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Lake Simcoe Region Conservation Authority

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​Beyond Political Boundaries: Rethinking Stormwater – Study the First of its Kind in Canada 

Addressing the environmental an​d societal impacts of stormwater is one of the most challenging issues LSRCA deals with. Stormwater’s impact on the watershed is also not very well understood. Stormwater contributes a significant amount of pollution to the lake and is responsible for flooding and erosion issues, particularly in urban environments.

For the past several decades, municipalities have managed stormwater through the use of stormwater ponds. Initially the ponds were designed to address water quantity, but it became evident that they could also address water quality and measures were put in place to help control pollution from entering the lake.

Unfortunately, stormwater pond maintenance and management have been dramatically underfunded to the point where Ontario now has a 6.8 billion dollar deficit in stormwater infrastructure.

Because stormwater plays a major role in the Lake’s health, and factors into flooding issues, we’ve embarked on a ground-breaking study to evaluate the most cost-effective infrastructure solution to stormwater runoff amongst the municipalities within our watershed.

Two men wearing construction hats and vests looking at site plans.

The reality is that political boundaries don’t match hydrological boundaries. The study will look at municipalities in the East Holland subwatershed – Aurora, Newmarket, Whitchurch-Stouffville and East Gwillimbury. 

First we’ll characterize the existing conditions based on data such as stream flow, precipitation, soil types and existing infrastructure and then run scenarios to track how best to manage stormwater to achieve the most effective environmental outcomes in the most cost effective way.​

Mastering Stormwater Maintenance 

Stormwater is a significant source of pollution to Lake Simcoe, bringing with it a variety of pollutants and contaminants, including phosphorus, to the Lake.

Did you know that urban areas account for 12% of the watershed, yet 31% of phosphorus loads to Lake Simcoe? 

Stormwater ponds are one of the culprits. Our research has identified them as sources of phosphorus to the Lake. While they were designed to reduce the pollution entering Lake Simcoe, the problem is that they have not always been maintained to the standards they need to be in order to continue to remove contaminants.

The result? We have a large number of stormwater ponds that are not operating at peak performance, an issue not isolated to the Lake Simcoe watershed, but one that exists throughout the entire province. In our watershed, we have more than 350 stormwater ponds, and we estimate around 19 more are added each year.

While stormwater pond maintenance is the responsibility of municipalities, staff at LSRCA have stormwater management expertise that we are partnering with municipalities to share. As such, we started offering stormwater maintenance training this year. Our first pilot training day took place on May 30 in Bradford, where we had around 40 staff from all municipalities participate.

Included in the training we offer is a prioritization methodology tool – a tool that allows municipalities to rank their stormwater pond maintenance priorities with the overall goal of improving stormwater pond efficiency and reducing the amount of phosphorus entering our waterways.​