~Peter Burjorjee for Oakvillegreen
It’s winter in Oakville and you’ve probably encountered the flashing blue lights of a salt truck or spread some salt on the shady parts of the steps or sidewalk yourself. No doubt, ice is not nice, but have you ever stopped to consider the true cost of all that salt?
Depending on the severity of the season, it is estimated that Canada uses between 4 and 8 million tonnes of road salt. The 5 year average use (and again it varies widely) for Oakville is approximately 18,000 metric tonnes which, to put in perspective, would be nearly 100 kg for each and every resident per year (that’s without accounting for salt use on MTO highways or on industrial or commercial properties!).
Whether it’s caught by soils and wetlands or heads straight for the storm sewer, ultimately all that NaCl and MgCl2 (the green stuff) is heading for local creeks, rivers and the lake. High salinity levels can be lethal to a variety of vertebrates and invertebrates such as fish, amphibians and mussels and importantly their eggs and larvae are particularly vulnerable. Aquatic plants may be at risk and increasing salt levels may also allow invasive species to thrive.
Oakville, as part of a wider Halton effort, has a Salt Management Plan which is being expanded to cover municipal property beyond roads, and will be updated this spring. The SMP (salt management plan) “strives to minimize the amount of salt entering the environment by including best salt management practices, and using new technologies to ensure its most effective use over the road system”. Oakville also has the ability to use a Direct Liquid Application (DLA system) whereby brine can be sprayed on the road before any snow has fallen preventing ice formation and reducing salt use in some situations. There are potentially safer alternatives under development or in use, including beet juice, various brines and calcium chloride. At $67/tonne common road salt is still the cheapest and most widely used amounting to a cost of $1.2 M or MORE THAN 20% of the Town’s winter budget for roads and sidewalks. The true cost with damages to cars, infrastructure such as bridges and the environment is clearly much, much higher.
In Waterloo region, Smart About Salt Council (SASC), a non-profit advocacy group is taking action to protect area watersheds by educating people working in the snow and ice control business to reduce and better manage the use of salt. They offer both education and certification for contractors and sites that can show that they comply with the Smart About Salt Council standards.
The STEP Water (Sustainable Technology Evaluation Program) is a joint effort of Credit Valley Conservation, Lake Simcoe Region Conservation, and Toronto and Region Conservation Authority that aims to advocate for better care of the environment through innovative research and testing of new methods and technologies. As part of their efforts to protect watersheds and surrounding land they have developed techniques for better use and mitigation of salt through their SAVE (Salt Application Verified Equipment) and SICLOPS (Snow and Ice Control for Parking Lots and Sidewalks) programs in particular.
Testing shows a baseline increase in chloride levels in Toronto area streams as well as short term peak levels after snowfall, melt and flushing events that are already harmful to our fragile ecosystems. Chloride levels in various Halton creeks and rivers are shown in Figure 1 and are nearly all above the guideline of 125 mg/L. (Source: CH Long Term Water Monitoring 2016)
Figure 2 shows the chloride levels over a week February 2018 in Sheridan Creek reaching 18000 mg/L after a flushing event – almost as saline as typical seawater! (Source: CVC Real-time Monitoring)
If we want our creeks and rivers to continue to support wildlife, such as the endangered redside dace (Clinostomus elongatus), we would do well to start passing on the salt. Initial steps could require the adoption of an SMP and certification to a standard such as SASC for all facilities and contractors. As citizens we can make sure our elected officials are aware of the issues, work towards the use of less toxic alternatives and think carefully about salting our steps, driveways and walkways!
Stay tuned for opportunities to have your say on salt use in the Town of Oakville as part of the update to the Salt Management Plan.
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