Climate change concerns raised for Lake Ontario

‘There is definitely worry that our current old infrastructure will not be able to protect our beaches and freshwater’

Climate change weighs heavily on the mind of environmental lawyer and Swim Drink Fish president Mark Mattson, who fears the current water infrastructure in cities such as Oakville and Burlington won’t keep up with the developing reality of the changing climate.

“There is definitely worry that our current old infrastructure will not be able to protect our beaches and freshwater,” Mattson told Inside Halton.

SDF gathers water samples in the province’s many recreational water bodies, including Lake Ontario. It then provides the data to the public via its app called Swim Guide. Mattson, and experts like him, have noticed an uptick in heavy rainstorms, which can contribute to increased water pollution close to the lake’s shore.

“Over the last five years on Lake Ontario, we have seen extreme weather. (Between) 2017 and 2019, we experienced extreme one-in-100-years levels of wet weather, while for most of 2020-21it was extremely dry,” Mattson added.

“Climate change makes everything harder to predict. That’s the kind textbook disruption climate change is going to play.”

As of publication on July 23, Halton Region says recent testing shows beaches in Oakville are unsafe for people to be in the water, including at Bronte Beach and Coronation Park. However, Rachel Gardner, spokesperson for Halton Region, told said inspections are carried out “weekly,” so that designation can change.

SDF’s Swim Guide states that at Bronte Beach, E.coli levels are historically above provincial limits almost twothirds of the time. Experts warn that this could get worse as climate change makes the rainy season last longer, and makes storms heavier and more frequent.

“The models for Canada project increasing precipitation in general,” professor of geography, environment and geomatics Ze’ev Gedalof said.

The rising temperature is also likely to decrease ice cover over the Great Lakes which, according to Gedalof, are a “water source to deliver that precipitation earlier in the year and later in the year. So we are going to have a longer season for intense rainfall.”

Ministry of the Environment, Conservation and Parks (MECP) spokesperson Lindsay Davidson confirms the ministry is seeing “more frequent and extreme events such as severe rain, ice storms, and prolonged droughts” due to climate change.

The City of Toronto has combined sewers, meaning both stormwater and wastewater share one piping system. During heavy rainfall, the system is overwhelmed, causing the E.coli from wastewater, called combined sewer overflows (CSOs), to be dumped into Lake Ontario.

The city is undergoing infrastructure projects in the hopes of eliminating “combined sewer outflows.”

Gardner added in her statement that the region “has separated sewers.” Both wastewater and stormwater have their own segregated systems. And yet, Halton Region’s own website says it is possible for rain to dirty the water at beaches like the one in Bronte Village.

Various kinds of surface runoff, like pet waste, farm waste and household waste, can make their way in.

The Town of Oakville did not provide info on why Bronte Beach is such a hot spot for E.coli. But town spokesperson Julia Le assured residents “the town has signage at Bronte Beach advising the public whether it is safe or unsafe to swim.”