City to spend more than $100,000 on new winter weapon
It’s invisible, it’s unpredictable and it’s putting lives in danger. It’s a winter threat everybody knows about, but nobody sees coming: black ice.
More dangerous than snow, slush and sleet, ice is an unavoidable reality of our indecisive climate. When the roads are wet and the temperature drops, Halifax drivers play a treacherous guessing game. Is that black pavement shining with rain or ice?
Many of the 403,000 people living in HRM will be unlucky. There have already been more than 60 car crashes this winter because of ice.
Now, HRM is experimenting with a new de-icing strategy that could keep more drivers on the road and out of the ditch. It’s as simple as brine.
HRM winter crews used the salty spray for the first time last week in Burnside. They sprayed one side of Commodore Drive with brine and used traditional rock salt on the other. Both methods were equally effective.
“It’s cheaper,” says Gordon Hayward, HRM’s winter work superintendant. “(The) industry says it requires three to five times less times salt than conventional
The new method is called direct liquid application, or DLA for short. It can be sprayed up to 12 hours before a storm and works by lowering the freezing point of water. This keeps roads ice-free. It can only be used on clear streets. Once snow starts falling, rock salt needs to be used.
The brine solution is brewed in small quantities in Halifax and at the Public Works depot in Burnside. “Have you ever sat down after work to make a rum and Coke? That’s more complex then making brine,” said Hayward.
Take a couple of tonnes of salt in a holding tank and fill it up with water. Test it to make sure it has a salinity of 23 per cent. (By comparison, the ocean has an average salinity of 3.5 per cent.)
For now, only one HRM snowtruck out of 40 is equipped to spray the brine, and there is no infrastructure in place to store the product. “Right now we can produce more than we can hold, which is a restricting factor to how much we can expand the brine
application,” said Hayward.
According to him, the city will spend $150,000 in the next year to construct a new facility that will make and store the brine. An extra $300,000 would be needed to fully expand the anti-ice program so that it covers the whole city. Eventually, Hayward said, HRM will look at buying a new snowtruck equipped to spray the brine, with a price tag of $255,000.
Before this happens, the city will run more tests.
“All of this stuff looks good on paper, but you really have to try it before you drop a big bag of money on it,” said Hayward.
In HRM, approximately 38,000 kilometers of road need to be kept ice-free. Hayward said it takes 361 tonnes of rock salt to cover every road. That’s roughly equivalent to nine 18-wheeler trucks made of salt. To cover all streets with brine would only take 76 tonnes of salt.
Hayward said brine will be most useful in the shoulder seasons, the spring and fall, when the temperature is hovering above and dipping below the freezing line – prime black ice conditions. Brine stops working in temperatures below –10 C.
The liquid salt solution acts faster than rock salt, and if adopted on a large scale would reduce salt runoff into waterways. Runoff is harmful to the environment. Brine sticks to the road better than rock salt, which bounces and rolls into ditches.
Ron Russell, a biology professor at Saint Mary’s University, says while brine may be a step in the right direction, it’s still toxic to plants and animals. “Salt is salt. Whether you are putting it on the roads in solid or brine form doesn’t change the fact that it’s bad for the environment,” says Russell.
He has been researching how road salt affects Nova Scotian ecosystems for more than 10 years. Specifically, he has been studying how salt runoff is affecting amphibians.
“In roadside ponds, salt concentrations are incredibly high,” he said. “Many sensitive species have simply disappeared.”
When salt runs off highways into ditches it destroys the habitat, making the area unlivable for species like frogs and salamanders. To cope, species are forced to retreat further into the woods.
Russell said a larger issue is the salinization of ground and surface water.
“Why is that a problem? That’s our drinking water,” he said.
Russell said there are alternatives to salt, but they’re just too expensive. He said government needs to find a balance between keeping drivers safe and protecting the environment.
Gordon Hayward of HRM said the city will continue testing brine on a small scale in different conditions, and on different roads for the rest of the winter.
“DLA is here to stay,” he said.