Salty solutions: the ravages of road salt in urban lakes

The use of road salt for de-icing in Halifax Regional Municipality has harmed the health of area lakes, the city’s environmental monitoring team says as it presses for an updated salt management plan. 

Chris Kennedy, co-ordinator of Lake Watchers, says the addition of salt to urban lakes increases the amount of chloride in the water, which creates harmful effects on local wildlife and water quality. 

“Salt’s cheap, it’s easy to spread and it works really well,” Kennedy said in an interview with the Signal.

“It’s doing a job that we need done … just no one was really paying attention to what it might be doing to freshwater environments for decades.” 

In 2022, as a response to the salt levels, HRM created Lake Watchers, an organization that facilitates volunteer-run lake water testing. The program has been keeping track of the city’s lakes’ health.  

As salt from the street melts snow and ice, the solution ends up in the city’s stormwater drains, which leads directly into lakes throughout the municipality. 

“Everything that goes into our storm drains ends up in our lakes,” said Kennedy. 

Lakes including Russell Lake, Chocolate Lake and Lovett Lake all have chloride levels exceeding the 150 milligrams of chloride per litre that the Canadian Council of Ministers of the Environment says is safe for freshwater species. 

As HRM expands its urban sprawl, more lakes, such as Sandy Lake in Bedford, which will soon see new urban development, will be put at risk of higher chloride levels. 

Sam Austin, HRM’s councillor for district five, Dartmouth Centre, sits on the city’s environment and sustainability committee. His district includes Lake Banook, another lake that exceeds healthy chloride levels. 

The lake is completely surrounded by development, meaning it gets a heavy dose of salt every time there is a weather event requiring de-icing. 

“We have spots where it’s literally — if you look at the storm drain on the street and walk directly over to the lakeshore, you can see the pipe. It’s direct from street to lake,” said Austin in a phone interview with the Signal. 

Solutions to the problem have varied, with HRM experimenting with reduced salt loads as well as brining, spreading a solution that uses less concentrated amounts of salt on roads. Other municipalities have experimented with beet juice, cheese brine and even garlic powder. 

Kennedy thinks a complete ban on road salt is unlikely. He said the most likely solution will come from a better approach to managing the city’s salt use. 

“I don’t know that we’re ever going to get away from it,” said Kennedy. “We’ve got a salt mine in Pugwash. It employs local people from Nova Scotia, it works really well and it’s reasonably cheap.” 

HRM’s salt management plan outlines its approach to road salt use. The plan emphasizes the effectiveness of pre-wetting surfaces with a brine before a snowfall event. 

“It is about spreading it in a smarter way, spreading it when it needs to be spread,” said Kennedy. “Then once it is spread, how can we divert it and prevent it from getting into lakes.”