Last week, I wrote a blog on what people can do to help keep lakes, rivers, and streams recreation-friendly and pollutant free for aquatic life, which can be found here.
One of the tips was using less pavement, or implementing permeable pavement options. The latter interested me, still a newbie to the ways of the sustainability world; I wanted to know more about it.
The Minnesota Stormwater Manual reads, “permeable pavement can be an important tool for retention and detention of stormwater runoff. Permeable pavement may provide additional benefits, including reducing the need for de-icing chemicals, and providing a durable and aesthetically pleasing surface.” That not only ticks off using less road salt to stop chloride buildup in our waters (another tip), but apparently it looks nice, too.
“The most commonly used permeable pavement surfaces are pervious concrete, porous asphalt, and permeable interlocking concrete pavers (PICP). Permeable pavements have been used for areas with light traffic at commercial and residential sites to replace traditional impervious surfaces in low-speed roads, alleys, parking lots, driveways, sidewalks, plazas, and patios,” (MN Stormwater Manual). In larger cities, pavement often caps off much of the landscape. When it rains, that water carries contaminants including (but not limited to) various car fluids, soaps, pesticides, fertilizers, and road salt – straight to sewers and surface waters. Permeable paving technology merges science with design to allow surface water to journey into the ground as it always has for proper filtration.
“While design details vary, all permeable pavements have a similar structure, consisting of a surface pavement layer, an underlying stone aggregate reservoir layer, optional underdrains and geotextile over uncompacted soil subgrade,” (MN Stormwater Manual). Because the pavement deals with the initial gush of rain, it captures all the contaminants and fine particulates involved. Research shows that microorganisms nesting in the base layer of the pavement systems digest the hydrocarbons, effectively treating the typical volumes of hydrocarbons that amount themselves in highly paved areas.
Porous pavement offers a practical solution to minimize the need for traditional hard infrastructure, like pipes and detention/retention ponds, which would typically add a host of spatial and monetary needs to a project. If pipes are part of the system, porous pavement can reduce the load and extend their lifespan. Plus, the pavement is sustainable, green stormwater infrastructure, and redeemable for LEED points. Keep an eye out for these pavement options popping up around town, coming to a parking lot near you.
To read the Minnesota Stormwater Manual in its entirety, click here.