Let’s Talk Salt and How We Can Improve Parking Lot Management

Photo Credit: Lake Simcoe Region Conservation Authority

The management of parking lots in winter has become an increasingly fraught exercise, with several issues effecting the decisions of parking lot managers and the contractors. Most of these decisions relate to public safety, liability, and the cost of insurance, but the environmental impacts of the salt we use on parking lots is becoming increasingly clear and should be a part of these decisions.

In 2004, Environment Canada released its Code of Practice for the Environmental Management of Road Salts and since then many provincial and municipal roads managers made strides in refining their practices and reducing salt use. However, we need to try to reduce the amount of salt being used in all sectors, and parking lots are still an area of concern. The decisions of parking lot managers and snow and ice management contractors play a critical role in reducing salt, but if we properly plan and design these parking lots it makes the jobs much easier for everyone, while keeping the parking lot users safe.

First let’s talk more about why road salt is an issue… since we started using salt for de-icing in the 1940s, it has been considered a safe substance that dissolves and ‘disappears’ when the snow melts, we now know this isn’t the case. Once salt dissolves it finds its way into area streams, rivers, wetlands, and other waterbodies, and even our groundwater, it is almost impossible to remove. Monitoring conducted through the Provincial Water Quality Monitoring Network have shown increasing levels of chloride (a main component of salt) across Ontario, even in rural areas, though the most striking increases are being seen in urban areas (Figure 1) Some urban streams regularly see levels as high as seawater.
    Impacts to aquatic systems

These high chloride levels are harmful to native aquatic communities. They cause changes in the functions of the ecosystems and communities shift to species that can tolerate harsh conditions. You might recall the 2012 case of an urban stream in the Toronto area that was able to support several blue crabs, a species that normally lives in briny waters – this is an extreme case, where the crabs were introduced to the stream, but highlights how these systems could change if we don’t curb our salt use.

High costs for property and infrastructure damage

Salt can also damage built infrastructure. Infrastructure damage can include:

• Deterioration of bridges and other road infrastructure.
• Potholes and cracking of concrete.
• Damage to masonry.
• Corrosion of railings, cart corrals, and doorways.
• Damage to flooring.
• Loss of landscaping materials.

The annual cost to repair and replace this damage can be high for property owners. The more salt that’s applied, the greater the damage, so there is incentive to apply less.

A role for planners

Planners can plan a role in combating this issue by requiring specific parking lot design features, through the site plan approval processes that will make them easier to maintain with less salt to achieve safe conditions. The Lake Simcoe Region Conservation Authority commissioned the development of the Parking Lot Design Guidelines to Reduce Salt Use in 2018 to highlight the features that can be used to achieve this goal. The features relate to effective grading and stormwater collection, snow pile storage location, sidewalk design and pedestrian flow, and the use of landscaping features. Please join us as we discuss these guidelines in part two of this blog series on salt. You can find the guidelines, and additional information on salt, on our website.