Your stormwater pond questions: ANSWERED

The City of Vaughan operates and maintains more than 150 stormwater management ponds across the community. But you may be wondering how they work? What are their benefits? What does the City do to maintain them?

We’re answering all of your top stormwater pond questions!

How do stormwater ponds work?

Stormwater ponds have at least one inlet (a small opening) that allows water to flow from the storm sewer system into the pond. Once the stormwater drains into the stormwater pond, any of the sand, dirt and other sediments swept up in the stormwater settle to the bottom of the pond. The pond's outlet (a small pipe) releases water into a nearby creek system at a controlled rate. This process helps make the water cleaner when it leaves the pond and goes back into rivers, creeks and lakes. 

Of note, this water is not treated at a treatment plant before entering the water cycle again; therefore, everyone must do their part to keep it clean by ensuring only rain goes down the drain.

What are the benefits of stormwater ponds?

Stormwater ponds have many benefits, including:

• reducing flooding on streets and in greenspaces.
• protecting the natural environment from contaminants and erosion.
• protecting rivers, creeks and lakes by trapping pollutants such as oil, pesticides, bacteria and trash.
• creating a habitat for wildlife.

What does the City do to maintain stormwater ponds?

Stormwater ponds must be properly maintained to control the water flow. Year-round, routine maintenance includes removing debris in and around the pond that may impede water flow, managing only the invasive vegetation to ensure it does not inhibit the function of the pond, and maintaining structures such as inlets and outlets. Additionally, from May to October, three rounds of litter pickup and grass cutting are completed at each pond to ensure staff have unobstructed access for operational purposes.

Why is there long grass or vegetation in and around stormwater ponds?

Vegetation, such as plants, shrubs, trees and grass growing in and around stormwater ponds are integral to how the ponds function. This is because they:

• act as safety barriers for people walking in the area.
• discourage geese from landing in ponds. 
• improve water quality.
• filter out coarse sediments (like sand or gravel) and pollutants from the water.
• prevent flooding.
• stabilize the ground when water levels fluctuate.

Why is there algae in stormwater ponds?

Misconceptions often arise regarding the health of stormwater ponds due to algae growth. However, algae in these ponds, especially during summer, does not necessarily indicate poor health. It is a natural response to nutrients being carried into the water, such as runoff from nearby lawns and gardens where fertilizers are used. When it rains, these fertilizers wash into the stormwater ponds, leading to green and cloudy water. From there, some algae may form in the ponds.

Algae can benefit a stormwater pond’s ecosystem by converting sunlight and nutrients into energy, providing food for organisms. A certain level of algae is expected and even valuable for a pond's overall health.

Do stormwater ponds attract wildlife?

Stormwater ponds are designed to create a balanced ecosystem, which includes various kinds of wildlife and rodents, as they are a natural part of a pond's biodiversity. Wildlife and rodents play an important role in the ecosystem, helping control populations of other creatures and contributing to overall environmental health and stability. 

Can stormwater ponds create odour?

At times, stormwater ponds may have odours. These ponds are designed to collect and treat rainwater runoff, including organic matter such as leaves, grass clippings, dirt and other debris, depending on the time of year. As this matter decomposes, it releases natural gases, which can contribute to the pond's smell. This is a natural part of the pond's ecosystem.

Can I swim or fish in stormwater ponds?

While stormwater ponds may look safe for fishing, swimming or playing around, they are not! Please keep a safe distance away. The water entering the ponds is not treated, and the ponds are designed to temporarily hold water before releasing it slowly into the environment. This process means water constantly flows in and out of the pond, so water levels always change, making any activity in or around it unsafe. 

For even more information on stormwater ponds, visit vaughan.ca/stormwater. 

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