The Importance of Porous Paving

Curving drive scaled

The Importance of Porous Paving

The number and cost of weatherrelated disasters are on the rise in the United States. This is due to increased exposure, greater intensity and damage caused, along with the rate at which these events are occurring. Reports from the Climate Change Committee attribute much of this increase to climate change. According to the National Centers for Environmental Information, the number of billion-dollar disasters in 2020 came from 22 separate events. The cost of these events exceeded $95 billion in damages. Of these, 13 were related to severe storms. The strain of stormwater events is especially hard on urban areas, where the landscape and the population are dense.

Most cities use municipal separate storm sewer systems. These are networks of ditches, curbs, gutters, sewer pipes and outfalls solely dedicated to moving runoff from everywhere in the city to the natural waterways that eventually carry it away. However, in the event of extreme rainfall, these waterways are not equipped to manage a deluge of water. Additionally, pollutants from the streets are washed into the waterways. Some cities have added concrete to the inside of channels to increase the water flow, but this diminishes the natural beauty of the landscape and does nothing to pull pollutants from the water.

Many municipalities are implementing and even requiring low impact solutions to better mitigate the effects ofstormwater and reduce pollutants in ourwater. Among these is requiring a certainpercentage of porous surface in newdevelopment and redoing existingimpervious surfaces. Many designprofessionals are opting to use permeablepaving on areas that have traditionallybeen paved with concrete or asphalt inorder to achieve these goals.

GP2 cross section

Permeable paving is a type of pavement orunder-surface structure that supports thepassage of rainfall or water runoff throughthe surface of the sub-surface below it.They are designed primarily to support theheavy load of traffic while also protectingthe surface from compaction and allowingdrainage. Permeable pavers can support awide range of traffic types, frompedestrian foot traffic and residentialparking to emergency vehicles. The depthof the base course beneath the paversdetermines the weight the pavers cansupport. With appropriate base course,permeable pavers can far exceed H-20loading and have a psi of over 15,000. concrete or asphalt, rigid plastic porouspavers and flexible plastic porous pavers.The functionality, flow rate, maintenanceand aesthetics vary with the type of porouspaver used; the use, weight and frequencyof traffic determine what type of paver canbe used.

Sky Lounge FIU

It is important to create surfaces that arepervious for several reasons. Permeablepavers can not only reduce flooding, but thewater is absorbed back into the earth,filtering out pollutants and rechargingground water. Urban areas can decreaseareas covered in concrete and asphalt andincrease natural surfaces and green space.This can reduce both heat and sound. Thereare also cold weather benefits, as the airtrapped in the pavement can store heat andrelease it to the surface, speeding themelting of snow and ice. Once melted, thesnow will dissipate back through the pavers.

Botanic Gardens

Pedestrian paths, parking lots and fire lanescan all be made using porous paving,creating areas around buildings that willdrain instead of pool or send runoff to otherareas. Certain porous pavers, namely ridgedor flexible ones filled with aggregate ortopped with grass, can add green space to the design, thus making an otherwise single-purpose area into a multifunctional space. Grass pavers can also reduce CO2 emissions.

Fire Lane

While using any permeable paver in lieu of concrete or asphalt is an environmentally better choice, rigid and flexible plastic pavers will have the greatest impact on extreme rain events, making them the best option in urban areas. They also have the greatest void space so will offer the highest flow rate and, because they are used in conjunction with aggregate or grass, they offer the greatest environmental benefits. These pavers can also be used in conjunction with underground water storage systems for maximum impact. Because natural bioremediation occurs when the water runs through sand, these systems can provide the opportunity for water reuse, further increasing the environmental benefits.

As populations continue to grow in urban areas, adding porous surfaces, along with other low-impact solutions, will beincreasingly important. Implementingbuilding and design practices that willhelp to mitigate stormwater events willaid in cities being more resilient. Inmoving toward greener urban planning,we can better preserve and protect thefuture of these cities.

Up close of gravel pave