Low Impact Development Manual for Michigan - OSEH - University ...

Repairs
• Surface should never be seal-coated,
• Damaged areas less than 50 sq. ft. can be patched
with pervious or standard pavement,
• Larger areas should be patched with an approved
pervious pavement,
• Permeable pavers should be repaired/replaced with
similar permeable paver block material, and
• Permeable pavers and gravel pavers may require
the addition of aggregate on an annual basis or as
needed, in order to replenish material used to fill
in the open areas of the pavers. Turf pavers may
require reseeding if bare areas appear.
Winter Considerations
Pervious pavement systems should perform equally
well in the winter, provided that infiltration bed design
considers the soil frost line, and proper snow removal
and deicing procedures are followed. Winter maintenance
for pervious pavement may be necessary but is
sometimes less intensive than that required for a standard
pavement (especially for pervious asphalt). The
underlying stone bed tends to absorb and retain heat
so that freezing rain and snow melt faster on pervious
pavement. Therefore, ice and light snow accumulation
are generally not as problematic. However, snow will
accumulate during heavier storms.
Abrasives such as sand or cinders should not be
applied on or adjacent to the pervious pavement.
Snow plowing is fine, provided it is done carefully (i.e.,
by setting the blade slightly higher than usual, about
an inch). Salt with low non-soluble solids content is
acceptable for use as a deicer on the pervious pavement.
Non-toxic, organic deicers applied either as
blended, magnesium chloride-based liquid products or
as pretreated salt, are preferred.
Cost
The majority of added cost of a pervious pavement/infiltration
system lies in the underlying stone bed, which
is generally deeper than a conventional subbase and
wrapped in geotextile. Costs may also be higher in areas
where experienced contractors are not readily available.
However, these additional costs are often offset
by the significant reduction in the required number of
inlets and pipes. Also, since pervious pavement areas
are often incorporated into the natural topography of
a site, there is generally less earthwork and/or deep
excavations involved. Furthermore, pervious pavement
areas with subsurface infiltration beds often eliminate
the need (and associated costs, space, etc.) for detention
basins. When all of these factors are considered, pervious
pavement with infiltration has often proven itself
less expensive than impervious pavement with associated
stormwater management.
• Porous asphalt, with additives, is generally 15
percent to 25 percent higher in cost than standard
asphalt on a unit area basis. Unit costs for pervious
asphalt (without infiltration bed) range from about
$4/SF to $5/SF.
• Pervious concrete as a material is generally more
expensive than asphalt and requires more labor and
expertise to install. Unit cost of a six-inch-thick
pervious concrete (without infiltration bed) section
is about $4/SF to $6/SF.
• Permeable paver blocks vary in cost depending on
type and manufacturer.
NOTE: The data provided are based on average market
costs. For greater accuracy, a site- and market-specific
cost estimate should be developed.
LID Manual for Michigan – Chapter 7 Page 254