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Low Salt Design principle: horizontal drainage considerations

This section of the manual is currently under construction.

Snow falls across an entire landscape filled with roads, buildings, parking lots, sidewalks, lawns, fields, gardens, sport fields and it all melts. The meltwater must go somewhere, and the saltable surface should be protected from meltwater intrusion. Wet pavement turns to icy winter pavement. By restricting the entry of snowmelt onto saltable surfaces, a safer winter surface emerges. Unless you are in a very windy area, this is likely to be the single most important concept in low salt design.

Image containing description of Low Salt Design strategy, Horizontal Drainage

Snow storage that obstructs storm drains can inhibit the flow of meltwater into drains resulting in icy, heavily salted areas when refreeze occurs. 

Applicability

 

Benefits and Limitations

Meltwater sprawl onto saltable surfaces can threaten public safety, drive up salt use, and shorten the lifespan of infrastructure. To get the best return on investment, restrict meltwater sprawl in critical areas. Wherever meltwater sprawl is eliminated, there are benefits to:

  • The users of the pavement (safer),
  • The maintenance crews (less work, less salt, less cost)
  • The property owners (less infrastructure damage, less vegetation damage)
  • The next generations (less water pollution)    

Design Criteria and Considerations

  • Understand where the snow will fall
    • Lawn, landscape, natural areas, unplowed areas, saltable surfaces
  • Understand where the snow will be pushed to
    • Along the perimeter of saltable surfaces
    • Roads, parking lots, sidewalks, trails, ramps
  • Design the snow melt path so it avoids reentry onto saltable surfaces  
  • No storm drains or curb cuts in ADA parking spot.
  • Avoid routing meltwater across ADA zone (i.e., crosswalk)

Retrofit suitability

High: Snow storage areas can often be adjusted to limit interference with meltwater drainage.

Permits and regulations

 

Potential conflicts

Winter design considerations versus summer design considerations can create conflict. Both must be considered to move ahead with the most optimal four-season design.

Winter design: Key objective is to reduce melt water sprawl.  

  • Once the surface recovers from a snow event (plowed/shoveled), do not let the meltwater sprawl across impervious surfaces, thus reducing the need to apply salt.
  • Snow on the perimeter of a paved surface (parking lot, sidewalk, etc.) encounters above freezing temperatures long enough so that the snow starts melting.  
  • Snow meltwater drains downhill and often cascades across impervious surfaces.
  • These wet pavements freeze as temperatures drop, become ice covered, unsafe and often get salted.   
  • A key strategy in winter design and safety is to keep the pavement dry.