Changes

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==Cold Climate==

==Cold Climate==

The majority of Ontario has a [https://en.wikipedia.org/wiki/Humid_continental_climate#Koppen_Dfb| "Humid continental" Dfb climate], which includes average temperatures in the coldest month well below -3°C. This condition is found in many other parts of the world where LID strategies are routinely employed, including many northern states in the USA and a large swath of northern Europe.

The majority of Ontario has a [https://en.wikipedia.org/wiki/Humid_continental_climate#Koppen_Dfb| "Humid continental" Dfb climate], which includes average temperatures in the coldest month well below -3°C. These conditions are found in many other parts of the world where LID strategies are routinely employed, including many northern states in the USA and a large swath of northern Europe.  

==De-icing Salt==

==De-icing Salt==

[[File:Snow_filter_strip.png|thumb|Snow being stored on a filter strip in Markham, ON]]

[[File:Snow_filter_strip.png|thumb|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 <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>

 

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 (Amrhein et al., 1992; Bauske and Goetz, 1993). </p>

 

http://www.unh.edu/unhsc/sites/unh.edu.unhsc/files/pubs_specs_info/jee_3_09_unhsc_cold_climate.pdf

<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).

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>

 

To minimize risk of groundwater or soil contamination, the following management approaches are recommended (Pitt et al., 1999; TRCA, 2009b):

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

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  

*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

*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.

*Apply [[pretreatment]] practices before infiltration of road or parking area runoff.

==Other freezing related concerns==

==Other freezing related concerns==

<h3>Rainwater harvesting</h3>

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]].

<h3>Green Roofs</h3>

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.

===Rainwater harvesting===

Freezing temperatures can cause problems with pipes and cisterns exposed above the [http://www.raqsb.mto.gov.on.ca/techpubs/ops.nsf/0/ee1f1756eacc00e18525808200628fbf/$FILE/OPSD3090.101%20Rev%231%20Nov2010.pdf frost penetration line]. This maybe a significant issue for [[Rainwater harvesting|rainwater harvesting systems]], including residential [[Rain Barrels|rain barrels]].

===Green Roofs===

The survival of [[Green roofs: Planting|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 are associated higher loss of vegetation on green roofs.