Porous ashpalt, pervious concrete, permeable interlocking concrete pavers, and grid pavers provide infiltration of stormwater directly under the street surface, and can be applied on any portion of the street provided appropriate surface and sub-surface conditions.
Pervious pavements are most often applied on bikeways, parking lanes, and streets with lower vehicle traffic volumes and limited heavy vehicles. Sidewalks may also employ porous concrete to increase infiltrative area.
Permeable pavements add space for infiltration, especially in contexts such as alleyways or against the curbline, where nuisance flooding and other issues must be addressed without sacrificing space for mobility.
Many different types of pervious surface can be applied to different contexts, adding quality and performance to the urban environment.
Pervious treatments must be carefully selected and installed for context and expected usage; permeable pavements are often not appropriate for travel surfaces with high volumes, heavy vehicles, or where frequent starting and stopping place additional force on road surface.
Interlocking pavers may settle or buckle, reducing surface smoothness and creating accessibility issues.
Review adjacent surfaces and assess where soil is more likely to erode or be tracked onto the permeable pavement surface (such as from gravel driveways on private property). More frequent street vacuuming of those areas may be required to remove sediment.
Permeable street surface requires regular maintenance to remain effective. Develop detailed plans and responsibilities for appropriate cleaning and maintenance of permeable pavements installed in the right-of-way, which may include sweeping, washing, or vacuuming to remove grease, oil, and other sediment.
Permeable pavements are most effective on shallow slopes (5% or less) to allow water to infiltrate and for efficiency in spacing temporary subsurface storage.
Assess operations during snowy conditions. Avoid placement of snow piles onto permeable pavements since those are areas where higher concentrations of sediment will occur, thus increasing maintenance cleaning of the permeable pavement surface. Consider integrating alternative plowing and de-icing techniques to maintain the longevity of the infrastructure.
For interlocking pavers, aggregate used between paving blocks may need to be periodically replaced as it becomes loose or is pulled from between blocks.