The City's director of roadway maintenance on the hard facts on the hard substance covering our streets and sidewalks.
By Ana Maria De La Fuente | March 1, 2012
In addition to melting ice and keeping you from being swept off your feet, it gets on the cuff of your pants, on your boots and, if you’re not careful, all over your house. A gritty mix of salt, limestone and sand gathers on the city’s streets and turns them into mucky messes – like a never-ending dirt floor – until they’re cleaned up for another year.
We asked Bob Dunford, the City’s director of roadway maintenance, for the hard facts on the hard substance covering our streets and sidewalks:
Edmonton road salt is blended with abrasives, including sand and black limestone chips from Rocky Mountain House.
Salt can cause environmental damage over time, such as weakening roadside vegetation and damaging underwater aquifers.
The City says it uses the bare minimum amount of salt needed, an average of 20,000 to 25,000 tonnes of salt per year. Dunford says a city comparable in population might use 250,000 tonnes a year.
The City uses pavement temperature as an indicator of how much salt to use because salt loses its effectiveness as the temperature drops.
The limestone chips have an angular shape, creating a “low-friction value,” so they don’t roll away when cars drive on the road.
At the end of spring, all the sand and gravel bits are swept up and put through a processing system. The sand gets stockpiled for at least a year to dry out and recycled when it’s mixed with salt and limestone all over again.