An Introduction to Permeable Pavement Systems

Increased runoff from impervious surfaces causes dangerous floods. Due to climate change and urbanization, increasingly frequent and intense precipitation events present higher damages from flooding each year. There are many methods utilized to help mitigate flooding, one method is the use of permeable pavement systems. Permeable pavement is a porous urban surface composed of open pore pavers, concrete, or asphalt with an underlying stone reservoir. Permeable pavement catches precipitation and surface runoff, storing it in the reservoir while slowly allowing it to infiltrate into the soil below or discharge via a drain tile. Permeable pavement systems are an alternatives to traditional pavement as they help reduce runoff by allowing water to permeate through the asphalt or concrete. These alternative materials allow rain to seep through the surface down to underlying layers of soil and gravel. In addition to reducing the runoff from the rain that falls on them, permeable pavements can help filter out pollutants that contribute to water pollution. Permeable pavements can also reduce the need for road salt and reduce construction costs for residential and commercial development by reducing the need for some conventional drainage on our city streets. The most common uses of permeable pavement are parking lots, low-traffic roads, sidewalks, and driveways. Porous pavement should be inspected and vacuumed or washed at least twice a year as preventative maintenance. Routine preventative maintenance will be more effective than corrective maintenance and ensure optimal performance of the system. It is essential to prevent opportunities for sediment to make its way onto porous pavement as this can clog the surface. Because water flows through porous pavement, the volume of runoff generated during a storm event is significantly decreased or eliminated altogether. This reduction in volume results in flood control and reduces the need for traditional storm water infrastructure (piping, catch basins, storm water ponds, curbing, etc.).