Changes

[[File:Salt by catchbasin.PNG|thumb|550px|Excess salt located by a curb and next to a stormwater catch basin in a parking lot. Salt entering a catch basin is one of the many ways rock salt and elevated levels of chloride can enter the local freshwater system. Rock salt has major impacts on infrastructure, as it increases the rate of erosion/decay of supporting materials (rebar in concrete, etc.) and can lead to structural failure if overused (Wallace, et al. 2022).<ref>Wallace, A., Hitch, C., Ruppert, J., Chomicki, K., Cartwright, L., and VanSeters, T. 2022. Freshwater Salinization. Water Canada. January/February 2022. WC122. Digital. https://cdn.watercanada.net/wp-content/uploads/2022/01/17161341/WC122_JanFeb2022_DIGITAL.pdf</ref> Photo Source: LSRCA, 2018. <ref>LSRCA. 2018. Parking Lot Design Guidelines: Municipal Policy Templates to Promote Salt Reduction in Parking Lots. https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking%20Lot%20Design%20Guidelines.pdf.</ref>]]

[[File:(LSRCA Logo) Atherley Narrows annual chloride concentrations (1971 - 2020).png|thumb|650px|A graph showing increasing average levels of chloride found in Atherley Narrows, (a rural sampling location, between Lake Couchiching and Lake Simcoe), over the past few decades, due in part to increased use of rock salt in parking lots, roadways and commercial and residential properties. From 2005 - 2020 the amount of chloride increase per year has doubled when compared to 1971 - 1986 (1.26 mg/L per yr. vs. 0.63 mg/L per yr.) (LSRCA, 2021). It is estimated that by 2120 the average level of chloride within the the Lake Simcoe watershed will exceed the 120mg/L guideline set by CWQG. (LSRCA, 2018)<ref name="example7">LSRCA. 2018. Parking Lot Design Guidelines: Municipal Policy Templates to Promote Salt Reduction in Parking Lots. https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking%20Lot%20Design%20Guidelines.pdf.</ref>]]

 

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==Overview==

==Overview==

Between 5 and 7 million tonnes of salt is applied every year in Canada for winter maintenance of roads and other paved surfaces, making it one of the most ubiquitous contaminants in urban environments. NaCl- is the most common de-icer applied for winter maintenance, comprised of 40% sodium and 60% chloride. Sodium chloride rock salt is often treated with liquid MgCl2 and CaCl2 to reduce the effective temperature range of salts. Liquid brines comprised of NaCl-, MgCl2 and CaCl2 or a combination of these products are increasingly being used on roads for anti-icing.

Between 5 and 7 million tonnes of salt is applied every year in Canada for winter maintenance of roads and other paved surfaces, making it one of the most ubiquitous contaminants in urban environments. Canadians spend over $1 billion in winter maintenance costs to clear snow/ice on public and private roads, parking lots and sidewalks, this includes the use and application of greater than 5 million tonnes of rock salt for both deicing and anti-icing operations (Hossain et al., 2015)<ref>Hossain, S.K., Fu, L. and Lake, R., 2015. Field evaluation of the performance of alternative deicers for winter maintenance of transportation facilities. Canadian Journal of Civil Engineering, 42(7), pp.437-448. https://cdnsciencepub.com/doi/abs/10.1139/cjce-2014-0423</ref>. While the use of salt is essential to ensure public safety, there is a growing concern regarding the large quantities of salt (mainly chloride ions), being released to the environment.  

[[File:(LSRCA Logo) Atherley Narrows annual chloride concentrations (1971 - 2020).png|thumb|700px|A graph showing increasing average levels of chloride found in Atherley Narrows, (located between Lake Couchiching and Lake Simcoe), over the past few decades, due in part to increased use of rock salt in parking lots, roadways and commercial and residential properties. From 2005 - 2020 the amount of chloride increase per year has doubled when compared to 1971 - 1986 (1.26 mg/L per yr. vs. 0.63 mg/L per yr.) (LSRCA, 2021). It is estimated that by 2120 the average level of chloride within the the Lake Simcoe watershed will exceed the 120mg/L guideline set by CWQG. (LSRCA, 2018)<ref>LSRCA. 2018. Parking Lot Design Guidelines: Municipal Policy Templates to Promote Salt Reduction in Parking Lots. https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking%20Lot%20Design%20Guidelines.pdf.</ref>]]

NaCl^- is the most common de-icer applied for winter maintenance, comprised of 40% sodium and 60% chloride.  Sodium chloride rock salt is often treated with liquid MgCl₂ and CaCl₂ to reduce the effective temperature range of salts. Liquid brines comprised of NaCl^- , MgCl₂ and CaCl₂ or a combination of these products are increasingly being used on roads for anti-icing to help reduce the amount of rock salt used and lower overall operations costs.

==Impacts on the Environment, Human Health and Built Infrastructure==

==Impacts on the Environment, Human Health and Built Infrastructure==

===Freshwater wildlife===  

===Freshwater wildlife===  

Just as we depend on air with the right makeup of oxygen, freshwater species – like fish, frogs, mussels, salamanders and zooplankton – need water with the right balance of chloride to survive. Having adapted to low levels of chloride in their habitats, increased levels begin to disrupt their basic functions – such as regulating their water content (osmoregulation) and breathing.  Studies have shown widespread effects of salt on ecosystems at all trophic levels from biofilms to fish species.  Specific effects vary based on exposure concentrations, and may include reductions in fecundity, size, shape, growth and abundance (Hintz and Relyea, 2019)<ref name="example1">Hintz, W.D. and Relyea, R.A. 2019. A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters. Freshwater biology, 64(6), pp.1081-1097. https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters</ref>

Just as we depend on air with the right makeup of oxygen, freshwater species – like fish, frogs, mussels, salamanders and zooplankton – need water with the right balance of chloride to survive. Having adapted to low levels of chloride in their habitats, increased levels begin to disrupt their basic functions – such as regulating their water content (osmoregulation) and breathing.  Studies have shown widespread effects of salt on ecosystems at all trophic levels from biofilms to fish species.  Specific effects vary based on exposure concentrations, and may include reductions in fecundity, size, shape, growth and abundance (Hintz and Relyea, 2019)<ref name="example1">Hintz, W.D. and Relyea, R.A. 2019. A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters. Freshwater biology, 64(6), pp.1081-1097. https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters</ref>

 

===Vegetation===

===Vegetation===

Salt affects vegetation in various ways.  Salt in soil water generally makes it more difficult for roots to take up water. This phenomenon mimics drought conditions for the plant and underlies the recommendation for salt tolerant plants in LID practices. If passing traffic sprays salty water onto [[plants]] it can reduce cold hardiness in buds and new twigs. These then become more susceptible to freezing, mortality or deformation. In high enough concentrations, sodium and chloride can also be directly toxic to plants. In some species the ions are absorbed by the plant and build up in the leaves causing them to die.

Salt affects vegetation in various ways.  Salt in soil water generally makes it more difficult for roots to take up water. This phenomenon mimics drought conditions for the plant and underlies the recommendation for salt tolerant plants in LID practices. If passing traffic sprays salty water onto [[plants]] it can reduce cold hardiness in buds and new twigs. These then become more susceptible to freezing, mortality or deformation. In high enough concentrations, sodium and chloride can also be directly toxic to plants. In some species the ions are absorbed by the plant and build up in the leaves causing them to die.

==Guidelines==

==Guidelines==

===Code of Practice===

===Code of Practice===

A comprehensive scientific assessment by Environment Canada and Health Canada determined that in sufficient concentrations, road salts containing inorganic chloride salts pose a risk to plants, animals and the aquatic environment (Environment Canada and Health Canada, 2001)<ref> Environment Canada and Health Canada. 2001. PRIORITY SUBSTANCES LIST ASSESSMENT REPORT. Road Salts. Canadian Environmental Protection Act, 1999. Environment Canada and Health Canada. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/contaminants/psl2-lsp2/road_salt_sels_voirie/road_salt_sels_voirie-eng.pdf</ref> and are toxic substances as defined by the Canadian Environmental Protection Act, 1999 (CEPA 1999). <ref>Canadian Environmental Protection Act, 1999. Environment Canada and Health Canada, Ottawa, Ontario. https://laws-lois.justice.gc.ca/eng/acts/c-15.31/FullText.html</ref>). April 2004. EPS 1/CC/5. https://publications.gc.ca/collections/collection_2012/ec/En49-31-1-5-eng.pdf</ref>. 

A comprehensive scientific assessment by Environment Canada and Health Canada determined that in sufficient concentrations, road salts containing inorganic chloride salts pose a risk to plants, animals and the aquatic environment (Environment Canada and Health Canada, 2001)<ref>Environment Canada and Health Canada. 2001. PRIORITY SUBSTANCES LIST ASSESSMENT REPORT. Road Salts. Canadian Environmental Protection Act, 1999. Environment Canada and Health Canada. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/contaminants/psl2-lsp2/road_salt_sels_voirie/road_salt_sels_voirie-eng.pdf</ref> and are toxic substances as defined by the Canadian Environmental Protection Act, 1999 (CEPA 1999).<ref>Canadian Environmental Protection Act. 1999. Environment Canada and Health Canada, Ottawa, Ontario. https://laws-lois.justice.gc.ca/eng/acts/c-15.31/FullText.html</ref>).  

Following the designation of chloride as a toxic substance, the Government of Canada established a Code of Practice for the Environmental Management of Road Salts under CEPA to help municipalities and other road authorities to better manage road salt use and reduce the adverse impacts of chloride, which maintaining road safety (Environment Canada, 2004)<ref> Environment Canada. 2004. Code of practice for the Environmental Management of Road Salts. Canadian Environmental Protection Act, 1999 (CEPA 1999). April 2004. EPS 1/CC/5. https://publications.gc.ca/collections/collection_2012/ec/En49-31-1-5-eng.pdf</ref>.

Following the designation of chloride as a toxic substance, the Government of Canada established a Code of Practice for the Environmental Management of Road Salts under CEPA to help municipalities and other road authorities to better manage road salt use and reduce the adverse impacts of chloride, which maintaining road safety (Environment Canada, 2004)<ref>Environment Canada. 2004. Code of Practice for the Environmental Management of Road Salts. Canadian Environmental Protection Act, 1999 (CEPA 1999). April 2004. EPS 1/CC/5. https://publications.gc.ca/collections/collection_2012/ec/En49-31-1-5-eng.pdf</ref>.

The Code recommended, on a voluntary basis, that road authorities and municipalities applying more than 500 tonnes of road salt per develop salt management plans and implement best management practices for salt application, salt storage and snow disposal as described in the Transportation Association of Canada’s (TAC) Synthesis of Salt Management Best Practices (TAC, 2015)<ref>Transportation Association Canada (TAC). 2013. Syntheses of Best Practices

The Code recommended, on a voluntary basis, that road authorities and municipalities applying more than 500 tonnes of road salt per develop salt management plans and implement best management practices for salt application, salt storage and snow disposal as described in the Transportation Association of Canada’s (TAC) Synthesis of Salt Management Best Practices (TAC, 2013)<ref>Transportation Association Canada (TAC). 2013. Syntheses of Best Practices

Road Salt Management - Salt Management Plans. April 2013. https://sustainabletechnologies.ca/app/uploads/2022/02/roadsalt-tac-full-doc.pdf</ref>. The Code does not address the use of road salt on parking lots and private property or its use as a dust suppressant but a Best Practice document specifically for these areas was developed by TAC in 2013.

Road Salt Management - Salt Management Plans. April 2013. https://sustainabletechnologies.ca/app/uploads/2022/02/roadsalt-tac-full-doc.pdf</ref>. The Code does not address the use of road salt on parking lots and private property or its use as a dust suppressant but a Best Practice document specifically for these areas was developed by TAC in 2013.

===Canadian Water Quality Guidelines for the Protection of Aquatic Life===

===Canadian Water Quality Guidelines for the Protection of Aquatic Life===

The Canadian Council of Ministers of the Environment (CCME) developed chloride toxicity thresholds for protection of aquatic in 2011 (Check this date) based on a comprehensive scientific review (provide link), as follows:

The [https://sustainabletechnologies.ca/app/uploads/2014/05/CWQG_chlorides.pdf Canadian Water Quality Guidelines for the Protection of Aquatic Life]<ref>Canadian Council of Ministers of the Environment. 2011. Canadian water quality guidelines for the protection of aquatic life: Chloride. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg. https://sustainabletechnologies.ca/app/uploads/2014/05/CWQG_chlorides.pdf</ref> document from the Canadian Council of Ministers of the Environment (CCME) is another valuable paper that discusses the direct toxic effects of chloride, based on studies using NaCl and CaCl² salts. The guideline can be used as a screening and management tool to ensure that chloride does not lead to the degradation of the aquatic environment. Further guidance on the application of these guidelines is provided in the scientific criteria document (CCME 2011), which can be found here - [https://www.ccme.ca/fr/res/2011-chloride-ceqg-scd-1460-en.pdf Scientific Criteria Document - Cl Ion]. Both documents developed chloride toxicity thresholds for protection of aquatic in 2011 based on a comprehensive scientific review.

*'''''Chronic toxicity''''' (long duration exposure): 120 mg/L

 

*'''''Acute toxicity''''' (short duration exposure): 640 mg/L

*'''Chronic toxicity''' (long duration exposure): 120 mg/L

*'''Acute toxicity''' (short duration exposure): 640 mg/L

 

===Canadian Drinking Water Guidelines===

===Canadian Drinking Water Guidelines===

The Canadian Drinking Water Guidelines (CDMG) are published by Health Canada. Health Canada updates its summary table for known irritants/pollutants and publishes it online every spring on their website here:(HC's Drinkign Water Quality Table) https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/water-quality/guidelines-canadian-drinking-water-quality-summary-table.html) (Health Canada, 2020)<ref>Health Canada. 2020. Guidelines for Canadian Drinking Water Quality Summary Table. In collaboration with the Federal-Provincial-Territorial Committee on Drinking Water of the Federal-Provincial-Territorial Committee on Health and the Environment. September 2020. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/pdf/pubs/water-eau/sum_guide-res_recom/summary-table-EN-2020-02-11.pdf</ref>. Below are the drinking water guidelines for both Chloride and Sodium found within rock salt:

The Canadian Drinking Water Guidelines (CDMG) are published by Health Canada. Health Canada updates its summary table for known irritants/pollutants and publishes it online every spring on their website here: [https://www.canada.ca/en/health-canada/services/environmental-workplace-health/reports-publications/water-quality/guidelines-canadian-drinking-water-quality-summary-table.html (Health Canada's, Drinking Water Quality Table)] (Health Canada, 2020)<ref>Health Canada. 2020. Guidelines for Canadian Drinking Water Quality Summary Table. In collaboration with the Federal-Provincial-Territorial Committee on Drinking Water of the Federal-Provincial-Territorial Committee on Health and the Environment. September 2020. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/pdf/pubs/water-eau/sum_guide-res_recom/summary-table-EN-2020-02-11.pdf</ref>. Below are the drinking water guidelines for both Chloride and Sodium found within rock salt:

*An aesthetic objective for Chloride of 250 mg/L was developed for drinking water supplies based on taste and potential for corrosion in the distribution system.  

*An aesthetic objective for Chloride of 250 mg/L was developed for drinking water supplies based on taste and potential for corrosion in the distribution system.  

*Sodium also has an aesthetic objective of 200 mg/L based on taste, as well as a guideline of 20 mg/L for people on sodium restricted diets

*Sodium also has an aesthetic objective of 200 mg/L based on taste, as well as a guideline of 20 mg/L for people on sodium restricted diets

Salt contamination in freshwater (freshwater salinization) is a major concern to Ontarians wellbeing as it can lead to:

In previous years, chloride concentrations greater than sea level concentrations ('''19,000 mg/L''') have been observed in tributaries of the Credit River.

*Unpleasant taste in drinking water

[https://sustainabletechnologies.ca/app/uploads/2020/03/Alternatives-to-salt-technical-brief.pdf STEP's Technical Brief: Alternatives to Salt: What else melts snow and ice?]<ref>STEP. 2020. Alternatives to Salt: What else melts snow and ice? Technical Brief. https://sustainabletechnologies.ca/app/uploads/2020/03/Alternatives-to-salt-technical-brief.pdf</ref> from 2020, highlights how municipalities across Canada using salt as their primary de-icing agent in winter, poses significant impacts to their regions. This includes, corrosion of infrastructure and other metal structures such as railings and doorways, damage to vehicles, contamination of surface and groundwater, impacts to roadside vegetation, increased wildlife collision rates and large amounts of product waste due to blowing or bouncing off roadways). You can read more about the benefits, drawbacks, cost estimates and lowest working temperature for a given deicing agent at the link above.

[[File:Bypass bioretention.png|thumb|250px|Example of a bypass in use to limit runoff from entering into a [[bioretention]] cell BMP. (Photo Source: TRCA, 2021)]]

[[File:LID Salt reduction.png|thumb|700px|The above graph shows research conducted by the STEP group comparing chloride level discharges between asphalt, and two commonly used LID practices ([[Permeable pavement]] and [[Bioretention]]). The results show that asphalt releases salt in concentrated bursts during winter whereas the LIDs release it more gradually over the entire year.]]

Furthermore, salt can contribute to both biodiversity and habitat loss for numerous species. In Ontario, road salt was identified as one of the threats to drinking water under the Clean Water Act, 2006 - as well as a known toxin to wildlife species<ref>Government of Ontario. 2006. Clean Water Act, 2006, S.O. 2006, c. 22. https://www.ontario.ca/laws/statute/06c22.</ref>. Salt can impacts bird species, many plants and trees growth ability, and decrease size, function and fecundify in fish, mollusks (snail, mussels, etc.), amphibians and benthic invertebrate species.

Since salt has deleterious effects on many plant species, there is often concern that [[plants]] in LID receiving salt laden road runoff will not fare well over time.  Several design features are meant to address these risks, including:

*Selection of plants tolerant to elevated soil concentrations of salt ([[Plant lists#Plant Characteristics|Salt tolerance in plants]])

*Inclusion of [[pretreatment|sumps or forebays]] without plants that reduce loads through infiltration

*Perforated distribution pipes that are offset from root balls to reduce exposure during early tree establishment ([[Stormwater Tree Trenches]])

A recent literature review by [https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters Hintz and Relyea (2019)])<ref name="example1" />.

In drinking water protection areas, bypasses may be used to limit exposure to road salts during winter months where aquifers are vulnerable and ensures that any heavily-laden stormwater will "bypass" the practice and flow to the downstream street inlet to the Municipality's storm sewer system.

discusses the impacts of road salt on local ecosystems and found that road salts negatively affect species at all trophic levels, from biofilms to fish species, but the concentration of road salt where adverse effects were observed varied and the effects themselves ranged from:

*Altered hydrology, oxygen, nitrogen and carbon level dynamics in lakes and streams.

===CCME Guidelines on Salt's Impact to Environment===

LID typically delays the release of salt to receiving waters through temporary storage of elevated chloride levels in soils and then slowly releases it over time. This can help to reduce peak concentrations in discharges and push discharges into the spring when streams have greater dilution capacity. Runoff infiltration in LID practices also helps reduce salt loading to streams that can harm riparian, aquatic and semi-aquatic fauna and flora species.

The [https://sustainabletechnologies.ca/app/uploads/2014/05/CWQG_chlorides.pdf Chloride - Canadian Water Quality Guidelines for the Protection of Aquatic Life]<ref>Canadian Council of Ministers of the Environment. 2011. Canadian water quality guidelines for the protection of aquatic life: Chloride. In: Canadian environmental quality guidelines, 1999, Canadian Council of Ministers of the Environment, Winnipeg. https://sustainabletechnologies.ca/app/uploads/2014/05/CWQG_chlorides.pdf</ref> document from the Canadian Council of Ministers of the Environment (CCME) is another valuable paper that discusses the direct toxic effects of chloride, based on studies using NaCl and CaCl² salts. The guideline can be used as a screening and management tool to ensure that chloride does not lead to the degradation of the aquatic environment. Further guidance on the application of these guidelines is provided in the scientific criteria document (CCME 2011), which can be found here - [https://www.ccme.ca/fr/res/2011-chloride-ceqg-scd-1460-en.pdf Scientific Criteria Document - Cl Ion]. The scientific criteria document goes into detail about the following related to chloride levels in the environment:

[[Permeable pavements]] can improve drainage and prevent melt water from ponding and refreezing. Some permeable pavements also have higher friction coefficients that may reduce the amount of salt needed to create slip-free surfaces.

[[File:Wood Frog (Rana sylvatica) (6236874620).png|thumb|450px|A study by researchers at Yale and Rensselaer Polytechnic Institute, in NY found the interactive effects of road salt on wood frog species' sex ratios and sexual size dimorphism. Over a series of experiments conducted, the authors of the paper in the Canadian Journal of Fisheries and Aquatic Sciences discovered that the number of females within the studied population of tadpoles decreased by ~10% when exposed to road salt. These findings suggest road salt may have a 'masculizing effect' on various amphibian species.<ref>Lambert, M.R., Stoler, A.B., Smylie, M.S., Relyea, R.A. and Skelly, D.K. 2017. Interactive effects of road salt and leaf litter on wood frog sex ratios and sexual size dimorphism. Canadian Journal of Fisheries and Aquatic Sciences, 74(2), pp.141-146. https://tspace.library.utoronto.ca/bitstream/1807/74970/1/cjfas-2016-0324.pdf</ref>]]

Since salt is not removed by traditional best practices, reducing application rates to only what is needed to achieve pavement safety requirements is the best means of managing impacts of salt on the environment and infrastructure. Pavement friction testing has shown that salting beyond the required amount does not translate into improved safety: [https://sustainabletechnologies.ca/app/uploads/2021/05/Friction-and-Parking-Lots.pdf LSRCA's Technical Bulletin: Alternatives to Salt].<ref name="example9">LSRCA. 2020. Friction and Parking Lots. Technical Bulletin, Volume 3 September 2020. https://sustainabletechnologies.ca/app/uploads/2021/05/Friction-and-Parking-Lots.pdf</ref>

 

A review of salt management best practices for parking lots, private drives and walkways is provided by [https://sustainabletechnologies.ca/app/uploads/2022/04/Snow-and-Ice-Control-BMPs-for-Parking-lots-and-Sidewalks.pdf STEP (2022)]<ref name="example6">Van Seters, T. 2022. Review of Snow and Ice Control Practices on Parking Lots and Walkways. Toronto and Region Conservation Authority, Sustainable Technologies Evaluation Program. Ontario. https://sustainabletechnologies.ca/app/uploads/2022/04/Snow-and-Ice-Control-BMPs-for-Parking-lots-and-Sidewalks.pdf</ref>. The Transportation Association of Canada's (TAC), [https://www.tac-atc.ca/sites/tac-atc.ca/files/site/doc/resources/roadsalt-1.pdf Synthesis of Salt Management Best Practices]<ref>Transportation Association of Canada (TAC). 2013. Syntheses of Best Practices Road Salt Management. April 2013. https://www.tac-atc.ca/sites/tac-atc.ca/files/site/doc/resources/roadsalt-1.pdf</ref> and [https://clearroads.org/research-by-topic/ Clear Roads research]<ref>Clear Roads. 2022. Research by Topic. Accessed - May 16 2022: https://clearroads.org/research-by-topic/</ref>and  provides best practice resources more relevant to municipalities and road authorities. The following sections outline what property owners/managers and winter maintenance professionals can do to avoid excess salting. 

 

Property owners and managers play a critical role in creating safe winter conditions and managing the environmental impacts of winter salt on their sites.  Some key activities property managers and owners can do to limit salt use without compromising safety include:

 

====Site Assessment and Planning====

This activity is often done with contractors to identify appropriate snow storage areas, vehicle impact hazards, problem areas such as grading that directs melt water or precipitation to walkways, roof downspouts directed to paved areas, or infrastructure that could be damaged by snowplows. A winter maintenance policy stipulating the expected weather-based level of service, areas requiring winter maintenance and other guiding elements should also be developed as part of a winter risk management strategy. Certification of the property(ies) through the [http://www.smartaboutsalt.com/becomesascertified Smart about Salt Council] can help property managers through the process of developing a plan and policy, while also demonstrating how the organization has endeavored to provide a reasonable level of care in the event of lawsuits.

 

Salt storage and spreading equipment, such as salt boxes, liquid storage containers, and walkway spreading devices can be used by building management staff for periodic or spot treatments, which may reduce requests for contractors to return to the site to apply more salt. On-site mobile or in-pavement temperature and salt residue sensors, along with weather forecasting tools are also useful to inform salting decisions and provide building managers with tools to verify that the salting approaches applied to the site and discussed with contractors as part of the winter maintenance plan are appropriately tailored to site conditions. 

 

[[File:Salt comparison.PNG|thumb|520px|link=https://sustainabletechnologies.ca/app/uploads/2019/06/Procurement-Guidance-Parking-Lot-Snow-and-Ice-Mgmt.pdf|Summary of Salt Reduction Measures and their estimated impact on salt use and contract costs from [https://sustainabletechnologies.ca/app/uploads/2019/06/Procurement-Guidance-Parking-Lot-Snow-and-Ice-Mgmt.pdf STEP's Procurement Guidance for Parking Lot Snow and Ice Management]<ref name="example5">STEP. 2019. Procurement Guidance for Parking Lot Snow and Ice Management. Version 2.0 https://sustainabletechnologies.ca/app/uploads/2019/06/Procurement-Guidance-Parking-Lot-Snow-and-Ice-Mgmt.pdf</ref>]]

 

Responsibilities for tracking winter conditions and maintenance activities should be shared by contractors and property management staff. On-site cameras can be particularly useful in this regard, particularly if the feeds' from these cameras are also shared remotely with contractors. Tracking equipment can help resolve potential conflicts between property management and contractors, contribute to learning through trial and error, ensure the winter maintenance plan is being followed and provide due diligence evidence in the event of slip and fall lawsuits. Liability for "slip and fall" claims associated with winter maintenance are outlined under "''[https://www.ontario.ca/laws/statute/s20033 Bill 118 - Ontario’s Occupiers’ Liability Act'']". The Act was recently amended in January of 2021 and effectively disallows "''any action for personal injury damages caused by snow or ice conditions against an occupier or independent contractor employed to remove snow or ice from the premises when the injury occurred unless a written notice of the claim is personally served on or sent by registered mail to such the occupier or independent contractor within 60 days''" - Robert Kennaley, 2021<ref name="example4">Kennaley, R. 2021. Legislative solutions to slip and fall liability - Ontario’s Bill 118 marks huge step in the right direction. Landscape Ontario. Accessed - May 8 2022: https://landscapeontario.com/legislative-solutions-to-slip-and-fall-liability</ref> (some exceptions apply if the injury results in death, along with other more extreme cases). These recent changes will result in a reduction in associated claims and insurance payouts, thus leading to likely lower insurance premiums for contractors that historically have been high since the 1990s (Kennaley, 2021)<ref name="example4" />.

 

Examples of the types of best management practices that may be considered when preparing contracts are also provided in the [https://sustainabletechnologies.ca/app/uploads/2019/06/Procurement-Guidance-Parking-Lot-Snow-and-Ice-Mgmt.pdf STEP's Procurement Guidance for Parking Lot Snow and Ice Management report] (STEP, 2019)<ref name="example5" />, along with estimates of the impact on salt use, and the potential influence these may have on contract costs.

*Ambient concentration in Canadian waters, sediment and soils

**broken down by province/region

*Toxicity of Chloride (Cl^-) to Aquatic life

**Influences, short-term toxicity - long-term for vertebrates, invertebrates, and plants and algal species

*Effects of (Cl^-) on water quality parameters

**Oxygen / Temperature / Hardness / Chloride and its association to other compounds and their toxicity

===Recent Local Findings===

====Minimizing the Area requiring Winter Maintenance====

Most recently, staff from the TRCA released an article in the January/February, 2022 edition of Water Canada magazine entitled, [https://cdn.watercanada.net/wp-content/uploads/2022/01/17161341/WC122_JanFeb2022_DIGITAL.pdf "Freshwater Salinization: Can we keep our freshwater fresh?",] highlighting the effects of rock salt's over use and application across Southern Ontario's watersheds and its impact on freshwater environments and species.

Properties with large parking lots often present owners with opportunities to close portions of parking lots and entranceways to public and employee use during the winter, either on a seasonal basis or during certain low use periods. Appropriate signage may need to be installed to inform staff and visitors that these areas are not to be used. This measure can generate significant savings through reduced material use and labour, while also reducing the potential area where snow and ice may contribute to safety and liability concerns.

*In Ontario chloride concentrations (Cl^-) are measured monthly under the Provincial Water Quality Monitoring Network (PWQMN)<ref>Ontario Government. 2021. Provincial (Stream) Water Quality Monitoring Network. https://data.ontario.ca/dataset/provincial-stream-water-quality-monitoring-network (Accessed: 25 Mar., 2022)</ref>. Concentrations in the mouth of the Don River has showcased levels three times that of the Canadian Water Quality Guidance (CWQG) for long-term chronic effects to the environment and species.

In new developments or when pavements are repaired or upgraded there are often opportunities to improve drainage, grading or pavement features to reduce the amount of salt needed during winter maintenance. Design changes may include, but is not limited to grading to keep meltwater away from trafficked areas, directing downspouts away from paved areas, installing windbreaks, avoiding flat grades that will eventually form depressions where water can puddle, creating designated snow storage areas that drain away from pavements and installing covers, heated pavements or pavement overlays that can be maintained with less salt (LSRCA, 2018)<ref>LSRCA. 2018. Parking Lot Design Guidelines - Municipal Policy Templates to Promote Salt Reduction in Parking Lots. https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking%20Lot%20Design%20Guidelines.pdf</ref>.  See below for more details.

*Although the PWQMN has ben an excellent tool for following the long-term trends of median concentration levels in the province's watersheds due to the infrequency of sampling, peak values will at times be missed, and extreme values and extreme values and outliers that result in excessive salt and chloride loadings in key areas with species at risk, etc.

*As a result, TRCA, along with its partners began a monitoring project at the mouths of the major tributaries within the GTA using high-frequency conductivity sensors, which make readings every 15 mins.

*Some of the results from their monitoring work found

**''Highland Creek'': (Peak concentration of ''8,400 mg/L'') - 70 times the CWQG limit for chronic effects & 13 times the CWQG limit for acute effects of aquatic organisms.

**''Duffins Creek'': (Peak concentration of ''~3,000 mg/L'') - 25 times the CWQG limit for chronic effects & ~5 times the CWQG limit for acute effects of aquatic organisms.

*These high concentrations pose a considerable threat to fish, aquatic organisms, and ecosystem health overall - especially considering the frequency and duration of these values in major watercourses in urbanized areas of the province. The findings highlight the need for increased water monitoring efforts and requirements for new sensor technology to capture an accurate representation of the current state of our rivers and streams. (Wallace, et al. 2022.)<ref>Wallace, A., Hitch, C., Ruppert, J., Chomicki, K., Cartwright, L., and VanSeters, T. 2022. Freshwater Salinization. Water Canada. January/February 2022. WC122. Digital. https://cdn.watercanada.net/wp-content/uploads/2022/01/17161341/WC122_JanFeb2022_DIGITAL.pdf</ref>

Good Ontario resources on winter maintenance strategies for private businesses and property owners/managers include: 

Due to rock salt's numerous impacts on both infrastructure and the environment numerous studies have been conducted to determine if there are adequate alternatives to the practice of salt application to parking lots and roads. These include sand, organic de-icing materials (agricultural by-products), and salt water brine to name a few.

* [https://www.hamilton.ca/sites/default/files/media/browser/2022-01-17/coh-salt-management-plan2021.pdf Hamilton Region]<br>

Below find a summary table of common de-icers and alternatives in comparison to rock salt regarding lowest working temperature, cost estimations and average application rates.

Selected best management practices for winter maintenance professionals include the following (Van Seters, 2022)<ref name="example6" />

{|class="wikitable"

{|class="wikitable"

|+Comparison of Commonly used De-icers

|+Best Practices for Winter Maintenance Professionals

|-

|-

!Deicer

!<br>'''Best Practice'''

!Cost Estimate (low $ - high $$$$)

!<br>'''General Description'''

!Typical Application Rates (average range)

!<br>'''Key Benefits'''

|-

|-

|NaCl (Rock Salt)

|'''Contract pricing by season or event'''<br>

|style="text-align: center;" |$

(contractor and property owner/manager)

|~130 kg/2 lane km, depending on conditions (range 70-220 kg/2-lane km in Lake Simcoe watershed)

|Snow and Ice professionals are paid a fixed priced per season or event.

|Reduces salt use by not incentivizing the use of salt through the pricing structure in contracts.

|-

|-

|MgCl2 (Liquid Brine)

|'''Site condition assessments and plans'''<br>

|style="text-align: center;" |$$

(contractor and property owner/manager)

|Liquid anti-icing: 35-59 L/2-lane km

|Site assessments and plans identify and document site conditions, problem areas to be rectified, service areas and levels, snow storage areas, and expectations. 

|style="text-align: center;" |-15

|Improves operational efficiencies; supports due diligence defense; prevents potential client contractor conflicts; reduces the need for repeat salt applications on problem areas.

|-

|-

|CaCl2 (Liquid Brine)

|'''Flexible level of service requirements'''<br>

|style="text-align: center;" |$$$

(depending on conditions)

|Since salt needs time to work, there is invariably a delay between when it is applied and when the specified bare pavement service level is met.  This delay can be lengthened under circumstances when bare pavement is needed only during daytime business hours and the snowstorm ends several hours before the day starts.  If applicable, flexible LOS requirements should be described in the site winter maintenance plan.

|style="text-align: center;" |-29

|Significantly reduces salt use because research has shown that the quantity of de-icer applied is strongly influenced by the bare pavement level of service target. 

|-

|-

|Treated Rock Salt

|'''Materials'''

|style="text-align: center;" |$$

|Rock salt pretreated with liquid MgCl₂ or CaCl₂ lowers the effective temperature range of salt and reduces losses to wind and scatter.  Low chloride alternatives can also significantly reduce the harmful effects of chloride-based salts. 

|72-130 kg/2-lane km

|Reduces salt release to the environment and lowers corrosion effects on infrastructure. May also lead to improved level of service. For more information see [https://sustainabletechnologies.ca/app/uploads/2020/03/Alternatives-to-salt-technical-brief.pdf STEP's Technical Brief: Alternatives to Salt (STEP, 2020)]<ref>STEP. 2020. Alternatives to Salt: What else melts snow and ice? Technical Brief. https://sustainabletechnologies.ca/app/uploads/2020/03/Alternatives-to-salt-technical-brief.pdf</ref>. Abrasives such as sand do not melt snow and ice but may be appropriate in some circumstances and LSRCA, 2018<ref name="example7" />.

|style="text-align: center;" |-17

|-

|-

|Calcium Magnesium Acetate

|'''Salt Specifications'''

|style="text-align: center;" |$$$$

|In Ontario, NaCl rock salts and brines used for snow and ice control should meet Ontario Provincial Standard Specifications ([https://www.roadauthority.com/Standards/?id=b3595fd2-0cc6-4d2c-b236-2ac8484a4249 OPSS 2502], [https://tcp.mto.gov.on.ca/sites/default/files/2021-10/NSSP%20MAIN0001_October_22_Clean%20.pdf OPSS (Update) 2502]) for moisture content, texture, and chemistry to ensure optimal performance. 

|219-292 kg/2-lane km (for first application, lower for subsequent due to residual effect)

|Rock salt texture and moisture helps regulate dilution rates, bounce, blow off and other factors that can negatively influence overall effectiveness.

|style="text-align: center;" |-7

|-

|-

|Agricultural By-Products

|'''Direct Liquid Application'''

|style="text-align: center;" |Varied Cost ($$ - $$$$)

|Varies; often used to pre-wet rock salt – less salt is required, lowest effective temperature is reduced

|style="text-align: center;" |-17 to -23

|'''Pre-Wetting'''

|Applying a concentrated liquid anti-icing  rock salt at the spinner or chute increases moisture content, which in turn promotes quicker activation and better adherence of salt to pavements.   

|May include use of RWIS, pavement temperature and residual salt monitoring, on-site cameras and decision support software/systems. Example [https://weather.decisionvue.net/peel RWIS: Wood Weather Information System]

|Helps optimize event-based winter maintenance strategy (timing, material selection, etc.); supports due diligence defense.

|-

(once a year and after repair)

|Salt spreading equipment (solid and liquid) is calibrated to ensure it is functioning and applying salt at the calibrated rates. Both vehicle spreaders and walk behind drop spreaders should be calibrated. 

|Ensures accurate and efficient delivery of material to pavements and walkways; avoids use of malfunctioning equipment; supports due diligence defense.

|Plow at snow depth accumulations > 2 to 3 cm.  Spreading salt on top of snow dilutes its effectiveness thereby requiring more salt to achieve desired level of service.   

|-

|Reduces salt use because the salt applied is not diluted by residual snow on the surface; may provide higher level of service while also offering some support to due diligence defense.

|Establishing target liquid and solid de-icing material rates for a range of conditions based on temperature, residual salt on pavements, snowfall depth and duration and other key parameters. Rates suited to different conditions are ranges to allow for some decision-making flexibility 

|Adjusting salt application rates according to conditions helps ensure that only the amount needed to promote safe conditions is used.  Documentation supporting the selection of rates can help support due diligence defense. 

|-

|Avoids unnecessary release of salt into the environment; reduces costs associated with material loss.

|Snow should be stored in low sections of site to prevent melt water and re-freeze on pavements.  Snow transported off site should go to proper snow disposal facility.

|Avoids release of salt into the environment; Reduces salt by eliminating re-freeze conditions that can cause repeat applications; supports due diligence defense.

|}

|}

For more information on the practices and research supporting the suggested benefits, see [https://sustainabletechnologies.ca/app/uploads/2022/04/Snow-and-Ice-Control-BMPs-for-Parking-lots-and-Sidewalks.pdf STEP, 2022]<ref name="example6" /> and [https://sustainabletechnologies.ca/app/uploads/2022/02/roadsalt-tac-full-doc.pdf TAC, 2013], and associated reference materials.

Many municipalities have found treated rock salt to be worth the extra investment, due to its increased effectiveness at lower temperatures and lower application rate when compared to standard rock salt application practices. The process of pre-wetting rock salt with brine or an agricultural by-product (beet juice for example) as it is applied can help the mixture better adhere to road and pavement surfaces better and reduce excess waste and can enhance the effectiveness of rock salt application below -12°C. To note, the effectiveness of agricultural by-products is still under some evaluation, as some major cities, including Toronto, use it under certain conditions, several Lake Simcoe watershed municipalities have tested it and found it not to be as effective as rock salt. Furthermore, agricultural by-products have to be applied before a snowfall event to melt the fallen snow in a relatively short period of time, which generally is not possible or practical (if applied after a snowfall event it takes a long time to begin the melting process). Read more about these alternative applications in [https://sustainabletechnologies.ca/app/uploads/2020/03/Alternatives-to-salt-technical-brief.pdf STEP's Technical Brief: Alternatives to Salt]<ref>STEP. 2020. Alternatives to Salt: What else melts snow and ice? Technical Brief. https://sustainabletechnologies.ca/app/uploads/2020/03/Alternatives-to-salt-technical-brief.pdf</ref>. 

 

[[File:Sand accumulated road.PNG|thumb|250px|Sand accumulates on the ride of the road after being applied after a snowfall event. Sand can travel into nearby watercourses, wetlands, and increases clean-up associated costs for the municipality. Photo source: [https://sustainabletechnologies.ca/app/uploads/2020/03/Sand-vs-Salt-tech-brief.pdf LSRCA, 2018.]<ref>LSRCA. 2018. Sand versus Salt: Should sand be used for winter maintenance? Technical Bulletin, Volume 1 October 2018. https://sustainabletechnologies.ca/app/uploads/2020/03/Sand-vs-Salt-tech-brief.pdf</ref>]]

 

Detailed analysis of the performance of varying de-icer agents and liquid brine can be found in STEP's earlier technical brief entitled, [https://sustainabletechnologies.ca/app/uploads/2015/11/AlternativeSalt_TechBrief_Nov2015.pdf Evaluation of Organic Anti-icing Materials for Winter Maintenance].<ref>STEP. 2015. Evaluation of Organic Anti-icing Materials for Winter Maintenance. Technical Brief. Salt Management. https://sustainabletechnologies.ca/app/uploads/2015/11/AlternativeSalt_TechBrief_Nov2015.pdf</ref>. The document describes the practice of "anti-icing", (applying liquid brine solutions to paved surfaces before a winter storm) to help prevent ice and snow from bonding to the roadway surface, which in turn helps to reduce the amount of rock salt required to remove salt and ice.

 

 

**The associated cost municipalities incur as a result of sand accumulation along roadways, curbsides and in SWM features are due to the additional effort required (more frequent catchbasin cleanouts, etc.) and the cost of sweeping up this material at the end of each winter season to reduce ongoing environmental impacts.

*Due to contamination of sand, disposal is becoming a more complicated, and therefore costly process causing a number of municipalities to re-evaluate their winter maintenance programs, when it comes to using sand.

==Site Design Strategies for Salt Reduction==

 

In 2017, LSRCA and its partner agencies developed the [https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf Parking Lot Design Guidelines]<ref name="example8">Lake Simcoe Region Conservation Authority. 2017. Parking Lot Design Guidelines to Promote Salt Reduction. GHD|11115623|Report No. 2| February 22 2017. https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref> that can be used by designers, regulatory agencies, property owners, contractors, and others to implement design elements within parking lots and related infrastructure that help limit the need for salt. The [https://www.lsrca.on.ca/parking-lot-guidelines web page for the initiative] includes the full guideline report, a fact sheet and a municipal policy template to facilitate incorporation of guidelines into municipal policy. The report identified four key design strategies.  

==Design Strategies for Salt Reduction==

 

Each year, Canadians spend over $1 billion in winter maintenance costs to clear snow/ice on public and private roads, parking lots and sidewalks, this includes the use and application of greater than 5 million tonnes of rock salt for both deicing and anti-icing operations (Hossain et al., 2015)<ref>Hossain, S.K., Fu, L. and Lake, R., 2015. Field evaluation of the performance of alternative deicers for winter maintenance of transportation facilities. Canadian Journal of Civil Engineering, 42(7), pp.437-448. https://cdnsciencepub.com/doi/abs/10.1139/cjce-2014-0423</ref>. While the use of salt is essential to ensure public safety, there is a growing concern regarding the large quantities of salt (mainly chloride ions), being released to the environment.

 

In their 2001 assessment under the Canadian Environmental Protection Act, it was found that high releases of road salts from winter maintenance activities were having an adverse effect on freshwater ecosystems, soil, vegetation, and wildlife (Environment Canada, 2001)<ref>Environment Canada. 2001. PRIORITY SUBSTANCES LIST ASSESSMENT REPORT. Road Salts. Canadian Environmental Protection Act, 1999. Environment Canada and Health Canada. https://www.canada.ca/content/dam/hc-sc/migration/hc-sc/ewh-semt/alt_formats/hecs-sesc/pdf/pubs/contaminants/psl2-lsp2/road_salt_sels_voirie/road_salt_sels_voirie-eng.pdf</ref>. Based on this conclusion, Environment Canada developed its “[https://publications.gc.ca/collections/collection_2012/ec/En49-31-1-5-eng.pdf Code of Practice the Environmental Management of Road Salts],” which focuses mainly on municipal and provincial road maintenance. This code, which requires the development of Salt Management Plans for those organizations using more than 500 tonnes of road salt annually, was released by Environment Canada in 2004 (Environment Canada, 2004)<ref>Environment Canada. 2004. Code of practice for the Environmental Management of Road Salts. Canadian Environmental Protection Act, 1999 (CEPA 1999). April 2004. EPS 1/CC/5. https://publications.gc.ca/collections/collection_2012/ec/En49-31-1-5-eng.pdf</ref>. While the uptake of this code of practice has been successful for municipalities, there is not a similar recognized guideline for parking lot contractors. That said, there are studies and training programs that address this issue, which aims to educate private contractors about best practices, and how these can improve their level of service, protect the environment, and reduce associated costs. However, uptake of these programs has been low. To address this gap, LSRCA and its partner agencies identified a need for a guideline document that could be used by designers, regulatory agencies, owners, contractors, and others to consider design elements in the design and layout of parking lots and related infrastructure that can help to reduce the requirement for salt application. This effort culminated in the development of [https://www.lsrca.on.ca/parking-lot-guidelines LSRCA's Parking Lot Design Guidelines​]<ref>LSRCA. n.d. Parking Lot Design Guidelines. Webpage. Accessed 25, Mar. 25. 2022. https://www.lsrca.on.ca/parking-lot-guidelines</ref>

 

*LSRCA has created a landing page with their partners, which include three key documents:

**[https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking%20Lot%20Design%20Guidelines.pdf Fact Sheet - Parking Lot Guidelines]: Highlights the impacts of elevated chloride levels in freshwater systems in the Lake Simcoe watershed and detailed, bullet-point descriptions of how to design parking lots to limit over application of rock salt.

**[https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf Parking Lot design Guidelines - Full Report]: Written in partnership with GHD the Parking Lot Design Guidelines to Promote Salt reduction is the primary document LSRCA uses to provide background on the issue of over salting roads and parking lots, primary design features for owners and contractors to consider, case study and site examples where the guidelines have been followed and Drawings of these sites that can be found on the main Parking Lot Guideline landing page.

**[https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Policy%20Templates.pdf Municipal Policy Template]: This template document aids municipalities in the drafting of their own parking lot design and salt reduction policy document based on the findings and design guidance from LSRCA's Parking Lot design Guidelines - Full Report, 2017.

 

The LSRCA's commissioned study with GHD describes preferred salt management design strategies for parking lots, which can be read here: [[LSRCA salt guide]]. The report identified four key design strategies. They can be seen summarized below:

===Effective Grading===

===Effective Grading===

*Proper grading can minimize the freezing of wet pavement surfaces and prevent melt water from ponding and re-freezing, reducing the need for re-application of salt.

*Proper grading can minimize the freezing of wet pavement surfaces and prevent melt water from ponding and re-freezing, reducing the need for re-application of salt.

*Areas for vehicular and pedestrian traffic should be [[grading|graded]] between 2 - 4 % to reduce the chances of depressions forming over time ([https://www.ontario.ca/laws/regulation/110191 maximum permitted 5% for AODA]). Small depressions can result in ponded water icing over in the winter.  

*Areas for vehicular and pedestrian traffic should have well compacted subgrades with surface [[grading|grades]] between 2 - 4 % to reduce the chances of depressions forming. Even shallow depressions will pond water and ice over in the winter, requiring frequent salting to avoid ice build-up.

*Subbase should be well compacted for the same reason.  

*Subbase should be well compacted for the same reason.  

*In [[winter]] months efficient salt application should be made along the top of slopes; melting snow will carry the salt solution down-gradient.

*In [[winter]] months salt should be applied efficiently along the top of slopes to allow melting snow to carry the salt solution down-gradient.

*Effective [[grading]] can also direct melt water towards strategically placed stormwater collection infrastructure (i.e. [[Overflow|catch basins]], [[Swales|vegetated swales]], [[bioretention]] features, [[Rain garden|landscaped areas]]), preventing salt application in heavy traffic areas that are also pathways for runoff.

*Effective [[grading]] can also direct melt water towards strategically placed stormwater collection infrastructure (i.e. [[Overflow|catch basins]], [[Swales|vegetated swales]], [[bioretention]] features, [[Rain garden|landscaped areas]]), preventing salt application in heavy traffic areas that are also pathways for runoff.

*The key to effective stormwater collection during winter is to ensure that melt water from high traffic areas or snow piles does not have to travel great distances to a collection point.<ref>LSRCA. 2015.Parking Lot Design Guidelines to Promote Salt Reduction. GHD. 11115623 (2). https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref>.

*The key to effective stormwater collection during winter is to ensure that melt water from high traffic areas or snow piles does not have to travel great distances to a collection point (LSRCA, 2017)<ref name="example8" />.

===Snow Pile Location===

===Snow Pile Location===

*Storage locations for snow piles should be around the outer edges of parking lots and downgradient from high traffic areas, in sunny areas where possible to accelerate melting.   

*Storage locations for snow piles should be around the outer edges of parking lots and downgradient from high traffic areas, in sunny areas where possible to accelerate melting.   

*Consider grading the storage location to distribute the melt-water as sheet flow over a grass filter strip into an adjacent BMP, such as a [[bioretention|bioretention cell]] or [[infiltration trench]]. In some cases, with careful vegetation selection and adequate drainage, the BMP itself can serve as a snow storage location. Designing specific drainage collection features for snow piles can ensure that melt water is quickly collected in the vicinity of the pile to reduce the opportunity for refreezing.

*Consider grading the storage location to distribute the melt-water as sheet flow over a grass filter strip into an adjacent BMP, such as a [[bioretention|bioretention cell]] or [[infiltration trench]]. In some cases, with careful vegetation selection and adequate drainage, the BMP itself can serve as a snow storage location. Designing specific drainage collection features for snow piles can ensure that melt water is quickly collected in the vicinity of the pile to reduce the opportunity for refreezing.

*Snow storage areas should be clearly marked for seasonal maintenance staff.<ref>LSRCA. 2015.Parking Lot Design Guidelines to Promote Salt Reduction. GHD. 11115623 (2). https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref>.

*Snow storage locations should be included in the winter maintenance plan and clearly marked for seasonal maintenance staff (LSRCA, 2017)<ref name="example8" />.

===Sidewalk Design and Pedestrian Flow===

===Sidewalk Design and Pedestrian Flow===

*Sidewalks that receive infrequent use could be closed for the winter season.  

*Sidewalks that receive infrequent use could be closed for the winter season.  

*Maintained sidewalks should be ≥ 1.5 m wide to accommodate plowing and minimize the salting required.  

*Maintained sidewalks should be ≥ 1.5 m wide to accommodate plowing and minimize the salting required.  

*Using textured pavers can improve grip for pedestrians, again reducing the salt required.  

*Using textured pavers or overlays can improve grip for pedestrians, reducing the salt required.  

*In busy areas around building entrances, covered walkways and heated mats also reduce salt requirements.<ref>LSRCA. 2015.Parking Lot Design Guidelines to Promote Salt Reduction. GHD. 11115623 (2). https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref>.

*In busy areas around building entrances, covered walkways and heated mats also reduce salt requirements (LSRCA, 2017)<ref name="example8" />.

===Landscaping Features===  

===Landscaping Features===  

*Landscaping features (i.e. [[Swales|vegetated swales]] or [[Rain gardens|landscaped islands]]) can lead to a reduced requirement of salt application by reducing the amount of paved surface.

*Landscaping features (i.e. [[Swales|vegetated swales]] or [[Rain gardens|landscaped islands]]) can lead to a reduced requirement of salt application by reducing the amount of paved surface.

*Specifying deciduous [[Trees: List|trees]] along walkways and near snow piles will maximize winter sunlight penetration. This will naturally enhance the melting of frozen surfaces, limiting the need for winter maintenance.

*Specifying deciduous [[Trees: List|trees]] along walkways and near snow piles will maximize winter sunlight penetration. This will naturally enhance the melting of frozen surfaces, limiting the need for winter maintenance.

*Coniferous [[Trees: List|trees]] can be used to create treed wind breaks along the site perimeter to avoid snow drifts.<ref>LSRCA. 2015.Parking Lot Design Guidelines to Promote Salt Reduction. GHD. 11115623 (2). https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref>.

*Coniferous [[Trees: List|trees]] can be used to create treed "wind breaks" along the site perimeter to avoid snow blowing onto pavement.(LSRCA, 2017)<ref name="example8" />.

====Other vegetation====  

====Other vegetation====  

*In high enough concentrations, sodium and chloride can also be directly toxic to plants. In some species the ions are absorbed by the plant and build up in the leaves causing them to die.

*In high enough concentrations, sodium and chloride can also be directly toxic to plants. In some species the ions are absorbed by the plant and build up in the leaves causing them to die.

Generally, the [[vegetation]] growing closest to the source will be most strongly affected by salt. Plants actively growing in late winter (when salt levels are highest) are also more significantly affected. So, warm season [[Graminoids: List|grasses]] offer an advantage over cool season grasses, because they emerge later in the spring when excess salt has been flushed away.

Generally, the [[vegetation]] growing closest to the source will be most strongly affected by salt. Plants actively growing in late winter (when salt levels are highest) are also more significantly affected. Therefore, warm season [[Graminoids: List|grasses]] offer an advantage over cool season grasses, because they emerge later in the spring when excess salt has been flushed away.

{{:turf}}

{{:turf}}  

[[File:Brine-Storage-Tank-1-scaled.jpg|thumb|430px|Example of three brine holding tanks that can reuse meltwater from salt induced snowmelt to be reused on a pavement surface i na high traffic area. These systems are generally built with corrosion-free materials to maximize the product's lifetime. Photo Source: [https://www.camionsystems.com/product/brine-storage-tank/ Camion]™<ref>Camion™. 2022. Brine Storage Tank. Accessed 28 Mar. 2022. https://www.camionsystems.com/product/brine-storage-tank/</ref>]]

[[File:Brine-Storage-Tank-1-scaled.jpg|thumb|430px|Example of three brine holding tanks that can reuse meltwater from salt induced snowmelt to be reused on a pavement surface i na high traffic area. These systems are generally built with corrosion-free materials to maximize the product's lifetime. Photo Source: [https://www.camionsystems.com/product/brine-storage-tank/ Camion]™<ref>Camion™. 2022. Brine Storage Tank. Accessed 28 Mar. 2022. https://www.camionsystems.com/product/brine-storage-tank/</ref>]]

===Other Design Features===

===Other Design Features===

Other options that can be considered to reduce the amount of salt that needs to be applied in a parking lot include:

Other options that can be considered to reduce the amount of salt that needs to be applied in a parking lot include:

*Seasonally closing parking areas: many parking lots have areas that are infrequently used outside of the holiday shopping period. These areas can be closed and not maintained through much of the winter season, reducing both the effort and amount of salt required.

*Seasonally closing parking areas: many parking lots have areas that are infrequently used outside of the holiday shopping period. These areas can be closed and not maintained through much of the winter season, reducing both the effort and amount of salt required.

*Shaded Canopies: With roof canopies over major pedestrian walkways and entrances from parking lots to building enclosures, little to no snow or ice will fall in these high-traffic areas, resulting in reduced salt application. Consideration should be taken for the runoff generated from the canopy stormwater or snowmelt when weather begins to warm to limit the potential for of ponding/refreezing on the walkway.

*Shaded Canopies: With roof canopies over major pedestrian walkways and entrances from parking lots to building enclosures, little to no snow or ice will fall in these high-traffic areas, resulting in reduced salt application. Consideration should be taken for the runoff generated from the canopy stormwater or snowmelt when weather begins to warm to limit the potential for of ponding/refreezing on the walkway.

*Brine holding tanks: Collection of first flush (high chloride concentration) melt water runoff from a salt induced snowmelt (as opposed to rain and temperature induced snowmelt) has the potential to be beneficial if captured and reused as an anti-icing or pre wetting solution. In order to collect the first flush runoff, an electronically actuated valve controlled by an electrical conductivity sensor would be installed at the desired conveyance point to divert and collect the high chloride concentration runoff into a brine holding tank. The brine holding tank would be placed below ground and a pump could be connected to pump the brine solution into an anti-icing tank or directly used to pre-wet rock salt. <ref>LSRCA. 2015.Parking Lot Design Guidelines to Promote Salt Reduction. GHD. 11115623 (2). https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref>

*Brine holding tanks: Collection of first flush (high chloride concentration) melt water runoff from a salt induced snowmelt (as opposed to rain and temperature induced snowmelt) has the potential to be beneficial if captured and reused as an anti-icing or pre wetting solution. In order to collect the first flush runoff, an electronically actuated valve controlled by an electrical conductivity sensor would be installed at the desired conveyance point to divert and collect the high chloride concentration runoff into a brine holding tank. The brine holding tank would be placed below ground and a pump could be connected to pump the brine solution into an anti-icing tank or directly used to pre-wet rock salt. <ref>LSRCA. 2015.Parking Lot Design Guidelines to Promote Salt Reduction. GHD. 11115623 (2). https://www.lsrca.on.ca/Shared%20Documents/Parking-Lot-Design-Guidelines/Parking-Lot-Guidelines-Salt-Reduction.pdf</ref>

==Procurement Guidance==

==Case Studies & External Links==

===Case Studies===

 

A series of STEP case studies highlighting the effectiveness of different salt management practices is currently being developed. A brief synopsis of some of these case studies is provided in Appendix B of Van Seters, 2022. Full case study documents will be posted here when available.

 

===Procurement Best Practices===

 

# '''Effective Pricing of Services''': Contract pricing by a lump sum by season or a fixed sum per event (with extra costs associated with standby time) are common, but a combination of both payment options in the contract may create a financial incentive for both the parking-lot owner and salt operator to require less salt.

# '''Accurate Salt Delivery''': Updated and well-maintained salt application devices (i.e. salt spreaders) that can be calibrated to function and apply salt automatically based on the speed of the vehicle can greatly reduce the amount of rock salt applied and can better digitally track the amount used as well.

# '''Trained Professionals''': Requesting evidence of experience and requiring training and certification through the [http://www.smartaboutsalt.com/training Ontario Smart about Salt Program] will help to ensure that the contractor selected and property management staff have the skills necessary to implement best practices for road salt application.

 

To learn more about STEP's [https://sustainabletechnologies.ca/app/uploads/2019/06/Salt-application-best-practices-for-winter-maintenance-contracts-brochure.pdf Salt Application Best Practices document for Winter Maintenance Contracts]<ref>STEP. 2019. Salt Application Best Practices for Winter Maintenance Contracts. Technical Brief. https://sustainabletechnologies.ca/app/uploads/2019/06/Salt-application-best-practices-for-winter-maintenance-contracts-brochure.pdf</ref> click on the hyperlink.

 

[https://sustainabletechnologies.ca/app/uploads/2021/05/Friction-and-Parking-Lots.pdf LSRCA's Technical Bulletin: Alternatives to Salt]<ref>LSRCA. 2020. Friction and Parking Lots. Technical Bulletin, Volume 3 September 2020. https://sustainabletechnologies.ca/app/uploads/2021/05/Friction-and-Parking-Lots.pdf</ref> is a valuable technical brief which covers BMPs that have been developed specifically for winter maintenance in parking lots. Along with recommendations around the proper use and calibration of equipment, many of these practices relate to plowing the lot and walkways before applying salt, and applying the recommended amount of salt for the conditions. Several studies have been conducted, by industry and academia, to determine what the “right” amount of salt is, and, while “proper” application can vary depending on temperature and conditions 58 g/m2 (or 13 lb/1000 ft2) has been suggested as a reasonable rate to use for “moderate” winter events (Hossain, K. and Fu, L., 2015), while in recent studies of commercial parking lots by LSRCA, the typical real-world application rates tended to be closer to 90 g/m2 (or 18 lb/1000 ft2), and can often be much higher.  

 

*What application rate should be used?

 

 

 

 

 

High volumes of salt are often applied because contractors, property managers, and parking lot users feel that the more salt there is, the safer the surface is to walk or drive on. However, a surface that has been treated at an appropriate rate, (which is slightly wet with a small amount of salt residue) has a much higher friction value (μ); with the level of service achieved far more efficiently, than when compared to the same surface where rock salt has been heavily applied (over salted).

 

Through this work, as referenced above - LSRCA staff documented higher friction values on untreated surfaces than on surfaces with large volumes of product; the µ value of a surface may remain low if it has only been shoveled or plowed. While shoveling is an important part of the winter maintenance process, practitioners need to consider the site and predicted conditions on a day-to-day basis to determine how to attain the safest surface for vehicle and foot traffic. In many cases the sun or traffic may melt the residual snow on a shoveled or plowed surface without any further treatment being necessary (saving both time and money); while in other cases, some salt, applied at an appropriate rate, may be necessary.

*[https://ottawariverkeeper.ca/2021-2022-road-salt/ The 2021-2022 Road Salt Program at Ottawa Riverkeeper]<ref>Oswald, 2021. Road salt reduction on Ryerson University campus. Information Sheet. Presentation by C. Oswald at the Ottawa Riverkeeper salt management forum in April 2021. Ottawa Riverkeeper. January 18, 2022. Accessed May 16 2022. https://ottawariverkeeper.ca/2021-2022-road-salt/</ref>

**This ongoing study is being conducted to evaluate the feasibility and environmental benefits (specifically, the reduction of chloride (Cl) entering the environment) of using direct liquid application (i.e., NaCl brine) on Ryerson campus for both anti-icing and de-icing. Updated reports and findings will be posted here once published

[[File:Anti-icing truck.PNG|thumb|500px|De-icer agent applied to a roadway before a precipitation rent (Source: STEP, 2019)<ref name="example10" />]]

Friction testing has demonstrated that bare pavement is safest, as it has the highest friction value, and that the over-application of salt does not always translate to safer conditions. Simply put, applying salt at the prescribed rate for the conditions and shoveling or plowing where appropriate will attain a higher friction rate than an overapplication of salt.

''What is a reasonable amount of time to achieve the desired level of service?'':  

*[https://www.regionofwaterloo.ca/en/living-here/resources/Documents/water/was-protect_closed_sign_program.PDF Closing Areas to Reduce Salt Use and Winter Maintenance Costs]<ref>Region of Waterloo. 2020. Salt reduction partnership. Region of Waterloo, Water Services. https://www.regionofwaterloo.ca/en/living-here/resources/Documents/water/was-protect_closed_sign_program.PDF</ref>

*Depending on the operating hours of the property being maintained, it may be possible to reduce the salt application rate without sacrificing the desired level of service.

**Ongoing study by the Region of Waterloo to explore the feasibility and interest in reducing salt use and maintenance costs by  establishing outreach campaigns and support programs that encourage property owners and managers (of ICI properties) to close under-used areas of their properties during the winter, which can be a very successful means to reduce salt use, and provide significant savings on winter maintenance costs.  

**For example, many commercial properties keep hours between 9:00 am and 9:00 pm, which would mean that the lot does not need to be clear until shortly before 9:00 am. The table below demonstrates the time it would take to reach bare pavement at typical industry-recommended application rates, in a situation where the temperature is between -7 and -9 °C, with between 0.5 and 1.5 cm of snow on the ground. The rate may need to be increased or decreased slightly to achieve the desired level of service depending on varying factors related to traffic, sunlight, type of snow, and/or pavement type.

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*[https://sustainabletechnologies.ca/app/uploads/2019/06/Salt-application-best-practices-for-winter-maintenance-contracts-brochure.pdf Salt Application Best Practices document for Winter Maintenance Contracts]<ref>STEP. 2019. Salt Application Best Practices for Winter Maintenance Contracts. Technical Brief. https://sustainabletechnologies.ca/app/uploads/2019/06/Salt-application-best-practices-for-winter-maintenance-contracts-brochure.pdf</ref>  

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!'''Application Rate (g/m2)'''

!'''<u><span title="Note: Assuming lot size of 15 ha (the approximate size of an LSRCA study lot).">Volume of salt used for each application (kg)*</span></u>'''

***Using Trained Professionals through the [http://www.smartaboutsalt.com/training Ontario Smart about Salt Program]

!'''<u><span title="Note: Assuming 70 applications.">Total salt applied/season (tonnes)**</span></u>'''

!'''Material costs/season (assuming $100/tonne)'''

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As the "''Time to Reach Bare Pavement Scenario Comparison''" above demonstrates, significant salt and cost savings could be seen in a typical big box store, commercial business or institutional building's parking lot by simply reducing the application rate of rock salt and extending the time to bare pavement by one hour. To note, this is only the material cost of the salt (which varies, but has been [https://www.cbc.ca/news/canada/ottawa/ottawa-contractors-road-salt-price-hike-1.4934369 higher than $100/tonne in recent years] (Tumilty, 2018)<ref>Tumilty, R. 2018. Rise in road salt prices hits local contractors. Available at: https://www.cbc.ca/news/canada/ottawa/ottawa-contractors-road-salt-price-hike-1.4934369 (Accessed: 24 Mar., 2022)</ref>. Over-application of salt has been noted to cause significant damage to parking lot infrastructure, including issues with concrete, corrosion of railings, damage to landscaping materials, and damage to interior buildings' flooring. Reducing the application rate would decrease the rate at which this damage occurs, as a result helping to minimize the amount needed to repair or replace at a given property each year. All of this without sacrificing the safety of parking lot users.

*[https://sustainabletechnologies.ca/app/uploads/2021/05/Friction-and-Parking-Lots.pdf LSRCA's Technical Bulletin: Alternatives to Salt].<ref name="example9" />

**This technical bulletin by LSRCA discusses the issue of high levels of salt application, and how contractors, property owners and municipalities can save time and money by looking at the emerging research which shows how salt use can also be optimized in parking lots. This research was done by using a friction tester, with a goal of quantifying the effectiveness of various practices and salt application rates.  

[[File:Smart about salt training.PNG|thumb|500px|Smart About Salt training program teaches winter contracting company staff and facility management staff how to appropriately apply rock salt and still being mindful about its environmental impact, all while reducing reducing liability and maintenance costs. To learn more, click the picture above.<ref>Smart About Salt Council (SASC). n.d. Smart About Salt: Winter Salt Management Program. http://www.smartaboutsalt.com/</ref>|link=http://www.smartaboutsalt.com/training]]

[[File:Smart about salt training.PNG|thumb|500px|Smart About Salt training program teaches winter contracting company staff and facility management staff how to appropriately apply rock salt and still being mindful about its environmental impact, all while reducing reducing liability and maintenance costs. To learn more, click the picture above.<ref>Smart About Salt Council (SASC). n.d. Smart About Salt: Winter Salt Management Program. http://www.smartaboutsalt.com/</ref>|link=http://www.smartaboutsalt.com/training]]

**The purpose of this manual By the Minnesota Pollution Control Agency (MPCA) is to deliver practical advice to those managing parking lots and sidewalks and help make proactive, cost-effective, environmentally conscious choices in winter parking lot and sidewalk management in the State of Minnesota. This knowledge will provide the opportunity to become a leader in the industry by operating more efficiently and reducing environmental impacts. The manual is  based on the Minnesota Snow and Ice Control Field Handbook for Snowplow Operators, produced by the Minnesota Local Technical Assistance Program Center, and on the training materials for the MPCA's Winter Maintenance of Parking Lots and Sidewalks training class.  

**The purpose of this manual By the Minnesota Pollution Control Agency (MPCA) is to deliver practical advice to those managing parking lots and sidewalks and help make proactive, cost-effective, environmentally conscious choices in winter parking lot and sidewalk management in the State of Minnesota. This knowledge will provide the opportunity to become a leader in the industry by operating more efficiently and reducing environmental impacts. The manual is  based on the Minnesota Snow and Ice Control Field Handbook for Snowplow Operators, produced by the Minnesota Local Technical Assistance Program Center, and on the training materials for the MPCA's Winter Maintenance of Parking Lots and Sidewalks training class.  

*[https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters]. <ref>Hintz, W.D. and Relyea, R.A. 2019. A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters. Freshwater biology, 64(6), pp.1081-1097. https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters</ref>.

*[https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters].<ref name="example10">Hintz, W.D. and Relyea, R.A. 2019. A review of the species, community, and ecosystem impacts of road salt salinisation in fresh waters. Freshwater biology, 64(6), pp.1081-1097. https://www.researchgate.net/publication/331991752_A_review_of_the_species_community_and_ecosystem_impacts_of_road_salt_salinisation_in_fresh_waters</ref>.

**This study of the impacts of road salt on local ecosystems by Hintz and Relyea (2019), found that road salts negatively affect species at all trophic levels, from biofilms to fish species but the concentration of road salt where adverse effects were observed varied and the effects themselves ranged from reductions in fecundity, size and shape to alterations to nutrient and energy flow at an ecosystem level and increased greenhouse gas emissions from contaminated wetlands and altered hydrology and oxygen, nitrogen and carbon level dynamics in lakes and streams. Concentrations at which road salt triggered an effect varied considerably. To read more about their findings, click the link above.

**This study of the impacts of road salt on local ecosystems by Hintz and Relyea (2019), found that road salts negatively affect species at all trophic levels, from biofilms to fish species but the concentration of road salt where adverse effects were observed varied and the effects themselves ranged from reductions in fecundity, size and shape to alterations to nutrient and energy flow at an ecosystem level and increased greenhouse gas emissions from contaminated wetlands and altered hydrology and oxygen, nitrogen and carbon level dynamics in lakes and streams. Concentrations at which road salt triggered an effect varied considerably. To read more about their findings, click the link above.