Difference between revisions of "Winter Management"

From LID SWM Planning and Design Guide
Jump to navigation Jump to search
 
(86 intermediate revisions by 4 users not shown)
Line 1: Line 1:
===Salt and Snow===
+
[[File:KoppenGeigerclimatezonesCanada_2017.jpg|thumb|500px|Koppen-Geiger Climate Zones of Canada, 2017]]
<div class="col-md-8">
 
 
{{TOClimit|2}}
 
{{TOClimit|2}}
<p>Sodium and chloride ions in de-icing salts applied to asphalt areas travel easily with the runoff water. De-icing salt can also increase the mobility of some heavy metals in soil (e.g. lead, copper or cadmium). This may increase the downstream concentration of these metals (Amrhein et al., 1992; Bauske and Goetz, 1993). </p>
+
==Cold climates==
<p> <strong>Very few studies have sampled groundwater below infiltration facilities or roadside ditches receiving de-icing salt laden runoff have found concentrations of heavy metals that exceed drinking water standards (e.g., Howard and Beck, 1993; Granato et al., 1995).</strong>  </p>
+
Most major cities and urban areas in Ontario have a "humid continental" climate featuring snow and warm summers, classified as "Dfb" according to the [https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification Koppen-Geiger climate zone classification system], which includes average temperatures in the coldest month well below -3°C. Other locations in Canada with a humid continental "Dfb" climate include portions of the British Columbia interior (Kamloops, Kelowna, Prince George), the prairies (Calgary, Edmonton, Regina, Saskatoon and Winnipeg), southern Quebec (Montreal, Quebec City), and Atlantic provinces (Charlottetown, Fredericton, Halifax, St. John's). Locations in the United States with a "Dfb" climate include portions of Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New York, North Dakota, Pennsylvania, Vermont and Wisconsin. Other locations around the world with a "Dfb" climate includes such cities as Oslo (Norway), Helsinki (Finland), Stockholm (Sweden), Moscow (Russia), Kiev (Ukraine) and Hokkaido and Sapporo (Japan). <br>  
<p>To minimize risk of groundwater or soil contamination, the following management approaches are recommended (Pitt et al., 1999; TRCA, 2009b):
+
<br>
<ol>
+
The southernmost portion of Ontario has a humid continental climate that features snow and hot summers, with a Koppen-Geiger climate zone classification of "Dfa". Other locations with "Dfa" climate include northern portions of Illinois, Indiana, Iowa and Ohio in the United States.
<li>Stormwater infiltration practices should not receive runoff from the following areas:
 
<ul>
 
<li>Where large amounts of de-icing salts are applied (e.g., busy highways), or </li>
 
<li>Pollution hot spots (e.g. vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials, and some heavy industry sites); </li>
 
</ul>
 
<li>Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as roofs, low traffic roads and parking areas; and </li>
 
<li>Apply [[pretreatment]] practices before infiltration of road or parking area runoff. </li>
 
</ol>
 
</p>
 
  
===Planning===
+
==De-icing [[salt]]==
Recommended planning strategies in designing sites for reduced salt usage:
+
[[File:Snow_filter_strip.png|thumb|Snow being stored on a filter strip in Markham, ON]]
<p><strong>Effective Grading</strong> Areas for vehicular and pedestrian traffic should be graded between 2 - 4% to reduce the chances of depressions forming. Sub bases should be well compacted for the same reason. Preventing ponding and ice formation reduces the salting requirements for those surfaces.  In winter months efficient salt application should be made along the top of slopes. Melting snow will carry the salt solution down-gradient. </p>
+
Sodium and chloride ions in de-icing [[salt|salts]] applied to asphalt areas travel easily with the runoff water. De-icing [[salt]] can increase the mobility of some [[heavy metals]] in soil (e.g. lead, copper or cadmium). This may increase the downstream concentration of these metals <ref>Amrhein, C., Strong, J.E., and Mosher, P.A. 1992. Effect of de-icing salts on metal and organic matter mobilization in roadside soils. Environmental Science and Technology. Vol. 26, No. 4, pp. 703-709</ref><ref>Bauske, B., Goetz, D. 1993. Effects of de-icing salts on heavy metal mobility. Acta Hydrochimica Hydrobiologica. Vol. 21. pp. 38-42., 1993).</ref>
<p><strong>Snow Piles</strong> Storage locations for snow piles should be in sunny areas with low traffic. Consider grading the storage location to distribute the melt-water as sheet flow over a [[Grass Filter Strips|grass filter strip]] into an adjacent BMP, such as a [[Bioretention Cells|bioretention cell]] or [[Infiltration Trenches|infiltration trench]]. In some cases, with careful vegetation selection and adequate drainage, the BMP itself can serve as a snow storage location. Snow storage areas should be clearly marked for seasonal maintenance staff.</p>
 
<p><strong>Sidewalk Design and Pedestrian Flow</strong> Sidewalks which 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. Using textured pavers can improve grip for pedestrians, again reducing the salt required. In busy areas around building entrances, covered walkways and heated mats also reduce salt requirements.</p>  
 
<p><strong>Trees</strong> Specifying deciduous trees will maximize winter sunlight penetration. This will naturally enhance the melting of frozen surfaces, limiting the need to winter maintenance. </p>
 
  
----
+
Very few studies have sampled groundwater below infiltration facilities or roadside ditches receiving de-icing salt laden runoff have found concentrations of heavy metals that exceed drinking water standards <ref>Howard, K.W.F. and Beck, P.J. 1993. Hydrogeochemical implications of groundwater contamination by road de-icing chemicals. Journal of Contaminant Hydrology. Vol. 12. pp. 245-268.</ref><ref>Granato, G.E., Church, P.E., Stone, V.J. 1995. Mobilization of Major and Trace Constituents of Highway Runoff in Groundwater Potentially Caused by De-icing Chemical Migration. Transportation Research Record. No. 1483.</ref>
<h5>Vegetation</h5>
 
<p>Vegetation varies in its reaction to salt-affected soils.  
 
<ul>
 
<li>Salt in soil water generally makes it more difficult for roots to take up water. This phenomenon mimics drought conditions for the plant. </li>
 
<li>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.</li>
 
<li>In high enough concentrations sodium and chloride can also be directly toxic to plants. In some species the ions are absorbed by t he plant and build up in the leaves causing them to die </li>
 
</ul>
 
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 grasses offer an advantage over cool season grasses, because they emerge later in the spring when excess salt has been flushed away. </p>  
 
  
</div>
+
===To minimize risk of groundwater or soil contamination, the following management approaches are recommended <ref>Pitt, R., Clark, S., Field, R. 1999. Groundwater contamination potential from stormwater infiltration. Urban Water. Vol.1. pp.217-236. https://www.sciencedirect.com/science/article/abs/pii/S146207589900014X </ref>, <ref> Toronto and Region Conservation Authority. 2009. Review of the Science and Practice of Stormwater Infiltration in Cold Climates. https://sustainabletechnologies.ca/app/uploads/2014/10/SW_Infiltration-Review_10.15.2014.pdf </ref>:===
<div class="col-md-4">
+
Stormwater infiltration practices should not receive runoff from the following areas:
<panelSuccess>
+
*Where large amounts of de-icing salts are applied (e.g., busy highways), or
<gallery mode="packed" widths=300px heights=300px>
+
*Pollution hot spots (e.g. vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials, and some heavy industry sites);
Snow_filter_strip.png| Snow being stored on a filter strip in Markham, ON
+
*Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as roofs, low traffic roads and parking areas; and
</gallery>
+
*Apply [[pretreatment]] practices before infiltration of road or parking area runoff.
</panelSuccess>
+
*Implement winter de-icing [[Salt management |salt management best practices]].
</div>
 
<div class="col-md-12">
 
----
 
  
===Other Freezing Related Concerns ===
+
==Cold climate considerations==
</div>
+
[[File:Ice storm (1).jpg|thumb|Ice storm (1)]]
<div class="col-md-8">
+
===[[Underdrain |Underdrains]] and flow control devices===
<p><strong>Rainwater harvesting</strong> Freezing temperatures can cause problems with pipes and cisterns exposed above the frost penetration line[http://www.raqsb.mto.gov.on.ca/techpubs/ops.nsf/0/ee1f1756eacc00e18525808200628fbf/$FILE/OPSD3090.101%20Rev%231%20Nov2010.pdf]. This maybe a significant issue for [[Rainwater Harvesting|rainwater harvesting systems]], including residential [[Rain Barrels|rain barrels]].</p>
+
[[Underdrain]] perforated pipes should be located below the frost line to reduce the threat of ice clogging. Ontario provincial standard drawings of frost penetration depth are available from the [https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx Ministry of Transportation] as OPSD 3090.100 for northern Ontario <ref> Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Northern Ontario. OPSD 3090.100. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx </ref> and OPSD 3090.101 for southern Ontario <ref> Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Southern Ontario. OPSD 3090.101. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx </ref>.<br>
<p><strong>Green Roofs</strong> Somewhat counter-intuitively, the survival of green roof planting is greater in winters with long deep sub-zero temperatures. Being shallow and very exposed to warming sunlight, green roofs thaw rapidly. Frequent freeze-thaw cycles in the early and late winter is associated higher loss of vegetation on green roofs.</p> 
+
<br>  
+
[[Weirs]] are generally less prone to clogging from ice than [[orifices]] or valves under all flow conditions. Proprietary low flow devices are also available which are designed to mitigate clogging from ice or other solid debris.
</div>
 
<div class="col-md-4">
 
IMAGES?
 
</div>
 
<div class="col-md-12">
 
----
 
  
===See Also===
+
===Plowing===
<ul>
+
Rubber plow blades are increasingly available and required in many jurisdictions. Their use reduces damage to all kinds of pavement surfaces and they are particularly recommended for application where LID facilities exist, such as permeable pavements and curb cut inlets of bioretention, bioswales, swales and stormwater tree trenches.
<li>[[Water Quality]]</li>
+
 
</ul>
+
===[[Rainwater harvesting]]===
----
+
Freezing temperatures can cause problems with exposed collection pipes and portions of cisterns and pipes located above the foundation frost penetration depth.  For standard drawings see [https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx Ontario Ministry of Transportation] OPSD 3090.100 for northern Ontario, and OPSD 3090.101 for southern Ontario. Rainwater harvesting systems designed for year-round operation in cold climates like those in Ontario are typically limited to underground cisterns and outlet pipes located below the frost penetration depth, or cisterns integrated within buildings.
<table class="table table-hover table-condensed table-bordered">
+
 
<td class="text-center"><i class="fa fa-envelope-open-o"></i>&nbsp;&nbsp;[[Special:SpecialContact|<strong>SEND US YOUR QUESTIONS & FEEDBACK ABOUT THIS PAGE</strong>]]</td>
+
===[[Green Roofs |Green roofs]]===
</table>
+
The survival of [[Green roofs: Planting|green roof plantings]] is greater in winters with long deep sub-zero temperatures. Being shallow and very exposed to warming sunlight, green roofs thaw rapidly. Frequent freeze-thaw cycles in the early and late winter are associated higher loss of vegetation on green roofs.
 +
 
 +
==References==

Latest revision as of 19:03, 30 November 2023

Koppen-Geiger Climate Zones of Canada, 2017

Cold climates[edit]

Most major cities and urban areas in Ontario have a "humid continental" climate featuring snow and warm summers, classified as "Dfb" according to the Koppen-Geiger climate zone classification system, which includes average temperatures in the coldest month well below -3°C. Other locations in Canada with a humid continental "Dfb" climate include portions of the British Columbia interior (Kamloops, Kelowna, Prince George), the prairies (Calgary, Edmonton, Regina, Saskatoon and Winnipeg), southern Quebec (Montreal, Quebec City), and Atlantic provinces (Charlottetown, Fredericton, Halifax, St. John's). Locations in the United States with a "Dfb" climate include portions of Maine, Massachusetts, Michigan, Minnesota, New Hampshire, New York, North Dakota, Pennsylvania, Vermont and Wisconsin. Other locations around the world with a "Dfb" climate includes such cities as Oslo (Norway), Helsinki (Finland), Stockholm (Sweden), Moscow (Russia), Kiev (Ukraine) and Hokkaido and Sapporo (Japan).

The southernmost portion of Ontario has a humid continental climate that features snow and hot summers, with a Koppen-Geiger climate zone classification of "Dfa". Other locations with "Dfa" climate include northern portions of Illinois, Indiana, Iowa and Ohio in the United States.

De-icing salt[edit]

Snow being stored on a filter strip in Markham, ON

Sodium and chloride ions in de-icing salts applied to asphalt areas travel easily with the runoff water. De-icing salt can increase the mobility of some heavy metals in soil (e.g. lead, copper or cadmium). This may increase the downstream concentration of these metals [1][2]

Very few studies have sampled groundwater below infiltration facilities or roadside ditches receiving de-icing salt laden runoff have found concentrations of heavy metals that exceed drinking water standards [3][4]

To minimize risk of groundwater or soil contamination, the following management approaches are recommended [5], [6]:[edit]

Stormwater infiltration practices should not receive runoff from the following areas:

  • Where large amounts of de-icing salts are applied (e.g., busy highways), or
  • Pollution hot spots (e.g. vehicle fuelling, servicing or demolition areas, outdoor storage or handling areas for hazardous materials, and some heavy industry sites);
  • Prioritize infiltration of runoff from source areas that are comparatively less contaminated such as roofs, low traffic roads and parking areas; and
  • Apply pretreatment practices before infiltration of road or parking area runoff.
  • Implement winter de-icing salt management best practices.

Cold climate considerations[edit]

Ice storm (1)

Underdrains and flow control devices[edit]

Underdrain perforated pipes should be located below the frost line to reduce the threat of ice clogging. Ontario provincial standard drawings of frost penetration depth are available from the Ministry of Transportation as OPSD 3090.100 for northern Ontario [7] and OPSD 3090.101 for southern Ontario [8].

Weirs are generally less prone to clogging from ice than orifices or valves under all flow conditions. Proprietary low flow devices are also available which are designed to mitigate clogging from ice or other solid debris.

Plowing[edit]

Rubber plow blades are increasingly available and required in many jurisdictions. Their use reduces damage to all kinds of pavement surfaces and they are particularly recommended for application where LID facilities exist, such as permeable pavements and curb cut inlets of bioretention, bioswales, swales and stormwater tree trenches.

Rainwater harvesting[edit]

Freezing temperatures can cause problems with exposed collection pipes and portions of cisterns and pipes located above the foundation frost penetration depth. For standard drawings see Ontario Ministry of Transportation OPSD 3090.100 for northern Ontario, and OPSD 3090.101 for southern Ontario. Rainwater harvesting systems designed for year-round operation in cold climates like those in Ontario are typically limited to underground cisterns and outlet pipes located below the frost penetration depth, or cisterns integrated within buildings.

Green roofs[edit]

The survival of green roof plantings is greater in winters with long deep sub-zero temperatures. Being shallow and very exposed to warming sunlight, green roofs thaw rapidly. Frequent freeze-thaw cycles in the early and late winter are associated higher loss of vegetation on green roofs.

References[edit]

  1. Amrhein, C., Strong, J.E., and Mosher, P.A. 1992. Effect of de-icing salts on metal and organic matter mobilization in roadside soils. Environmental Science and Technology. Vol. 26, No. 4, pp. 703-709
  2. Bauske, B., Goetz, D. 1993. Effects of de-icing salts on heavy metal mobility. Acta Hydrochimica Hydrobiologica. Vol. 21. pp. 38-42., 1993).
  3. Howard, K.W.F. and Beck, P.J. 1993. Hydrogeochemical implications of groundwater contamination by road de-icing chemicals. Journal of Contaminant Hydrology. Vol. 12. pp. 245-268.
  4. Granato, G.E., Church, P.E., Stone, V.J. 1995. Mobilization of Major and Trace Constituents of Highway Runoff in Groundwater Potentially Caused by De-icing Chemical Migration. Transportation Research Record. No. 1483.
  5. Pitt, R., Clark, S., Field, R. 1999. Groundwater contamination potential from stormwater infiltration. Urban Water. Vol.1. pp.217-236. https://www.sciencedirect.com/science/article/abs/pii/S146207589900014X
  6. Toronto and Region Conservation Authority. 2009. Review of the Science and Practice of Stormwater Infiltration in Cold Climates. https://sustainabletechnologies.ca/app/uploads/2014/10/SW_Infiltration-Review_10.15.2014.pdf
  7. Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Northern Ontario. OPSD 3090.100. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx
  8. Ministry of Transportation. 2010. Foundation Frost Penetration Depths for Southern Ontario. OPSD 3090.101. Nov 2010. Rev.1. https://www.library.mto.gov.on.ca/SydneyPLUS/TechPubs/Portal/tp/opsViews.aspx