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→Salt and Snow
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<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 the metal(Amrhein et al., 1992; Bauske and Goetz, 1993). </p>
<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>
<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>
<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>
<p>To minimize risk of groundwater or soil contamination, the following management approaches are recommended (Pitt et al., 1999; TRCA, 2009b):
<p>To minimize risk of groundwater or soil contamination, the following management approaches are recommended (Pitt et al., 1999; TRCA, 2009b):
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===Planning===
Recommended planning strategies in designing sites for reduced salt usage:
<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. Reducing the chances of ponding and ice formation reduces the salting requirements for those surfaces. </p>
<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 meltwater 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]].
<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. Check that these are compatible with plowing. </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>
<h5>Vegetation</h5>
<p>Vegetation varies in its reaction to salt-affected soils.
<p>Vegetation varies in its reaction to salt-affected soils.
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