Although there is ongoing research into the use of alternative materials for winter maintenance, road salts continue to be the most cost-effective de-icers.
The City believes in using the right amount of salt or sanding product in the right place and at the right time.
- The use of sand or salt is dependent on road surface temperatures and weather conditions.
- When road surface temperatures are between 0 and -10 degrees Celsius, salt is used to melt accumulated snow and ice.
- For road surface temperatures below -5 degrees Celsius, a sanding chip mixture (3% salt, 97% fine gravel) is used.
All sanding trucks are equipped with automatic controls that spread a pre-determined amount of material depending on road conditions. Under certain conditions salt or calcium chloride brine may be applied to roads or bridges just before a snowfall is expected. This treatment prevents snow and ice from adhering to the road or bridge surface, reducing the amount of salt or sanding chips needed during the snowfall.
Frequently asked questions about the road salt management plan:
- What are road salts?
- Are road salts harmful?
- How is The City managing the environmental impact of road salts?
- How does The City's Salt Management Plan help the environment?
- How much road salt does The City of Calgary use?
1. What are road salts?
Road salts include sodium chloride (NaCl), calcium chloride (CaCl2), potassium chloride (KCl) and magnesium chloride (MgCl2). The City of Calgary only uses sodium chloride and calcium chloride. Roads salts used for snow and ice control may be solid or liquid brines.
2. Are road salts harmful?
Health Canada released a report in 2001 that indicates road salts are not harmful to humans. However, a 2001 assessment report by Environment Canada indicates that road salts are entering the environment in amounts large enough to pose a risk to plants, animals, birds, fish, lake and stream ecosystems and groundwater.
As a result of the scientific assessment, Environment Canada recommended adding road salts to Schedule 1 (Priority Substances List) of the Canadian Environment Protection Act (CEPA). This recommendation led Environment Canada to release the Code of Practice for the Environmental Management of Road Salts in 2004. For more information on Environment Canada's Code of Practice, visit Environment Canada and type "road salts" in the search box.
3. How is The City managing the environmental impact of road salts?
The City of Calgary has a Road Salt Management Plan in accordance with Environment Canada's Code of Practice. This Management Plan sets out the policies and procedures for ensuring that The City continuously improves the management of road salt in its snow and ice control operations. The overall goal of the plan is to improve environmental protection without compromising road safety. These efforts demonstrate The City's commitment to reducing the adverse effects of salt use, in keeping with Environment Canada's stated objectives.
4. How does The City's Salt Management Plan help the environment?
The City's Salt Management Plan outlines best practices for salt use and storage. For example:
- Controls – Sophisticated electronics are used on all of The City's sanding and salting equipment. The electronic controls are set to deliver precise amounts of sanding and salting product and are calibrated regularly.
- Storage – The City has implemented measures to prevent the release of stored road salts into the environment. The road salt storage depot at 194 Avenue and Macleod Trail South is an example of The City's leadership in this regard. Two large tent structures were built at the site to house road salt products used for snow and ice control on roads in the south. The tents fulfill the following functions:
- Prevent wind erosion of road salt products.
- Prevent stockpile run-off by keeping precipitation off stored products.
The tents are built on an impermeable surface consisting of compacted clay and asphalt, which prevent salt from seeping into the surface drainage water, groundwater and soil beneath the depot. In the unlikely event of salt run-off from the site, The City has also built an emergency containment pond adjacent to the depot.
5. How much road salt does The City of Calgary use?
The City applies approximately 30,000 to 40,000 tonnes of road salts annually in order to keep Calgary on the move in difficult winter driving conditions.
