it is crucial to report them appropriately. You can share your observations of algae blooms through the Province of BC’s online reporting system or contact the Water Smart department at the City of Kelowna.

Warning signs regarding harmful blue-green algae blooms have been posted at the entrances of Hidden Lake and Still Pond Park by the City of Kelowna as a precautionary measure. It’s important to note that the verification of harmful algae blooms requires laboratory testing, and conditions can change rapidly.

The City of Kelowna has informed us that they are conducting regular water sampling and testing. Additionally, they are collaborating with researchers from UBC Okanagan to gain further insights into the occurrence of algae blooms in ponds. We will share results and provide more information as it becomes available.

Contribution of fertilizers to algae growth is usually minimal in non-agricultural areas like Wilden, as long as fertilizers don’t make it into the storm water drainage. A spokesperson at the City of Kelowna’s Water Smart department shared that residents can play a role by ensuring that on-site water run-off is retained on property as much as possible and be mindful that anything washed onto the street can ultimately end up in the ponds.

According to the Kelowna Water Smart department, while regular and ongoing aeration measures may offer some solution, it is important to note that it is not a cure-all, as they have seen with other ponds. It comes down to a complex inter-relationship between water chemistry, vegetation, temperature, flow volumes, depth, and more that impact algae growth. It is crucial to consider that implementing aeration measures in the ponds involves intervening with the natural ecosystem.

Ponds outside of Wilden, such as Lightblue Lake in nearby Steven Coyote Ridge, as well as several small ponds in Wilden’s private backcountry serve as a comparison and example of natural and untouched waters, which also show abundant algae growth and bloom.

Algae growth or bloom in Wilden’s ponds is a yearly occurrence. While some blooms may be harmless, it is crucial to remain cautious as conditions can change suddenly. We kindly remind everyone that these ponds serve as natural habitats for Wilden’s wildlife, including turtles and waterfowl. They are not intended for recreational use. It is vital to refrain from drinking the water or swimming in the ponds, and this caution also applies to your pets.

Maintaining a balanced aquatic ecosystem in Wilden is among our highest goals and we spare no effort or investment when it comes to the health of our wildlife habitats. Our residents can support us by keeping up the open conversation and voicing their concerns to the appropriate authorities.

We hope you found this article helpful and insightful.